Close-up pan-type mount Rossi 15 Clean installation fuel lines aids streamlining bit helps Fuel filter extends life expensive engine IF AT SOMETIME have consid ered extending AMA gas involvement include FAI power usual reasons have balked prospect quite possibly what follows may special interest Lets examine few usual reasons getting volved see much popular mythology can dispell complaint hear often late has recent reduction FAI engine run seven seconds Appar ently feel required time effort expense cant justified brief engine run resultant difficulty achieving max error made judging FAI power AMA gas standards AMA gas FAI power very different events stress ing different parameters performance such no legitimate basis direct comparison truth matter three minutes very possible seven-second engine run Only mar gin error has severely reduced pays keep mind also power flyers have cope identical set circumstances As result reduced engine run overall level competitive ness event heightened feel conducive interesting volvement quick look present develop ment FAI power designs points up few usual reasons non involve ment might easily concluded ex pensive super-tuned engines sophisticated sheeted construction complicated variable incidence devices very least necessary ingredients hope success however really case stock Rossi 15 very competi tive right out box costs less hot domestic class C engines now seem prevelant As con struction conventional techniques prop erly applied entirely sufficient concept variable incidence should create apprehension usually does among modelers have yet try actuality auto-stab -rudder make high-speed power model easier trim fly single impor tant reason auto mech anisms allow power trim glide trim ad justments made totally independent another first used auto-stab system presented 1961 very simple well-proven system can applied anyone real minimum effort Further details auto systems applications appear plans trimming section article Also further simplify prospective power fliers initial involvement have cluded names addresses suppli ers necessary accessories put first ship air specific design considerations rele vant Cathexis conceived under 1971 rules allowed ten-second en gine run felt time general trend placed too much emphasis climb enough consideration given glide duration selected moderately high aspect ratio wing 101 CP 5408 airfoil personally reverse climb-oriented trend CP 5408 section devised Hank Cole use FAI power models late Fifties supposedly gave excellent glide affecting fast climb As turns out claims valid glide Cathexis truly excellent climb appears nearly equal thin flat-bottomed air foils earlier ships advent seven-second engine run consid erations seem have made just right time Cathexis performs admirably indeed under new rules competitive arena FAI Power flying attractive succeed ing team selection process represents worthy challenge advice take first step An excellent place gin relatively uncomplicated 38 Model Aviation competitive design Cathexis meets criteria well added advantage being very forgiving easily trimmed novice power flier Construction Notes model construction relatively con ventional straightforward fullsize plans very well detailed should pose no problems few general comments warranted however Wood selection important entirely possible end up ounce overweight using poor quality rather dense balsa Use own best judgment try balance strength lightness throughout model first two versions Cathexis covered Monokote proved unsatisfactory number reasons present models double-covered Japanese tissue combination strength surface rigidity would difficult improve upon As rule build surfaces first like think building fuselage around surfaces helps have finished surfaces facilitate end Also good idea cure covered surfaces couple weeks fore flying Just letting completed wing stab set period time seems eliminate much creeping warp ing characteristic freshly finished sur faces introduced hot sun flying field Stabilizer Because shimmed TE create 050 droop ribs necessarily wont sit flat building board reason bottom main spar added until basic framework lifted board Turn stab upside down add 1/16 webbing rib bays glue bottom spar Finally turn stab right side up add diagonal ribs tips finished stabilizer should weigh about ounce Wing wing requires some attention detail because undercambered section tapered wing tip planform careful LE TE shimmed properly pinned down building board Also point place 1/8 sheet shim under LE both right main panel right tip panel tip dihedral joint creates neces sary wash-in right main panel allows tip panel built back flat very tip joined main panel left wing panels both built flat spars spar webbing diagonal ribs added same order out lined stabilizer tip panel full diagonal ribs cut using main panel rib templates Tip rib blanks cut length fit respective locations Next ribs marked new height LE TE rib station rib height necessarily diminishes outward towards tip After marking removing tip ribs use main panel rib template cut new upper lower cambers accomplished aligning LE template mark rib sim ply rotating template down over rib blank until template lines up mark TE rib blank Follow same procedure undercamber diagonal tip ribs Now locate spar positions tip rib cut spar notches assemble After wing panels assembled glue thoroughly dry shape upper curve LE Add LE sheet ing lapping over LE sheet ing dry trim away excess finish shaping LE Double cover wing whatever technique suits after doping set aside cure After curing few days November1975 39 Auto-rudder stop power position left glide position Right Checking everything hooked up properly before launching Below Clean efficient set-up timer makes less chance foul-up Pictures Dee Fair Bill Booth Bob Meuser Ca thex check wing panel proper warps Correct unintentional warps using steam Its best over-correct little invariably surface will creep back slightly mean time begin construc tion fuselage Fuselage fuselage built its side good straight building board definite prerequisite What actually deter mines height fuselage fire wall dimension whatever engine pan choose balsa cheeks can shaped facilitate either round square type pans technique find useful build fuselage nose about inch longer plans show very last steps con struction will involve installation tank firewall method allows strap everything together check CG location Depending weight particular front-end hardware choose utilize nose length may somewhat shorter longer indicated plans Youll notice tank has no vent tube reason tank vents through pressure line during fill ing tank filled through suction line flood-off line must pinched off crankshaft rotated intake port open venturi allowing tank vent via pressure line through engine fuel appears pressure line just aft pressure fitting stop filling wont flood crankcase system practice ulti mately simple Only fuel line need disconnected fill tank no need extra vent tube tank top fuselage straight line zero reference line inci dence thrust angles measured reference line model uses no down- side-thrust VIT AR tank timer instal lation finely detailed isometric draw ings full-size plans self ex planatory distance timer point VIT DT line enter fuselage important VIT bracket invariably remains stab TE model dethermalizes therefore neces sary both VIT DT lines free travel distance equal move ment stab dethermalized before being stopped point entering fuselage rudder glued fuselage until near complete fuselage has chance equalize its stresses No fuselage ever ends up perfectly straight reason glue rudder top fuselage rather build fuselage Align rudder carefully using pylon reference Later adding epoxy fillet rudder joins fuse lage advisable fuselage represents largest mass wood model exercise special care selecting balsa reasons strength fuselage sides longerons should good medium C-grain balsa formers diagonals should light balsa rudder very light C-grain stock use 30-lb monofilament lines stretches just enough eliminate need rubber bands springs other tension devices Ive never prob lems breaking losing its elasticity Its good simple method John James fellow Oakland Cloud Duster has recently completed building Cathexis performs admirably Johns first FAI ship trimmed out power five flights appears may now look forward being beaten own model Trim course preliminary trim began building board point alignments intentional warps should have checked rechecked Also time assure yourself CG properly located no unintentional warps As spinoff variable incidence system CG altered facilitate flight trim usually case fixed-incidence gas models first experience trim ming VIT-AR model will undoubt edly pleasant surprise Its really very easy Begin hand gliding model VIT AR lines discon nected timer ship now continued page 85 November1975 41 Side-mounted engine keeps exhaust away Seelig timer Spacer between pan firewall required mount gear Prop brake must 7-sec motor runseliminates run-down affect Brake modification Brodersen brake Below Auto-stab detail stab held down against fuselage auto-stab line power mode Right auto-stab dethermalizer line has released allowing stab bracket pop up DT position Removal fuel line required fill tank Tank vents through pressure fitting its glide mode stab should up against its glide trim stop TE should /8 3/16 up off fuse lage auto-rudder should deflected right 10-15 degrees stage game required flat glide gentle right turn Tweak rudder stab stop necessary achieve satisfactory hand glide Before light off Rossi get involved serious trimming let brief ly outline particular utilization VIT AR auto-rudder just transition device also determines glide circle model has no builtin stab tilt allows rather large deflection auto-rudder power setting glide setting result rudder tab very effective end power run So effective fact have never found necessary deploy auto-rudder before flood-off initiated usual timer sequencing might go something like flood-off twosecond delay rudder two-second delay auto stab course delay sequence varies model model order deployment doesnt vary After power pattern has trimmed autostab rudder delays can played achieve perfect transition way affecting either power glide trim adjustments rather important plus favor gimmicks Id say initial power flights made maximum power model must gain speed rapidly function properly very cautious types take heed maximum rpms very first flight way proceed first several powered flights auto-stab should de ploy 3-4 seconds after flood-off DT line should attached timer allows model detherma lize shortly after engine stops some air speed lost insuring soft landing regardless models attitude alti tude auto-rudder power setting should about 1/32 right no flood-off set go about 3 seconds Elevate nose about 600 give good chuck model under power flying very little incidence will just fly out hands first flight will tell you careful setting model up boost confidence some about Cathexis ideally should just follow through steep launch display very slight tendency go right climb appears steepen flatten within 3 seconds add subtract incidence stab 1/64 time ac complished shimming either stab LE TE didnt possess VIT Correct power turn adjusting auto-rudder half turn 2-56 screw will make significant difference Now go about S seconds floodoff paying particular attention models tendencies during last second Make corrections feel neces sary small increments retest 5-second engine run ship requires left rudder under power keep right wing tip up problem probably enough wash-in right main panel other hand model requires 1/16 right rudder under power because wants roll left problem too much wash-in char acteristics solved over steam kettle just cant trim around success seven seconds Cathexis should make very steep rapid ascent scribe onehalf circle As engine stops model should just over right shoulder pointed down wind As glide adjust ments initiated ship should transit smoothly come around rig. o wind Repeat procedure . DT line attached timer set dethermalize about 30-45 seconds like about 300 ft diameter glide circles mini mal drift conditions tighter circles drift increases model stalls badly will DT fore reaches ground reason short DT first glide test Slightly bend aluminum stab stop alter models glide incidence nec essary practice trim glide very slight stall back off incidence just bit Providing didnt end up overweight Im confident will impressed glide Cathexis thanks should go Hank Cole Becoming successful FAT power unlike success other event takes awful lot practice Super airfoils horsepower no substitutes experi ence furthermore wont fool mother nature Understanding both equipment air key ingre dients consistency consistency name game FAI power will happy answer questions modelers undertaking project Write Dave Parsons 202 Linda Ave Piedmont CA 94611 Suppliers Accessories Seelig Timers Doug Galbreath 707 Second St Davis Ca 95616 Pans Guy N Shaw 1851 So Euclid Ontario Ca 91761 Ken Oliver 2213 El Cejo Ct Rancho Cordova Ca 95670 Line Guide Tubing NFFS Supplies c/o Peggy Xenakis 1288 Oak Knoll Dr San Jose Ca 95129 Rossi Mr McGraw 1325 Carol Dr Memphis Tenn 38116 Flood-off Choker Jim Crocket Replicas 1442 N Fruit Ave Fresno Ca 93728 Props K & W Enterprises PO Box 18895 Philadelphia Pa 19119 November 1975 85 Cathexis/Parsons continued page 41 Aluminum stab mount Lip platform angled back over leading edge prevents possibility stab jumping over top platform during abrupt hand launching
Edition: Model Aviation - 1975/11
Page Numbers: 38, 39, 41, 85
Close-up pan-type mount Rossi 15 Clean installation fuel lines aids streamlining bit helps Fuel filter extends life expensive engine IF AT SOMETIME have consid ered extending AMA gas involvement include FAI power usual reasons have balked prospect quite possibly what follows may special interest Lets examine few usual reasons getting volved see much popular mythology can dispell complaint hear often late has recent reduction FAI engine run seven seconds Appar ently feel required time effort expense cant justified brief engine run resultant difficulty achieving max error made judging FAI power AMA gas standards AMA gas FAI power very different events stress ing different parameters performance such no legitimate basis direct comparison truth matter three minutes very possible seven-second engine run Only mar gin error has severely reduced pays keep mind also power flyers have cope identical set circumstances As result reduced engine run overall level competitive ness event heightened feel conducive interesting volvement quick look present develop ment FAI power designs points up few usual reasons non involve ment might easily concluded ex pensive super-tuned engines sophisticated sheeted construction complicated variable incidence devices very least necessary ingredients hope success however really case stock Rossi 15 very competi tive right out box costs less hot domestic class C engines now seem prevelant As con struction conventional techniques prop erly applied entirely sufficient concept variable incidence should create apprehension usually does among modelers have yet try actuality auto-stab -rudder make high-speed power model easier trim fly single impor tant reason auto mech anisms allow power trim glide trim ad justments made totally independent another first used auto-stab system presented 1961 very simple well-proven system can applied anyone real minimum effort Further details auto systems applications appear plans trimming section article Also further simplify prospective power fliers initial involvement have cluded names addresses suppli ers necessary accessories put first ship air specific design considerations rele vant Cathexis conceived under 1971 rules allowed ten-second en gine run felt time general trend placed too much emphasis climb enough consideration given glide duration selected moderately high aspect ratio wing 101 CP 5408 airfoil personally reverse climb-oriented trend CP 5408 section devised Hank Cole use FAI power models late Fifties supposedly gave excellent glide affecting fast climb As turns out claims valid glide Cathexis truly excellent climb appears nearly equal thin flat-bottomed air foils earlier ships advent seven-second engine run consid erations seem have made just right time Cathexis performs admirably indeed under new rules competitive arena FAI Power flying attractive succeed ing team selection process represents worthy challenge advice take first step An excellent place gin relatively uncomplicated 38 Model Aviation competitive design Cathexis meets criteria well added advantage being very forgiving easily trimmed novice power flier Construction Notes model construction relatively con ventional straightforward fullsize plans very well detailed should pose no problems few general comments warranted however Wood selection important entirely possible end up ounce overweight using poor quality rather dense balsa Use own best judgment try balance strength lightness throughout model first two versions Cathexis covered Monokote proved unsatisfactory number reasons present models double-covered Japanese tissue combination strength surface rigidity would difficult improve upon As rule build surfaces first like think building fuselage around surfaces helps have finished surfaces facilitate end Also good idea cure covered surfaces couple weeks fore flying Just letting completed wing stab set period time seems eliminate much creeping warp ing characteristic freshly finished sur faces introduced hot sun flying field Stabilizer Because shimmed TE create 050 droop ribs necessarily wont sit flat building board reason bottom main spar added until basic framework lifted board Turn stab upside down add 1/16 webbing rib bays glue bottom spar Finally turn stab right side up add diagonal ribs tips finished stabilizer should weigh about ounce Wing wing requires some attention detail because undercambered section tapered wing tip planform careful LE TE shimmed properly pinned down building board Also point place 1/8 sheet shim under LE both right main panel right tip panel tip dihedral joint creates neces sary wash-in right main panel allows tip panel built back flat very tip joined main panel left wing panels both built flat spars spar webbing diagonal ribs added same order out lined stabilizer tip panel full diagonal ribs cut using main panel rib templates Tip rib blanks cut length fit respective locations Next ribs marked new height LE TE rib station rib height necessarily diminishes outward towards tip After marking removing tip ribs use main panel rib template cut new upper lower cambers accomplished aligning LE template mark rib sim ply rotating template down over rib blank until template lines up mark TE rib blank Follow same procedure undercamber diagonal tip ribs Now locate spar positions tip rib cut spar notches assemble After wing panels assembled glue thoroughly dry shape upper curve LE Add LE sheet ing lapping over LE sheet ing dry trim away excess finish shaping LE Double cover wing whatever technique suits after doping set aside cure After curing few days November1975 39 Auto-rudder stop power position left glide position Right Checking everything hooked up properly before launching Below Clean efficient set-up timer makes less chance foul-up Pictures Dee Fair Bill Booth Bob Meuser Ca thex check wing panel proper warps Correct unintentional warps using steam Its best over-correct little invariably surface will creep back slightly mean time begin construc tion fuselage Fuselage fuselage built its side good straight building board definite prerequisite What actually deter mines height fuselage fire wall dimension whatever engine pan choose balsa cheeks can shaped facilitate either round square type pans technique find useful build fuselage nose about inch longer plans show very last steps con struction will involve installation tank firewall method allows strap everything together check CG location Depending weight particular front-end hardware choose utilize nose length may somewhat shorter longer indicated plans Youll notice tank has no vent tube reason tank vents through pressure line during fill ing tank filled through suction line flood-off line must pinched off crankshaft rotated intake port open venturi allowing tank vent via pressure line through engine fuel appears pressure line just aft pressure fitting stop filling wont flood crankcase system practice ulti mately simple Only fuel line need disconnected fill tank no need extra vent tube tank top fuselage straight line zero reference line inci dence thrust angles measured reference line model uses no down- side-thrust VIT AR tank timer instal lation finely detailed isometric draw ings full-size plans self ex planatory distance timer point VIT DT line enter fuselage important VIT bracket invariably remains stab TE model dethermalizes therefore neces sary both VIT DT lines free travel distance equal move ment stab dethermalized before being stopped point entering fuselage rudder glued fuselage until near complete fuselage has chance equalize its stresses No fuselage ever ends up perfectly straight reason glue rudder top fuselage rather build fuselage Align rudder carefully using pylon reference Later adding epoxy fillet rudder joins fuse lage advisable fuselage represents largest mass wood model exercise special care selecting balsa reasons strength fuselage sides longerons should good medium C-grain balsa formers diagonals should light balsa rudder very light C-grain stock use 30-lb monofilament lines stretches just enough eliminate need rubber bands springs other tension devices Ive never prob lems breaking losing its elasticity Its good simple method John James fellow Oakland Cloud Duster has recently completed building Cathexis performs admirably Johns first FAI ship trimmed out power five flights appears may now look forward being beaten own model Trim course preliminary trim began building board point alignments intentional warps should have checked rechecked Also time assure yourself CG properly located no unintentional warps As spinoff variable incidence system CG altered facilitate flight trim usually case fixed-incidence gas models first experience trim ming VIT-AR model will undoubt edly pleasant surprise Its really very easy Begin hand gliding model VIT AR lines discon nected timer ship now continued page 85 November1975 41 Side-mounted engine keeps exhaust away Seelig timer Spacer between pan firewall required mount gear Prop brake must 7-sec motor runseliminates run-down affect Brake modification Brodersen brake Below Auto-stab detail stab held down against fuselage auto-stab line power mode Right auto-stab dethermalizer line has released allowing stab bracket pop up DT position Removal fuel line required fill tank Tank vents through pressure fitting its glide mode stab should up against its glide trim stop TE should /8 3/16 up off fuse lage auto-rudder should deflected right 10-15 degrees stage game required flat glide gentle right turn Tweak rudder stab stop necessary achieve satisfactory hand glide Before light off Rossi get involved serious trimming let brief ly outline particular utilization VIT AR auto-rudder just transition device also determines glide circle model has no builtin stab tilt allows rather large deflection auto-rudder power setting glide setting result rudder tab very effective end power run So effective fact have never found necessary deploy auto-rudder before flood-off initiated usual timer sequencing might go something like flood-off twosecond delay rudder two-second delay auto stab course delay sequence varies model model order deployment doesnt vary After power pattern has trimmed autostab rudder delays can played achieve perfect transition way affecting either power glide trim adjustments rather important plus favor gimmicks Id say initial power flights made maximum power model must gain speed rapidly function properly very cautious types take heed maximum rpms very first flight way proceed first several powered flights auto-stab should de ploy 3-4 seconds after flood-off DT line should attached timer allows model detherma lize shortly after engine stops some air speed lost insuring soft landing regardless models attitude alti tude auto-rudder power setting should about 1/32 right no flood-off set go about 3 seconds Elevate nose about 600 give good chuck model under power flying very little incidence will just fly out hands first flight will tell you careful setting model up boost confidence some about Cathexis ideally should just follow through steep launch display very slight tendency go right climb appears steepen flatten within 3 seconds add subtract incidence stab 1/64 time ac complished shimming either stab LE TE didnt possess VIT Correct power turn adjusting auto-rudder half turn 2-56 screw will make significant difference Now go about S seconds floodoff paying particular attention models tendencies during last second Make corrections feel neces sary small increments retest 5-second engine run ship requires left rudder under power keep right wing tip up problem probably enough wash-in right main panel other hand model requires 1/16 right rudder under power because wants roll left problem too much wash-in char acteristics solved over steam kettle just cant trim around success seven seconds Cathexis should make very steep rapid ascent scribe onehalf circle As engine stops model should just over right shoulder pointed down wind As glide adjust ments initiated ship should transit smoothly come around rig. o wind Repeat procedure . DT line attached timer set dethermalize about 30-45 seconds like about 300 ft diameter glide circles mini mal drift conditions tighter circles drift increases model stalls badly will DT fore reaches ground reason short DT first glide test Slightly bend aluminum stab stop alter models glide incidence nec essary practice trim glide very slight stall back off incidence just bit Providing didnt end up overweight Im confident will impressed glide Cathexis thanks should go Hank Cole Becoming successful FAT power unlike success other event takes awful lot practice Super airfoils horsepower no substitutes experi ence furthermore wont fool mother nature Understanding both equipment air key ingre dients consistency consistency name game FAI power will happy answer questions modelers undertaking project Write Dave Parsons 202 Linda Ave Piedmont CA 94611 Suppliers Accessories Seelig Timers Doug Galbreath 707 Second St Davis Ca 95616 Pans Guy N Shaw 1851 So Euclid Ontario Ca 91761 Ken Oliver 2213 El Cejo Ct Rancho Cordova Ca 95670 Line Guide Tubing NFFS Supplies c/o Peggy Xenakis 1288 Oak Knoll Dr San Jose Ca 95129 Rossi Mr McGraw 1325 Carol Dr Memphis Tenn 38116 Flood-off Choker Jim Crocket Replicas 1442 N Fruit Ave Fresno Ca 93728 Props K & W Enterprises PO Box 18895 Philadelphia Pa 19119 November 1975 85 Cathexis/Parsons continued page 41 Aluminum stab mount Lip platform angled back over leading edge prevents possibility stab jumping over top platform during abrupt hand launching
Edition: Model Aviation - 1975/11
Page Numbers: 38, 39, 41, 85
Close-up pan-type mount Rossi 15 Clean installation fuel lines aids streamlining bit helps Fuel filter extends life expensive engine IF AT SOMETIME have consid ered extending AMA gas involvement include FAI power usual reasons have balked prospect quite possibly what follows may special interest Lets examine few usual reasons getting volved see much popular mythology can dispell complaint hear often late has recent reduction FAI engine run seven seconds Appar ently feel required time effort expense cant justified brief engine run resultant difficulty achieving max error made judging FAI power AMA gas standards AMA gas FAI power very different events stress ing different parameters performance such no legitimate basis direct comparison truth matter three minutes very possible seven-second engine run Only mar gin error has severely reduced pays keep mind also power flyers have cope identical set circumstances As result reduced engine run overall level competitive ness event heightened feel conducive interesting volvement quick look present develop ment FAI power designs points up few usual reasons non involve ment might easily concluded ex pensive super-tuned engines sophisticated sheeted construction complicated variable incidence devices very least necessary ingredients hope success however really case stock Rossi 15 very competi tive right out box costs less hot domestic class C engines now seem prevelant As con struction conventional techniques prop erly applied entirely sufficient concept variable incidence should create apprehension usually does among modelers have yet try actuality auto-stab -rudder make high-speed power model easier trim fly single impor tant reason auto mech anisms allow power trim glide trim ad justments made totally independent another first used auto-stab system presented 1961 very simple well-proven system can applied anyone real minimum effort Further details auto systems applications appear plans trimming section article Also further simplify prospective power fliers initial involvement have cluded names addresses suppli ers necessary accessories put first ship air specific design considerations rele vant Cathexis conceived under 1971 rules allowed ten-second en gine run felt time general trend placed too much emphasis climb enough consideration given glide duration selected moderately high aspect ratio wing 101 CP 5408 airfoil personally reverse climb-oriented trend CP 5408 section devised Hank Cole use FAI power models late Fifties supposedly gave excellent glide affecting fast climb As turns out claims valid glide Cathexis truly excellent climb appears nearly equal thin flat-bottomed air foils earlier ships advent seven-second engine run consid erations seem have made just right time Cathexis performs admirably indeed under new rules competitive arena FAI Power flying attractive succeed ing team selection process represents worthy challenge advice take first step An excellent place gin relatively uncomplicated 38 Model Aviation competitive design Cathexis meets criteria well added advantage being very forgiving easily trimmed novice power flier Construction Notes model construction relatively con ventional straightforward fullsize plans very well detailed should pose no problems few general comments warranted however Wood selection important entirely possible end up ounce overweight using poor quality rather dense balsa Use own best judgment try balance strength lightness throughout model first two versions Cathexis covered Monokote proved unsatisfactory number reasons present models double-covered Japanese tissue combination strength surface rigidity would difficult improve upon As rule build surfaces first like think building fuselage around surfaces helps have finished surfaces facilitate end Also good idea cure covered surfaces couple weeks fore flying Just letting completed wing stab set period time seems eliminate much creeping warp ing characteristic freshly finished sur faces introduced hot sun flying field Stabilizer Because shimmed TE create 050 droop ribs necessarily wont sit flat building board reason bottom main spar added until basic framework lifted board Turn stab upside down add 1/16 webbing rib bays glue bottom spar Finally turn stab right side up add diagonal ribs tips finished stabilizer should weigh about ounce Wing wing requires some attention detail because undercambered section tapered wing tip planform careful LE TE shimmed properly pinned down building board Also point place 1/8 sheet shim under LE both right main panel right tip panel tip dihedral joint creates neces sary wash-in right main panel allows tip panel built back flat very tip joined main panel left wing panels both built flat spars spar webbing diagonal ribs added same order out lined stabilizer tip panel full diagonal ribs cut using main panel rib templates Tip rib blanks cut length fit respective locations Next ribs marked new height LE TE rib station rib height necessarily diminishes outward towards tip After marking removing tip ribs use main panel rib template cut new upper lower cambers accomplished aligning LE template mark rib sim ply rotating template down over rib blank until template lines up mark TE rib blank Follow same procedure undercamber diagonal tip ribs Now locate spar positions tip rib cut spar notches assemble After wing panels assembled glue thoroughly dry shape upper curve LE Add LE sheet ing lapping over LE sheet ing dry trim away excess finish shaping LE Double cover wing whatever technique suits after doping set aside cure After curing few days November1975 39 Auto-rudder stop power position left glide position Right Checking everything hooked up properly before launching Below Clean efficient set-up timer makes less chance foul-up Pictures Dee Fair Bill Booth Bob Meuser Ca thex check wing panel proper warps Correct unintentional warps using steam Its best over-correct little invariably surface will creep back slightly mean time begin construc tion fuselage Fuselage fuselage built its side good straight building board definite prerequisite What actually deter mines height fuselage fire wall dimension whatever engine pan choose balsa cheeks can shaped facilitate either round square type pans technique find useful build fuselage nose about inch longer plans show very last steps con struction will involve installation tank firewall method allows strap everything together check CG location Depending weight particular front-end hardware choose utilize nose length may somewhat shorter longer indicated plans Youll notice tank has no vent tube reason tank vents through pressure line during fill ing tank filled through suction line flood-off line must pinched off crankshaft rotated intake port open venturi allowing tank vent via pressure line through engine fuel appears pressure line just aft pressure fitting stop filling wont flood crankcase system practice ulti mately simple Only fuel line need disconnected fill tank no need extra vent tube tank top fuselage straight line zero reference line inci dence thrust angles measured reference line model uses no down- side-thrust VIT AR tank timer instal lation finely detailed isometric draw ings full-size plans self ex planatory distance timer point VIT DT line enter fuselage important VIT bracket invariably remains stab TE model dethermalizes therefore neces sary both VIT DT lines free travel distance equal move ment stab dethermalized before being stopped point entering fuselage rudder glued fuselage until near complete fuselage has chance equalize its stresses No fuselage ever ends up perfectly straight reason glue rudder top fuselage rather build fuselage Align rudder carefully using pylon reference Later adding epoxy fillet rudder joins fuse lage advisable fuselage represents largest mass wood model exercise special care selecting balsa reasons strength fuselage sides longerons should good medium C-grain balsa formers diagonals should light balsa rudder very light C-grain stock use 30-lb monofilament lines stretches just enough eliminate need rubber bands springs other tension devices Ive never prob lems breaking losing its elasticity Its good simple method John James fellow Oakland Cloud Duster has recently completed building Cathexis performs admirably Johns first FAI ship trimmed out power five flights appears may now look forward being beaten own model Trim course preliminary trim began building board point alignments intentional warps should have checked rechecked Also time assure yourself CG properly located no unintentional warps As spinoff variable incidence system CG altered facilitate flight trim usually case fixed-incidence gas models first experience trim ming VIT-AR model will undoubt edly pleasant surprise Its really very easy Begin hand gliding model VIT AR lines discon nected timer ship now continued page 85 November1975 41 Side-mounted engine keeps exhaust away Seelig timer Spacer between pan firewall required mount gear Prop brake must 7-sec motor runseliminates run-down affect Brake modification Brodersen brake Below Auto-stab detail stab held down against fuselage auto-stab line power mode Right auto-stab dethermalizer line has released allowing stab bracket pop up DT position Removal fuel line required fill tank Tank vents through pressure fitting its glide mode stab should up against its glide trim stop TE should /8 3/16 up off fuse lage auto-rudder should deflected right 10-15 degrees stage game required flat glide gentle right turn Tweak rudder stab stop necessary achieve satisfactory hand glide Before light off Rossi get involved serious trimming let brief ly outline particular utilization VIT AR auto-rudder just transition device also determines glide circle model has no builtin stab tilt allows rather large deflection auto-rudder power setting glide setting result rudder tab very effective end power run So effective fact have never found necessary deploy auto-rudder before flood-off initiated usual timer sequencing might go something like flood-off twosecond delay rudder two-second delay auto stab course delay sequence varies model model order deployment doesnt vary After power pattern has trimmed autostab rudder delays can played achieve perfect transition way affecting either power glide trim adjustments rather important plus favor gimmicks Id say initial power flights made maximum power model must gain speed rapidly function properly very cautious types take heed maximum rpms very first flight way proceed first several powered flights auto-stab should de ploy 3-4 seconds after flood-off DT line should attached timer allows model detherma lize shortly after engine stops some air speed lost insuring soft landing regardless models attitude alti tude auto-rudder power setting should about 1/32 right no flood-off set go about 3 seconds Elevate nose about 600 give good chuck model under power flying very little incidence will just fly out hands first flight will tell you careful setting model up boost confidence some about Cathexis ideally should just follow through steep launch display very slight tendency go right climb appears steepen flatten within 3 seconds add subtract incidence stab 1/64 time ac complished shimming either stab LE TE didnt possess VIT Correct power turn adjusting auto-rudder half turn 2-56 screw will make significant difference Now go about S seconds floodoff paying particular attention models tendencies during last second Make corrections feel neces sary small increments retest 5-second engine run ship requires left rudder under power keep right wing tip up problem probably enough wash-in right main panel other hand model requires 1/16 right rudder under power because wants roll left problem too much wash-in char acteristics solved over steam kettle just cant trim around success seven seconds Cathexis should make very steep rapid ascent scribe onehalf circle As engine stops model should just over right shoulder pointed down wind As glide adjust ments initiated ship should transit smoothly come around rig. o wind Repeat procedure . DT line attached timer set dethermalize about 30-45 seconds like about 300 ft diameter glide circles mini mal drift conditions tighter circles drift increases model stalls badly will DT fore reaches ground reason short DT first glide test Slightly bend aluminum stab stop alter models glide incidence nec essary practice trim glide very slight stall back off incidence just bit Providing didnt end up overweight Im confident will impressed glide Cathexis thanks should go Hank Cole Becoming successful FAT power unlike success other event takes awful lot practice Super airfoils horsepower no substitutes experi ence furthermore wont fool mother nature Understanding both equipment air key ingre dients consistency consistency name game FAI power will happy answer questions modelers undertaking project Write Dave Parsons 202 Linda Ave Piedmont CA 94611 Suppliers Accessories Seelig Timers Doug Galbreath 707 Second St Davis Ca 95616 Pans Guy N Shaw 1851 So Euclid Ontario Ca 91761 Ken Oliver 2213 El Cejo Ct Rancho Cordova Ca 95670 Line Guide Tubing NFFS Supplies c/o Peggy Xenakis 1288 Oak Knoll Dr San Jose Ca 95129 Rossi Mr McGraw 1325 Carol Dr Memphis Tenn 38116 Flood-off Choker Jim Crocket Replicas 1442 N Fruit Ave Fresno Ca 93728 Props K & W Enterprises PO Box 18895 Philadelphia Pa 19119 November 1975 85 Cathexis/Parsons continued page 41 Aluminum stab mount Lip platform angled back over leading edge prevents possibility stab jumping over top platform during abrupt hand launching
Edition: Model Aviation - 1975/11
Page Numbers: 38, 39, 41, 85
Close-up pan-type mount Rossi 15 Clean installation fuel lines aids streamlining bit helps Fuel filter extends life expensive engine IF AT SOMETIME have consid ered extending AMA gas involvement include FAI power usual reasons have balked prospect quite possibly what follows may special interest Lets examine few usual reasons getting volved see much popular mythology can dispell complaint hear often late has recent reduction FAI engine run seven seconds Appar ently feel required time effort expense cant justified brief engine run resultant difficulty achieving max error made judging FAI power AMA gas standards AMA gas FAI power very different events stress ing different parameters performance such no legitimate basis direct comparison truth matter three minutes very possible seven-second engine run Only mar gin error has severely reduced pays keep mind also power flyers have cope identical set circumstances As result reduced engine run overall level competitive ness event heightened feel conducive interesting volvement quick look present develop ment FAI power designs points up few usual reasons non involve ment might easily concluded ex pensive super-tuned engines sophisticated sheeted construction complicated variable incidence devices very least necessary ingredients hope success however really case stock Rossi 15 very competi tive right out box costs less hot domestic class C engines now seem prevelant As con struction conventional techniques prop erly applied entirely sufficient concept variable incidence should create apprehension usually does among modelers have yet try actuality auto-stab -rudder make high-speed power model easier trim fly single impor tant reason auto mech anisms allow power trim glide trim ad justments made totally independent another first used auto-stab system presented 1961 very simple well-proven system can applied anyone real minimum effort Further details auto systems applications appear plans trimming section article Also further simplify prospective power fliers initial involvement have cluded names addresses suppli ers necessary accessories put first ship air specific design considerations rele vant Cathexis conceived under 1971 rules allowed ten-second en gine run felt time general trend placed too much emphasis climb enough consideration given glide duration selected moderately high aspect ratio wing 101 CP 5408 airfoil personally reverse climb-oriented trend CP 5408 section devised Hank Cole use FAI power models late Fifties supposedly gave excellent glide affecting fast climb As turns out claims valid glide Cathexis truly excellent climb appears nearly equal thin flat-bottomed air foils earlier ships advent seven-second engine run consid erations seem have made just right time Cathexis performs admirably indeed under new rules competitive arena FAI Power flying attractive succeed ing team selection process represents worthy challenge advice take first step An excellent place gin relatively uncomplicated 38 Model Aviation competitive design Cathexis meets criteria well added advantage being very forgiving easily trimmed novice power flier Construction Notes model construction relatively con ventional straightforward fullsize plans very well detailed should pose no problems few general comments warranted however Wood selection important entirely possible end up ounce overweight using poor quality rather dense balsa Use own best judgment try balance strength lightness throughout model first two versions Cathexis covered Monokote proved unsatisfactory number reasons present models double-covered Japanese tissue combination strength surface rigidity would difficult improve upon As rule build surfaces first like think building fuselage around surfaces helps have finished surfaces facilitate end Also good idea cure covered surfaces couple weeks fore flying Just letting completed wing stab set period time seems eliminate much creeping warp ing characteristic freshly finished sur faces introduced hot sun flying field Stabilizer Because shimmed TE create 050 droop ribs necessarily wont sit flat building board reason bottom main spar added until basic framework lifted board Turn stab upside down add 1/16 webbing rib bays glue bottom spar Finally turn stab right side up add diagonal ribs tips finished stabilizer should weigh about ounce Wing wing requires some attention detail because undercambered section tapered wing tip planform careful LE TE shimmed properly pinned down building board Also point place 1/8 sheet shim under LE both right main panel right tip panel tip dihedral joint creates neces sary wash-in right main panel allows tip panel built back flat very tip joined main panel left wing panels both built flat spars spar webbing diagonal ribs added same order out lined stabilizer tip panel full diagonal ribs cut using main panel rib templates Tip rib blanks cut length fit respective locations Next ribs marked new height LE TE rib station rib height necessarily diminishes outward towards tip After marking removing tip ribs use main panel rib template cut new upper lower cambers accomplished aligning LE template mark rib sim ply rotating template down over rib blank until template lines up mark TE rib blank Follow same procedure undercamber diagonal tip ribs Now locate spar positions tip rib cut spar notches assemble After wing panels assembled glue thoroughly dry shape upper curve LE Add LE sheet ing lapping over LE sheet ing dry trim away excess finish shaping LE Double cover wing whatever technique suits after doping set aside cure After curing few days November1975 39 Auto-rudder stop power position left glide position Right Checking everything hooked up properly before launching Below Clean efficient set-up timer makes less chance foul-up Pictures Dee Fair Bill Booth Bob Meuser Ca thex check wing panel proper warps Correct unintentional warps using steam Its best over-correct little invariably surface will creep back slightly mean time begin construc tion fuselage Fuselage fuselage built its side good straight building board definite prerequisite What actually deter mines height fuselage fire wall dimension whatever engine pan choose balsa cheeks can shaped facilitate either round square type pans technique find useful build fuselage nose about inch longer plans show very last steps con struction will involve installation tank firewall method allows strap everything together check CG location Depending weight particular front-end hardware choose utilize nose length may somewhat shorter longer indicated plans Youll notice tank has no vent tube reason tank vents through pressure line during fill ing tank filled through suction line flood-off line must pinched off crankshaft rotated intake port open venturi allowing tank vent via pressure line through engine fuel appears pressure line just aft pressure fitting stop filling wont flood crankcase system practice ulti mately simple Only fuel line need disconnected fill tank no need extra vent tube tank top fuselage straight line zero reference line inci dence thrust angles measured reference line model uses no down- side-thrust VIT AR tank timer instal lation finely detailed isometric draw ings full-size plans self ex planatory distance timer point VIT DT line enter fuselage important VIT bracket invariably remains stab TE model dethermalizes therefore neces sary both VIT DT lines free travel distance equal move ment stab dethermalized before being stopped point entering fuselage rudder glued fuselage until near complete fuselage has chance equalize its stresses No fuselage ever ends up perfectly straight reason glue rudder top fuselage rather build fuselage Align rudder carefully using pylon reference Later adding epoxy fillet rudder joins fuse lage advisable fuselage represents largest mass wood model exercise special care selecting balsa reasons strength fuselage sides longerons should good medium C-grain balsa formers diagonals should light balsa rudder very light C-grain stock use 30-lb monofilament lines stretches just enough eliminate need rubber bands springs other tension devices Ive never prob lems breaking losing its elasticity Its good simple method John James fellow Oakland Cloud Duster has recently completed building Cathexis performs admirably Johns first FAI ship trimmed out power five flights appears may now look forward being beaten own model Trim course preliminary trim began building board point alignments intentional warps should have checked rechecked Also time assure yourself CG properly located no unintentional warps As spinoff variable incidence system CG altered facilitate flight trim usually case fixed-incidence gas models first experience trim ming VIT-AR model will undoubt edly pleasant surprise Its really very easy Begin hand gliding model VIT AR lines discon nected timer ship now continued page 85 November1975 41 Side-mounted engine keeps exhaust away Seelig timer Spacer between pan firewall required mount gear Prop brake must 7-sec motor runseliminates run-down affect Brake modification Brodersen brake Below Auto-stab detail stab held down against fuselage auto-stab line power mode Right auto-stab dethermalizer line has released allowing stab bracket pop up DT position Removal fuel line required fill tank Tank vents through pressure fitting its glide mode stab should up against its glide trim stop TE should /8 3/16 up off fuse lage auto-rudder should deflected right 10-15 degrees stage game required flat glide gentle right turn Tweak rudder stab stop necessary achieve satisfactory hand glide Before light off Rossi get involved serious trimming let brief ly outline particular utilization VIT AR auto-rudder just transition device also determines glide circle model has no builtin stab tilt allows rather large deflection auto-rudder power setting glide setting result rudder tab very effective end power run So effective fact have never found necessary deploy auto-rudder before flood-off initiated usual timer sequencing might go something like flood-off twosecond delay rudder two-second delay auto stab course delay sequence varies model model order deployment doesnt vary After power pattern has trimmed autostab rudder delays can played achieve perfect transition way affecting either power glide trim adjustments rather important plus favor gimmicks Id say initial power flights made maximum power model must gain speed rapidly function properly very cautious types take heed maximum rpms very first flight way proceed first several powered flights auto-stab should de ploy 3-4 seconds after flood-off DT line should attached timer allows model detherma lize shortly after engine stops some air speed lost insuring soft landing regardless models attitude alti tude auto-rudder power setting should about 1/32 right no flood-off set go about 3 seconds Elevate nose about 600 give good chuck model under power flying very little incidence will just fly out hands first flight will tell you careful setting model up boost confidence some about Cathexis ideally should just follow through steep launch display very slight tendency go right climb appears steepen flatten within 3 seconds add subtract incidence stab 1/64 time ac complished shimming either stab LE TE didnt possess VIT Correct power turn adjusting auto-rudder half turn 2-56 screw will make significant difference Now go about S seconds floodoff paying particular attention models tendencies during last second Make corrections feel neces sary small increments retest 5-second engine run ship requires left rudder under power keep right wing tip up problem probably enough wash-in right main panel other hand model requires 1/16 right rudder under power because wants roll left problem too much wash-in char acteristics solved over steam kettle just cant trim around success seven seconds Cathexis should make very steep rapid ascent scribe onehalf circle As engine stops model should just over right shoulder pointed down wind As glide adjust ments initiated ship should transit smoothly come around rig. o wind Repeat procedure . DT line attached timer set dethermalize about 30-45 seconds like about 300 ft diameter glide circles mini mal drift conditions tighter circles drift increases model stalls badly will DT fore reaches ground reason short DT first glide test Slightly bend aluminum stab stop alter models glide incidence nec essary practice trim glide very slight stall back off incidence just bit Providing didnt end up overweight Im confident will impressed glide Cathexis thanks should go Hank Cole Becoming successful FAT power unlike success other event takes awful lot practice Super airfoils horsepower no substitutes experi ence furthermore wont fool mother nature Understanding both equipment air key ingre dients consistency consistency name game FAI power will happy answer questions modelers undertaking project Write Dave Parsons 202 Linda Ave Piedmont CA 94611 Suppliers Accessories Seelig Timers Doug Galbreath 707 Second St Davis Ca 95616 Pans Guy N Shaw 1851 So Euclid Ontario Ca 91761 Ken Oliver 2213 El Cejo Ct Rancho Cordova Ca 95670 Line Guide Tubing NFFS Supplies c/o Peggy Xenakis 1288 Oak Knoll Dr San Jose Ca 95129 Rossi Mr McGraw 1325 Carol Dr Memphis Tenn 38116 Flood-off Choker Jim Crocket Replicas 1442 N Fruit Ave Fresno Ca 93728 Props K & W Enterprises PO Box 18895 Philadelphia Pa 19119 November 1975 85 Cathexis/Parsons continued page 41 Aluminum stab mount Lip platform angled back over leading edge prevents possibility stab jumping over top platform during abrupt hand launching