Control Line SPEED Gene Hem pet MANY times have asked feedback modelers conceming some type information Speed column month con tinued next column want share letter Mr Jerry Rautio has spent enormous amount time drafting letter retired Plant Engineer General Electric has developed interest propulsion sys tems models subject will propeller design matching engine power pro peller reference book Mr Rautios article Aircraft Propeller Design Fred Weick am writing thank publishing two interesting magazine columns recent memory specifically Charlie Liebers Fly FA Speed July September 1982 issues ModelAviation say despite fact am CL flier Its because appreci ate logical approach youve taken designing winning Speed airplane interest design propulsion sys 09 na 07 06 05 tems competition models especially Formula Pylon Racers own satisfaction have made comparative study FAI CL Speed airplane using own methods design thought might find something interest study am taking liberty enclos ing work letter pleasantly surprised calculate thrust hp required called drag hp 1230 compared 1134 attribute difference between two difficulty calculating exact drag variation due skewing two control lines r-factor rules permitted line spacing diameter parallel flight r-factor would 04 method calculating line THP elegant calcu lus does give clear picture line drag has reduced article assumed engine output 14 bhp 35000 rpm 165 mph calculated fur ther power would insufficient assumed propeller efficiency 81% would true very low tip-speeds condi tion have High tip-speeds have devas tating effect efficiency power requirement data necessary designing propeller thrust hp required rated maximum bhp rpm engine speed model relative air density designing speed 165 mph 170 mph have found thrust hp required assume standard sealevel air density can obtain vital engine information way testing engine/pipe assembly torque-stand out lined articles 'The Whatley Torque Stand Sport Aviation January 1983 Cla rence Lees Engine Clinic RCM June 1981 strobe would required accurate revcounting Since present have required torque-stand information forced cal culate required bhp propeller design performance assuming did maxi mum power occurs exactly 35000 rpm must employ NACA propeller charts showing curves efficiency V/nd ID 2-Blade ThhIfl-___ D eterAF 93/hIu e P h R us bchord -- h kness activity factor3-mild h/hAll 756/ lade 04 ----- ------..-- -------------H Blade Angle O3R propeller tip 03 02 I12345676910 f/H column next devoted propeller design chart will used example design problems relates prop blade width thickness 2- 3-bladed props coefficient effective pitch advance per rev plotted against C, speed-power coefficient series propellers varying pitch pitch propellers terms blade angle section 075 x blade tip-radius re lationship P/D tr tan 13 lled speed-power coefficient because contains rotational forward speeds power ab sorbed propeller engineering units three essential formulas written I C x mph x 615 bhp5 X rpm25 2Prop Dia 1056 X mph rpm x J 3 Prop Pitch X X D X tan130 e b relative density ea level J V velocity ft/sec nprop revolutions/sec D diam ft tan ent functon blade angle blade angle deg 075 x blade radius Note mph rpm must same 2 establish correct C, bhp J sev eral trials necessary ie 14 17 19 bhp until THPa see below C established can read following propeller chart 130 75 J fl, have now cal culated correct bhp propeller diameter pitch inches applying efficiency correction high tip-speed below critical propeller efficiency have calculated thrust horsepower available THPa design airspeed THPa Also thrust lb available Ta lb total static thrust V n calculated engine torque static rpm can read engine curves estimating torque see below propeller blade section width thickness distributions chart designs blade form sections modified Clark Y blade angles along propeller radius can calculated equation given chart Five examples follow Example 1 Given conditions 2-bladed propeller 14 bhp available 35000 rpm 165 mph clean airplane Liebers text February 1982 edition Hempels CL Speed column having thrust horsepower required THPr Problem Determine 14 bhp sufficient obtain 165 mph model Calculate Speed-Power Coefficient C C _ 0638 x mph x bhp25 x rpm5 0638 x _________________ charts C 130 75 21lJ i, C Cq 855 zero airspeed Calculate propeller diameter D XV _ 056 x 165 N X J 35000 x 0795 Calculate propeller pitch Pitch x x D x tan135 75 075 X 62 X tan 2110 inContinued page 168 70 Model Aviation h/h h/fl Prepeller Blade Width & Thickness Dutrihutien 40 36 3228 year future sites dates will recom mended approved even-numbered years Send C/L Scale items Bill Boss 77-06 269th World Championships held use Street New Hyde Park NY 11040 following odd-numbered years will team-selection years Editors note Bill Boss say subject time since wrote column AMA President John Grigg has approved NASA proposal So 1984 Scale Team Selec tion Finals both CL RC will held E P Sawyer State Park Louisville KY August 12-14 1983 See item dealing pro gram Competition Newslettr section issue RMcM Contest news 12th Annual Northwest Re gional Control Line Championships will held Mahlon Sweet Airport Eugene OR May 28-29 1983 Memorial Day weekend meet sponsored Eugene Prop Spinners Club Over $2000 merchandise prizes will offered addition trophies first three places 26 Control Line events being offered Among events will two Scale modelersa Profile Scale event AMA Scale flyer did state whether Precision Sport details about contest contact Dave Green-CD 200 W Franklin Ave As toria OR 97103 Telephone 503 325-7005 N )2J112 60 11467 x 1652 62 12 35 000 2j 1/2 60 987 ft/sec K Efficiency correction tip speed Propulsive efficiency maximum speed K x 0 0759 x 0800 Thrust horsepower available THPa x 714 x 0607 0850 165 mph Note less thrust horsepower required model 165 mph 1134 Pitch-to-diameter ratio P/D Prop tip speed 11476 V2 2 Thrust available Ta x 375 0850 x 375 mph165 1932 lb 165 mph Conclusion power insufficient 165 mph Liebers clean system calculated THPr Example 2 Given conditions 3-bladed propeller 1134 thp required 165 mph 35000 rpm same THP used Example Problem Calculate engine bhp required design propeller furnish required thrust horsepower conditions Calculate Speed-Power Coefficient C x mph x b5 bhp5 X rpm215 0638 x 165 X l 1573 19x07x350002/5 charts C J 0807, C zero airspeed C4 Calculate propeller diameter D x V — 1056 x 165 N x J35000 x 0807 6169 3-blade Calculate propeller pitch Pitch x ir x D x tan j35 i 075 x r x 6169 x tan 213 5667 Pitch-to-diameter ratio P/D Prop tip speed [I 467V2 2 N )2]112 60 [1467 x 165 6169 12 x 350002]/2 60 ft/sec K Efficiency correction tip speed 0770 Propulsive efficiency maximum speed K x 71 x 0776 5 Thrust horsepower available THP x 17 05975 165 mph Note actually solved bhp since efficiency thrust horsepower available inputs equation BE LEADER Join NATIONAL FREE FLIGHT SOCIETY help develop thresh old low speed aeronautical tech nology NFFS AMA special interest group promotes scien tific nature model aeronautics yearly publishes SYMPOSIUM volume 10 issues NFFS DIGEST AGRESSIVE parti cipate THINKING group Checks Payable MFFS HAL WOODS JR SR/OP 707 Second St 1 YR 750 1500 Davis CA 95616 2 YR 1350 2700 168 Model Aviation CL Speed/Hempel Continued page 70 IN STOCK FOR IMMEDIATE SHIPMENT New 30 CID QUADRA $22450 New 22 CID QUADRA *10950 Reg 22 QUADRA $10450 Brisighella Flywheel$1245O Reg 22 QUADRA POWER ASSEMBLY ONLY$6450 QUADRA REPAIR 000 pIus parts Jin Masse ERCOUPEPLANS $2396 KIT $22995 Jim Messer TOMAHAWKPLANS $2390 KIT $24995 Jim Messer 8BALL TRAINER PLANS $1896 KIT $9996 BALSA BASSWOOD sizesl 35% OFF Concept FLEET PLANS $2996 KIT $17995 COWL $1996 P&W RADIAL ENGINES Fleet $2296 VICKERS LEWIS MACHINE GUN KITS $1496 CECONITE Products 10% OFF Sig J3 CUB KIT $12996 PLANS SUPER STEARMAN V Godfreyl $2800 STARDUSTER TOO V. IBrisighellal V J-3 CUB Nelit $1996 VOLKEPLANE V Chicken Cherliel $2396 COCKPIT KITS Tomahawk F4U-1 Spitfire $2195 Ercoupe $1996 Stearman $2295 Citebria $2096 J3Cub $1995 ME109 $2150 Fleet $2096 US Quadra FUELTANKSlEoz $e96 32oz $796 FIBERGLASS ARROW SHAFTS 5116 x22 long 6$1000 24-Hour Service. Add $250 postage Send Bank Check Money Order JIM MESSERS QUALITY MODEL PRODUCTS 106 Valley View Dr Allegany NY 14706 _____________ 2579 lb 165 mph Estimated performance zero airspeed RPM 085 x RPM,a x 35000 0 Prop tip speed 1260 tT6169 29750 1260 800 ft/sec K Efficiency correction tip speed RPM Q engine torque RPM BHP x5250 x 1085 RPMa 19 x 5250 x 1085 35000 03092 ft-lb Prop dia 12 051408 ft 12 Static thrustT 9 \CiXK DC5 03092 x 845 x 0885 051408 4498lb Note Q estimated static rpm torque real design work read exact torque BHP/torque curve actual engine Conclusion Engine must produce 9 bhp 35000rpm airspeed 165 mph prop 3-bladed diameter 6169 pitch 5667 pitch 75R point must 2130 airfoil modified Clark Y Blade activity factor 756 P/D similar manner three examples done Example 3 case 2bladed prop turning 35000 rpm de livering 1134 thrust horsepower 165 mph As preceding two examples propel ler factors calculated dis covered engine brake horsepower available 21 needed give desired level performance interest note prop has calculated diameter pitch 6895 5865 respec tively tip speed 1080 ft/sec design speed resulted tip-speed efficiency-correction factor 0687 69% ef ficient turn gave propulsive effici ency 0540 looks like going right direction horsepower required keeps going up fourth example used 3-bladed prop 35000 rpm delivering 1230 thrust horse power 165 mphthe value used Lieber average model came out required bhp 21 agaln prop have diameter 6301 m pitch 56 99 prop tip speed 818 ftIsec propulsive efficiency greater preceding example fifth example wanted 2-bladed prop under same rpm airspeed thrust horsepower conditions fourth ex ample prop turned out 709 1 diameter pitch 5801 tip BUILD WITH THE FINEST IN RC COVERING MATERIALS CECONITE RC FABRIC Heat shrinkable up 100/0 Will over lighten Attached dope Apply direction Fill weave dope 66 inch width Clear Very strong 1 8 oz/so yd 1 yd length 1 83 sq ydl $695 3 yd length 549 act yd $1995 5 yd length 916 yd 95 FILLER COAT Waler base paint replaces coals clear dope Apply 1 2 coals loam rubber brush Dries 30 minutes 1 qt covers 75sq ft Fuel proof gas glow Use over Ceco nile other fabrics Protects fabric sun Apoly type color paint over Filler Goat Pint $895 Quart $1695 SUPER SEAM Lacquer base glue Used standard model building cement Also extra slrengthwhen applying Geconite Other fabrics Clear color Sands easily dries quickly Quart $995 ORDER DIRECT OR AT HOBBY SHOP MASTER CARD VISA accepted USA add $300 postage tax Nevada orders Add $200 COD Send $1 00 information Jerry Nelson & Company Post Oflice Box 12863 Reno Nevada 89510 702-322-0664 May1983 169 Thrust available THP x 375 mph 1135 x 375 — 165 speed back up again because creased diameter Therefore propulsive efficiency down again resulting need engine power output 239 bhp very doubtful could ever get kind performance out 15 cu engine What really trying show interrelation between number blades prop amount thrust trying get constant values rpm airspeed Note chief enemy high tip speed propthe propulsive ef ficiency gets lots lower tip speeds get up around 1000 ft/sec Also evident fact weve got have clean model have hope getting high speeds power available 15 discussion will continued next column Gene Hempel 301 N Yale Dr Garland TX 75042 CL Racing/Ballard Continued page 71 subsejiber support contributions Picture qual ity excellent Ads planned limited materials interest Control Line smaller suppliers Computer-filed supplier lists member ship lists like will available Full-sized plans will available models published Copies technical reports etc planned future availability selected hard-to-get spe cialty supplies etc Frankly experiment see Control Line really dead way some people say dont think Write support Coalition concept refuse believe Control Line gone sample copy 37g stamp & envelope subscriptioni $15/yr Laird Jackson 2322 Wil son Ave Bristol PA 19007 Editors note subscription price persons aged 19 years older plus residents foreign countries Persons age 18 younger can subscribe $750/year Both subscription rates include 50 NCLC membership fee RMcM received copy Flying Lines excellent Northwestern newsletter published Mike Hazel 1411 Bryant Ave Cottage Grove OR 97424 particular newsletter virtually full con test results random building tips flea market items soapbox opinionated modelers Mike also periodically has rating system Northwestern Iliers rates contest performance throughout year newsletter certainly gives observation competitors doing Northwest area provides some interesting reading Racing competitors John Ballard 10102 Kimblewick Dr Louis ville KY 40223 Lii Pieces/Randolph Continued page 74 two tissue tubes airplane completed method wing mounting makes possible adjust incidence well remove wing storage Incidentally airplane another just like will fit shoe box ease Cover surfaces tissue glue stick sold stationery stores school supply sections other stores makes good adhesive tissue glue stick easy clean use doesnt wet tissue structure After covering rudder stab glue stab place above rudder boom left tip about /2 higher right seen back helps airplane circle left Cover wing center first glue tips place proper dihedral glue has set cover tips Cut two wing posts balsa dowel front longer back shown plan glue wtng /2 right center Looking front bottom forward post should slanted slightly left centeror towards right wing posts inserted tubes will cause some washin left wing leading edge higher trailing edge Cut propeller blades 1/32 sheet Drill carve piece 3/32 sq balsa shown plans form hub glue blades place should right angles other 450 angle shaft Bend shaft 1/32-in wire glue prop hub Slip small glass bead over shaft insert shaft front bearing rotate little until slips rear bearing Place loop rublr motor stick prop/stab/rudder assemblage find center balance looping thread around motor stick moving fore aft until balance point found Mark spot Cut two tissue tubes /4-in length piece balsa dowel dont crush Glue motor stick front tube should 11/4 ward mark aft 2 behind first sure straight up down flat against motor stick airplane now complete best rubber motor airplane/ prop combination 10- 12-in loop 040 x 043-in FAI Rubber isnt available loop three #16 rubberbands together thats skinny kind comes wrapped around newspaper Lubricate rubber motor little Armor-All stretch out about five times its length hold minute two stretching will break rubber make possible wind few extra turns Slip wing posts tissue tubes way bottom Install rubber motor wind about 100 turns launch model should have sort powered glide rather tight flat circle no sign stall model dives raise front wing post tube stalls raise aft post correct rubber motor can best wound unhooking rear hook attach ing geared winder stretching rubber out about three times its length pack ing turns winder moved back original length motor newspaper rubberbands will take about 800 turns good contest rubber about 1500 Beamed ceilings arent good flat smooth ones let Lil Pieces gather lot cobwebs Thrill/Younger Continued paqe 75 best ways introduce boys girls modeling teach class build fly Delta Dart simple almost fool-proof novice builder can build hour can buy inexpensively large quantities Complete instructions included kit have helped teach about 30 classes can assure piece cake modeler cati classes taught can 170 Model Aviation
Edition: Model Aviation - 1983/05
Page Numbers: 70, 168, 169, 170
Control Line SPEED Gene Hem pet MANY times have asked feedback modelers conceming some type information Speed column month con tinued next column want share letter Mr Jerry Rautio has spent enormous amount time drafting letter retired Plant Engineer General Electric has developed interest propulsion sys tems models subject will propeller design matching engine power pro peller reference book Mr Rautios article Aircraft Propeller Design Fred Weick am writing thank publishing two interesting magazine columns recent memory specifically Charlie Liebers Fly FA Speed July September 1982 issues ModelAviation say despite fact am CL flier Its because appreci ate logical approach youve taken designing winning Speed airplane interest design propulsion sys 09 na 07 06 05 tems competition models especially Formula Pylon Racers own satisfaction have made comparative study FAI CL Speed airplane using own methods design thought might find something interest study am taking liberty enclos ing work letter pleasantly surprised calculate thrust hp required called drag hp 1230 compared 1134 attribute difference between two difficulty calculating exact drag variation due skewing two control lines r-factor rules permitted line spacing diameter parallel flight r-factor would 04 method calculating line THP elegant calcu lus does give clear picture line drag has reduced article assumed engine output 14 bhp 35000 rpm 165 mph calculated fur ther power would insufficient assumed propeller efficiency 81% would true very low tip-speeds condi tion have High tip-speeds have devas tating effect efficiency power requirement data necessary designing propeller thrust hp required rated maximum bhp rpm engine speed model relative air density designing speed 165 mph 170 mph have found thrust hp required assume standard sealevel air density can obtain vital engine information way testing engine/pipe assembly torque-stand out lined articles 'The Whatley Torque Stand Sport Aviation January 1983 Cla rence Lees Engine Clinic RCM June 1981 strobe would required accurate revcounting Since present have required torque-stand information forced cal culate required bhp propeller design performance assuming did maxi mum power occurs exactly 35000 rpm must employ NACA propeller charts showing curves efficiency V/nd ID 2-Blade ThhIfl-___ D eterAF 93/hIu e P h R us bchord -- h kness activity factor3-mild h/hAll 756/ lade 04 ----- ------..-- -------------H Blade Angle O3R propeller tip 03 02 I12345676910 f/H column next devoted propeller design chart will used example design problems relates prop blade width thickness 2- 3-bladed props coefficient effective pitch advance per rev plotted against C, speed-power coefficient series propellers varying pitch pitch propellers terms blade angle section 075 x blade tip-radius re lationship P/D tr tan 13 lled speed-power coefficient because contains rotational forward speeds power ab sorbed propeller engineering units three essential formulas written I C x mph x 615 bhp5 X rpm25 2Prop Dia 1056 X mph rpm x J 3 Prop Pitch X X D X tan130 e b relative density ea level J V velocity ft/sec nprop revolutions/sec D diam ft tan ent functon blade angle blade angle deg 075 x blade radius Note mph rpm must same 2 establish correct C, bhp J sev eral trials necessary ie 14 17 19 bhp until THPa see below C established can read following propeller chart 130 75 J fl, have now cal culated correct bhp propeller diameter pitch inches applying efficiency correction high tip-speed below critical propeller efficiency have calculated thrust horsepower available THPa design airspeed THPa Also thrust lb available Ta lb total static thrust V n calculated engine torque static rpm can read engine curves estimating torque see below propeller blade section width thickness distributions chart designs blade form sections modified Clark Y blade angles along propeller radius can calculated equation given chart Five examples follow Example 1 Given conditions 2-bladed propeller 14 bhp available 35000 rpm 165 mph clean airplane Liebers text February 1982 edition Hempels CL Speed column having thrust horsepower required THPr Problem Determine 14 bhp sufficient obtain 165 mph model Calculate Speed-Power Coefficient C C _ 0638 x mph x bhp25 x rpm5 0638 x _________________ charts C 130 75 21lJ i, C Cq 855 zero airspeed Calculate propeller diameter D XV _ 056 x 165 N X J 35000 x 0795 Calculate propeller pitch Pitch x x D x tan135 75 075 X 62 X tan 2110 inContinued page 168 70 Model Aviation h/h h/fl Prepeller Blade Width & Thickness Dutrihutien 40 36 3228 year future sites dates will recom mended approved even-numbered years Send C/L Scale items Bill Boss 77-06 269th World Championships held use Street New Hyde Park NY 11040 following odd-numbered years will team-selection years Editors note Bill Boss say subject time since wrote column AMA President John Grigg has approved NASA proposal So 1984 Scale Team Selec tion Finals both CL RC will held E P Sawyer State Park Louisville KY August 12-14 1983 See item dealing pro gram Competition Newslettr section issue RMcM Contest news 12th Annual Northwest Re gional Control Line Championships will held Mahlon Sweet Airport Eugene OR May 28-29 1983 Memorial Day weekend meet sponsored Eugene Prop Spinners Club Over $2000 merchandise prizes will offered addition trophies first three places 26 Control Line events being offered Among events will two Scale modelersa Profile Scale event AMA Scale flyer did state whether Precision Sport details about contest contact Dave Green-CD 200 W Franklin Ave As toria OR 97103 Telephone 503 325-7005 N )2J112 60 11467 x 1652 62 12 35 000 2j 1/2 60 987 ft/sec K Efficiency correction tip speed Propulsive efficiency maximum speed K x 0 0759 x 0800 Thrust horsepower available THPa x 714 x 0607 0850 165 mph Note less thrust horsepower required model 165 mph 1134 Pitch-to-diameter ratio P/D Prop tip speed 11476 V2 2 Thrust available Ta x 375 0850 x 375 mph165 1932 lb 165 mph Conclusion power insufficient 165 mph Liebers clean system calculated THPr Example 2 Given conditions 3-bladed propeller 1134 thp required 165 mph 35000 rpm same THP used Example Problem Calculate engine bhp required design propeller furnish required thrust horsepower conditions Calculate Speed-Power Coefficient C x mph x b5 bhp5 X rpm215 0638 x 165 X l 1573 19x07x350002/5 charts C J 0807, C zero airspeed C4 Calculate propeller diameter D x V — 1056 x 165 N x J35000 x 0807 6169 3-blade Calculate propeller pitch Pitch x ir x D x tan j35 i 075 x r x 6169 x tan 213 5667 Pitch-to-diameter ratio P/D Prop tip speed [I 467V2 2 N )2]112 60 [1467 x 165 6169 12 x 350002]/2 60 ft/sec K Efficiency correction tip speed 0770 Propulsive efficiency maximum speed K x 71 x 0776 5 Thrust horsepower available THP x 17 05975 165 mph Note actually solved bhp since efficiency thrust horsepower available inputs equation BE LEADER Join NATIONAL FREE FLIGHT SOCIETY help develop thresh old low speed aeronautical tech nology NFFS AMA special interest group promotes scien tific nature model aeronautics yearly publishes SYMPOSIUM volume 10 issues NFFS DIGEST AGRESSIVE parti cipate THINKING group Checks Payable MFFS HAL WOODS JR SR/OP 707 Second St 1 YR 750 1500 Davis CA 95616 2 YR 1350 2700 168 Model Aviation CL Speed/Hempel Continued page 70 IN STOCK FOR IMMEDIATE SHIPMENT New 30 CID QUADRA $22450 New 22 CID QUADRA *10950 Reg 22 QUADRA $10450 Brisighella Flywheel$1245O Reg 22 QUADRA POWER ASSEMBLY ONLY$6450 QUADRA REPAIR 000 pIus parts Jin Masse ERCOUPEPLANS $2396 KIT $22995 Jim Messer TOMAHAWKPLANS $2390 KIT $24995 Jim Messer 8BALL TRAINER PLANS $1896 KIT $9996 BALSA BASSWOOD sizesl 35% OFF Concept FLEET PLANS $2996 KIT $17995 COWL $1996 P&W RADIAL ENGINES Fleet $2296 VICKERS LEWIS MACHINE GUN KITS $1496 CECONITE Products 10% OFF Sig J3 CUB KIT $12996 PLANS SUPER STEARMAN V Godfreyl $2800 STARDUSTER TOO V. IBrisighellal V J-3 CUB Nelit $1996 VOLKEPLANE V Chicken Cherliel $2396 COCKPIT KITS Tomahawk F4U-1 Spitfire $2195 Ercoupe $1996 Stearman $2295 Citebria $2096 J3Cub $1995 ME109 $2150 Fleet $2096 US Quadra FUELTANKSlEoz $e96 32oz $796 FIBERGLASS ARROW SHAFTS 5116 x22 long 6$1000 24-Hour Service. Add $250 postage Send Bank Check Money Order JIM MESSERS QUALITY MODEL PRODUCTS 106 Valley View Dr Allegany NY 14706 _____________ 2579 lb 165 mph Estimated performance zero airspeed RPM 085 x RPM,a x 35000 0 Prop tip speed 1260 tT6169 29750 1260 800 ft/sec K Efficiency correction tip speed RPM Q engine torque RPM BHP x5250 x 1085 RPMa 19 x 5250 x 1085 35000 03092 ft-lb Prop dia 12 051408 ft 12 Static thrustT 9 \CiXK DC5 03092 x 845 x 0885 051408 4498lb Note Q estimated static rpm torque real design work read exact torque BHP/torque curve actual engine Conclusion Engine must produce 9 bhp 35000rpm airspeed 165 mph prop 3-bladed diameter 6169 pitch 5667 pitch 75R point must 2130 airfoil modified Clark Y Blade activity factor 756 P/D similar manner three examples done Example 3 case 2bladed prop turning 35000 rpm de livering 1134 thrust horsepower 165 mph As preceding two examples propel ler factors calculated dis covered engine brake horsepower available 21 needed give desired level performance interest note prop has calculated diameter pitch 6895 5865 respec tively tip speed 1080 ft/sec design speed resulted tip-speed efficiency-correction factor 0687 69% ef ficient turn gave propulsive effici ency 0540 looks like going right direction horsepower required keeps going up fourth example used 3-bladed prop 35000 rpm delivering 1230 thrust horse power 165 mphthe value used Lieber average model came out required bhp 21 agaln prop have diameter 6301 m pitch 56 99 prop tip speed 818 ftIsec propulsive efficiency greater preceding example fifth example wanted 2-bladed prop under same rpm airspeed thrust horsepower conditions fourth ex ample prop turned out 709 1 diameter pitch 5801 tip BUILD WITH THE FINEST IN RC COVERING MATERIALS CECONITE RC FABRIC Heat shrinkable up 100/0 Will over lighten Attached dope Apply direction Fill weave dope 66 inch width Clear Very strong 1 8 oz/so yd 1 yd length 1 83 sq ydl $695 3 yd length 549 act yd $1995 5 yd length 916 yd 95 FILLER COAT Waler base paint replaces coals clear dope Apply 1 2 coals loam rubber brush Dries 30 minutes 1 qt covers 75sq ft Fuel proof gas glow Use over Ceco nile other fabrics Protects fabric sun Apoly type color paint over Filler Goat Pint $895 Quart $1695 SUPER SEAM Lacquer base glue Used standard model building cement Also extra slrengthwhen applying Geconite Other fabrics Clear color Sands easily dries quickly Quart $995 ORDER DIRECT OR AT HOBBY SHOP MASTER CARD VISA accepted USA add $300 postage tax Nevada orders Add $200 COD Send $1 00 information Jerry Nelson & Company Post Oflice Box 12863 Reno Nevada 89510 702-322-0664 May1983 169 Thrust available THP x 375 mph 1135 x 375 — 165 speed back up again because creased diameter Therefore propulsive efficiency down again resulting need engine power output 239 bhp very doubtful could ever get kind performance out 15 cu engine What really trying show interrelation between number blades prop amount thrust trying get constant values rpm airspeed Note chief enemy high tip speed propthe propulsive ef ficiency gets lots lower tip speeds get up around 1000 ft/sec Also evident fact weve got have clean model have hope getting high speeds power available 15 discussion will continued next column Gene Hempel 301 N Yale Dr Garland TX 75042 CL Racing/Ballard Continued page 71 subsejiber support contributions Picture qual ity excellent Ads planned limited materials interest Control Line smaller suppliers Computer-filed supplier lists member ship lists like will available Full-sized plans will available models published Copies technical reports etc planned future availability selected hard-to-get spe cialty supplies etc Frankly experiment see Control Line really dead way some people say dont think Write support Coalition concept refuse believe Control Line gone sample copy 37g stamp & envelope subscriptioni $15/yr Laird Jackson 2322 Wil son Ave Bristol PA 19007 Editors note subscription price persons aged 19 years older plus residents foreign countries Persons age 18 younger can subscribe $750/year Both subscription rates include 50 NCLC membership fee RMcM received copy Flying Lines excellent Northwestern newsletter published Mike Hazel 1411 Bryant Ave Cottage Grove OR 97424 particular newsletter virtually full con test results random building tips flea market items soapbox opinionated modelers Mike also periodically has rating system Northwestern Iliers rates contest performance throughout year newsletter certainly gives observation competitors doing Northwest area provides some interesting reading Racing competitors John Ballard 10102 Kimblewick Dr Louis ville KY 40223 Lii Pieces/Randolph Continued page 74 two tissue tubes airplane completed method wing mounting makes possible adjust incidence well remove wing storage Incidentally airplane another just like will fit shoe box ease Cover surfaces tissue glue stick sold stationery stores school supply sections other stores makes good adhesive tissue glue stick easy clean use doesnt wet tissue structure After covering rudder stab glue stab place above rudder boom left tip about /2 higher right seen back helps airplane circle left Cover wing center first glue tips place proper dihedral glue has set cover tips Cut two wing posts balsa dowel front longer back shown plan glue wtng /2 right center Looking front bottom forward post should slanted slightly left centeror towards right wing posts inserted tubes will cause some washin left wing leading edge higher trailing edge Cut propeller blades 1/32 sheet Drill carve piece 3/32 sq balsa shown plans form hub glue blades place should right angles other 450 angle shaft Bend shaft 1/32-in wire glue prop hub Slip small glass bead over shaft insert shaft front bearing rotate little until slips rear bearing Place loop rublr motor stick prop/stab/rudder assemblage find center balance looping thread around motor stick moving fore aft until balance point found Mark spot Cut two tissue tubes /4-in length piece balsa dowel dont crush Glue motor stick front tube should 11/4 ward mark aft 2 behind first sure straight up down flat against motor stick airplane now complete best rubber motor airplane/ prop combination 10- 12-in loop 040 x 043-in FAI Rubber isnt available loop three #16 rubberbands together thats skinny kind comes wrapped around newspaper Lubricate rubber motor little Armor-All stretch out about five times its length hold minute two stretching will break rubber make possible wind few extra turns Slip wing posts tissue tubes way bottom Install rubber motor wind about 100 turns launch model should have sort powered glide rather tight flat circle no sign stall model dives raise front wing post tube stalls raise aft post correct rubber motor can best wound unhooking rear hook attach ing geared winder stretching rubber out about three times its length pack ing turns winder moved back original length motor newspaper rubberbands will take about 800 turns good contest rubber about 1500 Beamed ceilings arent good flat smooth ones let Lil Pieces gather lot cobwebs Thrill/Younger Continued paqe 75 best ways introduce boys girls modeling teach class build fly Delta Dart simple almost fool-proof novice builder can build hour can buy inexpensively large quantities Complete instructions included kit have helped teach about 30 classes can assure piece cake modeler cati classes taught can 170 Model Aviation
Edition: Model Aviation - 1983/05
Page Numbers: 70, 168, 169, 170
Control Line SPEED Gene Hem pet MANY times have asked feedback modelers conceming some type information Speed column month con tinued next column want share letter Mr Jerry Rautio has spent enormous amount time drafting letter retired Plant Engineer General Electric has developed interest propulsion sys tems models subject will propeller design matching engine power pro peller reference book Mr Rautios article Aircraft Propeller Design Fred Weick am writing thank publishing two interesting magazine columns recent memory specifically Charlie Liebers Fly FA Speed July September 1982 issues ModelAviation say despite fact am CL flier Its because appreci ate logical approach youve taken designing winning Speed airplane interest design propulsion sys 09 na 07 06 05 tems competition models especially Formula Pylon Racers own satisfaction have made comparative study FAI CL Speed airplane using own methods design thought might find something interest study am taking liberty enclos ing work letter pleasantly surprised calculate thrust hp required called drag hp 1230 compared 1134 attribute difference between two difficulty calculating exact drag variation due skewing two control lines r-factor rules permitted line spacing diameter parallel flight r-factor would 04 method calculating line THP elegant calcu lus does give clear picture line drag has reduced article assumed engine output 14 bhp 35000 rpm 165 mph calculated fur ther power would insufficient assumed propeller efficiency 81% would true very low tip-speeds condi tion have High tip-speeds have devas tating effect efficiency power requirement data necessary designing propeller thrust hp required rated maximum bhp rpm engine speed model relative air density designing speed 165 mph 170 mph have found thrust hp required assume standard sealevel air density can obtain vital engine information way testing engine/pipe assembly torque-stand out lined articles 'The Whatley Torque Stand Sport Aviation January 1983 Cla rence Lees Engine Clinic RCM June 1981 strobe would required accurate revcounting Since present have required torque-stand information forced cal culate required bhp propeller design performance assuming did maxi mum power occurs exactly 35000 rpm must employ NACA propeller charts showing curves efficiency V/nd ID 2-Blade ThhIfl-___ D eterAF 93/hIu e P h R us bchord -- h kness activity factor3-mild h/hAll 756/ lade 04 ----- ------..-- -------------H Blade Angle O3R propeller tip 03 02 I12345676910 f/H column next devoted propeller design chart will used example design problems relates prop blade width thickness 2- 3-bladed props coefficient effective pitch advance per rev plotted against C, speed-power coefficient series propellers varying pitch pitch propellers terms blade angle section 075 x blade tip-radius re lationship P/D tr tan 13 lled speed-power coefficient because contains rotational forward speeds power ab sorbed propeller engineering units three essential formulas written I C x mph x 615 bhp5 X rpm25 2Prop Dia 1056 X mph rpm x J 3 Prop Pitch X X D X tan130 e b relative density ea level J V velocity ft/sec nprop revolutions/sec D diam ft tan ent functon blade angle blade angle deg 075 x blade radius Note mph rpm must same 2 establish correct C, bhp J sev eral trials necessary ie 14 17 19 bhp until THPa see below C established can read following propeller chart 130 75 J fl, have now cal culated correct bhp propeller diameter pitch inches applying efficiency correction high tip-speed below critical propeller efficiency have calculated thrust horsepower available THPa design airspeed THPa Also thrust lb available Ta lb total static thrust V n calculated engine torque static rpm can read engine curves estimating torque see below propeller blade section width thickness distributions chart designs blade form sections modified Clark Y blade angles along propeller radius can calculated equation given chart Five examples follow Example 1 Given conditions 2-bladed propeller 14 bhp available 35000 rpm 165 mph clean airplane Liebers text February 1982 edition Hempels CL Speed column having thrust horsepower required THPr Problem Determine 14 bhp sufficient obtain 165 mph model Calculate Speed-Power Coefficient C C _ 0638 x mph x bhp25 x rpm5 0638 x _________________ charts C 130 75 21lJ i, C Cq 855 zero airspeed Calculate propeller diameter D XV _ 056 x 165 N X J 35000 x 0795 Calculate propeller pitch Pitch x x D x tan135 75 075 X 62 X tan 2110 inContinued page 168 70 Model Aviation h/h h/fl Prepeller Blade Width & Thickness Dutrihutien 40 36 3228 year future sites dates will recom mended approved even-numbered years Send C/L Scale items Bill Boss 77-06 269th World Championships held use Street New Hyde Park NY 11040 following odd-numbered years will team-selection years Editors note Bill Boss say subject time since wrote column AMA President John Grigg has approved NASA proposal So 1984 Scale Team Selec tion Finals both CL RC will held E P Sawyer State Park Louisville KY August 12-14 1983 See item dealing pro gram Competition Newslettr section issue RMcM Contest news 12th Annual Northwest Re gional Control Line Championships will held Mahlon Sweet Airport Eugene OR May 28-29 1983 Memorial Day weekend meet sponsored Eugene Prop Spinners Club Over $2000 merchandise prizes will offered addition trophies first three places 26 Control Line events being offered Among events will two Scale modelersa Profile Scale event AMA Scale flyer did state whether Precision Sport details about contest contact Dave Green-CD 200 W Franklin Ave As toria OR 97103 Telephone 503 325-7005 N )2J112 60 11467 x 1652 62 12 35 000 2j 1/2 60 987 ft/sec K Efficiency correction tip speed Propulsive efficiency maximum speed K x 0 0759 x 0800 Thrust horsepower available THPa x 714 x 0607 0850 165 mph Note less thrust horsepower required model 165 mph 1134 Pitch-to-diameter ratio P/D Prop tip speed 11476 V2 2 Thrust available Ta x 375 0850 x 375 mph165 1932 lb 165 mph Conclusion power insufficient 165 mph Liebers clean system calculated THPr Example 2 Given conditions 3-bladed propeller 1134 thp required 165 mph 35000 rpm same THP used Example Problem Calculate engine bhp required design propeller furnish required thrust horsepower conditions Calculate Speed-Power Coefficient C x mph x b5 bhp5 X rpm215 0638 x 165 X l 1573 19x07x350002/5 charts C J 0807, C zero airspeed C4 Calculate propeller diameter D x V — 1056 x 165 N x J35000 x 0807 6169 3-blade Calculate propeller pitch Pitch x ir x D x tan j35 i 075 x r x 6169 x tan 213 5667 Pitch-to-diameter ratio P/D Prop tip speed [I 467V2 2 N )2]112 60 [1467 x 165 6169 12 x 350002]/2 60 ft/sec K Efficiency correction tip speed 0770 Propulsive efficiency maximum speed K x 71 x 0776 5 Thrust horsepower available THP x 17 05975 165 mph Note actually solved bhp since efficiency thrust horsepower available inputs equation BE LEADER Join NATIONAL FREE FLIGHT SOCIETY help develop thresh old low speed aeronautical tech nology NFFS AMA special interest group promotes scien tific nature model aeronautics yearly publishes SYMPOSIUM volume 10 issues NFFS DIGEST AGRESSIVE parti cipate THINKING group Checks Payable MFFS HAL WOODS JR SR/OP 707 Second St 1 YR 750 1500 Davis CA 95616 2 YR 1350 2700 168 Model Aviation CL Speed/Hempel Continued page 70 IN STOCK FOR IMMEDIATE SHIPMENT New 30 CID QUADRA $22450 New 22 CID QUADRA *10950 Reg 22 QUADRA $10450 Brisighella Flywheel$1245O Reg 22 QUADRA POWER ASSEMBLY ONLY$6450 QUADRA REPAIR 000 pIus parts Jin Masse ERCOUPEPLANS $2396 KIT $22995 Jim Messer TOMAHAWKPLANS $2390 KIT $24995 Jim Messer 8BALL TRAINER PLANS $1896 KIT $9996 BALSA BASSWOOD sizesl 35% OFF Concept FLEET PLANS $2996 KIT $17995 COWL $1996 P&W RADIAL ENGINES Fleet $2296 VICKERS LEWIS MACHINE GUN KITS $1496 CECONITE Products 10% OFF Sig J3 CUB KIT $12996 PLANS SUPER STEARMAN V Godfreyl $2800 STARDUSTER TOO V. IBrisighellal V J-3 CUB Nelit $1996 VOLKEPLANE V Chicken Cherliel $2396 COCKPIT KITS Tomahawk F4U-1 Spitfire $2195 Ercoupe $1996 Stearman $2295 Citebria $2096 J3Cub $1995 ME109 $2150 Fleet $2096 US Quadra FUELTANKSlEoz $e96 32oz $796 FIBERGLASS ARROW SHAFTS 5116 x22 long 6$1000 24-Hour Service. Add $250 postage Send Bank Check Money Order JIM MESSERS QUALITY MODEL PRODUCTS 106 Valley View Dr Allegany NY 14706 _____________ 2579 lb 165 mph Estimated performance zero airspeed RPM 085 x RPM,a x 35000 0 Prop tip speed 1260 tT6169 29750 1260 800 ft/sec K Efficiency correction tip speed RPM Q engine torque RPM BHP x5250 x 1085 RPMa 19 x 5250 x 1085 35000 03092 ft-lb Prop dia 12 051408 ft 12 Static thrustT 9 \CiXK DC5 03092 x 845 x 0885 051408 4498lb Note Q estimated static rpm torque real design work read exact torque BHP/torque curve actual engine Conclusion Engine must produce 9 bhp 35000rpm airspeed 165 mph prop 3-bladed diameter 6169 pitch 5667 pitch 75R point must 2130 airfoil modified Clark Y Blade activity factor 756 P/D similar manner three examples done Example 3 case 2bladed prop turning 35000 rpm de livering 1134 thrust horsepower 165 mph As preceding two examples propel ler factors calculated dis covered engine brake horsepower available 21 needed give desired level performance interest note prop has calculated diameter pitch 6895 5865 respec tively tip speed 1080 ft/sec design speed resulted tip-speed efficiency-correction factor 0687 69% ef ficient turn gave propulsive effici ency 0540 looks like going right direction horsepower required keeps going up fourth example used 3-bladed prop 35000 rpm delivering 1230 thrust horse power 165 mphthe value used Lieber average model came out required bhp 21 agaln prop have diameter 6301 m pitch 56 99 prop tip speed 818 ftIsec propulsive efficiency greater preceding example fifth example wanted 2-bladed prop under same rpm airspeed thrust horsepower conditions fourth ex ample prop turned out 709 1 diameter pitch 5801 tip BUILD WITH THE FINEST IN RC COVERING MATERIALS CECONITE RC FABRIC Heat shrinkable up 100/0 Will over lighten Attached dope Apply direction Fill weave dope 66 inch width Clear Very strong 1 8 oz/so yd 1 yd length 1 83 sq ydl $695 3 yd length 549 act yd $1995 5 yd length 916 yd 95 FILLER COAT Waler base paint replaces coals clear dope Apply 1 2 coals loam rubber brush Dries 30 minutes 1 qt covers 75sq ft Fuel proof gas glow Use over Ceco nile other fabrics Protects fabric sun Apoly type color paint over Filler Goat Pint $895 Quart $1695 SUPER SEAM Lacquer base glue Used standard model building cement Also extra slrengthwhen applying Geconite Other fabrics Clear color Sands easily dries quickly Quart $995 ORDER DIRECT OR AT HOBBY SHOP MASTER CARD VISA accepted USA add $300 postage tax Nevada orders Add $200 COD Send $1 00 information Jerry Nelson & Company Post Oflice Box 12863 Reno Nevada 89510 702-322-0664 May1983 169 Thrust available THP x 375 mph 1135 x 375 — 165 speed back up again because creased diameter Therefore propulsive efficiency down again resulting need engine power output 239 bhp very doubtful could ever get kind performance out 15 cu engine What really trying show interrelation between number blades prop amount thrust trying get constant values rpm airspeed Note chief enemy high tip speed propthe propulsive ef ficiency gets lots lower tip speeds get up around 1000 ft/sec Also evident fact weve got have clean model have hope getting high speeds power available 15 discussion will continued next column Gene Hempel 301 N Yale Dr Garland TX 75042 CL Racing/Ballard Continued page 71 subsejiber support contributions Picture qual ity excellent Ads planned limited materials interest Control Line smaller suppliers Computer-filed supplier lists member ship lists like will available Full-sized plans will available models published Copies technical reports etc planned future availability selected hard-to-get spe cialty supplies etc Frankly experiment see Control Line really dead way some people say dont think Write support Coalition concept refuse believe Control Line gone sample copy 37g stamp & envelope subscriptioni $15/yr Laird Jackson 2322 Wil son Ave Bristol PA 19007 Editors note subscription price persons aged 19 years older plus residents foreign countries Persons age 18 younger can subscribe $750/year Both subscription rates include 50 NCLC membership fee RMcM received copy Flying Lines excellent Northwestern newsletter published Mike Hazel 1411 Bryant Ave Cottage Grove OR 97424 particular newsletter virtually full con test results random building tips flea market items soapbox opinionated modelers Mike also periodically has rating system Northwestern Iliers rates contest performance throughout year newsletter certainly gives observation competitors doing Northwest area provides some interesting reading Racing competitors John Ballard 10102 Kimblewick Dr Louis ville KY 40223 Lii Pieces/Randolph Continued page 74 two tissue tubes airplane completed method wing mounting makes possible adjust incidence well remove wing storage Incidentally airplane another just like will fit shoe box ease Cover surfaces tissue glue stick sold stationery stores school supply sections other stores makes good adhesive tissue glue stick easy clean use doesnt wet tissue structure After covering rudder stab glue stab place above rudder boom left tip about /2 higher right seen back helps airplane circle left Cover wing center first glue tips place proper dihedral glue has set cover tips Cut two wing posts balsa dowel front longer back shown plan glue wtng /2 right center Looking front bottom forward post should slanted slightly left centeror towards right wing posts inserted tubes will cause some washin left wing leading edge higher trailing edge Cut propeller blades 1/32 sheet Drill carve piece 3/32 sq balsa shown plans form hub glue blades place should right angles other 450 angle shaft Bend shaft 1/32-in wire glue prop hub Slip small glass bead over shaft insert shaft front bearing rotate little until slips rear bearing Place loop rublr motor stick prop/stab/rudder assemblage find center balance looping thread around motor stick moving fore aft until balance point found Mark spot Cut two tissue tubes /4-in length piece balsa dowel dont crush Glue motor stick front tube should 11/4 ward mark aft 2 behind first sure straight up down flat against motor stick airplane now complete best rubber motor airplane/ prop combination 10- 12-in loop 040 x 043-in FAI Rubber isnt available loop three #16 rubberbands together thats skinny kind comes wrapped around newspaper Lubricate rubber motor little Armor-All stretch out about five times its length hold minute two stretching will break rubber make possible wind few extra turns Slip wing posts tissue tubes way bottom Install rubber motor wind about 100 turns launch model should have sort powered glide rather tight flat circle no sign stall model dives raise front wing post tube stalls raise aft post correct rubber motor can best wound unhooking rear hook attach ing geared winder stretching rubber out about three times its length pack ing turns winder moved back original length motor newspaper rubberbands will take about 800 turns good contest rubber about 1500 Beamed ceilings arent good flat smooth ones let Lil Pieces gather lot cobwebs Thrill/Younger Continued paqe 75 best ways introduce boys girls modeling teach class build fly Delta Dart simple almost fool-proof novice builder can build hour can buy inexpensively large quantities Complete instructions included kit have helped teach about 30 classes can assure piece cake modeler cati classes taught can 170 Model Aviation
Edition: Model Aviation - 1983/05
Page Numbers: 70, 168, 169, 170
Control Line SPEED Gene Hem pet MANY times have asked feedback modelers conceming some type information Speed column month con tinued next column want share letter Mr Jerry Rautio has spent enormous amount time drafting letter retired Plant Engineer General Electric has developed interest propulsion sys tems models subject will propeller design matching engine power pro peller reference book Mr Rautios article Aircraft Propeller Design Fred Weick am writing thank publishing two interesting magazine columns recent memory specifically Charlie Liebers Fly FA Speed July September 1982 issues ModelAviation say despite fact am CL flier Its because appreci ate logical approach youve taken designing winning Speed airplane interest design propulsion sys 09 na 07 06 05 tems competition models especially Formula Pylon Racers own satisfaction have made comparative study FAI CL Speed airplane using own methods design thought might find something interest study am taking liberty enclos ing work letter pleasantly surprised calculate thrust hp required called drag hp 1230 compared 1134 attribute difference between two difficulty calculating exact drag variation due skewing two control lines r-factor rules permitted line spacing diameter parallel flight r-factor would 04 method calculating line THP elegant calcu lus does give clear picture line drag has reduced article assumed engine output 14 bhp 35000 rpm 165 mph calculated fur ther power would insufficient assumed propeller efficiency 81% would true very low tip-speeds condi tion have High tip-speeds have devas tating effect efficiency power requirement data necessary designing propeller thrust hp required rated maximum bhp rpm engine speed model relative air density designing speed 165 mph 170 mph have found thrust hp required assume standard sealevel air density can obtain vital engine information way testing engine/pipe assembly torque-stand out lined articles 'The Whatley Torque Stand Sport Aviation January 1983 Cla rence Lees Engine Clinic RCM June 1981 strobe would required accurate revcounting Since present have required torque-stand information forced cal culate required bhp propeller design performance assuming did maxi mum power occurs exactly 35000 rpm must employ NACA propeller charts showing curves efficiency V/nd ID 2-Blade ThhIfl-___ D eterAF 93/hIu e P h R us bchord -- h kness activity factor3-mild h/hAll 756/ lade 04 ----- ------..-- -------------H Blade Angle O3R propeller tip 03 02 I12345676910 f/H column next devoted propeller design chart will used example design problems relates prop blade width thickness 2- 3-bladed props coefficient effective pitch advance per rev plotted against C, speed-power coefficient series propellers varying pitch pitch propellers terms blade angle section 075 x blade tip-radius re lationship P/D tr tan 13 lled speed-power coefficient because contains rotational forward speeds power ab sorbed propeller engineering units three essential formulas written I C x mph x 615 bhp5 X rpm25 2Prop Dia 1056 X mph rpm x J 3 Prop Pitch X X D X tan130 e b relative density ea level J V velocity ft/sec nprop revolutions/sec D diam ft tan ent functon blade angle blade angle deg 075 x blade radius Note mph rpm must same 2 establish correct C, bhp J sev eral trials necessary ie 14 17 19 bhp until THPa see below C established can read following propeller chart 130 75 J fl, have now cal culated correct bhp propeller diameter pitch inches applying efficiency correction high tip-speed below critical propeller efficiency have calculated thrust horsepower available THPa design airspeed THPa Also thrust lb available Ta lb total static thrust V n calculated engine torque static rpm can read engine curves estimating torque see below propeller blade section width thickness distributions chart designs blade form sections modified Clark Y blade angles along propeller radius can calculated equation given chart Five examples follow Example 1 Given conditions 2-bladed propeller 14 bhp available 35000 rpm 165 mph clean airplane Liebers text February 1982 edition Hempels CL Speed column having thrust horsepower required THPr Problem Determine 14 bhp sufficient obtain 165 mph model Calculate Speed-Power Coefficient C C _ 0638 x mph x bhp25 x rpm5 0638 x _________________ charts C 130 75 21lJ i, C Cq 855 zero airspeed Calculate propeller diameter D XV _ 056 x 165 N X J 35000 x 0795 Calculate propeller pitch Pitch x x D x tan135 75 075 X 62 X tan 2110 inContinued page 168 70 Model Aviation h/h h/fl Prepeller Blade Width & Thickness Dutrihutien 40 36 3228 year future sites dates will recom mended approved even-numbered years Send C/L Scale items Bill Boss 77-06 269th World Championships held use Street New Hyde Park NY 11040 following odd-numbered years will team-selection years Editors note Bill Boss say subject time since wrote column AMA President John Grigg has approved NASA proposal So 1984 Scale Team Selec tion Finals both CL RC will held E P Sawyer State Park Louisville KY August 12-14 1983 See item dealing pro gram Competition Newslettr section issue RMcM Contest news 12th Annual Northwest Re gional Control Line Championships will held Mahlon Sweet Airport Eugene OR May 28-29 1983 Memorial Day weekend meet sponsored Eugene Prop Spinners Club Over $2000 merchandise prizes will offered addition trophies first three places 26 Control Line events being offered Among events will two Scale modelersa Profile Scale event AMA Scale flyer did state whether Precision Sport details about contest contact Dave Green-CD 200 W Franklin Ave As toria OR 97103 Telephone 503 325-7005 N )2J112 60 11467 x 1652 62 12 35 000 2j 1/2 60 987 ft/sec K Efficiency correction tip speed Propulsive efficiency maximum speed K x 0 0759 x 0800 Thrust horsepower available THPa x 714 x 0607 0850 165 mph Note less thrust horsepower required model 165 mph 1134 Pitch-to-diameter ratio P/D Prop tip speed 11476 V2 2 Thrust available Ta x 375 0850 x 375 mph165 1932 lb 165 mph Conclusion power insufficient 165 mph Liebers clean system calculated THPr Example 2 Given conditions 3-bladed propeller 1134 thp required 165 mph 35000 rpm same THP used Example Problem Calculate engine bhp required design propeller furnish required thrust horsepower conditions Calculate Speed-Power Coefficient C x mph x b5 bhp5 X rpm215 0638 x 165 X l 1573 19x07x350002/5 charts C J 0807, C zero airspeed C4 Calculate propeller diameter D x V — 1056 x 165 N x J35000 x 0807 6169 3-blade Calculate propeller pitch Pitch x ir x D x tan j35 i 075 x r x 6169 x tan 213 5667 Pitch-to-diameter ratio P/D Prop tip speed [I 467V2 2 N )2]112 60 [1467 x 165 6169 12 x 350002]/2 60 ft/sec K Efficiency correction tip speed 0770 Propulsive efficiency maximum speed K x 71 x 0776 5 Thrust horsepower available THP x 17 05975 165 mph Note actually solved bhp since efficiency thrust horsepower available inputs equation BE LEADER Join NATIONAL FREE FLIGHT SOCIETY help develop thresh old low speed aeronautical tech nology NFFS AMA special interest group promotes scien tific nature model aeronautics yearly publishes SYMPOSIUM volume 10 issues NFFS DIGEST AGRESSIVE parti cipate THINKING group Checks Payable MFFS HAL WOODS JR SR/OP 707 Second St 1 YR 750 1500 Davis CA 95616 2 YR 1350 2700 168 Model Aviation CL Speed/Hempel Continued page 70 IN STOCK FOR IMMEDIATE SHIPMENT New 30 CID QUADRA $22450 New 22 CID QUADRA *10950 Reg 22 QUADRA $10450 Brisighella Flywheel$1245O Reg 22 QUADRA POWER ASSEMBLY ONLY$6450 QUADRA REPAIR 000 pIus parts Jin Masse ERCOUPEPLANS $2396 KIT $22995 Jim Messer TOMAHAWKPLANS $2390 KIT $24995 Jim Messer 8BALL TRAINER PLANS $1896 KIT $9996 BALSA BASSWOOD sizesl 35% OFF Concept FLEET PLANS $2996 KIT $17995 COWL $1996 P&W RADIAL ENGINES Fleet $2296 VICKERS LEWIS MACHINE GUN KITS $1496 CECONITE Products 10% OFF Sig J3 CUB KIT $12996 PLANS SUPER STEARMAN V Godfreyl $2800 STARDUSTER TOO V. IBrisighellal V J-3 CUB Nelit $1996 VOLKEPLANE V Chicken Cherliel $2396 COCKPIT KITS Tomahawk F4U-1 Spitfire $2195 Ercoupe $1996 Stearman $2295 Citebria $2096 J3Cub $1995 ME109 $2150 Fleet $2096 US Quadra FUELTANKSlEoz $e96 32oz $796 FIBERGLASS ARROW SHAFTS 5116 x22 long 6$1000 24-Hour Service. Add $250 postage Send Bank Check Money Order JIM MESSERS QUALITY MODEL PRODUCTS 106 Valley View Dr Allegany NY 14706 _____________ 2579 lb 165 mph Estimated performance zero airspeed RPM 085 x RPM,a x 35000 0 Prop tip speed 1260 tT6169 29750 1260 800 ft/sec K Efficiency correction tip speed RPM Q engine torque RPM BHP x5250 x 1085 RPMa 19 x 5250 x 1085 35000 03092 ft-lb Prop dia 12 051408 ft 12 Static thrustT 9 \CiXK DC5 03092 x 845 x 0885 051408 4498lb Note Q estimated static rpm torque real design work read exact torque BHP/torque curve actual engine Conclusion Engine must produce 9 bhp 35000rpm airspeed 165 mph prop 3-bladed diameter 6169 pitch 5667 pitch 75R point must 2130 airfoil modified Clark Y Blade activity factor 756 P/D similar manner three examples done Example 3 case 2bladed prop turning 35000 rpm de livering 1134 thrust horsepower 165 mph As preceding two examples propel ler factors calculated dis covered engine brake horsepower available 21 needed give desired level performance interest note prop has calculated diameter pitch 6895 5865 respec tively tip speed 1080 ft/sec design speed resulted tip-speed efficiency-correction factor 0687 69% ef ficient turn gave propulsive effici ency 0540 looks like going right direction horsepower required keeps going up fourth example used 3-bladed prop 35000 rpm delivering 1230 thrust horse power 165 mphthe value used Lieber average model came out required bhp 21 agaln prop have diameter 6301 m pitch 56 99 prop tip speed 818 ftIsec propulsive efficiency greater preceding example fifth example wanted 2-bladed prop under same rpm airspeed thrust horsepower conditions fourth ex ample prop turned out 709 1 diameter pitch 5801 tip BUILD WITH THE FINEST IN RC COVERING MATERIALS CECONITE RC FABRIC Heat shrinkable up 100/0 Will over lighten Attached dope Apply direction Fill weave dope 66 inch width Clear Very strong 1 8 oz/so yd 1 yd length 1 83 sq ydl $695 3 yd length 549 act yd $1995 5 yd length 916 yd 95 FILLER COAT Waler base paint replaces coals clear dope Apply 1 2 coals loam rubber brush Dries 30 minutes 1 qt covers 75sq ft Fuel proof gas glow Use over Ceco nile other fabrics Protects fabric sun Apoly type color paint over Filler Goat Pint $895 Quart $1695 SUPER SEAM Lacquer base glue Used standard model building cement Also extra slrengthwhen applying Geconite Other fabrics Clear color Sands easily dries quickly Quart $995 ORDER DIRECT OR AT HOBBY SHOP MASTER CARD VISA accepted USA add $300 postage tax Nevada orders Add $200 COD Send $1 00 information Jerry Nelson & Company Post Oflice Box 12863 Reno Nevada 89510 702-322-0664 May1983 169 Thrust available THP x 375 mph 1135 x 375 — 165 speed back up again because creased diameter Therefore propulsive efficiency down again resulting need engine power output 239 bhp very doubtful could ever get kind performance out 15 cu engine What really trying show interrelation between number blades prop amount thrust trying get constant values rpm airspeed Note chief enemy high tip speed propthe propulsive ef ficiency gets lots lower tip speeds get up around 1000 ft/sec Also evident fact weve got have clean model have hope getting high speeds power available 15 discussion will continued next column Gene Hempel 301 N Yale Dr Garland TX 75042 CL Racing/Ballard Continued page 71 subsejiber support contributions Picture qual ity excellent Ads planned limited materials interest Control Line smaller suppliers Computer-filed supplier lists member ship lists like will available Full-sized plans will available models published Copies technical reports etc planned future availability selected hard-to-get spe cialty supplies etc Frankly experiment see Control Line really dead way some people say dont think Write support Coalition concept refuse believe Control Line gone sample copy 37g stamp & envelope subscriptioni $15/yr Laird Jackson 2322 Wil son Ave Bristol PA 19007 Editors note subscription price persons aged 19 years older plus residents foreign countries Persons age 18 younger can subscribe $750/year Both subscription rates include 50 NCLC membership fee RMcM received copy Flying Lines excellent Northwestern newsletter published Mike Hazel 1411 Bryant Ave Cottage Grove OR 97424 particular newsletter virtually full con test results random building tips flea market items soapbox opinionated modelers Mike also periodically has rating system Northwestern Iliers rates contest performance throughout year newsletter certainly gives observation competitors doing Northwest area provides some interesting reading Racing competitors John Ballard 10102 Kimblewick Dr Louis ville KY 40223 Lii Pieces/Randolph Continued page 74 two tissue tubes airplane completed method wing mounting makes possible adjust incidence well remove wing storage Incidentally airplane another just like will fit shoe box ease Cover surfaces tissue glue stick sold stationery stores school supply sections other stores makes good adhesive tissue glue stick easy clean use doesnt wet tissue structure After covering rudder stab glue stab place above rudder boom left tip about /2 higher right seen back helps airplane circle left Cover wing center first glue tips place proper dihedral glue has set cover tips Cut two wing posts balsa dowel front longer back shown plan glue wtng /2 right center Looking front bottom forward post should slanted slightly left centeror towards right wing posts inserted tubes will cause some washin left wing leading edge higher trailing edge Cut propeller blades 1/32 sheet Drill carve piece 3/32 sq balsa shown plans form hub glue blades place should right angles other 450 angle shaft Bend shaft 1/32-in wire glue prop hub Slip small glass bead over shaft insert shaft front bearing rotate little until slips rear bearing Place loop rublr motor stick prop/stab/rudder assemblage find center balance looping thread around motor stick moving fore aft until balance point found Mark spot Cut two tissue tubes /4-in length piece balsa dowel dont crush Glue motor stick front tube should 11/4 ward mark aft 2 behind first sure straight up down flat against motor stick airplane now complete best rubber motor airplane/ prop combination 10- 12-in loop 040 x 043-in FAI Rubber isnt available loop three #16 rubberbands together thats skinny kind comes wrapped around newspaper Lubricate rubber motor little Armor-All stretch out about five times its length hold minute two stretching will break rubber make possible wind few extra turns Slip wing posts tissue tubes way bottom Install rubber motor wind about 100 turns launch model should have sort powered glide rather tight flat circle no sign stall model dives raise front wing post tube stalls raise aft post correct rubber motor can best wound unhooking rear hook attach ing geared winder stretching rubber out about three times its length pack ing turns winder moved back original length motor newspaper rubberbands will take about 800 turns good contest rubber about 1500 Beamed ceilings arent good flat smooth ones let Lil Pieces gather lot cobwebs Thrill/Younger Continued paqe 75 best ways introduce boys girls modeling teach class build fly Delta Dart simple almost fool-proof novice builder can build hour can buy inexpensively large quantities Complete instructions included kit have helped teach about 30 classes can assure piece cake modeler cati classes taught can 170 Model Aviation