A Primer Aerodynamics master model builder talks about airplanes fly tells us selector modify sound design U Harold deBolt 7~HE URGE produce aircraft own hits modelers sooner later ambitious goal would original design Something less might modification existing craft often evaluate someone elses creation help us own thinking about new design understand basic aerodynamics can perform desired task much intelligently profusion model designs available today person accomplished designer can draw upon what someone else has perfected acquire generalities what wishesand can attain some success result However evaluating concepteither own boffowed onewe can have assurance success understand very basics aerody naniics subject often cloudy us & 0 0000 0000 0 0 000 0 0 0 0000 0 jO 000000000o 00 00 0000 0 0000000000o~o0oo00 000 0 oOoooo~00000 0oooooOO006~ LNEOF-YLIHT00000000000000 0000000000000 0 00 0 0009 0000 000Co 000 0 0 0 00 00 O00Q0Ob0o0oDo0o0o0oO0C0O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Upper sketch upper curve airfoil displaces air molecules depicted little bubbles lower side planes air pressure differential creating lift Lower sketch streamlined symmetrical curves airfoil displace air molecules equally side no lift created objective short article enlighten reader about basics aerodynamics provide some tools can understand craft flies whether contemplated design sound idea take thoughts offered apply characteristics design question commence should understand definition aerodynamics laws govern aliflight Aero course refers air medium craft operates Dynamics refers resultant action created object moving through air aerodynamic laws formulated found air reacts distinct predictable ways shapes objects RESIS TA N C F S LIST LIFT LIFT GRAVFY LINEOF FLIGHT LIFT L[FT zero-zero incidence force arrangement shown climbing attitude angle gravity force acts opposes thrust force reducing aircrafts speed 28 Model Aviation author today replica first Free Flight design built 1938 moving through Using laws has enabled us design aircraft fly Investigators found airfoil shapes create lift streamlined shapes have minimum drag etc Experience helped create aerodynamic laws discovered various objects could have useful shapes arranged relation other produce flight day laws have become fundamental basic laws pertain aircraft Violate flight will suffer some extent So understand basics apply design may considering can assured flight Beyond basic design details simply enhance type flight objective desired points remember basic aerodynamics gospel air considered stationary flight created craft moving through Any respectable Engineer realizes must understand medium working before can commence effort Aero engineers work medium air necessary understand its characteristics People take air granted just However use some purpose other breathing sustain life such flight must understand its peculiarities Lets consider air engineers viewpoint First lets say substances mediums vary composition loosely knit dense solid solid Gas loosely knit fluid dense wood metals etc have varying amounts solidity Air being gas loosely knita medium easily displaced characteristic makes flight possible displacing air foundation aerodynamics Air composed molecules nitrogen oxygen could describe little balloons space between Thus displaced moving object molecules simply close up become closer together objects speed too great Molecule compression occurs object moves through air speed sound force created release compression hear sonic boom Thankfully model speeds low allowing us have consider displacement air molecules Another consideration because effects gravity air has varying densitymore dense sea level much less high altitude Again flights models low altitude latter condition normally ignored also important realize aircraft flight surrounded air effect air upon aircraft equal sides However say aerodynamic force effects equal sides Thus aerodynamic laws apply equally whether craft level flight vertical attitude flying inverted change forces acting THRUSTLIFT 0 RE SISTA N CE GRAVITYLIFT LI FT o LINE OF FLIGHT RESISTANCELIFT _THRUST JIEILINE OF FLIGHT\ LIFT ANGLE OF ATTACF GRAVITY Force Diagram 1 OOOO incidence force arrangement top forces balance except gravity negative Flight impossible until introduce force bottom tilt angles attack wing stab producing enough positive wing stab lift overcome gravity Flight now possible aircraft its attitude changes comes change direction gravity acting craft say aerodynamic forces neutralize gravity flight follows gravity will detract planes speed climbing attitude increase speed diving attitude power gravity detracts planes power climb attitude adds power dive gravity has no effect aerodynamics course gravity provides power moves glider-type machine through air thereby allowing aerodynamics create flight Such craft always flying downhill speak THRUST4 INCDLIFT RESISTANCEGRAVITY OF FLIGHT increase decrease addition aerodynamic forces vary linear fashion respect speed aircraft example lift drag increase square increases speed As result stability over large speed ranges desired important forces arranged proportionally other seems like should complex achieve relatively simple proper design also must understand airplanes configured Just explained makeup word aerodynamics LI FT 1 LIFT Force Diagram 2 classic force arrangement created successful model flight tails down force negative lift balanced very forward application gravity models center-of-gravity produce equilibrium particular flying speed Remember aerodynamic laws apply line offlight attitude plane respect horizon other factor same aerodynamic forces present plane vertical inverted attitude present planes flight level horizon force changes attitude gravity because becomes applied different angles aircraft force gravity itself does WING LIFT MEAN LIFT THRUSTI 1 I/2 LIKEOFFLIGHT RESISTANCEGRAVITY name craft itself offers clues plane literally surface say surface can plane medium boats bottom water example So can say airplane has surfaces plane aira simple description deep meaning Aircraft have various surfaces labeled airfoils Continued page 31 LIFT Force Diagram 3 modern force arrangement produces neutral stability maximum efficiency RC models proportionrepresented mean lift force established between wing tail lift CG now positioned relative mean center lift Line flight maintained over wide speed range September 1992 29 Primer Aerodynamics Continued page 29 term actually applies entire surface such wing rudder stabilizer canard etc importance fact surfaces used because produces force needed create maintain flight some surface aircraft creating force no value aerodynamically Surfaces horizontal plane labeled wings Thus normal monoplane configuration aircraft has two wings main forward surface aft stabilizing wing stabilizer short should also understand airfoil surface restrained some manner stable Simply put pick up such surface drop height few feet surface initially parallel ground will tend rotate about spanwise axis falls wing main support flight some other force must used restrain position angle attack contributes useful lift simplest way accomplish use force created second aft wing affect forward wings tendency rotate lock desired angle attack summation point flight surfaces including stabilizing surfaces aircraft work generating desirable forces Since should striving efficiency factor consider forces applied add efficiency offlight just stabilize some other surface apply considerations going discuss force arrangements simply diagrams depict way forces will act upon contemplated aircraft design can complex purposes simpler versions will give us light Important realize forces relative line offlight criterion reference material available use reasoning behind generalities force arrangements brief article purely academic example know thrust engine must applied particular point must wing tail distinct other Since brief discussion can assume whatever reference use supplied such details within realm aerodynamic laws What hope to show both some typical some unusual aircraft configurations what force arrangement depicts aircrafts attitude changes Someone said picture Continued poge 32 rxxxxxrxxxxxxxxxxxxxflxxxxxNNrxxxxnxxxNxJ ___ ___ _ -CHEAP SENSATION- P ARF FUN-FLY ur GENERIX TAMPA EL 33615t 54-KITSN4~ P0 BOX 262035 S M NOW AVAILABLE P 1/12 SCALE COMBATSPECS 69 $ P51 MUSTANG$49 Span44 ngine 2-40MEETSAMA RULES$7 S&HArea770 sq $7 5&H 59oosizo 301 5-32Engine28-40 xxxxxxxxxxxxtxrxxxxxxxtkxxxxxnxxxxxx now flight enhanced timing Ittablock option Ouadm aid Zonodi slow landings course easyengbu oniy-sdd$18 start slow 611*10 Mb bai retahiedStilt M-80 114 x 32 spalqiug.*10 REICHMUTH IGNITION featuresKMEe1l4xquig*13 llGIo-pIug end magneto replacernentii Electronic . .. Ft PM controled timing No moving parts break came looseitkde battery protectionPPU aid handtg$5 514-ceII nicad operationlintemai over-voltage Pro -COD add$5 tectionFflegulated power supply extended2nd day ak dd$3 flight timelB Screw driver easy Installation QuadrflandZerioawswithlNSlABLOCK exasstyieSaxengineswimmeuminge linked carburetor easily converted withonlyadritaDremeltoolandatap.. ot. Ask Original RiE LaunihEr & Pit ErewTM Local Hobby Shop Send $9995 5&H tCall TodayDealer Inquiries Welcome September 1992 31 fl/c Launcher & Pit Crew 5806 Lancelot Ct SW Olympia WA 98502 206 786-8461 THE BEST FLY WITH GENE BARTON Gene Barton now introduces new P51-B Mustang contest quality fo beg nne Sem K n cludes fiberglass parts fit elage oop cowl heliy pan foam cores supplied wing vertical horizon tal stabs Scale spun aluminum spinner machined hack plate canopy also included rolled set plans buy own balsa wood wing span 79 fly ing weight around 20 lbs designed around 25 35 cc engine Price 5395 Package price available retracts stints tires wheels Call write Gene Barton 11640 Salinas Garden Grove CA 92643 714 539-9142 FAX 714 539-9288 ANNIVERSARY ffiJ LII}Zzri 10th ANNIVERSARY JCLJTFIWEST\ first finest FLYDucted Fan Gathering NIin US! AMA SANCTIONED JPO SPONSORED Sept 11-12-13 1992 Lockhart Texas SASE full details Rick Schafer Custom Model Products 5321 Industrial Oaks Austin TX 78735 Phone 512-892-6908 WingDesigner0 N fli II IIIIIII LiIIIIActual program pint lr.lr & E w Headquarters Plum Creek Inn 512-398-4911 tnsured reservations August 15 EditFoilo EditFoil FEATURES Enter airfoil data join published tabisa Prints data table Modify correct surface enperfectiotta graphically on-screen. ModiPy chord thicltneaa ratio WlnDeslgw supplied 24 airfoils Plots sample l0 rib requires MlngDeslgner. programs written speczfically model aircraft design NOT modified general purpose CAD programs NfrwDesfrner FEATURES PUTER SYSTEM REOUIREMENTS 9Jlowsdlffereuil root rip airfoils Plots ALL transition ribsIBM 100% eampatible 286 386 486 CPU aplota ribs ALL spar slots coned size andpotttoii. Math co-processor desirable NOTrequired Plots ribs sheelinVGA SVGA COLOR graphics display tionJiail portiot length apsis 18 MaximumD05 version 31 higher Adds extraribs atibe endsofailerons flaps Rib #dIn nsegofhard diskspaor 512kb RAM Position up toS extra ribs / panel Rib 02 example3-112 floppy drive 5-1/4 diskette available LumtesJl.rdhoks esch rib building OCCUISCYEoI matrix 9 24 pin laser printer PRO version *USER FR lEWDLY GRAPHICAL INTERFACEcan output pen plotter HPOL fomiat COLOR *QUICK EASY LEARN TED TIME INTRODUCTORY PRICE *ACCURATR PROFESSIONAL RESULTSBittFoil$ 5995 ttlngDertner$ 7995 EtItFott.$l2995 *SEE YOUR DESIGN ON-SCREENtVIngDerIgnerPRO$12495 withEitrFoil.$16995 TI/1irrnVivhmv Add $350 Shipping & Handling Parcel Post C $100 #10 SASE information P0 Box 8367 Bartlett IL 601 03-4203 32 Model Aviation Cmon down Celebrate Primer Aerodynamics Continued page 31 worth thousand words hope sketches will provide some Concept situation diagrams Ive made assumed line thrust also line flight various forces effect possible thrust may forced some slight angle line flighthow great angle being extremely difficult determine However such difference can assumed inconsequential thrust line used reference base line sometimes referred datum line forces incidence angles center drag etc related might ask what happens downor up-thrust prescribed offset thrust lines can assume actual line flight will fall somewhere between actual thrust line what would offset plane tends fly along line thrust reaction between thrust aerodynamic forces result compromise between two observe effect offset thrust present simply tilt force arrangement diagram direction offset note relation various forces line flighta line will remain horizontal speaking line thrust note relates center resistance point assumed drag forces acting plane concentrated First note thrust line some angle line flight things like fuselage no longer parallel line flight thus increasing amount drag present importantly note moving line thrust away center resistance creates physical force can have effect aerodynamics example thrust line higher point resistance thrust will create nose-down coupling thrust line lower center resistance noseup moment will generated practical example could aerobatic design high thrust line could prove advantageous inverted flight Diagram No 1 depicts typical popular so-called zero-zero force arrangement symmetrical airfoils used note respect line flight neither wing nor stabilizer produces plus force drag negative force aerodynamic forces equalized Thus would seem line flight must something other design line actuality force must added tilts angle attack wing sufficient lift will generated could Conrinued page 38 Primer Aerodynamics Continued page 32 done thrust/resistance physical force spoke earlier event will note some force has used position wing tail lifting angles sustain level flight Otherwise should wing have semisymmetrical airfoil set same zero-incidence angle such airfoil does produce lift ball game different Effectively have wing positive lifting angle stab has symmetrical airfoil section zero lift flight wing lift would force stabilizer away zero creating positive stabilizer lift until some point equilibrium reached Thus would deviation design line flight Diagram No 2 depicts what might said original force arrangement models arrangement got Free flights flying purely academic standpoint thrust line line flight same Note have wing lifting angle stabilizer producing negative lift vely typical OT Free Flight obtain equilibrium gravity force CGcenter-of-gravity applied far enough forward wings center lift balances out tails negative lift Note longitudinal pivot forces wings center lift C/U case situation what could labeled constant speed arrangement stabilizer adjusted produce just enough negative lift some desired flying speed balance out pitch-down force created location CG being forward wings center lift Free Flight models desired combination speed attitude found glide mode Assuming objective flight FF model climb power glide power off trick becomes use just enough power upset established forces create desired climb getting stall loopwhich increased speed encountered during power-on portion flight would tend produce Developed FF considered safe arrangement because whenever speed increases beyond norm misproportion between wing tail lift will cause planes nose rise instead pitching down toward earth RC sometimes see arrangement used design speed full-bore power offering safety factor trainer types Obviously finding just right compromise between three forces wing lift tail lift CU involved always critical successful flight Diagram No3 relates diagram No 1 among other things shows objective No 1 can obtained greater efficiency No 3 carries aerodynamics further create what known neutral stability NS Simply put ability model fly desired attitude over wide speed range no nose-up -down reaction often said model NS goes point aerodynamics used involve striking proportion between wing tail lift will prevail over wide speed range Note case both wing tail producing positive lift visualize remember forces pivot models center lift C/L can wings C/L diagram No 2 aft CI case Understand both wing tail lifting models C/L resultant two forces mean C/L must fall aft wings C/L point total wing plus stabilizer lift applied So CU must located relative mean point wings CIL previous cases Note lift moment arm wing C/L tail CIL mean point Normally tail moment arm will roughly 12 times longer wings lever Thus two surfaces exert equal force mean point amount lift actually generated tail would far less wing due its much longer leverage allows tail size much smaller agreeable situation Over desired speed range wing exhibits definite changes its characteristics some intermediate speed specific amount lift drag produced Increase decrease speed lift/drag will change like manner such changes speed stabilizer responds manner exactly like wing have needed proportion continuing balance lift So can say line flight altered upward angle elevator control model will continue fly established angle same will occur downward angle will no inherent tendency nose up down same could expected should model bounced rough air gravity force constant fixed value regardless speed attitude So purely academic viewpoint could say straight level flight reduced power going full power would increase forward speed turn would increase lift causing model rise like elevator nosing up Likewise reducing power below cruise would cause similar elevator-like loss altitude no nose down Actually usually design models fly full power little normally seen such balance forces can have model follows design line U UUU . I. Ije Macfi tetbflv O49 REED VALVE ENGINE First introduced 1973 Black Widow powerful popular O 049 reed valve engine Its great types control line models including 1/2A Stunt Mouse Racing Beginner Combat Powered R/C Sailplanes too Widow precision built specially selected steel aluminum q P alloys tolerances measured millionths inch Cox Snap Stajtei provides easy no hassle starting The Black Widow recommended engine new 1/2A series Famous Fighters World War II Midwest Products available favorite Hobby Retailer now COX HOBBIES INC Corona CA 91720 OCOXHOBBIES INC. ISBI 38 Model Aviation 1 61 Im 6 him Im flight attitude over wide speed range say neutral stability NS has proven very desirable types RC models obviously must able control attitude order change direction Pointed toward heaven model NS might get thereor reach hell its pointed other direction Lets explain force diagram Both wing tail producing positive lift Note tail greater angle wing Scary Experience proves should reason being additional angle needed achieve proper lift balance having use oversize tail design speed total lift exactly cancels gravity force Note difference diagram No 1 resultant lift force has added mean lift point used design purposes No 1 CC located relation wings CIL Now CC must moved aft relate mean lift point same manner basic aerodynamics laws just used greater extent might assumed designing neutral stability could complex task considering necessity having exactly correct proportion between wing tail lift Experience over years designs has proven otherwise Fortunately practice has shown normal-size stabilizers having Success Series U-Control Kits respectable symmetrical airfoil adequate does help initial phase provide ability adjust stabilizers angle incidence achieve proper proportioning lift However given airfoils once successful relationship has determined will hold true over wide variety designs Give try will surprised pilot will sometimes say first flying neutrally stable model Boy model feels real solid really grooves flies rails thats actually very satisfying feeling model has no tendency wander goes last pointed until ask change direction likeable characteristic neutral stability As might expect shortcoming must maintain control times No self-recovery built arrangement other hand accomplished pilot such designs joy fly nothing ownonly what tell conclusion let hasten add discussion has hardly cracked ice aerodynamics design engineering However brief considerations applied wants will have much assurance reaching goals Foremost understand medium model airplane operates 10 TU$iieS 09 Midwests new Success Series 049 U-Control kits perfect introduction building flying Featuring illustrated step-by-step Success Series construction manuals teach build paint fly models Kits include Micro-Cut Quality parts pre-formed wire parts wheels belicrank colorful self adhesive markingsqp line Famous Fighters World War II designed use Cox Black Widow engine See products favorite hobby retailer todayl Famous Fighters World War II Models Available #258 Zero #259 Corsairshown #260 Thunderbolt #261 FockeWuif Midwest Products Co inc 400 S indiana St PO Box 564 HobartiN46342 2191942-1134 PAxl2I9l547-Z34701992 Midwest Productsco inc aerodynamics happenings will have much meaning Also like insurance policy make up force arrangement diagram showing what desire will have good indication what expect design Just compare force arrangement design another want delve further aerodynamics Its basic force arrangement proven good design makes excellent comparison thats unknown Whats good goose good gander bottom line could once have some experience fundamentals will find simple delve little deeper deeply wind up having understanding can lead designing own plane discussion has provided reader basic knowledge aerodynamics Interested modelers could now ask question Now know basics apply factors improve modeling answer will found Part II series Aerodynamic Primer-Trimmer coming soon Good luck CL Vintage Stunt Continued page 23 finest Bob Hunts Tucker Special Although plagued tank/engine problems newly finished model Im sure well see next year Other notables Cecil Meade Fan Dancer garnered Spirit 64 award Jim Levell gorgeous yellow Ares winner Concours award Larry Cunninghams Road Runner Greg Zajacks Patriot 59 Nostalgia entrants 47 made least official flight flights posted 500 pm stark testimony efficiency Cholla Choppers Carl Marshenki David Reynolds pits circle directors Walt Menges Bart Klapinski fliers came circles ready fly first met Bob Baron 57 AMA Nationals placed second Senior event continued success national international competition makes no surprise accident won Nostalgia event flying Netzeband designed Humbug Former Nationals winner Bob Whitely second flying stretched Continued page 40 September 1992 39 Beginners
Edition: Model Aviation - 1992/09
Page Numbers: 28, 29, 31, 32, 38, 39
A Primer Aerodynamics master model builder talks about airplanes fly tells us selector modify sound design U Harold deBolt 7~HE URGE produce aircraft own hits modelers sooner later ambitious goal would original design Something less might modification existing craft often evaluate someone elses creation help us own thinking about new design understand basic aerodynamics can perform desired task much intelligently profusion model designs available today person accomplished designer can draw upon what someone else has perfected acquire generalities what wishesand can attain some success result However evaluating concepteither own boffowed onewe can have assurance success understand very basics aerody naniics subject often cloudy us & 0 0000 0000 0 0 000 0 0 0 0000 0 jO 000000000o 00 00 0000 0 0000000000o~o0oo00 000 0 oOoooo~00000 0oooooOO006~ LNEOF-YLIHT00000000000000 0000000000000 0 00 0 0009 0000 000Co 000 0 0 0 00 00 O00Q0Ob0o0oDo0o0o0oO0C0O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Upper sketch upper curve airfoil displaces air molecules depicted little bubbles lower side planes air pressure differential creating lift Lower sketch streamlined symmetrical curves airfoil displace air molecules equally side no lift created objective short article enlighten reader about basics aerodynamics provide some tools can understand craft flies whether contemplated design sound idea take thoughts offered apply characteristics design question commence should understand definition aerodynamics laws govern aliflight Aero course refers air medium craft operates Dynamics refers resultant action created object moving through air aerodynamic laws formulated found air reacts distinct predictable ways shapes objects RESIS TA N C F S LIST LIFT LIFT GRAVFY LINEOF FLIGHT LIFT L[FT zero-zero incidence force arrangement shown climbing attitude angle gravity force acts opposes thrust force reducing aircrafts speed 28 Model Aviation author today replica first Free Flight design built 1938 moving through Using laws has enabled us design aircraft fly Investigators found airfoil shapes create lift streamlined shapes have minimum drag etc Experience helped create aerodynamic laws discovered various objects could have useful shapes arranged relation other produce flight day laws have become fundamental basic laws pertain aircraft Violate flight will suffer some extent So understand basics apply design may considering can assured flight Beyond basic design details simply enhance type flight objective desired points remember basic aerodynamics gospel air considered stationary flight created craft moving through Any respectable Engineer realizes must understand medium working before can commence effort Aero engineers work medium air necessary understand its characteristics People take air granted just However use some purpose other breathing sustain life such flight must understand its peculiarities Lets consider air engineers viewpoint First lets say substances mediums vary composition loosely knit dense solid solid Gas loosely knit fluid dense wood metals etc have varying amounts solidity Air being gas loosely knita medium easily displaced characteristic makes flight possible displacing air foundation aerodynamics Air composed molecules nitrogen oxygen could describe little balloons space between Thus displaced moving object molecules simply close up become closer together objects speed too great Molecule compression occurs object moves through air speed sound force created release compression hear sonic boom Thankfully model speeds low allowing us have consider displacement air molecules Another consideration because effects gravity air has varying densitymore dense sea level much less high altitude Again flights models low altitude latter condition normally ignored also important realize aircraft flight surrounded air effect air upon aircraft equal sides However say aerodynamic force effects equal sides Thus aerodynamic laws apply equally whether craft level flight vertical attitude flying inverted change forces acting THRUSTLIFT 0 RE SISTA N CE GRAVITYLIFT LI FT o LINE OF FLIGHT RESISTANCELIFT _THRUST JIEILINE OF FLIGHT\ LIFT ANGLE OF ATTACF GRAVITY Force Diagram 1 OOOO incidence force arrangement top forces balance except gravity negative Flight impossible until introduce force bottom tilt angles attack wing stab producing enough positive wing stab lift overcome gravity Flight now possible aircraft its attitude changes comes change direction gravity acting craft say aerodynamic forces neutralize gravity flight follows gravity will detract planes speed climbing attitude increase speed diving attitude power gravity detracts planes power climb attitude adds power dive gravity has no effect aerodynamics course gravity provides power moves glider-type machine through air thereby allowing aerodynamics create flight Such craft always flying downhill speak THRUST4 INCDLIFT RESISTANCEGRAVITY OF FLIGHT increase decrease addition aerodynamic forces vary linear fashion respect speed aircraft example lift drag increase square increases speed As result stability over large speed ranges desired important forces arranged proportionally other seems like should complex achieve relatively simple proper design also must understand airplanes configured Just explained makeup word aerodynamics LI FT 1 LIFT Force Diagram 2 classic force arrangement created successful model flight tails down force negative lift balanced very forward application gravity models center-of-gravity produce equilibrium particular flying speed Remember aerodynamic laws apply line offlight attitude plane respect horizon other factor same aerodynamic forces present plane vertical inverted attitude present planes flight level horizon force changes attitude gravity because becomes applied different angles aircraft force gravity itself does WING LIFT MEAN LIFT THRUSTI 1 I/2 LIKEOFFLIGHT RESISTANCEGRAVITY name craft itself offers clues plane literally surface say surface can plane medium boats bottom water example So can say airplane has surfaces plane aira simple description deep meaning Aircraft have various surfaces labeled airfoils Continued page 31 LIFT Force Diagram 3 modern force arrangement produces neutral stability maximum efficiency RC models proportionrepresented mean lift force established between wing tail lift CG now positioned relative mean center lift Line flight maintained over wide speed range September 1992 29 Primer Aerodynamics Continued page 29 term actually applies entire surface such wing rudder stabilizer canard etc importance fact surfaces used because produces force needed create maintain flight some surface aircraft creating force no value aerodynamically Surfaces horizontal plane labeled wings Thus normal monoplane configuration aircraft has two wings main forward surface aft stabilizing wing stabilizer short should also understand airfoil surface restrained some manner stable Simply put pick up such surface drop height few feet surface initially parallel ground will tend rotate about spanwise axis falls wing main support flight some other force must used restrain position angle attack contributes useful lift simplest way accomplish use force created second aft wing affect forward wings tendency rotate lock desired angle attack summation point flight surfaces including stabilizing surfaces aircraft work generating desirable forces Since should striving efficiency factor consider forces applied add efficiency offlight just stabilize some other surface apply considerations going discuss force arrangements simply diagrams depict way forces will act upon contemplated aircraft design can complex purposes simpler versions will give us light Important realize forces relative line offlight criterion reference material available use reasoning behind generalities force arrangements brief article purely academic example know thrust engine must applied particular point must wing tail distinct other Since brief discussion can assume whatever reference use supplied such details within realm aerodynamic laws What hope to show both some typical some unusual aircraft configurations what force arrangement depicts aircrafts attitude changes Someone said picture Continued poge 32 rxxxxxrxxxxxxxxxxxxxflxxxxxNNrxxxxnxxxNxJ ___ ___ _ -CHEAP SENSATION- P ARF FUN-FLY ur GENERIX TAMPA EL 33615t 54-KITSN4~ P0 BOX 262035 S M NOW AVAILABLE P 1/12 SCALE COMBATSPECS 69 $ P51 MUSTANG$49 Span44 ngine 2-40MEETSAMA RULES$7 S&HArea770 sq $7 5&H 59oosizo 301 5-32Engine28-40 xxxxxxxxxxxxtxrxxxxxxxtkxxxxxnxxxxxx now flight enhanced timing Ittablock option Ouadm aid Zonodi slow landings course easyengbu oniy-sdd$18 start slow 611*10 Mb bai retahiedStilt M-80 114 x 32 spalqiug.*10 REICHMUTH IGNITION featuresKMEe1l4xquig*13 llGIo-pIug end magneto replacernentii Electronic . .. Ft PM controled timing No moving parts break came looseitkde battery protectionPPU aid handtg$5 514-ceII nicad operationlintemai over-voltage Pro -COD add$5 tectionFflegulated power supply extended2nd day ak dd$3 flight timelB Screw driver easy Installation QuadrflandZerioawswithlNSlABLOCK exasstyieSaxengineswimmeuminge linked carburetor easily converted withonlyadritaDremeltoolandatap.. ot. Ask Original RiE LaunihEr & Pit ErewTM Local Hobby Shop Send $9995 5&H tCall TodayDealer Inquiries Welcome September 1992 31 fl/c Launcher & Pit Crew 5806 Lancelot Ct SW Olympia WA 98502 206 786-8461 THE BEST FLY WITH GENE BARTON Gene Barton now introduces new P51-B Mustang contest quality fo beg nne Sem K n cludes fiberglass parts fit elage oop cowl heliy pan foam cores supplied wing vertical horizon tal stabs Scale spun aluminum spinner machined hack plate canopy also included rolled set plans buy own balsa wood wing span 79 fly ing weight around 20 lbs designed around 25 35 cc engine Price 5395 Package price available retracts stints tires wheels Call write Gene Barton 11640 Salinas Garden Grove CA 92643 714 539-9142 FAX 714 539-9288 ANNIVERSARY ffiJ LII}Zzri 10th ANNIVERSARY JCLJTFIWEST\ first finest FLYDucted Fan Gathering NIin US! AMA SANCTIONED JPO SPONSORED Sept 11-12-13 1992 Lockhart Texas SASE full details Rick Schafer Custom Model Products 5321 Industrial Oaks Austin TX 78735 Phone 512-892-6908 WingDesigner0 N fli II IIIIIII LiIIIIActual program pint lr.lr & E w Headquarters Plum Creek Inn 512-398-4911 tnsured reservations August 15 EditFoilo EditFoil FEATURES Enter airfoil data join published tabisa Prints data table Modify correct surface enperfectiotta graphically on-screen. ModiPy chord thicltneaa ratio WlnDeslgw supplied 24 airfoils Plots sample l0 rib requires MlngDeslgner. programs written speczfically model aircraft design NOT modified general purpose CAD programs NfrwDesfrner FEATURES PUTER SYSTEM REOUIREMENTS 9Jlowsdlffereuil root rip airfoils Plots ALL transition ribsIBM 100% eampatible 286 386 486 CPU aplota ribs ALL spar slots coned size andpotttoii. Math co-processor desirable NOTrequired Plots ribs sheelinVGA SVGA COLOR graphics display tionJiail portiot length apsis 18 MaximumD05 version 31 higher Adds extraribs atibe endsofailerons flaps Rib #dIn nsegofhard diskspaor 512kb RAM Position up toS extra ribs / panel Rib 02 example3-112 floppy drive 5-1/4 diskette available LumtesJl.rdhoks esch rib building OCCUISCYEoI matrix 9 24 pin laser printer PRO version *USER FR lEWDLY GRAPHICAL INTERFACEcan output pen plotter HPOL fomiat COLOR *QUICK EASY LEARN TED TIME INTRODUCTORY PRICE *ACCURATR PROFESSIONAL RESULTSBittFoil$ 5995 ttlngDertner$ 7995 EtItFott.$l2995 *SEE YOUR DESIGN ON-SCREENtVIngDerIgnerPRO$12495 withEitrFoil.$16995 TI/1irrnVivhmv Add $350 Shipping & Handling Parcel Post C $100 #10 SASE information P0 Box 8367 Bartlett IL 601 03-4203 32 Model Aviation Cmon down Celebrate Primer Aerodynamics Continued page 31 worth thousand words hope sketches will provide some Concept situation diagrams Ive made assumed line thrust also line flight various forces effect possible thrust may forced some slight angle line flighthow great angle being extremely difficult determine However such difference can assumed inconsequential thrust line used reference base line sometimes referred datum line forces incidence angles center drag etc related might ask what happens downor up-thrust prescribed offset thrust lines can assume actual line flight will fall somewhere between actual thrust line what would offset plane tends fly along line thrust reaction between thrust aerodynamic forces result compromise between two observe effect offset thrust present simply tilt force arrangement diagram direction offset note relation various forces line flighta line will remain horizontal speaking line thrust note relates center resistance point assumed drag forces acting plane concentrated First note thrust line some angle line flight things like fuselage no longer parallel line flight thus increasing amount drag present importantly note moving line thrust away center resistance creates physical force can have effect aerodynamics example thrust line higher point resistance thrust will create nose-down coupling thrust line lower center resistance noseup moment will generated practical example could aerobatic design high thrust line could prove advantageous inverted flight Diagram No 1 depicts typical popular so-called zero-zero force arrangement symmetrical airfoils used note respect line flight neither wing nor stabilizer produces plus force drag negative force aerodynamic forces equalized Thus would seem line flight must something other design line actuality force must added tilts angle attack wing sufficient lift will generated could Conrinued page 38 Primer Aerodynamics Continued page 32 done thrust/resistance physical force spoke earlier event will note some force has used position wing tail lifting angles sustain level flight Otherwise should wing have semisymmetrical airfoil set same zero-incidence angle such airfoil does produce lift ball game different Effectively have wing positive lifting angle stab has symmetrical airfoil section zero lift flight wing lift would force stabilizer away zero creating positive stabilizer lift until some point equilibrium reached Thus would deviation design line flight Diagram No 2 depicts what might said original force arrangement models arrangement got Free flights flying purely academic standpoint thrust line line flight same Note have wing lifting angle stabilizer producing negative lift vely typical OT Free Flight obtain equilibrium gravity force CGcenter-of-gravity applied far enough forward wings center lift balances out tails negative lift Note longitudinal pivot forces wings center lift C/U case situation what could labeled constant speed arrangement stabilizer adjusted produce just enough negative lift some desired flying speed balance out pitch-down force created location CG being forward wings center lift Free Flight models desired combination speed attitude found glide mode Assuming objective flight FF model climb power glide power off trick becomes use just enough power upset established forces create desired climb getting stall loopwhich increased speed encountered during power-on portion flight would tend produce Developed FF considered safe arrangement because whenever speed increases beyond norm misproportion between wing tail lift will cause planes nose rise instead pitching down toward earth RC sometimes see arrangement used design speed full-bore power offering safety factor trainer types Obviously finding just right compromise between three forces wing lift tail lift CU involved always critical successful flight Diagram No3 relates diagram No 1 among other things shows objective No 1 can obtained greater efficiency No 3 carries aerodynamics further create what known neutral stability NS Simply put ability model fly desired attitude over wide speed range no nose-up -down reaction often said model NS goes point aerodynamics used involve striking proportion between wing tail lift will prevail over wide speed range Note case both wing tail producing positive lift visualize remember forces pivot models center lift C/L can wings C/L diagram No 2 aft CI case Understand both wing tail lifting models C/L resultant two forces mean C/L must fall aft wings C/L point total wing plus stabilizer lift applied So CU must located relative mean point wings CIL previous cases Note lift moment arm wing C/L tail CIL mean point Normally tail moment arm will roughly 12 times longer wings lever Thus two surfaces exert equal force mean point amount lift actually generated tail would far less wing due its much longer leverage allows tail size much smaller agreeable situation Over desired speed range wing exhibits definite changes its characteristics some intermediate speed specific amount lift drag produced Increase decrease speed lift/drag will change like manner such changes speed stabilizer responds manner exactly like wing have needed proportion continuing balance lift So can say line flight altered upward angle elevator control model will continue fly established angle same will occur downward angle will no inherent tendency nose up down same could expected should model bounced rough air gravity force constant fixed value regardless speed attitude So purely academic viewpoint could say straight level flight reduced power going full power would increase forward speed turn would increase lift causing model rise like elevator nosing up Likewise reducing power below cruise would cause similar elevator-like loss altitude no nose down Actually usually design models fly full power little normally seen such balance forces can have model follows design line U UUU . I. Ije Macfi tetbflv O49 REED VALVE ENGINE First introduced 1973 Black Widow powerful popular O 049 reed valve engine Its great types control line models including 1/2A Stunt Mouse Racing Beginner Combat Powered R/C Sailplanes too Widow precision built specially selected steel aluminum q P alloys tolerances measured millionths inch Cox Snap Stajtei provides easy no hassle starting The Black Widow recommended engine new 1/2A series Famous Fighters World War II Midwest Products available favorite Hobby Retailer now COX HOBBIES INC Corona CA 91720 OCOXHOBBIES INC. ISBI 38 Model Aviation 1 61 Im 6 him Im flight attitude over wide speed range say neutral stability NS has proven very desirable types RC models obviously must able control attitude order change direction Pointed toward heaven model NS might get thereor reach hell its pointed other direction Lets explain force diagram Both wing tail producing positive lift Note tail greater angle wing Scary Experience proves should reason being additional angle needed achieve proper lift balance having use oversize tail design speed total lift exactly cancels gravity force Note difference diagram No 1 resultant lift force has added mean lift point used design purposes No 1 CC located relation wings CIL Now CC must moved aft relate mean lift point same manner basic aerodynamics laws just used greater extent might assumed designing neutral stability could complex task considering necessity having exactly correct proportion between wing tail lift Experience over years designs has proven otherwise Fortunately practice has shown normal-size stabilizers having Success Series U-Control Kits respectable symmetrical airfoil adequate does help initial phase provide ability adjust stabilizers angle incidence achieve proper proportioning lift However given airfoils once successful relationship has determined will hold true over wide variety designs Give try will surprised pilot will sometimes say first flying neutrally stable model Boy model feels real solid really grooves flies rails thats actually very satisfying feeling model has no tendency wander goes last pointed until ask change direction likeable characteristic neutral stability As might expect shortcoming must maintain control times No self-recovery built arrangement other hand accomplished pilot such designs joy fly nothing ownonly what tell conclusion let hasten add discussion has hardly cracked ice aerodynamics design engineering However brief considerations applied wants will have much assurance reaching goals Foremost understand medium model airplane operates 10 TU$iieS 09 Midwests new Success Series 049 U-Control kits perfect introduction building flying Featuring illustrated step-by-step Success Series construction manuals teach build paint fly models Kits include Micro-Cut Quality parts pre-formed wire parts wheels belicrank colorful self adhesive markingsqp line Famous Fighters World War II designed use Cox Black Widow engine See products favorite hobby retailer todayl Famous Fighters World War II Models Available #258 Zero #259 Corsairshown #260 Thunderbolt #261 FockeWuif Midwest Products Co inc 400 S indiana St PO Box 564 HobartiN46342 2191942-1134 PAxl2I9l547-Z34701992 Midwest Productsco inc aerodynamics happenings will have much meaning Also like insurance policy make up force arrangement diagram showing what desire will have good indication what expect design Just compare force arrangement design another want delve further aerodynamics Its basic force arrangement proven good design makes excellent comparison thats unknown Whats good goose good gander bottom line could once have some experience fundamentals will find simple delve little deeper deeply wind up having understanding can lead designing own plane discussion has provided reader basic knowledge aerodynamics Interested modelers could now ask question Now know basics apply factors improve modeling answer will found Part II series Aerodynamic Primer-Trimmer coming soon Good luck CL Vintage Stunt Continued page 23 finest Bob Hunts Tucker Special Although plagued tank/engine problems newly finished model Im sure well see next year Other notables Cecil Meade Fan Dancer garnered Spirit 64 award Jim Levell gorgeous yellow Ares winner Concours award Larry Cunninghams Road Runner Greg Zajacks Patriot 59 Nostalgia entrants 47 made least official flight flights posted 500 pm stark testimony efficiency Cholla Choppers Carl Marshenki David Reynolds pits circle directors Walt Menges Bart Klapinski fliers came circles ready fly first met Bob Baron 57 AMA Nationals placed second Senior event continued success national international competition makes no surprise accident won Nostalgia event flying Netzeband designed Humbug Former Nationals winner Bob Whitely second flying stretched Continued page 40 September 1992 39 Beginners
Edition: Model Aviation - 1992/09
Page Numbers: 28, 29, 31, 32, 38, 39
A Primer Aerodynamics master model builder talks about airplanes fly tells us selector modify sound design U Harold deBolt 7~HE URGE produce aircraft own hits modelers sooner later ambitious goal would original design Something less might modification existing craft often evaluate someone elses creation help us own thinking about new design understand basic aerodynamics can perform desired task much intelligently profusion model designs available today person accomplished designer can draw upon what someone else has perfected acquire generalities what wishesand can attain some success result However evaluating concepteither own boffowed onewe can have assurance success understand very basics aerody naniics subject often cloudy us & 0 0000 0000 0 0 000 0 0 0 0000 0 jO 000000000o 00 00 0000 0 0000000000o~o0oo00 000 0 oOoooo~00000 0oooooOO006~ LNEOF-YLIHT00000000000000 0000000000000 0 00 0 0009 0000 000Co 000 0 0 0 00 00 O00Q0Ob0o0oDo0o0o0oO0C0O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Upper sketch upper curve airfoil displaces air molecules depicted little bubbles lower side planes air pressure differential creating lift Lower sketch streamlined symmetrical curves airfoil displace air molecules equally side no lift created objective short article enlighten reader about basics aerodynamics provide some tools can understand craft flies whether contemplated design sound idea take thoughts offered apply characteristics design question commence should understand definition aerodynamics laws govern aliflight Aero course refers air medium craft operates Dynamics refers resultant action created object moving through air aerodynamic laws formulated found air reacts distinct predictable ways shapes objects RESIS TA N C F S LIST LIFT LIFT GRAVFY LINEOF FLIGHT LIFT L[FT zero-zero incidence force arrangement shown climbing attitude angle gravity force acts opposes thrust force reducing aircrafts speed 28 Model Aviation author today replica first Free Flight design built 1938 moving through Using laws has enabled us design aircraft fly Investigators found airfoil shapes create lift streamlined shapes have minimum drag etc Experience helped create aerodynamic laws discovered various objects could have useful shapes arranged relation other produce flight day laws have become fundamental basic laws pertain aircraft Violate flight will suffer some extent So understand basics apply design may considering can assured flight Beyond basic design details simply enhance type flight objective desired points remember basic aerodynamics gospel air considered stationary flight created craft moving through Any respectable Engineer realizes must understand medium working before can commence effort Aero engineers work medium air necessary understand its characteristics People take air granted just However use some purpose other breathing sustain life such flight must understand its peculiarities Lets consider air engineers viewpoint First lets say substances mediums vary composition loosely knit dense solid solid Gas loosely knit fluid dense wood metals etc have varying amounts solidity Air being gas loosely knita medium easily displaced characteristic makes flight possible displacing air foundation aerodynamics Air composed molecules nitrogen oxygen could describe little balloons space between Thus displaced moving object molecules simply close up become closer together objects speed too great Molecule compression occurs object moves through air speed sound force created release compression hear sonic boom Thankfully model speeds low allowing us have consider displacement air molecules Another consideration because effects gravity air has varying densitymore dense sea level much less high altitude Again flights models low altitude latter condition normally ignored also important realize aircraft flight surrounded air effect air upon aircraft equal sides However say aerodynamic force effects equal sides Thus aerodynamic laws apply equally whether craft level flight vertical attitude flying inverted change forces acting THRUSTLIFT 0 RE SISTA N CE GRAVITYLIFT LI FT o LINE OF FLIGHT RESISTANCELIFT _THRUST JIEILINE OF FLIGHT\ LIFT ANGLE OF ATTACF GRAVITY Force Diagram 1 OOOO incidence force arrangement top forces balance except gravity negative Flight impossible until introduce force bottom tilt angles attack wing stab producing enough positive wing stab lift overcome gravity Flight now possible aircraft its attitude changes comes change direction gravity acting craft say aerodynamic forces neutralize gravity flight follows gravity will detract planes speed climbing attitude increase speed diving attitude power gravity detracts planes power climb attitude adds power dive gravity has no effect aerodynamics course gravity provides power moves glider-type machine through air thereby allowing aerodynamics create flight Such craft always flying downhill speak THRUST4 INCDLIFT RESISTANCEGRAVITY OF FLIGHT increase decrease addition aerodynamic forces vary linear fashion respect speed aircraft example lift drag increase square increases speed As result stability over large speed ranges desired important forces arranged proportionally other seems like should complex achieve relatively simple proper design also must understand airplanes configured Just explained makeup word aerodynamics LI FT 1 LIFT Force Diagram 2 classic force arrangement created successful model flight tails down force negative lift balanced very forward application gravity models center-of-gravity produce equilibrium particular flying speed Remember aerodynamic laws apply line offlight attitude plane respect horizon other factor same aerodynamic forces present plane vertical inverted attitude present planes flight level horizon force changes attitude gravity because becomes applied different angles aircraft force gravity itself does WING LIFT MEAN LIFT THRUSTI 1 I/2 LIKEOFFLIGHT RESISTANCEGRAVITY name craft itself offers clues plane literally surface say surface can plane medium boats bottom water example So can say airplane has surfaces plane aira simple description deep meaning Aircraft have various surfaces labeled airfoils Continued page 31 LIFT Force Diagram 3 modern force arrangement produces neutral stability maximum efficiency RC models proportionrepresented mean lift force established between wing tail lift CG now positioned relative mean center lift Line flight maintained over wide speed range September 1992 29 Primer Aerodynamics Continued page 29 term actually applies entire surface such wing rudder stabilizer canard etc importance fact surfaces used because produces force needed create maintain flight some surface aircraft creating force no value aerodynamically Surfaces horizontal plane labeled wings Thus normal monoplane configuration aircraft has two wings main forward surface aft stabilizing wing stabilizer short should also understand airfoil surface restrained some manner stable Simply put pick up such surface drop height few feet surface initially parallel ground will tend rotate about spanwise axis falls wing main support flight some other force must used restrain position angle attack contributes useful lift simplest way accomplish use force created second aft wing affect forward wings tendency rotate lock desired angle attack summation point flight surfaces including stabilizing surfaces aircraft work generating desirable forces Since should striving efficiency factor consider forces applied add efficiency offlight just stabilize some other surface apply considerations going discuss force arrangements simply diagrams depict way forces will act upon contemplated aircraft design can complex purposes simpler versions will give us light Important realize forces relative line offlight criterion reference material available use reasoning behind generalities force arrangements brief article purely academic example know thrust engine must applied particular point must wing tail distinct other Since brief discussion can assume whatever reference use supplied such details within realm aerodynamic laws What hope to show both some typical some unusual aircraft configurations what force arrangement depicts aircrafts attitude changes Someone said picture Continued poge 32 rxxxxxrxxxxxxxxxxxxxflxxxxxNNrxxxxnxxxNxJ ___ ___ _ -CHEAP SENSATION- P ARF FUN-FLY ur GENERIX TAMPA EL 33615t 54-KITSN4~ P0 BOX 262035 S M NOW AVAILABLE P 1/12 SCALE COMBATSPECS 69 $ P51 MUSTANG$49 Span44 ngine 2-40MEETSAMA RULES$7 S&HArea770 sq $7 5&H 59oosizo 301 5-32Engine28-40 xxxxxxxxxxxxtxrxxxxxxxtkxxxxxnxxxxxx now flight enhanced timing Ittablock option Ouadm aid Zonodi slow landings course easyengbu oniy-sdd$18 start slow 611*10 Mb bai retahiedStilt M-80 114 x 32 spalqiug.*10 REICHMUTH IGNITION featuresKMEe1l4xquig*13 llGIo-pIug end magneto replacernentii Electronic . .. Ft PM controled timing No moving parts break came looseitkde battery protectionPPU aid handtg$5 514-ceII nicad operationlintemai over-voltage Pro -COD add$5 tectionFflegulated power supply extended2nd day ak dd$3 flight timelB Screw driver easy Installation QuadrflandZerioawswithlNSlABLOCK exasstyieSaxengineswimmeuminge linked carburetor easily converted withonlyadritaDremeltoolandatap.. ot. Ask Original RiE LaunihEr & Pit ErewTM Local Hobby Shop Send $9995 5&H tCall TodayDealer Inquiries Welcome September 1992 31 fl/c Launcher & Pit Crew 5806 Lancelot Ct SW Olympia WA 98502 206 786-8461 THE BEST FLY WITH GENE BARTON Gene Barton now introduces new P51-B Mustang contest quality fo beg nne Sem K n cludes fiberglass parts fit elage oop cowl heliy pan foam cores supplied wing vertical horizon tal stabs Scale spun aluminum spinner machined hack plate canopy also included rolled set plans buy own balsa wood wing span 79 fly ing weight around 20 lbs designed around 25 35 cc engine Price 5395 Package price available retracts stints tires wheels Call write Gene Barton 11640 Salinas Garden Grove CA 92643 714 539-9142 FAX 714 539-9288 ANNIVERSARY ffiJ LII}Zzri 10th ANNIVERSARY JCLJTFIWEST\ first finest FLYDucted Fan Gathering NIin US! AMA SANCTIONED JPO SPONSORED Sept 11-12-13 1992 Lockhart Texas SASE full details Rick Schafer Custom Model Products 5321 Industrial Oaks Austin TX 78735 Phone 512-892-6908 WingDesigner0 N fli II IIIIIII LiIIIIActual program pint lr.lr & E w Headquarters Plum Creek Inn 512-398-4911 tnsured reservations August 15 EditFoilo EditFoil FEATURES Enter airfoil data join published tabisa Prints data table Modify correct surface enperfectiotta graphically on-screen. ModiPy chord thicltneaa ratio WlnDeslgw supplied 24 airfoils Plots sample l0 rib requires MlngDeslgner. programs written speczfically model aircraft design NOT modified general purpose CAD programs NfrwDesfrner FEATURES PUTER SYSTEM REOUIREMENTS 9Jlowsdlffereuil root rip airfoils Plots ALL transition ribsIBM 100% eampatible 286 386 486 CPU aplota ribs ALL spar slots coned size andpotttoii. Math co-processor desirable NOTrequired Plots ribs sheelinVGA SVGA COLOR graphics display tionJiail portiot length apsis 18 MaximumD05 version 31 higher Adds extraribs atibe endsofailerons flaps Rib #dIn nsegofhard diskspaor 512kb RAM Position up toS extra ribs / panel Rib 02 example3-112 floppy drive 5-1/4 diskette available LumtesJl.rdhoks esch rib building OCCUISCYEoI matrix 9 24 pin laser printer PRO version *USER FR lEWDLY GRAPHICAL INTERFACEcan output pen plotter HPOL fomiat COLOR *QUICK EASY LEARN TED TIME INTRODUCTORY PRICE *ACCURATR PROFESSIONAL RESULTSBittFoil$ 5995 ttlngDertner$ 7995 EtItFott.$l2995 *SEE YOUR DESIGN ON-SCREENtVIngDerIgnerPRO$12495 withEitrFoil.$16995 TI/1irrnVivhmv Add $350 Shipping & Handling Parcel Post C $100 #10 SASE information P0 Box 8367 Bartlett IL 601 03-4203 32 Model Aviation Cmon down Celebrate Primer Aerodynamics Continued page 31 worth thousand words hope sketches will provide some Concept situation diagrams Ive made assumed line thrust also line flight various forces effect possible thrust may forced some slight angle line flighthow great angle being extremely difficult determine However such difference can assumed inconsequential thrust line used reference base line sometimes referred datum line forces incidence angles center drag etc related might ask what happens downor up-thrust prescribed offset thrust lines can assume actual line flight will fall somewhere between actual thrust line what would offset plane tends fly along line thrust reaction between thrust aerodynamic forces result compromise between two observe effect offset thrust present simply tilt force arrangement diagram direction offset note relation various forces line flighta line will remain horizontal speaking line thrust note relates center resistance point assumed drag forces acting plane concentrated First note thrust line some angle line flight things like fuselage no longer parallel line flight thus increasing amount drag present importantly note moving line thrust away center resistance creates physical force can have effect aerodynamics example thrust line higher point resistance thrust will create nose-down coupling thrust line lower center resistance noseup moment will generated practical example could aerobatic design high thrust line could prove advantageous inverted flight Diagram No 1 depicts typical popular so-called zero-zero force arrangement symmetrical airfoils used note respect line flight neither wing nor stabilizer produces plus force drag negative force aerodynamic forces equalized Thus would seem line flight must something other design line actuality force must added tilts angle attack wing sufficient lift will generated could Conrinued page 38 Primer Aerodynamics Continued page 32 done thrust/resistance physical force spoke earlier event will note some force has used position wing tail lifting angles sustain level flight Otherwise should wing have semisymmetrical airfoil set same zero-incidence angle such airfoil does produce lift ball game different Effectively have wing positive lifting angle stab has symmetrical airfoil section zero lift flight wing lift would force stabilizer away zero creating positive stabilizer lift until some point equilibrium reached Thus would deviation design line flight Diagram No 2 depicts what might said original force arrangement models arrangement got Free flights flying purely academic standpoint thrust line line flight same Note have wing lifting angle stabilizer producing negative lift vely typical OT Free Flight obtain equilibrium gravity force CGcenter-of-gravity applied far enough forward wings center lift balances out tails negative lift Note longitudinal pivot forces wings center lift C/U case situation what could labeled constant speed arrangement stabilizer adjusted produce just enough negative lift some desired flying speed balance out pitch-down force created location CG being forward wings center lift Free Flight models desired combination speed attitude found glide mode Assuming objective flight FF model climb power glide power off trick becomes use just enough power upset established forces create desired climb getting stall loopwhich increased speed encountered during power-on portion flight would tend produce Developed FF considered safe arrangement because whenever speed increases beyond norm misproportion between wing tail lift will cause planes nose rise instead pitching down toward earth RC sometimes see arrangement used design speed full-bore power offering safety factor trainer types Obviously finding just right compromise between three forces wing lift tail lift CU involved always critical successful flight Diagram No3 relates diagram No 1 among other things shows objective No 1 can obtained greater efficiency No 3 carries aerodynamics further create what known neutral stability NS Simply put ability model fly desired attitude over wide speed range no nose-up -down reaction often said model NS goes point aerodynamics used involve striking proportion between wing tail lift will prevail over wide speed range Note case both wing tail producing positive lift visualize remember forces pivot models center lift C/L can wings C/L diagram No 2 aft CI case Understand both wing tail lifting models C/L resultant two forces mean C/L must fall aft wings C/L point total wing plus stabilizer lift applied So CU must located relative mean point wings CIL previous cases Note lift moment arm wing C/L tail CIL mean point Normally tail moment arm will roughly 12 times longer wings lever Thus two surfaces exert equal force mean point amount lift actually generated tail would far less wing due its much longer leverage allows tail size much smaller agreeable situation Over desired speed range wing exhibits definite changes its characteristics some intermediate speed specific amount lift drag produced Increase decrease speed lift/drag will change like manner such changes speed stabilizer responds manner exactly like wing have needed proportion continuing balance lift So can say line flight altered upward angle elevator control model will continue fly established angle same will occur downward angle will no inherent tendency nose up down same could expected should model bounced rough air gravity force constant fixed value regardless speed attitude So purely academic viewpoint could say straight level flight reduced power going full power would increase forward speed turn would increase lift causing model rise like elevator nosing up Likewise reducing power below cruise would cause similar elevator-like loss altitude no nose down Actually usually design models fly full power little normally seen such balance forces can have model follows design line U UUU . I. Ije Macfi tetbflv O49 REED VALVE ENGINE First introduced 1973 Black Widow powerful popular O 049 reed valve engine Its great types control line models including 1/2A Stunt Mouse Racing Beginner Combat Powered R/C Sailplanes too Widow precision built specially selected steel aluminum q P alloys tolerances measured millionths inch Cox Snap Stajtei provides easy no hassle starting The Black Widow recommended engine new 1/2A series Famous Fighters World War II Midwest Products available favorite Hobby Retailer now COX HOBBIES INC Corona CA 91720 OCOXHOBBIES INC. ISBI 38 Model Aviation 1 61 Im 6 him Im flight attitude over wide speed range say neutral stability NS has proven very desirable types RC models obviously must able control attitude order change direction Pointed toward heaven model NS might get thereor reach hell its pointed other direction Lets explain force diagram Both wing tail producing positive lift Note tail greater angle wing Scary Experience proves should reason being additional angle needed achieve proper lift balance having use oversize tail design speed total lift exactly cancels gravity force Note difference diagram No 1 resultant lift force has added mean lift point used design purposes No 1 CC located relation wings CIL Now CC must moved aft relate mean lift point same manner basic aerodynamics laws just used greater extent might assumed designing neutral stability could complex task considering necessity having exactly correct proportion between wing tail lift Experience over years designs has proven otherwise Fortunately practice has shown normal-size stabilizers having Success Series U-Control Kits respectable symmetrical airfoil adequate does help initial phase provide ability adjust stabilizers angle incidence achieve proper proportioning lift However given airfoils once successful relationship has determined will hold true over wide variety designs Give try will surprised pilot will sometimes say first flying neutrally stable model Boy model feels real solid really grooves flies rails thats actually very satisfying feeling model has no tendency wander goes last pointed until ask change direction likeable characteristic neutral stability As might expect shortcoming must maintain control times No self-recovery built arrangement other hand accomplished pilot such designs joy fly nothing ownonly what tell conclusion let hasten add discussion has hardly cracked ice aerodynamics design engineering However brief considerations applied wants will have much assurance reaching goals Foremost understand medium model airplane operates 10 TU$iieS 09 Midwests new Success Series 049 U-Control kits perfect introduction building flying Featuring illustrated step-by-step Success Series construction manuals teach build paint fly models Kits include Micro-Cut Quality parts pre-formed wire parts wheels belicrank colorful self adhesive markingsqp line Famous Fighters World War II designed use Cox Black Widow engine See products favorite hobby retailer todayl Famous Fighters World War II Models Available #258 Zero #259 Corsairshown #260 Thunderbolt #261 FockeWuif Midwest Products Co inc 400 S indiana St PO Box 564 HobartiN46342 2191942-1134 PAxl2I9l547-Z34701992 Midwest Productsco inc aerodynamics happenings will have much meaning Also like insurance policy make up force arrangement diagram showing what desire will have good indication what expect design Just compare force arrangement design another want delve further aerodynamics Its basic force arrangement proven good design makes excellent comparison thats unknown Whats good goose good gander bottom line could once have some experience fundamentals will find simple delve little deeper deeply wind up having understanding can lead designing own plane discussion has provided reader basic knowledge aerodynamics Interested modelers could now ask question Now know basics apply factors improve modeling answer will found Part II series Aerodynamic Primer-Trimmer coming soon Good luck CL Vintage Stunt Continued page 23 finest Bob Hunts Tucker Special Although plagued tank/engine problems newly finished model Im sure well see next year Other notables Cecil Meade Fan Dancer garnered Spirit 64 award Jim Levell gorgeous yellow Ares winner Concours award Larry Cunninghams Road Runner Greg Zajacks Patriot 59 Nostalgia entrants 47 made least official flight flights posted 500 pm stark testimony efficiency Cholla Choppers Carl Marshenki David Reynolds pits circle directors Walt Menges Bart Klapinski fliers came circles ready fly first met Bob Baron 57 AMA Nationals placed second Senior event continued success national international competition makes no surprise accident won Nostalgia event flying Netzeband designed Humbug Former Nationals winner Bob Whitely second flying stretched Continued page 40 September 1992 39 Beginners
Edition: Model Aviation - 1992/09
Page Numbers: 28, 29, 31, 32, 38, 39
A Primer Aerodynamics master model builder talks about airplanes fly tells us selector modify sound design U Harold deBolt 7~HE URGE produce aircraft own hits modelers sooner later ambitious goal would original design Something less might modification existing craft often evaluate someone elses creation help us own thinking about new design understand basic aerodynamics can perform desired task much intelligently profusion model designs available today person accomplished designer can draw upon what someone else has perfected acquire generalities what wishesand can attain some success result However evaluating concepteither own boffowed onewe can have assurance success understand very basics aerody naniics subject often cloudy us & 0 0000 0000 0 0 000 0 0 0 0000 0 jO 000000000o 00 00 0000 0 0000000000o~o0oo00 000 0 oOoooo~00000 0oooooOO006~ LNEOF-YLIHT00000000000000 0000000000000 0 00 0 0009 0000 000Co 000 0 0 0 00 00 O00Q0Ob0o0oDo0o0o0oO0C0O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Upper sketch upper curve airfoil displaces air molecules depicted little bubbles lower side planes air pressure differential creating lift Lower sketch streamlined symmetrical curves airfoil displace air molecules equally side no lift created objective short article enlighten reader about basics aerodynamics provide some tools can understand craft flies whether contemplated design sound idea take thoughts offered apply characteristics design question commence should understand definition aerodynamics laws govern aliflight Aero course refers air medium craft operates Dynamics refers resultant action created object moving through air aerodynamic laws formulated found air reacts distinct predictable ways shapes objects RESIS TA N C F S LIST LIFT LIFT GRAVFY LINEOF FLIGHT LIFT L[FT zero-zero incidence force arrangement shown climbing attitude angle gravity force acts opposes thrust force reducing aircrafts speed 28 Model Aviation author today replica first Free Flight design built 1938 moving through Using laws has enabled us design aircraft fly Investigators found airfoil shapes create lift streamlined shapes have minimum drag etc Experience helped create aerodynamic laws discovered various objects could have useful shapes arranged relation other produce flight day laws have become fundamental basic laws pertain aircraft Violate flight will suffer some extent So understand basics apply design may considering can assured flight Beyond basic design details simply enhance type flight objective desired points remember basic aerodynamics gospel air considered stationary flight created craft moving through Any respectable Engineer realizes must understand medium working before can commence effort Aero engineers work medium air necessary understand its characteristics People take air granted just However use some purpose other breathing sustain life such flight must understand its peculiarities Lets consider air engineers viewpoint First lets say substances mediums vary composition loosely knit dense solid solid Gas loosely knit fluid dense wood metals etc have varying amounts solidity Air being gas loosely knita medium easily displaced characteristic makes flight possible displacing air foundation aerodynamics Air composed molecules nitrogen oxygen could describe little balloons space between Thus displaced moving object molecules simply close up become closer together objects speed too great Molecule compression occurs object moves through air speed sound force created release compression hear sonic boom Thankfully model speeds low allowing us have consider displacement air molecules Another consideration because effects gravity air has varying densitymore dense sea level much less high altitude Again flights models low altitude latter condition normally ignored also important realize aircraft flight surrounded air effect air upon aircraft equal sides However say aerodynamic force effects equal sides Thus aerodynamic laws apply equally whether craft level flight vertical attitude flying inverted change forces acting THRUSTLIFT 0 RE SISTA N CE GRAVITYLIFT LI FT o LINE OF FLIGHT RESISTANCELIFT _THRUST JIEILINE OF FLIGHT\ LIFT ANGLE OF ATTACF GRAVITY Force Diagram 1 OOOO incidence force arrangement top forces balance except gravity negative Flight impossible until introduce force bottom tilt angles attack wing stab producing enough positive wing stab lift overcome gravity Flight now possible aircraft its attitude changes comes change direction gravity acting craft say aerodynamic forces neutralize gravity flight follows gravity will detract planes speed climbing attitude increase speed diving attitude power gravity detracts planes power climb attitude adds power dive gravity has no effect aerodynamics course gravity provides power moves glider-type machine through air thereby allowing aerodynamics create flight Such craft always flying downhill speak THRUST4 INCDLIFT RESISTANCEGRAVITY OF FLIGHT increase decrease addition aerodynamic forces vary linear fashion respect speed aircraft example lift drag increase square increases speed As result stability over large speed ranges desired important forces arranged proportionally other seems like should complex achieve relatively simple proper design also must understand airplanes configured Just explained makeup word aerodynamics LI FT 1 LIFT Force Diagram 2 classic force arrangement created successful model flight tails down force negative lift balanced very forward application gravity models center-of-gravity produce equilibrium particular flying speed Remember aerodynamic laws apply line offlight attitude plane respect horizon other factor same aerodynamic forces present plane vertical inverted attitude present planes flight level horizon force changes attitude gravity because becomes applied different angles aircraft force gravity itself does WING LIFT MEAN LIFT THRUSTI 1 I/2 LIKEOFFLIGHT RESISTANCEGRAVITY name craft itself offers clues plane literally surface say surface can plane medium boats bottom water example So can say airplane has surfaces plane aira simple description deep meaning Aircraft have various surfaces labeled airfoils Continued page 31 LIFT Force Diagram 3 modern force arrangement produces neutral stability maximum efficiency RC models proportionrepresented mean lift force established between wing tail lift CG now positioned relative mean center lift Line flight maintained over wide speed range September 1992 29 Primer Aerodynamics Continued page 29 term actually applies entire surface such wing rudder stabilizer canard etc importance fact surfaces used because produces force needed create maintain flight some surface aircraft creating force no value aerodynamically Surfaces horizontal plane labeled wings Thus normal monoplane configuration aircraft has two wings main forward surface aft stabilizing wing stabilizer short should also understand airfoil surface restrained some manner stable Simply put pick up such surface drop height few feet surface initially parallel ground will tend rotate about spanwise axis falls wing main support flight some other force must used restrain position angle attack contributes useful lift simplest way accomplish use force created second aft wing affect forward wings tendency rotate lock desired angle attack summation point flight surfaces including stabilizing surfaces aircraft work generating desirable forces Since should striving efficiency factor consider forces applied add efficiency offlight just stabilize some other surface apply considerations going discuss force arrangements simply diagrams depict way forces will act upon contemplated aircraft design can complex purposes simpler versions will give us light Important realize forces relative line offlight criterion reference material available use reasoning behind generalities force arrangements brief article purely academic example know thrust engine must applied particular point must wing tail distinct other Since brief discussion can assume whatever reference use supplied such details within realm aerodynamic laws What hope to show both some typical some unusual aircraft configurations what force arrangement depicts aircrafts attitude changes Someone said picture Continued poge 32 rxxxxxrxxxxxxxxxxxxxflxxxxxNNrxxxxnxxxNxJ ___ ___ _ -CHEAP SENSATION- P ARF FUN-FLY ur GENERIX TAMPA EL 33615t 54-KITSN4~ P0 BOX 262035 S M NOW AVAILABLE P 1/12 SCALE COMBATSPECS 69 $ P51 MUSTANG$49 Span44 ngine 2-40MEETSAMA RULES$7 S&HArea770 sq $7 5&H 59oosizo 301 5-32Engine28-40 xxxxxxxxxxxxtxrxxxxxxxtkxxxxxnxxxxxx now flight enhanced timing Ittablock option Ouadm aid Zonodi slow landings course easyengbu oniy-sdd$18 start slow 611*10 Mb bai retahiedStilt M-80 114 x 32 spalqiug.*10 REICHMUTH IGNITION featuresKMEe1l4xquig*13 llGIo-pIug end magneto replacernentii Electronic . .. Ft PM controled timing No moving parts break came looseitkde battery protectionPPU aid handtg$5 514-ceII nicad operationlintemai over-voltage Pro -COD add$5 tectionFflegulated power supply extended2nd day ak dd$3 flight timelB Screw driver easy Installation QuadrflandZerioawswithlNSlABLOCK exasstyieSaxengineswimmeuminge linked carburetor easily converted withonlyadritaDremeltoolandatap.. ot. Ask Original RiE LaunihEr & Pit ErewTM Local Hobby Shop Send $9995 5&H tCall TodayDealer Inquiries Welcome September 1992 31 fl/c Launcher & Pit Crew 5806 Lancelot Ct SW Olympia WA 98502 206 786-8461 THE BEST FLY WITH GENE BARTON Gene Barton now introduces new P51-B Mustang contest quality fo beg nne Sem K n cludes fiberglass parts fit elage oop cowl heliy pan foam cores supplied wing vertical horizon tal stabs Scale spun aluminum spinner machined hack plate canopy also included rolled set plans buy own balsa wood wing span 79 fly ing weight around 20 lbs designed around 25 35 cc engine Price 5395 Package price available retracts stints tires wheels Call write Gene Barton 11640 Salinas Garden Grove CA 92643 714 539-9142 FAX 714 539-9288 ANNIVERSARY ffiJ LII}Zzri 10th ANNIVERSARY JCLJTFIWEST\ first finest FLYDucted Fan Gathering NIin US! AMA SANCTIONED JPO SPONSORED Sept 11-12-13 1992 Lockhart Texas SASE full details Rick Schafer Custom Model Products 5321 Industrial Oaks Austin TX 78735 Phone 512-892-6908 WingDesigner0 N fli II IIIIIII LiIIIIActual program pint lr.lr & E w Headquarters Plum Creek Inn 512-398-4911 tnsured reservations August 15 EditFoilo EditFoil FEATURES Enter airfoil data join published tabisa Prints data table Modify correct surface enperfectiotta graphically on-screen. ModiPy chord thicltneaa ratio WlnDeslgw supplied 24 airfoils Plots sample l0 rib requires MlngDeslgner. programs written speczfically model aircraft design NOT modified general purpose CAD programs NfrwDesfrner FEATURES PUTER SYSTEM REOUIREMENTS 9Jlowsdlffereuil root rip airfoils Plots ALL transition ribsIBM 100% eampatible 286 386 486 CPU aplota ribs ALL spar slots coned size andpotttoii. Math co-processor desirable NOTrequired Plots ribs sheelinVGA SVGA COLOR graphics display tionJiail portiot length apsis 18 MaximumD05 version 31 higher Adds extraribs atibe endsofailerons flaps Rib #dIn nsegofhard diskspaor 512kb RAM Position up toS extra ribs / panel Rib 02 example3-112 floppy drive 5-1/4 diskette available LumtesJl.rdhoks esch rib building OCCUISCYEoI matrix 9 24 pin laser printer PRO version *USER FR lEWDLY GRAPHICAL INTERFACEcan output pen plotter HPOL fomiat COLOR *QUICK EASY LEARN TED TIME INTRODUCTORY PRICE *ACCURATR PROFESSIONAL RESULTSBittFoil$ 5995 ttlngDertner$ 7995 EtItFott.$l2995 *SEE YOUR DESIGN ON-SCREENtVIngDerIgnerPRO$12495 withEitrFoil.$16995 TI/1irrnVivhmv Add $350 Shipping & Handling Parcel Post C $100 #10 SASE information P0 Box 8367 Bartlett IL 601 03-4203 32 Model Aviation Cmon down Celebrate Primer Aerodynamics Continued page 31 worth thousand words hope sketches will provide some Concept situation diagrams Ive made assumed line thrust also line flight various forces effect possible thrust may forced some slight angle line flighthow great angle being extremely difficult determine However such difference can assumed inconsequential thrust line used reference base line sometimes referred datum line forces incidence angles center drag etc related might ask what happens downor up-thrust prescribed offset thrust lines can assume actual line flight will fall somewhere between actual thrust line what would offset plane tends fly along line thrust reaction between thrust aerodynamic forces result compromise between two observe effect offset thrust present simply tilt force arrangement diagram direction offset note relation various forces line flighta line will remain horizontal speaking line thrust note relates center resistance point assumed drag forces acting plane concentrated First note thrust line some angle line flight things like fuselage no longer parallel line flight thus increasing amount drag present importantly note moving line thrust away center resistance creates physical force can have effect aerodynamics example thrust line higher point resistance thrust will create nose-down coupling thrust line lower center resistance noseup moment will generated practical example could aerobatic design high thrust line could prove advantageous inverted flight Diagram No 1 depicts typical popular so-called zero-zero force arrangement symmetrical airfoils used note respect line flight neither wing nor stabilizer produces plus force drag negative force aerodynamic forces equalized Thus would seem line flight must something other design line actuality force must added tilts angle attack wing sufficient lift will generated could Conrinued page 38 Primer Aerodynamics Continued page 32 done thrust/resistance physical force spoke earlier event will note some force has used position wing tail lifting angles sustain level flight Otherwise should wing have semisymmetrical airfoil set same zero-incidence angle such airfoil does produce lift ball game different Effectively have wing positive lifting angle stab has symmetrical airfoil section zero lift flight wing lift would force stabilizer away zero creating positive stabilizer lift until some point equilibrium reached Thus would deviation design line flight Diagram No 2 depicts what might said original force arrangement models arrangement got Free flights flying purely academic standpoint thrust line line flight same Note have wing lifting angle stabilizer producing negative lift vely typical OT Free Flight obtain equilibrium gravity force CGcenter-of-gravity applied far enough forward wings center lift balances out tails negative lift Note longitudinal pivot forces wings center lift C/U case situation what could labeled constant speed arrangement stabilizer adjusted produce just enough negative lift some desired flying speed balance out pitch-down force created location CG being forward wings center lift Free Flight models desired combination speed attitude found glide mode Assuming objective flight FF model climb power glide power off trick becomes use just enough power upset established forces create desired climb getting stall loopwhich increased speed encountered during power-on portion flight would tend produce Developed FF considered safe arrangement because whenever speed increases beyond norm misproportion between wing tail lift will cause planes nose rise instead pitching down toward earth RC sometimes see arrangement used design speed full-bore power offering safety factor trainer types Obviously finding just right compromise between three forces wing lift tail lift CU involved always critical successful flight Diagram No3 relates diagram No 1 among other things shows objective No 1 can obtained greater efficiency No 3 carries aerodynamics further create what known neutral stability NS Simply put ability model fly desired attitude over wide speed range no nose-up -down reaction often said model NS goes point aerodynamics used involve striking proportion between wing tail lift will prevail over wide speed range Note case both wing tail producing positive lift visualize remember forces pivot models center lift C/L can wings C/L diagram No 2 aft CI case Understand both wing tail lifting models C/L resultant two forces mean C/L must fall aft wings C/L point total wing plus stabilizer lift applied So CU must located relative mean point wings CIL previous cases Note lift moment arm wing C/L tail CIL mean point Normally tail moment arm will roughly 12 times longer wings lever Thus two surfaces exert equal force mean point amount lift actually generated tail would far less wing due its much longer leverage allows tail size much smaller agreeable situation Over desired speed range wing exhibits definite changes its characteristics some intermediate speed specific amount lift drag produced Increase decrease speed lift/drag will change like manner such changes speed stabilizer responds manner exactly like wing have needed proportion continuing balance lift So can say line flight altered upward angle elevator control model will continue fly established angle same will occur downward angle will no inherent tendency nose up down same could expected should model bounced rough air gravity force constant fixed value regardless speed attitude So purely academic viewpoint could say straight level flight reduced power going full power would increase forward speed turn would increase lift causing model rise like elevator nosing up Likewise reducing power below cruise would cause similar elevator-like loss altitude no nose down Actually usually design models fly full power little normally seen such balance forces can have model follows design line U UUU . I. Ije Macfi tetbflv O49 REED VALVE ENGINE First introduced 1973 Black Widow powerful popular O 049 reed valve engine Its great types control line models including 1/2A Stunt Mouse Racing Beginner Combat Powered R/C Sailplanes too Widow precision built specially selected steel aluminum q P alloys tolerances measured millionths inch Cox Snap Stajtei provides easy no hassle starting The Black Widow recommended engine new 1/2A series Famous Fighters World War II Midwest Products available favorite Hobby Retailer now COX HOBBIES INC Corona CA 91720 OCOXHOBBIES INC. ISBI 38 Model Aviation 1 61 Im 6 him Im flight attitude over wide speed range say neutral stability NS has proven very desirable types RC models obviously must able control attitude order change direction Pointed toward heaven model NS might get thereor reach hell its pointed other direction Lets explain force diagram Both wing tail producing positive lift Note tail greater angle wing Scary Experience proves should reason being additional angle needed achieve proper lift balance having use oversize tail design speed total lift exactly cancels gravity force Note difference diagram No 1 resultant lift force has added mean lift point used design purposes No 1 CC located relation wings CIL Now CC must moved aft relate mean lift point same manner basic aerodynamics laws just used greater extent might assumed designing neutral stability could complex task considering necessity having exactly correct proportion between wing tail lift Experience over years designs has proven otherwise Fortunately practice has shown normal-size stabilizers having Success Series U-Control Kits respectable symmetrical airfoil adequate does help initial phase provide ability adjust stabilizers angle incidence achieve proper proportioning lift However given airfoils once successful relationship has determined will hold true over wide variety designs Give try will surprised pilot will sometimes say first flying neutrally stable model Boy model feels real solid really grooves flies rails thats actually very satisfying feeling model has no tendency wander goes last pointed until ask change direction likeable characteristic neutral stability As might expect shortcoming must maintain control times No self-recovery built arrangement other hand accomplished pilot such designs joy fly nothing ownonly what tell conclusion let hasten add discussion has hardly cracked ice aerodynamics design engineering However brief considerations applied wants will have much assurance reaching goals Foremost understand medium model airplane operates 10 TU$iieS 09 Midwests new Success Series 049 U-Control kits perfect introduction building flying Featuring illustrated step-by-step Success Series construction manuals teach build paint fly models Kits include Micro-Cut Quality parts pre-formed wire parts wheels belicrank colorful self adhesive markingsqp line Famous Fighters World War II designed use Cox Black Widow engine See products favorite hobby retailer todayl Famous Fighters World War II Models Available #258 Zero #259 Corsairshown #260 Thunderbolt #261 FockeWuif Midwest Products Co inc 400 S indiana St PO Box 564 HobartiN46342 2191942-1134 PAxl2I9l547-Z34701992 Midwest Productsco inc aerodynamics happenings will have much meaning Also like insurance policy make up force arrangement diagram showing what desire will have good indication what expect design Just compare force arrangement design another want delve further aerodynamics Its basic force arrangement proven good design makes excellent comparison thats unknown Whats good goose good gander bottom line could once have some experience fundamentals will find simple delve little deeper deeply wind up having understanding can lead designing own plane discussion has provided reader basic knowledge aerodynamics Interested modelers could now ask question Now know basics apply factors improve modeling answer will found Part II series Aerodynamic Primer-Trimmer coming soon Good luck CL Vintage Stunt Continued page 23 finest Bob Hunts Tucker Special Although plagued tank/engine problems newly finished model Im sure well see next year Other notables Cecil Meade Fan Dancer garnered Spirit 64 award Jim Levell gorgeous yellow Ares winner Concours award Larry Cunninghams Road Runner Greg Zajacks Patriot 59 Nostalgia entrants 47 made least official flight flights posted 500 pm stark testimony efficiency Cholla Choppers Carl Marshenki David Reynolds pits circle directors Walt Menges Bart Klapinski fliers came circles ready fly first met Bob Baron 57 AMA Nationals placed second Senior event continued success national international competition makes no surprise accident won Nostalgia event flying Netzeband designed Humbug Former Nationals winner Bob Whitely second flying stretched Continued page 40 September 1992 39 Beginners
Edition: Model Aviation - 1992/09
Page Numbers: 28, 29, 31, 32, 38, 39
A Primer Aerodynamics master model builder talks about airplanes fly tells us selector modify sound design U Harold deBolt 7~HE URGE produce aircraft own hits modelers sooner later ambitious goal would original design Something less might modification existing craft often evaluate someone elses creation help us own thinking about new design understand basic aerodynamics can perform desired task much intelligently profusion model designs available today person accomplished designer can draw upon what someone else has perfected acquire generalities what wishesand can attain some success result However evaluating concepteither own boffowed onewe can have assurance success understand very basics aerody naniics subject often cloudy us & 0 0000 0000 0 0 000 0 0 0 0000 0 jO 000000000o 00 00 0000 0 0000000000o~o0oo00 000 0 oOoooo~00000 0oooooOO006~ LNEOF-YLIHT00000000000000 0000000000000 0 00 0 0009 0000 000Co 000 0 0 0 00 00 O00Q0Ob0o0oDo0o0o0oO0C0O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Upper sketch upper curve airfoil displaces air molecules depicted little bubbles lower side planes air pressure differential creating lift Lower sketch streamlined symmetrical curves airfoil displace air molecules equally side no lift created objective short article enlighten reader about basics aerodynamics provide some tools can understand craft flies whether contemplated design sound idea take thoughts offered apply characteristics design question commence should understand definition aerodynamics laws govern aliflight Aero course refers air medium craft operates Dynamics refers resultant action created object moving through air aerodynamic laws formulated found air reacts distinct predictable ways shapes objects RESIS TA N C F S LIST LIFT LIFT GRAVFY LINEOF FLIGHT LIFT L[FT zero-zero incidence force arrangement shown climbing attitude angle gravity force acts opposes thrust force reducing aircrafts speed 28 Model Aviation author today replica first Free Flight design built 1938 moving through Using laws has enabled us design aircraft fly Investigators found airfoil shapes create lift streamlined shapes have minimum drag etc Experience helped create aerodynamic laws discovered various objects could have useful shapes arranged relation other produce flight day laws have become fundamental basic laws pertain aircraft Violate flight will suffer some extent So understand basics apply design may considering can assured flight Beyond basic design details simply enhance type flight objective desired points remember basic aerodynamics gospel air considered stationary flight created craft moving through Any respectable Engineer realizes must understand medium working before can commence effort Aero engineers work medium air necessary understand its characteristics People take air granted just However use some purpose other breathing sustain life such flight must understand its peculiarities Lets consider air engineers viewpoint First lets say substances mediums vary composition loosely knit dense solid solid Gas loosely knit fluid dense wood metals etc have varying amounts solidity Air being gas loosely knita medium easily displaced characteristic makes flight possible displacing air foundation aerodynamics Air composed molecules nitrogen oxygen could describe little balloons space between Thus displaced moving object molecules simply close up become closer together objects speed too great Molecule compression occurs object moves through air speed sound force created release compression hear sonic boom Thankfully model speeds low allowing us have consider displacement air molecules Another consideration because effects gravity air has varying densitymore dense sea level much less high altitude Again flights models low altitude latter condition normally ignored also important realize aircraft flight surrounded air effect air upon aircraft equal sides However say aerodynamic force effects equal sides Thus aerodynamic laws apply equally whether craft level flight vertical attitude flying inverted change forces acting THRUSTLIFT 0 RE SISTA N CE GRAVITYLIFT LI FT o LINE OF FLIGHT RESISTANCELIFT _THRUST JIEILINE OF FLIGHT\ LIFT ANGLE OF ATTACF GRAVITY Force Diagram 1 OOOO incidence force arrangement top forces balance except gravity negative Flight impossible until introduce force bottom tilt angles attack wing stab producing enough positive wing stab lift overcome gravity Flight now possible aircraft its attitude changes comes change direction gravity acting craft say aerodynamic forces neutralize gravity flight follows gravity will detract planes speed climbing attitude increase speed diving attitude power gravity detracts planes power climb attitude adds power dive gravity has no effect aerodynamics course gravity provides power moves glider-type machine through air thereby allowing aerodynamics create flight Such craft always flying downhill speak THRUST4 INCDLIFT RESISTANCEGRAVITY OF FLIGHT increase decrease addition aerodynamic forces vary linear fashion respect speed aircraft example lift drag increase square increases speed As result stability over large speed ranges desired important forces arranged proportionally other seems like should complex achieve relatively simple proper design also must understand airplanes configured Just explained makeup word aerodynamics LI FT 1 LIFT Force Diagram 2 classic force arrangement created successful model flight tails down force negative lift balanced very forward application gravity models center-of-gravity produce equilibrium particular flying speed Remember aerodynamic laws apply line offlight attitude plane respect horizon other factor same aerodynamic forces present plane vertical inverted attitude present planes flight level horizon force changes attitude gravity because becomes applied different angles aircraft force gravity itself does WING LIFT MEAN LIFT THRUSTI 1 I/2 LIKEOFFLIGHT RESISTANCEGRAVITY name craft itself offers clues plane literally surface say surface can plane medium boats bottom water example So can say airplane has surfaces plane aira simple description deep meaning Aircraft have various surfaces labeled airfoils Continued page 31 LIFT Force Diagram 3 modern force arrangement produces neutral stability maximum efficiency RC models proportionrepresented mean lift force established between wing tail lift CG now positioned relative mean center lift Line flight maintained over wide speed range September 1992 29 Primer Aerodynamics Continued page 29 term actually applies entire surface such wing rudder stabilizer canard etc importance fact surfaces used because produces force needed create maintain flight some surface aircraft creating force no value aerodynamically Surfaces horizontal plane labeled wings Thus normal monoplane configuration aircraft has two wings main forward surface aft stabilizing wing stabilizer short should also understand airfoil surface restrained some manner stable Simply put pick up such surface drop height few feet surface initially parallel ground will tend rotate about spanwise axis falls wing main support flight some other force must used restrain position angle attack contributes useful lift simplest way accomplish use force created second aft wing affect forward wings tendency rotate lock desired angle attack summation point flight surfaces including stabilizing surfaces aircraft work generating desirable forces Since should striving efficiency factor consider forces applied add efficiency offlight just stabilize some other surface apply considerations going discuss force arrangements simply diagrams depict way forces will act upon contemplated aircraft design can complex purposes simpler versions will give us light Important realize forces relative line offlight criterion reference material available use reasoning behind generalities force arrangements brief article purely academic example know thrust engine must applied particular point must wing tail distinct other Since brief discussion can assume whatever reference use supplied such details within realm aerodynamic laws What hope to show both some typical some unusual aircraft configurations what force arrangement depicts aircrafts attitude changes Someone said picture Continued poge 32 rxxxxxrxxxxxxxxxxxxxflxxxxxNNrxxxxnxxxNxJ ___ ___ _ -CHEAP SENSATION- P ARF FUN-FLY ur GENERIX TAMPA EL 33615t 54-KITSN4~ P0 BOX 262035 S M NOW AVAILABLE P 1/12 SCALE COMBATSPECS 69 $ P51 MUSTANG$49 Span44 ngine 2-40MEETSAMA RULES$7 S&HArea770 sq $7 5&H 59oosizo 301 5-32Engine28-40 xxxxxxxxxxxxtxrxxxxxxxtkxxxxxnxxxxxx now flight enhanced timing Ittablock option Ouadm aid Zonodi slow landings course easyengbu oniy-sdd$18 start slow 611*10 Mb bai retahiedStilt M-80 114 x 32 spalqiug.*10 REICHMUTH IGNITION featuresKMEe1l4xquig*13 llGIo-pIug end magneto replacernentii Electronic . .. Ft PM controled timing No moving parts break came looseitkde battery protectionPPU aid handtg$5 514-ceII nicad operationlintemai over-voltage Pro -COD add$5 tectionFflegulated power supply extended2nd day ak dd$3 flight timelB Screw driver easy Installation QuadrflandZerioawswithlNSlABLOCK exasstyieSaxengineswimmeuminge linked carburetor easily converted withonlyadritaDremeltoolandatap.. ot. Ask Original RiE LaunihEr & Pit ErewTM Local Hobby Shop Send $9995 5&H tCall TodayDealer Inquiries Welcome September 1992 31 fl/c Launcher & Pit Crew 5806 Lancelot Ct SW Olympia WA 98502 206 786-8461 THE BEST FLY WITH GENE BARTON Gene Barton now introduces new P51-B Mustang contest quality fo beg nne Sem K n cludes fiberglass parts fit elage oop cowl heliy pan foam cores supplied wing vertical horizon tal stabs Scale spun aluminum spinner machined hack plate canopy also included rolled set plans buy own balsa wood wing span 79 fly ing weight around 20 lbs designed around 25 35 cc engine Price 5395 Package price available retracts stints tires wheels Call write Gene Barton 11640 Salinas Garden Grove CA 92643 714 539-9142 FAX 714 539-9288 ANNIVERSARY ffiJ LII}Zzri 10th ANNIVERSARY JCLJTFIWEST\ first finest FLYDucted Fan Gathering NIin US! AMA SANCTIONED JPO SPONSORED Sept 11-12-13 1992 Lockhart Texas SASE full details Rick Schafer Custom Model Products 5321 Industrial Oaks Austin TX 78735 Phone 512-892-6908 WingDesigner0 N fli II IIIIIII LiIIIIActual program pint lr.lr & E w Headquarters Plum Creek Inn 512-398-4911 tnsured reservations August 15 EditFoilo EditFoil FEATURES Enter airfoil data join published tabisa Prints data table Modify correct surface enperfectiotta graphically on-screen. ModiPy chord thicltneaa ratio WlnDeslgw supplied 24 airfoils Plots sample l0 rib requires MlngDeslgner. programs written speczfically model aircraft design NOT modified general purpose CAD programs NfrwDesfrner FEATURES PUTER SYSTEM REOUIREMENTS 9Jlowsdlffereuil root rip airfoils Plots ALL transition ribsIBM 100% eampatible 286 386 486 CPU aplota ribs ALL spar slots coned size andpotttoii. Math co-processor desirable NOTrequired Plots ribs sheelinVGA SVGA COLOR graphics display tionJiail portiot length apsis 18 MaximumD05 version 31 higher Adds extraribs atibe endsofailerons flaps Rib #dIn nsegofhard diskspaor 512kb RAM Position up toS extra ribs / panel Rib 02 example3-112 floppy drive 5-1/4 diskette available LumtesJl.rdhoks esch rib building OCCUISCYEoI matrix 9 24 pin laser printer PRO version *USER FR lEWDLY GRAPHICAL INTERFACEcan output pen plotter HPOL fomiat COLOR *QUICK EASY LEARN TED TIME INTRODUCTORY PRICE *ACCURATR PROFESSIONAL RESULTSBittFoil$ 5995 ttlngDertner$ 7995 EtItFott.$l2995 *SEE YOUR DESIGN ON-SCREENtVIngDerIgnerPRO$12495 withEitrFoil.$16995 TI/1irrnVivhmv Add $350 Shipping & Handling Parcel Post C $100 #10 SASE information P0 Box 8367 Bartlett IL 601 03-4203 32 Model Aviation Cmon down Celebrate Primer Aerodynamics Continued page 31 worth thousand words hope sketches will provide some Concept situation diagrams Ive made assumed line thrust also line flight various forces effect possible thrust may forced some slight angle line flighthow great angle being extremely difficult determine However such difference can assumed inconsequential thrust line used reference base line sometimes referred datum line forces incidence angles center drag etc related might ask what happens downor up-thrust prescribed offset thrust lines can assume actual line flight will fall somewhere between actual thrust line what would offset plane tends fly along line thrust reaction between thrust aerodynamic forces result compromise between two observe effect offset thrust present simply tilt force arrangement diagram direction offset note relation various forces line flighta line will remain horizontal speaking line thrust note relates center resistance point assumed drag forces acting plane concentrated First note thrust line some angle line flight things like fuselage no longer parallel line flight thus increasing amount drag present importantly note moving line thrust away center resistance creates physical force can have effect aerodynamics example thrust line higher point resistance thrust will create nose-down coupling thrust line lower center resistance noseup moment will generated practical example could aerobatic design high thrust line could prove advantageous inverted flight Diagram No 1 depicts typical popular so-called zero-zero force arrangement symmetrical airfoils used note respect line flight neither wing nor stabilizer produces plus force drag negative force aerodynamic forces equalized Thus would seem line flight must something other design line actuality force must added tilts angle attack wing sufficient lift will generated could Conrinued page 38 Primer Aerodynamics Continued page 32 done thrust/resistance physical force spoke earlier event will note some force has used position wing tail lifting angles sustain level flight Otherwise should wing have semisymmetrical airfoil set same zero-incidence angle such airfoil does produce lift ball game different Effectively have wing positive lifting angle stab has symmetrical airfoil section zero lift flight wing lift would force stabilizer away zero creating positive stabilizer lift until some point equilibrium reached Thus would deviation design line flight Diagram No 2 depicts what might said original force arrangement models arrangement got Free flights flying purely academic standpoint thrust line line flight same Note have wing lifting angle stabilizer producing negative lift vely typical OT Free Flight obtain equilibrium gravity force CGcenter-of-gravity applied far enough forward wings center lift balances out tails negative lift Note longitudinal pivot forces wings center lift C/U case situation what could labeled constant speed arrangement stabilizer adjusted produce just enough negative lift some desired flying speed balance out pitch-down force created location CG being forward wings center lift Free Flight models desired combination speed attitude found glide mode Assuming objective flight FF model climb power glide power off trick becomes use just enough power upset established forces create desired climb getting stall loopwhich increased speed encountered during power-on portion flight would tend produce Developed FF considered safe arrangement because whenever speed increases beyond norm misproportion between wing tail lift will cause planes nose rise instead pitching down toward earth RC sometimes see arrangement used design speed full-bore power offering safety factor trainer types Obviously finding just right compromise between three forces wing lift tail lift CU involved always critical successful flight Diagram No3 relates diagram No 1 among other things shows objective No 1 can obtained greater efficiency No 3 carries aerodynamics further create what known neutral stability NS Simply put ability model fly desired attitude over wide speed range no nose-up -down reaction often said model NS goes point aerodynamics used involve striking proportion between wing tail lift will prevail over wide speed range Note case both wing tail producing positive lift visualize remember forces pivot models center lift C/L can wings C/L diagram No 2 aft CI case Understand both wing tail lifting models C/L resultant two forces mean C/L must fall aft wings C/L point total wing plus stabilizer lift applied So CU must located relative mean point wings CIL previous cases Note lift moment arm wing C/L tail CIL mean point Normally tail moment arm will roughly 12 times longer wings lever Thus two surfaces exert equal force mean point amount lift actually generated tail would far less wing due its much longer leverage allows tail size much smaller agreeable situation Over desired speed range wing exhibits definite changes its characteristics some intermediate speed specific amount lift drag produced Increase decrease speed lift/drag will change like manner such changes speed stabilizer responds manner exactly like wing have needed proportion continuing balance lift So can say line flight altered upward angle elevator control model will continue fly established angle same will occur downward angle will no inherent tendency nose up down same could expected should model bounced rough air gravity force constant fixed value regardless speed attitude So purely academic viewpoint could say straight level flight reduced power going full power would increase forward speed turn would increase lift causing model rise like elevator nosing up Likewise reducing power below cruise would cause similar elevator-like loss altitude no nose down Actually usually design models fly full power little normally seen such balance forces can have model follows design line U UUU . I. Ije Macfi tetbflv O49 REED VALVE ENGINE First introduced 1973 Black Widow powerful popular O 049 reed valve engine Its great types control line models including 1/2A Stunt Mouse Racing Beginner Combat Powered R/C Sailplanes too Widow precision built specially selected steel aluminum q P alloys tolerances measured millionths inch Cox Snap Stajtei provides easy no hassle starting The Black Widow recommended engine new 1/2A series Famous Fighters World War II Midwest Products available favorite Hobby Retailer now COX HOBBIES INC Corona CA 91720 OCOXHOBBIES INC. ISBI 38 Model Aviation 1 61 Im 6 him Im flight attitude over wide speed range say neutral stability NS has proven very desirable types RC models obviously must able control attitude order change direction Pointed toward heaven model NS might get thereor reach hell its pointed other direction Lets explain force diagram Both wing tail producing positive lift Note tail greater angle wing Scary Experience proves should reason being additional angle needed achieve proper lift balance having use oversize tail design speed total lift exactly cancels gravity force Note difference diagram No 1 resultant lift force has added mean lift point used design purposes No 1 CC located relation wings CIL Now CC must moved aft relate mean lift point same manner basic aerodynamics laws just used greater extent might assumed designing neutral stability could complex task considering necessity having exactly correct proportion between wing tail lift Experience over years designs has proven otherwise Fortunately practice has shown normal-size stabilizers having Success Series U-Control Kits respectable symmetrical airfoil adequate does help initial phase provide ability adjust stabilizers angle incidence achieve proper proportioning lift However given airfoils once successful relationship has determined will hold true over wide variety designs Give try will surprised pilot will sometimes say first flying neutrally stable model Boy model feels real solid really grooves flies rails thats actually very satisfying feeling model has no tendency wander goes last pointed until ask change direction likeable characteristic neutral stability As might expect shortcoming must maintain control times No self-recovery built arrangement other hand accomplished pilot such designs joy fly nothing ownonly what tell conclusion let hasten add discussion has hardly cracked ice aerodynamics design engineering However brief considerations applied wants will have much assurance reaching goals Foremost understand medium model airplane operates 10 TU$iieS 09 Midwests new Success Series 049 U-Control kits perfect introduction building flying Featuring illustrated step-by-step Success Series construction manuals teach build paint fly models Kits include Micro-Cut Quality parts pre-formed wire parts wheels belicrank colorful self adhesive markingsqp line Famous Fighters World War II designed use Cox Black Widow engine See products favorite hobby retailer todayl Famous Fighters World War II Models Available #258 Zero #259 Corsairshown #260 Thunderbolt #261 FockeWuif Midwest Products Co inc 400 S indiana St PO Box 564 HobartiN46342 2191942-1134 PAxl2I9l547-Z34701992 Midwest Productsco inc aerodynamics happenings will have much meaning Also like insurance policy make up force arrangement diagram showing what desire will have good indication what expect design Just compare force arrangement design another want delve further aerodynamics Its basic force arrangement proven good design makes excellent comparison thats unknown Whats good goose good gander bottom line could once have some experience fundamentals will find simple delve little deeper deeply wind up having understanding can lead designing own plane discussion has provided reader basic knowledge aerodynamics Interested modelers could now ask question Now know basics apply factors improve modeling answer will found Part II series Aerodynamic Primer-Trimmer coming soon Good luck CL Vintage Stunt Continued page 23 finest Bob Hunts Tucker Special Although plagued tank/engine problems newly finished model Im sure well see next year Other notables Cecil Meade Fan Dancer garnered Spirit 64 award Jim Levell gorgeous yellow Ares winner Concours award Larry Cunninghams Road Runner Greg Zajacks Patriot 59 Nostalgia entrants 47 made least official flight flights posted 500 pm stark testimony efficiency Cholla Choppers Carl Marshenki David Reynolds pits circle directors Walt Menges Bart Klapinski fliers came circles ready fly first met Bob Baron 57 AMA Nationals placed second Senior event continued success national international competition makes no surprise accident won Nostalgia event flying Netzeband designed Humbug Former Nationals winner Bob Whitely second flying stretched Continued page 40 September 1992 39 Beginners
Edition: Model Aviation - 1992/09
Page Numbers: 28, 29, 31, 32, 38, 39
A Primer Aerodynamics master model builder talks about airplanes fly tells us selector modify sound design U Harold deBolt 7~HE URGE produce aircraft own hits modelers sooner later ambitious goal would original design Something less might modification existing craft often evaluate someone elses creation help us own thinking about new design understand basic aerodynamics can perform desired task much intelligently profusion model designs available today person accomplished designer can draw upon what someone else has perfected acquire generalities what wishesand can attain some success result However evaluating concepteither own boffowed onewe can have assurance success understand very basics aerody naniics subject often cloudy us & 0 0000 0000 0 0 000 0 0 0 0000 0 jO 000000000o 00 00 0000 0 0000000000o~o0oo00 000 0 oOoooo~00000 0oooooOO006~ LNEOF-YLIHT00000000000000 0000000000000 0 00 0 0009 0000 000Co 000 0 0 0 00 00 O00Q0Ob0o0oDo0o0o0oO0C0O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Upper sketch upper curve airfoil displaces air molecules depicted little bubbles lower side planes air pressure differential creating lift Lower sketch streamlined symmetrical curves airfoil displace air molecules equally side no lift created objective short article enlighten reader about basics aerodynamics provide some tools can understand craft flies whether contemplated design sound idea take thoughts offered apply characteristics design question commence should understand definition aerodynamics laws govern aliflight Aero course refers air medium craft operates Dynamics refers resultant action created object moving through air aerodynamic laws formulated found air reacts distinct predictable ways shapes objects RESIS TA N C F S LIST LIFT LIFT GRAVFY LINEOF FLIGHT LIFT L[FT zero-zero incidence force arrangement shown climbing attitude angle gravity force acts opposes thrust force reducing aircrafts speed 28 Model Aviation author today replica first Free Flight design built 1938 moving through Using laws has enabled us design aircraft fly Investigators found airfoil shapes create lift streamlined shapes have minimum drag etc Experience helped create aerodynamic laws discovered various objects could have useful shapes arranged relation other produce flight day laws have become fundamental basic laws pertain aircraft Violate flight will suffer some extent So understand basics apply design may considering can assured flight Beyond basic design details simply enhance type flight objective desired points remember basic aerodynamics gospel air considered stationary flight created craft moving through Any respectable Engineer realizes must understand medium working before can commence effort Aero engineers work medium air necessary understand its characteristics People take air granted just However use some purpose other breathing sustain life such flight must understand its peculiarities Lets consider air engineers viewpoint First lets say substances mediums vary composition loosely knit dense solid solid Gas loosely knit fluid dense wood metals etc have varying amounts solidity Air being gas loosely knita medium easily displaced characteristic makes flight possible displacing air foundation aerodynamics Air composed molecules nitrogen oxygen could describe little balloons space between Thus displaced moving object molecules simply close up become closer together objects speed too great Molecule compression occurs object moves through air speed sound force created release compression hear sonic boom Thankfully model speeds low allowing us have consider displacement air molecules Another consideration because effects gravity air has varying densitymore dense sea level much less high altitude Again flights models low altitude latter condition normally ignored also important realize aircraft flight surrounded air effect air upon aircraft equal sides However say aerodynamic force effects equal sides Thus aerodynamic laws apply equally whether craft level flight vertical attitude flying inverted change forces acting THRUSTLIFT 0 RE SISTA N CE GRAVITYLIFT LI FT o LINE OF FLIGHT RESISTANCELIFT _THRUST JIEILINE OF FLIGHT\ LIFT ANGLE OF ATTACF GRAVITY Force Diagram 1 OOOO incidence force arrangement top forces balance except gravity negative Flight impossible until introduce force bottom tilt angles attack wing stab producing enough positive wing stab lift overcome gravity Flight now possible aircraft its attitude changes comes change direction gravity acting craft say aerodynamic forces neutralize gravity flight follows gravity will detract planes speed climbing attitude increase speed diving attitude power gravity detracts planes power climb attitude adds power dive gravity has no effect aerodynamics course gravity provides power moves glider-type machine through air thereby allowing aerodynamics create flight Such craft always flying downhill speak THRUST4 INCDLIFT RESISTANCEGRAVITY OF FLIGHT increase decrease addition aerodynamic forces vary linear fashion respect speed aircraft example lift drag increase square increases speed As result stability over large speed ranges desired important forces arranged proportionally other seems like should complex achieve relatively simple proper design also must understand airplanes configured Just explained makeup word aerodynamics LI FT 1 LIFT Force Diagram 2 classic force arrangement created successful model flight tails down force negative lift balanced very forward application gravity models center-of-gravity produce equilibrium particular flying speed Remember aerodynamic laws apply line offlight attitude plane respect horizon other factor same aerodynamic forces present plane vertical inverted attitude present planes flight level horizon force changes attitude gravity because becomes applied different angles aircraft force gravity itself does WING LIFT MEAN LIFT THRUSTI 1 I/2 LIKEOFFLIGHT RESISTANCEGRAVITY name craft itself offers clues plane literally surface say surface can plane medium boats bottom water example So can say airplane has surfaces plane aira simple description deep meaning Aircraft have various surfaces labeled airfoils Continued page 31 LIFT Force Diagram 3 modern force arrangement produces neutral stability maximum efficiency RC models proportionrepresented mean lift force established between wing tail lift CG now positioned relative mean center lift Line flight maintained over wide speed range September 1992 29 Primer Aerodynamics Continued page 29 term actually applies entire surface such wing rudder stabilizer canard etc importance fact surfaces used because produces force needed create maintain flight some surface aircraft creating force no value aerodynamically Surfaces horizontal plane labeled wings Thus normal monoplane configuration aircraft has two wings main forward surface aft stabilizing wing stabilizer short should also understand airfoil surface restrained some manner stable Simply put pick up such surface drop height few feet surface initially parallel ground will tend rotate about spanwise axis falls wing main support flight some other force must used restrain position angle attack contributes useful lift simplest way accomplish use force created second aft wing affect forward wings tendency rotate lock desired angle attack summation point flight surfaces including stabilizing surfaces aircraft work generating desirable forces Since should striving efficiency factor consider forces applied add efficiency offlight just stabilize some other surface apply considerations going discuss force arrangements simply diagrams depict way forces will act upon contemplated aircraft design can complex purposes simpler versions will give us light Important realize forces relative line offlight criterion reference material available use reasoning behind generalities force arrangements brief article purely academic example know thrust engine must applied particular point must wing tail distinct other Since brief discussion can assume whatever reference use supplied such details within realm aerodynamic laws What hope to show both some typical some unusual aircraft configurations what force arrangement depicts aircrafts attitude changes Someone said picture Continued poge 32 rxxxxxrxxxxxxxxxxxxxflxxxxxNNrxxxxnxxxNxJ ___ ___ _ -CHEAP SENSATION- P ARF FUN-FLY ur GENERIX TAMPA EL 33615t 54-KITSN4~ P0 BOX 262035 S M NOW AVAILABLE P 1/12 SCALE COMBATSPECS 69 $ P51 MUSTANG$49 Span44 ngine 2-40MEETSAMA RULES$7 S&HArea770 sq $7 5&H 59oosizo 301 5-32Engine28-40 xxxxxxxxxxxxtxrxxxxxxxtkxxxxxnxxxxxx now flight enhanced timing Ittablock option Ouadm aid Zonodi slow landings course easyengbu oniy-sdd$18 start slow 611*10 Mb bai retahiedStilt M-80 114 x 32 spalqiug.*10 REICHMUTH IGNITION featuresKMEe1l4xquig*13 llGIo-pIug end magneto replacernentii Electronic . .. Ft PM controled timing No moving parts break came looseitkde battery protectionPPU aid handtg$5 514-ceII nicad operationlintemai over-voltage Pro -COD add$5 tectionFflegulated power supply extended2nd day ak dd$3 flight timelB Screw driver easy Installation QuadrflandZerioawswithlNSlABLOCK exasstyieSaxengineswimmeuminge linked carburetor easily converted withonlyadritaDremeltoolandatap.. ot. Ask Original RiE LaunihEr & Pit ErewTM Local Hobby Shop Send $9995 5&H tCall TodayDealer Inquiries Welcome September 1992 31 fl/c Launcher & Pit Crew 5806 Lancelot Ct SW Olympia WA 98502 206 786-8461 THE BEST FLY WITH GENE BARTON Gene Barton now introduces new P51-B Mustang contest quality fo beg nne Sem K n cludes fiberglass parts fit elage oop cowl heliy pan foam cores supplied wing vertical horizon tal stabs Scale spun aluminum spinner machined hack plate canopy also included rolled set plans buy own balsa wood wing span 79 fly ing weight around 20 lbs designed around 25 35 cc engine Price 5395 Package price available retracts stints tires wheels Call write Gene Barton 11640 Salinas Garden Grove CA 92643 714 539-9142 FAX 714 539-9288 ANNIVERSARY ffiJ LII}Zzri 10th ANNIVERSARY JCLJTFIWEST\ first finest FLYDucted Fan Gathering NIin US! AMA SANCTIONED JPO SPONSORED Sept 11-12-13 1992 Lockhart Texas SASE full details Rick Schafer Custom Model Products 5321 Industrial Oaks Austin TX 78735 Phone 512-892-6908 WingDesigner0 N fli II IIIIIII LiIIIIActual program pint lr.lr & E w Headquarters Plum Creek Inn 512-398-4911 tnsured reservations August 15 EditFoilo EditFoil FEATURES Enter airfoil data join published tabisa Prints data table Modify correct surface enperfectiotta graphically on-screen. ModiPy chord thicltneaa ratio WlnDeslgw supplied 24 airfoils Plots sample l0 rib requires MlngDeslgner. programs written speczfically model aircraft design NOT modified general purpose CAD programs NfrwDesfrner FEATURES PUTER SYSTEM REOUIREMENTS 9Jlowsdlffereuil root rip airfoils Plots ALL transition ribsIBM 100% eampatible 286 386 486 CPU aplota ribs ALL spar slots coned size andpotttoii. Math co-processor desirable NOTrequired Plots ribs sheelinVGA SVGA COLOR graphics display tionJiail portiot length apsis 18 MaximumD05 version 31 higher Adds extraribs atibe endsofailerons flaps Rib #dIn nsegofhard diskspaor 512kb RAM Position up toS extra ribs / panel Rib 02 example3-112 floppy drive 5-1/4 diskette available LumtesJl.rdhoks esch rib building OCCUISCYEoI matrix 9 24 pin laser printer PRO version *USER FR lEWDLY GRAPHICAL INTERFACEcan output pen plotter HPOL fomiat COLOR *QUICK EASY LEARN TED TIME INTRODUCTORY PRICE *ACCURATR PROFESSIONAL RESULTSBittFoil$ 5995 ttlngDertner$ 7995 EtItFott.$l2995 *SEE YOUR DESIGN ON-SCREENtVIngDerIgnerPRO$12495 withEitrFoil.$16995 TI/1irrnVivhmv Add $350 Shipping & Handling Parcel Post C $100 #10 SASE information P0 Box 8367 Bartlett IL 601 03-4203 32 Model Aviation Cmon down Celebrate Primer Aerodynamics Continued page 31 worth thousand words hope sketches will provide some Concept situation diagrams Ive made assumed line thrust also line flight various forces effect possible thrust may forced some slight angle line flighthow great angle being extremely difficult determine However such difference can assumed inconsequential thrust line used reference base line sometimes referred datum line forces incidence angles center drag etc related might ask what happens downor up-thrust prescribed offset thrust lines can assume actual line flight will fall somewhere between actual thrust line what would offset plane tends fly along line thrust reaction between thrust aerodynamic forces result compromise between two observe effect offset thrust present simply tilt force arrangement diagram direction offset note relation various forces line flighta line will remain horizontal speaking line thrust note relates center resistance point assumed drag forces acting plane concentrated First note thrust line some angle line flight things like fuselage no longer parallel line flight thus increasing amount drag present importantly note moving line thrust away center resistance creates physical force can have effect aerodynamics example thrust line higher point resistance thrust will create nose-down coupling thrust line lower center resistance noseup moment will generated practical example could aerobatic design high thrust line could prove advantageous inverted flight Diagram No 1 depicts typical popular so-called zero-zero force arrangement symmetrical airfoils used note respect line flight neither wing nor stabilizer produces plus force drag negative force aerodynamic forces equalized Thus would seem line flight must something other design line actuality force must added tilts angle attack wing sufficient lift will generated could Conrinued page 38 Primer Aerodynamics Continued page 32 done thrust/resistance physical force spoke earlier event will note some force has used position wing tail lifting angles sustain level flight Otherwise should wing have semisymmetrical airfoil set same zero-incidence angle such airfoil does produce lift ball game different Effectively have wing positive lifting angle stab has symmetrical airfoil section zero lift flight wing lift would force stabilizer away zero creating positive stabilizer lift until some point equilibrium reached Thus would deviation design line flight Diagram No 2 depicts what might said original force arrangement models arrangement got Free flights flying purely academic standpoint thrust line line flight same Note have wing lifting angle stabilizer producing negative lift vely typical OT Free Flight obtain equilibrium gravity force CGcenter-of-gravity applied far enough forward wings center lift balances out tails negative lift Note longitudinal pivot forces wings center lift C/U case situation what could labeled constant speed arrangement stabilizer adjusted produce just enough negative lift some desired flying speed balance out pitch-down force created location CG being forward wings center lift Free Flight models desired combination speed attitude found glide mode Assuming objective flight FF model climb power glide power off trick becomes use just enough power upset established forces create desired climb getting stall loopwhich increased speed encountered during power-on portion flight would tend produce Developed FF considered safe arrangement because whenever speed increases beyond norm misproportion between wing tail lift will cause planes nose rise instead pitching down toward earth RC sometimes see arrangement used design speed full-bore power offering safety factor trainer types Obviously finding just right compromise between three forces wing lift tail lift CU involved always critical successful flight Diagram No3 relates diagram No 1 among other things shows objective No 1 can obtained greater efficiency No 3 carries aerodynamics further create what known neutral stability NS Simply put ability model fly desired attitude over wide speed range no nose-up -down reaction often said model NS goes point aerodynamics used involve striking proportion between wing tail lift will prevail over wide speed range Note case both wing tail producing positive lift visualize remember forces pivot models center lift C/L can wings C/L diagram No 2 aft CI case Understand both wing tail lifting models C/L resultant two forces mean C/L must fall aft wings C/L point total wing plus stabilizer lift applied So CU must located relative mean point wings CIL previous cases Note lift moment arm wing C/L tail CIL mean point Normally tail moment arm will roughly 12 times longer wings lever Thus two surfaces exert equal force mean point amount lift actually generated tail would far less wing due its much longer leverage allows tail size much smaller agreeable situation Over desired speed range wing exhibits definite changes its characteristics some intermediate speed specific amount lift drag produced Increase decrease speed lift/drag will change like manner such changes speed stabilizer responds manner exactly like wing have needed proportion continuing balance lift So can say line flight altered upward angle elevator control model will continue fly established angle same will occur downward angle will no inherent tendency nose up down same could expected should model bounced rough air gravity force constant fixed value regardless speed attitude So purely academic viewpoint could say straight level flight reduced power going full power would increase forward speed turn would increase lift causing model rise like elevator nosing up Likewise reducing power below cruise would cause similar elevator-like loss altitude no nose down Actually usually design models fly full power little normally seen such balance forces can have model follows design line U UUU . 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ISBI 38 Model Aviation 1 61 Im 6 him Im flight attitude over wide speed range say neutral stability NS has proven very desirable types RC models obviously must able control attitude order change direction Pointed toward heaven model NS might get thereor reach hell its pointed other direction Lets explain force diagram Both wing tail producing positive lift Note tail greater angle wing Scary Experience proves should reason being additional angle needed achieve proper lift balance having use oversize tail design speed total lift exactly cancels gravity force Note difference diagram No 1 resultant lift force has added mean lift point used design purposes No 1 CC located relation wings CIL Now CC must moved aft relate mean lift point same manner basic aerodynamics laws just used greater extent might assumed designing neutral stability could complex task considering necessity having exactly correct proportion between wing tail lift Experience over years designs has proven otherwise Fortunately practice has shown normal-size stabilizers having Success Series U-Control Kits respectable symmetrical airfoil adequate does help initial phase provide ability adjust stabilizers angle incidence achieve proper proportioning lift However given airfoils once successful relationship has determined will hold true over wide variety designs Give try will surprised pilot will sometimes say first flying neutrally stable model Boy model feels real solid really grooves flies rails thats actually very satisfying feeling model has no tendency wander goes last pointed until ask change direction likeable characteristic neutral stability As might expect shortcoming must maintain control times No self-recovery built arrangement other hand accomplished pilot such designs joy fly nothing ownonly what tell conclusion let hasten add discussion has hardly cracked ice aerodynamics design engineering However brief considerations applied wants will have much assurance reaching goals Foremost understand medium model airplane operates 10 TU$iieS 09 Midwests new Success Series 049 U-Control kits perfect introduction building flying Featuring illustrated step-by-step Success Series construction manuals teach build paint fly models Kits include Micro-Cut Quality parts pre-formed wire parts wheels belicrank colorful self adhesive markingsqp line Famous Fighters World War II designed use Cox Black Widow engine See products favorite hobby retailer todayl Famous Fighters World War II Models Available #258 Zero #259 Corsairshown #260 Thunderbolt #261 FockeWuif Midwest Products Co inc 400 S indiana St PO Box 564 HobartiN46342 2191942-1134 PAxl2I9l547-Z34701992 Midwest Productsco inc aerodynamics happenings will have much meaning Also like insurance policy make up force arrangement diagram showing what desire will have good indication what expect design Just compare force arrangement design another want delve further aerodynamics Its basic force arrangement proven good design makes excellent comparison thats unknown Whats good goose good gander bottom line could once have some experience fundamentals will find simple delve little deeper deeply wind up having understanding can lead designing own plane discussion has provided reader basic knowledge aerodynamics Interested modelers could now ask question Now know basics apply factors improve modeling answer will found Part II series Aerodynamic Primer-Trimmer coming soon Good luck CL Vintage Stunt Continued page 23 finest Bob Hunts Tucker Special Although plagued tank/engine problems newly finished model Im sure well see next year Other notables Cecil Meade Fan Dancer garnered Spirit 64 award Jim Levell gorgeous yellow Ares winner Concours award Larry Cunninghams Road Runner Greg Zajacks Patriot 59 Nostalgia entrants 47 made least official flight flights posted 500 pm stark testimony efficiency Cholla Choppers Carl Marshenki David Reynolds pits circle directors Walt Menges Bart Klapinski fliers came circles ready fly first met Bob Baron 57 AMA Nationals placed second Senior event continued success national international competition makes no surprise accident won Nostalgia event flying Netzeband designed Humbug Former Nationals winner Bob Whitely second flying stretched Continued page 40 September 1992 39 Beginners