How Mold FalansentReinforced Props taking time cast own props may seem like lot trouble equates tailor-made suit compared off rack Nothing can fit specific needs better EBob Dunham USING PROCEDURES developed serious Control Line Free Flight fliers description make rein forced plastic propellers using split mold procedure has refined recent years point consistent reliable results can produced great dif ficulty propeller tip-to-tip fiberglass carbon fiber hereinafter referred FG/CF rovings tows almost neces sity using high-revving Schnuerle-ported engines turning speed approaching excess 28000 rpm important maintain both blade pitch efficiency structural integrity safety lower rpm forces blade some propellersin both outward twisting directionscan cause blade shedding failure usually oc curring hub area can endanger operator others within 30-ft radius FG/CF other blade reinforcement material prop unexpected blade separation can still some times occur always good practice use protective eye gear check prop carefully after flight obscure landing damage over-stressing previous flight several advantages making own FG/CF props model interests mainstream popu larity already have found model shops simply stock props suitable high-revving engines leaves choices substituting less-de sirable prop writing manufacturer cottage industry molder possibly wait ing several weeks delivery Also like original can carve prop own specifications reproduce FG/CF over over Similarly ex 42 Model Aviation isting prop can thinned repitched re shaped generally reworked close relative can molded new prop produced incorporating modifica tions mold presented satisfactory use reinforcing materials fiber glass carbon fiber combination Making mold first step both Keviar has also used have no experience application Materials produce several molds enough epoxy resin strand material make 30 40 props will cost neighborhood $75 Above Lineup principal Ingredients will used make mold Below Ma terials used produce reinforced prop Source list end text contains addresses contact special materials may able find locally Pattern prop mounted base piate shaft place Smooth-flowing clay lines desirable Take special note 150 parting line hub tip treatment difficult part project done care will reward quality product can used times over molding matrix can either auto body filler polyester base steelfilled epoxy resin first attempt please try body filler easily obtained will produce very satisfactory mold steel-filled epoxy harder durable does shrink however expensive delivery listed source slow main disadvantages auto body filler produces somewhat softer mold prone wear chipping shrinks slightly cured makes copy prop slightly diminished size original enough cause problem Construction mold same regardless matrix choose will need polyester resin thinning purposes polyvinyl alcohol PVA re lease agent PVA vital its importance will become apparent read along green-tinted water-soluble liquid applied brush has consistency thin dope dries rapidly metal base plate needed should approximately -in thick absolutely flat smooth since shapes mold parting line base plate should least 2 wide 12 long Using care drill press position hole midpoint match prop shaft diameter best hole tight fit 3-in length steel rod mold side frames can cut plywood awidthof 1 4 Lengths wooden yardstick make very suitable substitute will need two long sides about 1 longer prop diameter two end pieces about 1 long mold frames should given two coats clear epoxy paint side allowed cure Choose prop wish reproduce varnished wood variety finish must removed sanding washing acetone suggest further thin prop blades sanding about five thousandths away top curved side makes allowance strand interference between mold faces two coats epoxy paint applied prop seal grain prevent absorbing liquids Spraying preferred over brushing minimize thickness build-up molding fiberglass nylon plastic prop go through same blade-thinning operation paint epoxy Check finished prop wish reproduce has no nicks scratches slightest imperfection wood grain brush marks will reproduced real business matter Mount pattern prop base plate top camber facing up center post inserted drilled hole aligned perpendicular plate directions Both blade tips should same distance above surface plate Make worms hand-warmed clay fill area underneath blades take care deform bend blades process Using tool such back edge single-edge razor blade carefully mold clay parting draft angle about 15 formed angle necessary get poured mold release properly hub area takes slightly different treatment can best shown photos tips leave tongue area extends about nd prop tip maintaining general slope con tour blade may take several tries resculpting attempts get things looking just right will soon get hang wet finger helpful obtain desired smoothness March 1986 43 PVA release agent applied surfaces retainer box absolute must order retrieve prop molding matrix C-clamps secure box sides base plate Auto body filler recommended first attempts making mold Instance though steel-filled epoxy being poured over clayed-up prop produce bottom half Actually procedure same whether body filler steel-filled epoxy used Once bottom half mold has cured isturned overand used asthe baseforpouring top half mold Secure box C-clamps again coat insides PVA black gunk being poured produce top half mold messy prepared lots rags newspapers drop cloth catch Inevitable drips refrain repeatedly going over area things seem get worse finished wash oil clay smears plate acetone Assemble mold frames rec tangular box joining 5-min epoxy sides box already painted epoxy should face inward end pieces located just barely enclose clay tongues Place box over clayed up prop secure base Cclamps done coat inside surfaces box well post prop clay two coats PVA applied soft brush After coating careful break disturb green PVA skinwhich will give good visual indication parts coated Allow PVA dry thoroughly During mixing pouring opera tions follow disposable vinyl gloves protective glasses should worn work area should well-ventilated Always read heed caution labels materials familiar know what accident should occur Pouring mold matrix next will describe use body filler though procedure steel-filled epoxy essen tially same personal preferences brands available CUZ White Knight both easily obtained An 8-in-dia prop mold will require about 7 oz 200 grams filler mixed about 1 oz 28 grams polyester resin milkshake-like con sistency amount thinning resin required will vary between brands Discard catalyst accompanied body filler use polyester resin catalyst instead liquid catalyst clear squeeze bottle easier measure control paste catalyst supplied filler amount thinned Before beginning lay-up rovings cutand arranged man orderlyfashion nearby wilt handy Longest rovings laid first Straddle center post center extend out both ends Proceed tothe shorter rovings 1-in steps Relieve ends mold producethis small gap will allow glass rovings run full length blade give additional strength Key markings mold ends prevent accidental disas trous reversing mold reassembly jreat definItion has attained mold produced auto body filler bottom half natural reservoIr will hold epoxy reinforcing strands during lay-up Note mold tip relieving does extend inward past edge mark left bythe prop Two coats applied surfaces before beginning lay-up e release agent must get mold halves apart Use care green skin forms easily broken Pack critical hub area blade sep aration Ia moat likely Occur short giass clippingeto firm up Watch see glass changes ocior good wetting body filler use thoroughly mix about 2 drops catalyst matrix slowly poured mold box using lengthwise back-and-forth motion pro duce build-up andto avoid bubbles After matrix has become firm 2-3 hr still pliable centerpost can removed exerting twisting pulling tug pliers C-clamps loos ened should able lift slide complete assembly plate Dis mantle wooden sides remove much clay possible fingers give access pattern prop Without marring mold face angled sides exposed gently lift prop using reasonable persuasion pop prop out mold Tag corresponding ends mold prop later reassembly can accomplished prop removed mold may still flexible re-clamp plate curing another couple hours until stiff complete part mold remove PVA clay residue washing soap water Pouring top half mold next first step give entire bottom half loose prop ooat PVA dry return prop bottom mold making sure orientation corresponds markings Insert center post assemble wooden frame around mold maintain tight fit C-clamps assure easy release later apply final coat PVA prop mold face center post inside sur faces frame Mix auto body matrix before Pour enclosure filling thickness about w top matrix set few hours remove side frames pull out center post may necessary trim away thin layer matrix has tendency seep past Continued page 122 ciosing act ideai viscosity EPON 815 resin controis overfiow ends though mold fuli brim close mold hand bringing two halves together too quickiy wiii wash too much roving out maid weaken prop C-ciamps used controi ciosing speed moid secure two haives gether once have mated Gioves must some may aiiergic resin Afterthe prop cures rod puiled outwith visegrips andthe mold can separated see text detaiis End spearsthatwere formed provide handiesto help removethe prop Lineup some props author has produced using methods Au combi nations giass carbon fiber possi bie Experiment best suits New Sensation Towing Friends Glider created first Big modified Clark-Y airfoil realistic docile flying STOL capabilities ideal Quadra precut firewall flies also well 90 Two-Stroke 120 Four-Stroke realistic spring-loaded telescopic landing gear - Flying Weight 18 lbs Weight 6 lbs 702 Functions Full House plus Optionals Optionals Fiaps mixed ailerons own discre tion Releasable tow-hook extra cost own discretion Engine Quadra Irecommended towingi Other Models Also Available Call Write Information IKAROS INTERNA TIONAL 7035 LAWN WOOD LANE HOUSTON TEXAS 77086 893-1418 Make Towfl torque twists out outsidesso far dont use choke starting quick starter though gross well over 8 lb no apparent need bigger Enyn 80 basically rebored 60 3 oz lighter Maybe hotshots 60 14-6 ship goes airborne during moderately fast taxi upon hitting slightest bump Dont ask plans Rosenstock sells plans authentic 1 960s version thing fourstroke engine necessary place 1000 mAh pack above CG instead nose word caution engine has front plug use remote booster hookup just seven flights two guys have nicked fingers Certain props size could easily remove finger though user responsibility now hold cylinder head same hand takes care detaching battery clip never locked really need metered glow driver sure dont load up engine due no battery contact loosens prop Don t count smart Bill Winter 4432 Altura Ct Fajifax VA 22030 Props/Dunham Continued page 45 framing edges reveal parting line sharp-edged tool deliver few tentative pecking-type blows ham mer several places along parting line mold halves should split apart cleanly trouble encountered getting mold halves separate let matrix cure another hour try again prop exposed halves parted should carefully pried loose removed Assemble halves together again reclamp allowing mold cure fully clamping cured bottom half bowing alignment prob lems top half will straighten out Wash mold remove traces PVA relieve ends tongue area sharp knife gap should approximately Y$2 just enough glass carbon strands extend beyond ends still allowing mold close tightly cutting down part go flush blade surface Leave slight ridge provide outline blade shape removing molding flash mold completed have marked corresponding ends assure correct assembly later Making prop epoxy resin chosen has proven very satisfactory application made Shell Chemical sold under trade name EPON 815 clear syrupy liquid mixed catalyst having tongue-twisting chemical name Tn ethylenetetramine TETA nicely wets FG/CF strands cures produce strong stiff yet too brittle struc tore Usable pot life about 1 hr room temperature ample viscosity sufficiently low permit FG/CF strands easily maneuvered high enough resin stay mold Fiberglass reinforcement rovings bun dle form resembling coarse twine easily handled bundle consists about 30-40 individual glass filaments CertainTeed Owens-Corning just two firms market form strand known gun roving descrip tive process after being chopped small lengths shot under pressure sprayed stream resin Familiar objects such hot tubs shower stalls boat hulls camper tops made using technique Any glass strand form choose unraveled cloth should chrome/silane sized improve wetting resin-compatibility character istics Carbon fiber commonly used alternate fiberglass combination FG same lay-up CF imparts great strength rigidity lighter weight adds color preferred some However CF brittle prone break age landing CF also expensive opinion bit difficult work imply CF desirable choice fact preferred users good quality beam-type scale almost necessity weighing resin catalyst strands As will dealing quantities weighing no 2 oz little small fraction ounce accuracy needed Guessing will get job done necessary build borrow scale better yet buy good such made Ohaus Other items required PVA release agent mixing containers clamps disposable brushes lots paper towels Again word warning about handling epoxies catalysts have history alergies working resins go further project others should take precautions using gloves face mask guard against toxicity materials Adequate ven tilation wash-up after skin contact recommended Cut reinforcing strands length before fingers become sticky resin difficult describe will vary prop size shape general always cut strands pairs starting longest lengths should least 1 longer mold extend well past end relief slots Prepare progressively shorter lengths 1-in increments until get some near half props diameter hub area can stuffed short clippings filling imparting hardness pos sible ratio resin weight roving weight should least 6040 weight strand material required attain ratio hard determine first try corrections can made later attempts 122Model Aviation CLEVIILAND GIANTS 78 onool Cot PSYSA $42621o JN4 Jenny$28 104 Co, Cot FBY5A$5660 V05 Co 945$25 96W gh Nooy8ooe $48 OOVogtCo F40$69 52W W,r0121 RodL$26SASODorrroooIeSI$4B 77WWnro21561$4872Co0251/4LbS045 84 Foblo 07 F52962 Hoooo 6 Rooo lb $46 60 Honoord F Boo 23377 8oe o B hG Fo $25 70 soylco G-5o $22 102 817G Fort $55 -60 Sopornronn 068 $24 68 toog O-46A Dl, $22 89 Soprr~orin 568 $22 108 Sikor 2-38 Aoph 049 * 62 Cort Honob F6E $42 OSBoc 10$ Sport . $26 94 CorOok P6E F, 95490 8oo 100 Spot . $49 02 Lookkeod Vogo 024 90 StinoAtono WI,0 $56 76 SooIrrlo GB 11 $40 8$ Mortir 7424141 $29 95 Monoooopo Sport $26 75 HFoo 5400 Bomb $25 80 BoIl Spr Soildog $42 100 8-Foe 0400 Born $49 107 Aeronoo C3 $pr $32 60 8Eooomoo VToil $29 -41 Doogloo 030 Ok $32 77 Loooonrbo Sodorr $25 * 122 Dooglo 030 0k04F 72NA Miroh Bonrb $49 94 Fog Cort Oooer $45- 65 TMMorooder 826 049 71 Morn 510 Bonb $29 81 80 Mooqoiro Sb $42 78 Torn, WW 80002510808 MoosoOoorb $55 64 Cor Goobk Fl tC2 842 90 Stoor FTl7toydet $56P4tor Gooblo FtIC2 $54 9NBlb Widomo 961 849 66 DeHoS Cooot Boo $24 71 Boog OC3 Torr $32. 52 floooMrMoIllgon 835 95 Looo tC3 Tron 055 * 94 KooM Molligoo $45r 06 Ho,k Yooooo 12 $29 63 Booing p38A FIr $36 108 CorOSO 1/4 L&$ $56r 84 Boeing P-26A Ftr $48 60 loo9loo 142 Moil $34 49 Wooo C4 Cobio $36 68 Briotol Boildog Fr $30 64 Beeoh C17B Stog $38 SF BrooonRooeMoLA $54r96 Beeoh C17B Stog $49 1070 Boo otFOF 854 55 Look 11 Eleotro 030 73 Troonl 6000 034 83 Look 11 Elootro $40 lO7Mo t MB 1 Boor $44 42 S8noon T/W S07 $16 91 Lodbergo NO211 81 Stlnoon 2/W $87 024 100 FoirohPT19 5 $29i 122 Stinoon 5/W SB7 038 90Wp W 0039 59 8ritol Fr 935 020 75 W4o 4 $32 78 Briotol Fr 93-B 032 100W4 4 110 Briotol FtrF2B $45 379 4rn 74TL Peooo Opeo 045769 4roA 3Sbyrook 59SF-I $24 1144noA $59 56 Cor Worbk 948 034 048 5 $56 8 Look Ligbog 938 050 93 $6 Sop Sco-Bee A, 024 58 G 4 BepSooB Anph 039 78 0 106 Piper J3 Cob 90 98 look Hodoon snob 038 117 Bo 43 Gonr 969 Helloot $38 68 55 Hooth Boby Bolt 024 54 C SoI4 Thro toolerFri0 Am, rotc oootroeo Qrjor OoerlAOO l4ore 500 Op 612 A44 tE% oil ordero Oo oh USA Con & 140 EIoooher 15% 125% lby oiI Potonol ooolog $2 00 Inolode Froce Loot Frioe loot * 00100 olon 81 0$ oo toregn odd 8100 LEVELAND MODEL & SUPPLY Co0 o,oWor 100050 t PAoo*OooIotrOoo Efl MOEOoOOOOoOFOCO* oOo008000000pOOo 183078 DETROIT AVE CLEVBLAND OHIO 44102 oonoooooooHooOooo ne 515 PM9ST 0221-12 161 9613600 E0noOOr 9 Prepare epoxy resin Wearing pro tective gloves using accurate scale carefully weigh out predetermined quan tity EPON 815 Dont forget record weight empty container can determine net amount resin amount TETA catalyst should range 15-20% resin weight 17% being about ideal example assume 8-in-dia prop will require 22 grams EPON amount TETA needed will additional 375 grams giving total liquid weight 25 75 grams Mix resin catalyst thoroughly allow settle about 10 min permit bubbles clear Because way mold con structed bottom half natural reser voir ideal trough lay-up prop Start giving trough area heavy coat epoxy resin lay longest rovings arranging straddle center post Always keep strands centered lengthwise mold assist equalizing blade balance Use small stick x smoothed rounded end spread out filaments cover much blade area possible Add resin progress shorter lengths using stick maneuver strands work out bubbles might trapped hub area can filled 1-in shorter clippings keeping whole mass wet resin Keep filaments confined blade area let slide closing faces will notice rovings begin take silver translucent appearance some seeming disappear entirely sign good wetting necessary resin penetration occurring glass place trough filled resin coat top mold face resin slide down onto center post Check make sure mold match marks correspond because mold closed reversed ends will never able reopen mold salvage what have done point Manually bring top mold down within about ing position four clamps shown pictures clamps should very slowly evenly tightened until faces close tightly will some loss glass lot oozing resin between faces normal Too much glass loss indicates either overstuffed mold closed too rapidly Cleaning up can accom plished acetone epoxy thinner Lay mold aside making sure level something underneath catch cascading drips normal room tem perature prop will take five six hours hardenconsiderably less left direct sun warm oven Check stiffness end spears doubt convinced epoxy firm loosen clamps use vice-grip pliers remove center post twisting pull advisable trim away washed-out rovings have formed long sides since will interfere opening mold Leave end spears untouched time five-minute soaking mold very hot water can sometimes wonders getting come apart Insert sharp knife screwdriver several places along parting line two halves should separate free prop again immerse hot water lift flashing flaps loosen grip especially hub area pull up end spears prop should snap free mold point should holding molded prop attached rectangle thin flashing Most flashing can cut away scissorsup within line sharp flat medium-coarse file used remove last ng along cleft line between flash prop Just few strokes will job nicely area around hub can best removed X-Acto knife file end spears cut away scissors after first filing groove across tongue sharp edge file Balancing prop acoomplished file and/or sandpaper progressing No 150 No 300 final polish Restrict balancing work top curved surface otherwise stand good chance altering blade pitch need help locating supplies cannot purchase small lots please contact Bob Dunham 4730 So Yorktown Tulsa OK 74105 starter kit consisting auto body filler PVA EPON 815 TETA vinyl gloves fiberglass rovings can furnished $60 postpaid US kit contains enough filler fiberglass other liquids make couple molds 20 25 medium-size props Material Sources Auto body filler CUZ NAPA Auto motive Stores White Knight K-Mart Wal Mart auto supply parts stores Steel-filled epoxy 1 qt kit EPOCAST #1 iB #9812 hardener EV Roberts & Assoc Box 868 Culver City CA 90232 phone 1-800-421-0824 Epoxy resin Shell Chemical EPON 815 EV Roberts & Assoc Epoxy catalyst TETA EV Roberts & Assoc Polyester resin K&B Manufacturing hobby shops Fiberglass rovings Owens-Corning Product #447-211 #352-211 CertainTeed Product #282-Bi See Yellow Pages under Fiberglass Materials Carbon fiber tows Gougeon Bros Box X908 Bay City MI 48707 NFFS Supplies 12 Cook St Rowayton CT 06853 RC History/Good Continued page 60 throttle offone time Panel lights indicated airborne pilot control signal being transmitted Continued page 126 March 1986 123 Will OPS 000 Sa#uoc4 specialists High Performance Model Airplane Engines stock parts back up will like doing business us See local hoppy shop P arts Peo pie Box 26247 New Orleans LA 70186 242-5967
Edition: Model Aviation - 1986/03
Page Numbers: 42, 43, 44, 45, 122, 123
How Mold FalansentReinforced Props taking time cast own props may seem like lot trouble equates tailor-made suit compared off rack Nothing can fit specific needs better EBob Dunham USING PROCEDURES developed serious Control Line Free Flight fliers description make rein forced plastic propellers using split mold procedure has refined recent years point consistent reliable results can produced great dif ficulty propeller tip-to-tip fiberglass carbon fiber hereinafter referred FG/CF rovings tows almost neces sity using high-revving Schnuerle-ported engines turning speed approaching excess 28000 rpm important maintain both blade pitch efficiency structural integrity safety lower rpm forces blade some propellersin both outward twisting directionscan cause blade shedding failure usually oc curring hub area can endanger operator others within 30-ft radius FG/CF other blade reinforcement material prop unexpected blade separation can still some times occur always good practice use protective eye gear check prop carefully after flight obscure landing damage over-stressing previous flight several advantages making own FG/CF props model interests mainstream popu larity already have found model shops simply stock props suitable high-revving engines leaves choices substituting less-de sirable prop writing manufacturer cottage industry molder possibly wait ing several weeks delivery Also like original can carve prop own specifications reproduce FG/CF over over Similarly ex 42 Model Aviation isting prop can thinned repitched re shaped generally reworked close relative can molded new prop produced incorporating modifica tions mold presented satisfactory use reinforcing materials fiber glass carbon fiber combination Making mold first step both Keviar has also used have no experience application Materials produce several molds enough epoxy resin strand material make 30 40 props will cost neighborhood $75 Above Lineup principal Ingredients will used make mold Below Ma terials used produce reinforced prop Source list end text contains addresses contact special materials may able find locally Pattern prop mounted base piate shaft place Smooth-flowing clay lines desirable Take special note 150 parting line hub tip treatment difficult part project done care will reward quality product can used times over molding matrix can either auto body filler polyester base steelfilled epoxy resin first attempt please try body filler easily obtained will produce very satisfactory mold steel-filled epoxy harder durable does shrink however expensive delivery listed source slow main disadvantages auto body filler produces somewhat softer mold prone wear chipping shrinks slightly cured makes copy prop slightly diminished size original enough cause problem Construction mold same regardless matrix choose will need polyester resin thinning purposes polyvinyl alcohol PVA re lease agent PVA vital its importance will become apparent read along green-tinted water-soluble liquid applied brush has consistency thin dope dries rapidly metal base plate needed should approximately -in thick absolutely flat smooth since shapes mold parting line base plate should least 2 wide 12 long Using care drill press position hole midpoint match prop shaft diameter best hole tight fit 3-in length steel rod mold side frames can cut plywood awidthof 1 4 Lengths wooden yardstick make very suitable substitute will need two long sides about 1 longer prop diameter two end pieces about 1 long mold frames should given two coats clear epoxy paint side allowed cure Choose prop wish reproduce varnished wood variety finish must removed sanding washing acetone suggest further thin prop blades sanding about five thousandths away top curved side makes allowance strand interference between mold faces two coats epoxy paint applied prop seal grain prevent absorbing liquids Spraying preferred over brushing minimize thickness build-up molding fiberglass nylon plastic prop go through same blade-thinning operation paint epoxy Check finished prop wish reproduce has no nicks scratches slightest imperfection wood grain brush marks will reproduced real business matter Mount pattern prop base plate top camber facing up center post inserted drilled hole aligned perpendicular plate directions Both blade tips should same distance above surface plate Make worms hand-warmed clay fill area underneath blades take care deform bend blades process Using tool such back edge single-edge razor blade carefully mold clay parting draft angle about 15 formed angle necessary get poured mold release properly hub area takes slightly different treatment can best shown photos tips leave tongue area extends about nd prop tip maintaining general slope con tour blade may take several tries resculpting attempts get things looking just right will soon get hang wet finger helpful obtain desired smoothness March 1986 43 PVA release agent applied surfaces retainer box absolute must order retrieve prop molding matrix C-clamps secure box sides base plate Auto body filler recommended first attempts making mold Instance though steel-filled epoxy being poured over clayed-up prop produce bottom half Actually procedure same whether body filler steel-filled epoxy used Once bottom half mold has cured isturned overand used asthe baseforpouring top half mold Secure box C-clamps again coat insides PVA black gunk being poured produce top half mold messy prepared lots rags newspapers drop cloth catch Inevitable drips refrain repeatedly going over area things seem get worse finished wash oil clay smears plate acetone Assemble mold frames rec tangular box joining 5-min epoxy sides box already painted epoxy should face inward end pieces located just barely enclose clay tongues Place box over clayed up prop secure base Cclamps done coat inside surfaces box well post prop clay two coats PVA applied soft brush After coating careful break disturb green PVA skinwhich will give good visual indication parts coated Allow PVA dry thoroughly During mixing pouring opera tions follow disposable vinyl gloves protective glasses should worn work area should well-ventilated Always read heed caution labels materials familiar know what accident should occur Pouring mold matrix next will describe use body filler though procedure steel-filled epoxy essen tially same personal preferences brands available CUZ White Knight both easily obtained An 8-in-dia prop mold will require about 7 oz 200 grams filler mixed about 1 oz 28 grams polyester resin milkshake-like con sistency amount thinning resin required will vary between brands Discard catalyst accompanied body filler use polyester resin catalyst instead liquid catalyst clear squeeze bottle easier measure control paste catalyst supplied filler amount thinned Before beginning lay-up rovings cutand arranged man orderlyfashion nearby wilt handy Longest rovings laid first Straddle center post center extend out both ends Proceed tothe shorter rovings 1-in steps Relieve ends mold producethis small gap will allow glass rovings run full length blade give additional strength Key markings mold ends prevent accidental disas trous reversing mold reassembly jreat definItion has attained mold produced auto body filler bottom half natural reservoIr will hold epoxy reinforcing strands during lay-up Note mold tip relieving does extend inward past edge mark left bythe prop Two coats applied surfaces before beginning lay-up e release agent must get mold halves apart Use care green skin forms easily broken Pack critical hub area blade sep aration Ia moat likely Occur short giass clippingeto firm up Watch see glass changes ocior good wetting body filler use thoroughly mix about 2 drops catalyst matrix slowly poured mold box using lengthwise back-and-forth motion pro duce build-up andto avoid bubbles After matrix has become firm 2-3 hr still pliable centerpost can removed exerting twisting pulling tug pliers C-clamps loos ened should able lift slide complete assembly plate Dis mantle wooden sides remove much clay possible fingers give access pattern prop Without marring mold face angled sides exposed gently lift prop using reasonable persuasion pop prop out mold Tag corresponding ends mold prop later reassembly can accomplished prop removed mold may still flexible re-clamp plate curing another couple hours until stiff complete part mold remove PVA clay residue washing soap water Pouring top half mold next first step give entire bottom half loose prop ooat PVA dry return prop bottom mold making sure orientation corresponds markings Insert center post assemble wooden frame around mold maintain tight fit C-clamps assure easy release later apply final coat PVA prop mold face center post inside sur faces frame Mix auto body matrix before Pour enclosure filling thickness about w top matrix set few hours remove side frames pull out center post may necessary trim away thin layer matrix has tendency seep past Continued page 122 ciosing act ideai viscosity EPON 815 resin controis overfiow ends though mold fuli brim close mold hand bringing two halves together too quickiy wiii wash too much roving out maid weaken prop C-ciamps used controi ciosing speed moid secure two haives gether once have mated Gioves must some may aiiergic resin Afterthe prop cures rod puiled outwith visegrips andthe mold can separated see text detaiis End spearsthatwere formed provide handiesto help removethe prop Lineup some props author has produced using methods Au combi nations giass carbon fiber possi bie Experiment best suits New Sensation Towing Friends Glider created first Big modified Clark-Y airfoil realistic docile flying STOL capabilities ideal Quadra precut firewall flies also well 90 Two-Stroke 120 Four-Stroke realistic spring-loaded telescopic landing gear - Flying Weight 18 lbs Weight 6 lbs 702 Functions Full House plus Optionals Optionals Fiaps mixed ailerons own discre tion Releasable tow-hook extra cost own discretion Engine Quadra Irecommended towingi Other Models Also Available Call Write Information IKAROS INTERNA TIONAL 7035 LAWN WOOD LANE HOUSTON TEXAS 77086 893-1418 Make Towfl torque twists out outsidesso far dont use choke starting quick starter though gross well over 8 lb no apparent need bigger Enyn 80 basically rebored 60 3 oz lighter Maybe hotshots 60 14-6 ship goes airborne during moderately fast taxi upon hitting slightest bump Dont ask plans Rosenstock sells plans authentic 1 960s version thing fourstroke engine necessary place 1000 mAh pack above CG instead nose word caution engine has front plug use remote booster hookup just seven flights two guys have nicked fingers Certain props size could easily remove finger though user responsibility now hold cylinder head same hand takes care detaching battery clip never locked really need metered glow driver sure dont load up engine due no battery contact loosens prop Don t count smart Bill Winter 4432 Altura Ct Fajifax VA 22030 Props/Dunham Continued page 45 framing edges reveal parting line sharp-edged tool deliver few tentative pecking-type blows ham mer several places along parting line mold halves should split apart cleanly trouble encountered getting mold halves separate let matrix cure another hour try again prop exposed halves parted should carefully pried loose removed Assemble halves together again reclamp allowing mold cure fully clamping cured bottom half bowing alignment prob lems top half will straighten out Wash mold remove traces PVA relieve ends tongue area sharp knife gap should approximately Y$2 just enough glass carbon strands extend beyond ends still allowing mold close tightly cutting down part go flush blade surface Leave slight ridge provide outline blade shape removing molding flash mold completed have marked corresponding ends assure correct assembly later Making prop epoxy resin chosen has proven very satisfactory application made Shell Chemical sold under trade name EPON 815 clear syrupy liquid mixed catalyst having tongue-twisting chemical name Tn ethylenetetramine TETA nicely wets FG/CF strands cures produce strong stiff yet too brittle struc tore Usable pot life about 1 hr room temperature ample viscosity sufficiently low permit FG/CF strands easily maneuvered high enough resin stay mold Fiberglass reinforcement rovings bun dle form resembling coarse twine easily handled bundle consists about 30-40 individual glass filaments CertainTeed Owens-Corning just two firms market form strand known gun roving descrip tive process after being chopped small lengths shot under pressure sprayed stream resin Familiar objects such hot tubs shower stalls boat hulls camper tops made using technique Any glass strand form choose unraveled cloth should chrome/silane sized improve wetting resin-compatibility character istics Carbon fiber commonly used alternate fiberglass combination FG same lay-up CF imparts great strength rigidity lighter weight adds color preferred some However CF brittle prone break age landing CF also expensive opinion bit difficult work imply CF desirable choice fact preferred users good quality beam-type scale almost necessity weighing resin catalyst strands As will dealing quantities weighing no 2 oz little small fraction ounce accuracy needed Guessing will get job done necessary build borrow scale better yet buy good such made Ohaus Other items required PVA release agent mixing containers clamps disposable brushes lots paper towels Again word warning about handling epoxies catalysts have history alergies working resins go further project others should take precautions using gloves face mask guard against toxicity materials Adequate ven tilation wash-up after skin contact recommended Cut reinforcing strands length before fingers become sticky resin difficult describe will vary prop size shape general always cut strands pairs starting longest lengths should least 1 longer mold extend well past end relief slots Prepare progressively shorter lengths 1-in increments until get some near half props diameter hub area can stuffed short clippings filling imparting hardness pos sible ratio resin weight roving weight should least 6040 weight strand material required attain ratio hard determine first try corrections can made later attempts 122Model Aviation CLEVIILAND GIANTS 78 onool Cot PSYSA $42621o JN4 Jenny$28 104 Co, Cot FBY5A$5660 V05 Co 945$25 96W gh Nooy8ooe $48 OOVogtCo F40$69 52W W,r0121 RodL$26SASODorrroooIeSI$4B 77WWnro21561$4872Co0251/4LbS045 84 Foblo 07 F52962 Hoooo 6 Rooo lb $46 60 Honoord F Boo 23377 8oe o B hG Fo $25 70 soylco G-5o $22 102 817G Fort $55 -60 Sopornronn 068 $24 68 toog O-46A Dl, $22 89 Soprr~orin 568 $22 108 Sikor 2-38 Aoph 049 * 62 Cort Honob F6E $42 OSBoc 10$ Sport . $26 94 CorOok P6E F, 95490 8oo 100 Spot . $49 02 Lookkeod Vogo 024 90 StinoAtono WI,0 $56 76 SooIrrlo GB 11 $40 8$ Mortir 7424141 $29 95 Monoooopo Sport $26 75 HFoo 5400 Bomb $25 80 BoIl Spr Soildog $42 100 8-Foe 0400 Born $49 107 Aeronoo C3 $pr $32 60 8Eooomoo VToil $29 -41 Doogloo 030 Ok $32 77 Loooonrbo Sodorr $25 * 122 Dooglo 030 0k04F 72NA Miroh Bonrb $49 94 Fog Cort Oooer $45- 65 TMMorooder 826 049 71 Morn 510 Bonb $29 81 80 Mooqoiro Sb $42 78 Torn, WW 80002510808 MoosoOoorb $55 64 Cor Goobk Fl tC2 842 90 Stoor FTl7toydet $56P4tor Gooblo FtIC2 $54 9NBlb Widomo 961 849 66 DeHoS Cooot Boo $24 71 Boog OC3 Torr $32. 52 floooMrMoIllgon 835 95 Looo tC3 Tron 055 * 94 KooM Molligoo $45r 06 Ho,k Yooooo 12 $29 63 Booing p38A FIr $36 108 CorOSO 1/4 L&$ $56r 84 Boeing P-26A Ftr $48 60 loo9loo 142 Moil $34 49 Wooo C4 Cobio $36 68 Briotol Boildog Fr $30 64 Beeoh C17B Stog $38 SF BrooonRooeMoLA $54r96 Beeoh C17B Stog $49 1070 Boo otFOF 854 55 Look 11 Eleotro 030 73 Troonl 6000 034 83 Look 11 Elootro $40 lO7Mo t MB 1 Boor $44 42 S8noon T/W S07 $16 91 Lodbergo NO211 81 Stlnoon 2/W $87 024 100 FoirohPT19 5 $29i 122 Stinoon 5/W SB7 038 90Wp W 0039 59 8ritol Fr 935 020 75 W4o 4 $32 78 Briotol Fr 93-B 032 100W4 4 110 Briotol FtrF2B $45 379 4rn 74TL Peooo Opeo 045769 4roA 3Sbyrook 59SF-I $24 1144noA $59 56 Cor Worbk 948 034 048 5 $56 8 Look Ligbog 938 050 93 $6 Sop Sco-Bee A, 024 58 G 4 BepSooB Anph 039 78 0 106 Piper J3 Cob 90 98 look Hodoon snob 038 117 Bo 43 Gonr 969 Helloot $38 68 55 Hooth Boby Bolt 024 54 C SoI4 Thro toolerFri0 Am, rotc oootroeo Qrjor OoerlAOO l4ore 500 Op 612 A44 tE% oil ordero Oo oh USA Con & 140 EIoooher 15% 125% lby oiI Potonol ooolog $2 00 Inolode Froce Loot Frioe loot * 00100 olon 81 0$ oo toregn odd 8100 LEVELAND MODEL & SUPPLY Co0 o,oWor 100050 t PAoo*OooIotrOoo Efl MOEOoOOOOoOFOCO* oOo008000000pOOo 183078 DETROIT AVE CLEVBLAND OHIO 44102 oonoooooooHooOooo ne 515 PM9ST 0221-12 161 9613600 E0noOOr 9 Prepare epoxy resin Wearing pro tective gloves using accurate scale carefully weigh out predetermined quan tity EPON 815 Dont forget record weight empty container can determine net amount resin amount TETA catalyst should range 15-20% resin weight 17% being about ideal example assume 8-in-dia prop will require 22 grams EPON amount TETA needed will additional 375 grams giving total liquid weight 25 75 grams Mix resin catalyst thoroughly allow settle about 10 min permit bubbles clear Because way mold con structed bottom half natural reser voir ideal trough lay-up prop Start giving trough area heavy coat epoxy resin lay longest rovings arranging straddle center post Always keep strands centered lengthwise mold assist equalizing blade balance Use small stick x smoothed rounded end spread out filaments cover much blade area possible Add resin progress shorter lengths using stick maneuver strands work out bubbles might trapped hub area can filled 1-in shorter clippings keeping whole mass wet resin Keep filaments confined blade area let slide closing faces will notice rovings begin take silver translucent appearance some seeming disappear entirely sign good wetting necessary resin penetration occurring glass place trough filled resin coat top mold face resin slide down onto center post Check make sure mold match marks correspond because mold closed reversed ends will never able reopen mold salvage what have done point Manually bring top mold down within about ing position four clamps shown pictures clamps should very slowly evenly tightened until faces close tightly will some loss glass lot oozing resin between faces normal Too much glass loss indicates either overstuffed mold closed too rapidly Cleaning up can accom plished acetone epoxy thinner Lay mold aside making sure level something underneath catch cascading drips normal room tem perature prop will take five six hours hardenconsiderably less left direct sun warm oven Check stiffness end spears doubt convinced epoxy firm loosen clamps use vice-grip pliers remove center post twisting pull advisable trim away washed-out rovings have formed long sides since will interfere opening mold Leave end spears untouched time five-minute soaking mold very hot water can sometimes wonders getting come apart Insert sharp knife screwdriver several places along parting line two halves should separate free prop again immerse hot water lift flashing flaps loosen grip especially hub area pull up end spears prop should snap free mold point should holding molded prop attached rectangle thin flashing Most flashing can cut away scissorsup within line sharp flat medium-coarse file used remove last ng along cleft line between flash prop Just few strokes will job nicely area around hub can best removed X-Acto knife file end spears cut away scissors after first filing groove across tongue sharp edge file Balancing prop acoomplished file and/or sandpaper progressing No 150 No 300 final polish Restrict balancing work top curved surface otherwise stand good chance altering blade pitch need help locating supplies cannot purchase small lots please contact Bob Dunham 4730 So Yorktown Tulsa OK 74105 starter kit consisting auto body filler PVA EPON 815 TETA vinyl gloves fiberglass rovings can furnished $60 postpaid US kit contains enough filler fiberglass other liquids make couple molds 20 25 medium-size props Material Sources Auto body filler CUZ NAPA Auto motive Stores White Knight K-Mart Wal Mart auto supply parts stores Steel-filled epoxy 1 qt kit EPOCAST #1 iB #9812 hardener EV Roberts & Assoc Box 868 Culver City CA 90232 phone 1-800-421-0824 Epoxy resin Shell Chemical EPON 815 EV Roberts & Assoc Epoxy catalyst TETA EV Roberts & Assoc Polyester resin K&B Manufacturing hobby shops Fiberglass rovings Owens-Corning Product #447-211 #352-211 CertainTeed Product #282-Bi See Yellow Pages under Fiberglass Materials Carbon fiber tows Gougeon Bros Box X908 Bay City MI 48707 NFFS Supplies 12 Cook St Rowayton CT 06853 RC History/Good Continued page 60 throttle offone time Panel lights indicated airborne pilot control signal being transmitted Continued page 126 March 1986 123 Will OPS 000 Sa#uoc4 specialists High Performance Model Airplane Engines stock parts back up will like doing business us See local hoppy shop P arts Peo pie Box 26247 New Orleans LA 70186 242-5967
Edition: Model Aviation - 1986/03
Page Numbers: 42, 43, 44, 45, 122, 123
How Mold FalansentReinforced Props taking time cast own props may seem like lot trouble equates tailor-made suit compared off rack Nothing can fit specific needs better EBob Dunham USING PROCEDURES developed serious Control Line Free Flight fliers description make rein forced plastic propellers using split mold procedure has refined recent years point consistent reliable results can produced great dif ficulty propeller tip-to-tip fiberglass carbon fiber hereinafter referred FG/CF rovings tows almost neces sity using high-revving Schnuerle-ported engines turning speed approaching excess 28000 rpm important maintain both blade pitch efficiency structural integrity safety lower rpm forces blade some propellersin both outward twisting directionscan cause blade shedding failure usually oc curring hub area can endanger operator others within 30-ft radius FG/CF other blade reinforcement material prop unexpected blade separation can still some times occur always good practice use protective eye gear check prop carefully after flight obscure landing damage over-stressing previous flight several advantages making own FG/CF props model interests mainstream popu larity already have found model shops simply stock props suitable high-revving engines leaves choices substituting less-de sirable prop writing manufacturer cottage industry molder possibly wait ing several weeks delivery Also like original can carve prop own specifications reproduce FG/CF over over Similarly ex 42 Model Aviation isting prop can thinned repitched re shaped generally reworked close relative can molded new prop produced incorporating modifica tions mold presented satisfactory use reinforcing materials fiber glass carbon fiber combination Making mold first step both Keviar has also used have no experience application Materials produce several molds enough epoxy resin strand material make 30 40 props will cost neighborhood $75 Above Lineup principal Ingredients will used make mold Below Ma terials used produce reinforced prop Source list end text contains addresses contact special materials may able find locally Pattern prop mounted base piate shaft place Smooth-flowing clay lines desirable Take special note 150 parting line hub tip treatment difficult part project done care will reward quality product can used times over molding matrix can either auto body filler polyester base steelfilled epoxy resin first attempt please try body filler easily obtained will produce very satisfactory mold steel-filled epoxy harder durable does shrink however expensive delivery listed source slow main disadvantages auto body filler produces somewhat softer mold prone wear chipping shrinks slightly cured makes copy prop slightly diminished size original enough cause problem Construction mold same regardless matrix choose will need polyester resin thinning purposes polyvinyl alcohol PVA re lease agent PVA vital its importance will become apparent read along green-tinted water-soluble liquid applied brush has consistency thin dope dries rapidly metal base plate needed should approximately -in thick absolutely flat smooth since shapes mold parting line base plate should least 2 wide 12 long Using care drill press position hole midpoint match prop shaft diameter best hole tight fit 3-in length steel rod mold side frames can cut plywood awidthof 1 4 Lengths wooden yardstick make very suitable substitute will need two long sides about 1 longer prop diameter two end pieces about 1 long mold frames should given two coats clear epoxy paint side allowed cure Choose prop wish reproduce varnished wood variety finish must removed sanding washing acetone suggest further thin prop blades sanding about five thousandths away top curved side makes allowance strand interference between mold faces two coats epoxy paint applied prop seal grain prevent absorbing liquids Spraying preferred over brushing minimize thickness build-up molding fiberglass nylon plastic prop go through same blade-thinning operation paint epoxy Check finished prop wish reproduce has no nicks scratches slightest imperfection wood grain brush marks will reproduced real business matter Mount pattern prop base plate top camber facing up center post inserted drilled hole aligned perpendicular plate directions Both blade tips should same distance above surface plate Make worms hand-warmed clay fill area underneath blades take care deform bend blades process Using tool such back edge single-edge razor blade carefully mold clay parting draft angle about 15 formed angle necessary get poured mold release properly hub area takes slightly different treatment can best shown photos tips leave tongue area extends about nd prop tip maintaining general slope con tour blade may take several tries resculpting attempts get things looking just right will soon get hang wet finger helpful obtain desired smoothness March 1986 43 PVA release agent applied surfaces retainer box absolute must order retrieve prop molding matrix C-clamps secure box sides base plate Auto body filler recommended first attempts making mold Instance though steel-filled epoxy being poured over clayed-up prop produce bottom half Actually procedure same whether body filler steel-filled epoxy used Once bottom half mold has cured isturned overand used asthe baseforpouring top half mold Secure box C-clamps again coat insides PVA black gunk being poured produce top half mold messy prepared lots rags newspapers drop cloth catch Inevitable drips refrain repeatedly going over area things seem get worse finished wash oil clay smears plate acetone Assemble mold frames rec tangular box joining 5-min epoxy sides box already painted epoxy should face inward end pieces located just barely enclose clay tongues Place box over clayed up prop secure base Cclamps done coat inside surfaces box well post prop clay two coats PVA applied soft brush After coating careful break disturb green PVA skinwhich will give good visual indication parts coated Allow PVA dry thoroughly During mixing pouring opera tions follow disposable vinyl gloves protective glasses should worn work area should well-ventilated Always read heed caution labels materials familiar know what accident should occur Pouring mold matrix next will describe use body filler though procedure steel-filled epoxy essen tially same personal preferences brands available CUZ White Knight both easily obtained An 8-in-dia prop mold will require about 7 oz 200 grams filler mixed about 1 oz 28 grams polyester resin milkshake-like con sistency amount thinning resin required will vary between brands Discard catalyst accompanied body filler use polyester resin catalyst instead liquid catalyst clear squeeze bottle easier measure control paste catalyst supplied filler amount thinned Before beginning lay-up rovings cutand arranged man orderlyfashion nearby wilt handy Longest rovings laid first Straddle center post center extend out both ends Proceed tothe shorter rovings 1-in steps Relieve ends mold producethis small gap will allow glass rovings run full length blade give additional strength Key markings mold ends prevent accidental disas trous reversing mold reassembly jreat definItion has attained mold produced auto body filler bottom half natural reservoIr will hold epoxy reinforcing strands during lay-up Note mold tip relieving does extend inward past edge mark left bythe prop Two coats applied surfaces before beginning lay-up e release agent must get mold halves apart Use care green skin forms easily broken Pack critical hub area blade sep aration Ia moat likely Occur short giass clippingeto firm up Watch see glass changes ocior good wetting body filler use thoroughly mix about 2 drops catalyst matrix slowly poured mold box using lengthwise back-and-forth motion pro duce build-up andto avoid bubbles After matrix has become firm 2-3 hr still pliable centerpost can removed exerting twisting pulling tug pliers C-clamps loos ened should able lift slide complete assembly plate Dis mantle wooden sides remove much clay possible fingers give access pattern prop Without marring mold face angled sides exposed gently lift prop using reasonable persuasion pop prop out mold Tag corresponding ends mold prop later reassembly can accomplished prop removed mold may still flexible re-clamp plate curing another couple hours until stiff complete part mold remove PVA clay residue washing soap water Pouring top half mold next first step give entire bottom half loose prop ooat PVA dry return prop bottom mold making sure orientation corresponds markings Insert center post assemble wooden frame around mold maintain tight fit C-clamps assure easy release later apply final coat PVA prop mold face center post inside sur faces frame Mix auto body matrix before Pour enclosure filling thickness about w top matrix set few hours remove side frames pull out center post may necessary trim away thin layer matrix has tendency seep past Continued page 122 ciosing act ideai viscosity EPON 815 resin controis overfiow ends though mold fuli brim close mold hand bringing two halves together too quickiy wiii wash too much roving out maid weaken prop C-ciamps used controi ciosing speed moid secure two haives gether once have mated Gioves must some may aiiergic resin Afterthe prop cures rod puiled outwith visegrips andthe mold can separated see text detaiis End spearsthatwere formed provide handiesto help removethe prop Lineup some props author has produced using methods Au combi nations giass carbon fiber possi bie Experiment best suits New Sensation Towing Friends Glider created first Big modified Clark-Y airfoil realistic docile flying STOL capabilities ideal Quadra precut firewall flies also well 90 Two-Stroke 120 Four-Stroke realistic spring-loaded telescopic landing gear - Flying Weight 18 lbs Weight 6 lbs 702 Functions Full House plus Optionals Optionals Fiaps mixed ailerons own discre tion Releasable tow-hook extra cost own discretion Engine Quadra Irecommended towingi Other Models Also Available Call Write Information IKAROS INTERNA TIONAL 7035 LAWN WOOD LANE HOUSTON TEXAS 77086 893-1418 Make Towfl torque twists out outsidesso far dont use choke starting quick starter though gross well over 8 lb no apparent need bigger Enyn 80 basically rebored 60 3 oz lighter Maybe hotshots 60 14-6 ship goes airborne during moderately fast taxi upon hitting slightest bump Dont ask plans Rosenstock sells plans authentic 1 960s version thing fourstroke engine necessary place 1000 mAh pack above CG instead nose word caution engine has front plug use remote booster hookup just seven flights two guys have nicked fingers Certain props size could easily remove finger though user responsibility now hold cylinder head same hand takes care detaching battery clip never locked really need metered glow driver sure dont load up engine due no battery contact loosens prop Don t count smart Bill Winter 4432 Altura Ct Fajifax VA 22030 Props/Dunham Continued page 45 framing edges reveal parting line sharp-edged tool deliver few tentative pecking-type blows ham mer several places along parting line mold halves should split apart cleanly trouble encountered getting mold halves separate let matrix cure another hour try again prop exposed halves parted should carefully pried loose removed Assemble halves together again reclamp allowing mold cure fully clamping cured bottom half bowing alignment prob lems top half will straighten out Wash mold remove traces PVA relieve ends tongue area sharp knife gap should approximately Y$2 just enough glass carbon strands extend beyond ends still allowing mold close tightly cutting down part go flush blade surface Leave slight ridge provide outline blade shape removing molding flash mold completed have marked corresponding ends assure correct assembly later Making prop epoxy resin chosen has proven very satisfactory application made Shell Chemical sold under trade name EPON 815 clear syrupy liquid mixed catalyst having tongue-twisting chemical name Tn ethylenetetramine TETA nicely wets FG/CF strands cures produce strong stiff yet too brittle struc tore Usable pot life about 1 hr room temperature ample viscosity sufficiently low permit FG/CF strands easily maneuvered high enough resin stay mold Fiberglass reinforcement rovings bun dle form resembling coarse twine easily handled bundle consists about 30-40 individual glass filaments CertainTeed Owens-Corning just two firms market form strand known gun roving descrip tive process after being chopped small lengths shot under pressure sprayed stream resin Familiar objects such hot tubs shower stalls boat hulls camper tops made using technique Any glass strand form choose unraveled cloth should chrome/silane sized improve wetting resin-compatibility character istics Carbon fiber commonly used alternate fiberglass combination FG same lay-up CF imparts great strength rigidity lighter weight adds color preferred some However CF brittle prone break age landing CF also expensive opinion bit difficult work imply CF desirable choice fact preferred users good quality beam-type scale almost necessity weighing resin catalyst strands As will dealing quantities weighing no 2 oz little small fraction ounce accuracy needed Guessing will get job done necessary build borrow scale better yet buy good such made Ohaus Other items required PVA release agent mixing containers clamps disposable brushes lots paper towels Again word warning about handling epoxies catalysts have history alergies working resins go further project others should take precautions using gloves face mask guard against toxicity materials Adequate ven tilation wash-up after skin contact recommended Cut reinforcing strands length before fingers become sticky resin difficult describe will vary prop size shape general always cut strands pairs starting longest lengths should least 1 longer mold extend well past end relief slots Prepare progressively shorter lengths 1-in increments until get some near half props diameter hub area can stuffed short clippings filling imparting hardness pos sible ratio resin weight roving weight should least 6040 weight strand material required attain ratio hard determine first try corrections can made later attempts 122Model Aviation CLEVIILAND GIANTS 78 onool Cot PSYSA $42621o JN4 Jenny$28 104 Co, Cot FBY5A$5660 V05 Co 945$25 96W gh Nooy8ooe $48 OOVogtCo F40$69 52W W,r0121 RodL$26SASODorrroooIeSI$4B 77WWnro21561$4872Co0251/4LbS045 84 Foblo 07 F52962 Hoooo 6 Rooo lb $46 60 Honoord F Boo 23377 8oe o B hG Fo $25 70 soylco G-5o $22 102 817G Fort $55 -60 Sopornronn 068 $24 68 toog O-46A Dl, $22 89 Soprr~orin 568 $22 108 Sikor 2-38 Aoph 049 * 62 Cort Honob F6E $42 OSBoc 10$ Sport . $26 94 CorOok P6E F, 95490 8oo 100 Spot . $49 02 Lookkeod Vogo 024 90 StinoAtono WI,0 $56 76 SooIrrlo GB 11 $40 8$ Mortir 7424141 $29 95 Monoooopo Sport $26 75 HFoo 5400 Bomb $25 80 BoIl Spr Soildog $42 100 8-Foe 0400 Born $49 107 Aeronoo C3 $pr $32 60 8Eooomoo VToil $29 -41 Doogloo 030 Ok $32 77 Loooonrbo Sodorr $25 * 122 Dooglo 030 0k04F 72NA Miroh Bonrb $49 94 Fog Cort Oooer $45- 65 TMMorooder 826 049 71 Morn 510 Bonb $29 81 80 Mooqoiro Sb $42 78 Torn, WW 80002510808 MoosoOoorb $55 64 Cor Goobk Fl tC2 842 90 Stoor FTl7toydet $56P4tor Gooblo FtIC2 $54 9NBlb Widomo 961 849 66 DeHoS Cooot Boo $24 71 Boog OC3 Torr $32. 52 floooMrMoIllgon 835 95 Looo tC3 Tron 055 * 94 KooM Molligoo $45r 06 Ho,k Yooooo 12 $29 63 Booing p38A FIr $36 108 CorOSO 1/4 L&$ $56r 84 Boeing P-26A Ftr $48 60 loo9loo 142 Moil $34 49 Wooo C4 Cobio $36 68 Briotol Boildog Fr $30 64 Beeoh C17B Stog $38 SF BrooonRooeMoLA $54r96 Beeoh C17B Stog $49 1070 Boo otFOF 854 55 Look 11 Eleotro 030 73 Troonl 6000 034 83 Look 11 Elootro $40 lO7Mo t MB 1 Boor $44 42 S8noon T/W S07 $16 91 Lodbergo NO211 81 Stlnoon 2/W $87 024 100 FoirohPT19 5 $29i 122 Stinoon 5/W SB7 038 90Wp W 0039 59 8ritol Fr 935 020 75 W4o 4 $32 78 Briotol Fr 93-B 032 100W4 4 110 Briotol FtrF2B $45 379 4rn 74TL Peooo Opeo 045769 4roA 3Sbyrook 59SF-I $24 1144noA $59 56 Cor Worbk 948 034 048 5 $56 8 Look Ligbog 938 050 93 $6 Sop Sco-Bee A, 024 58 G 4 BepSooB Anph 039 78 0 106 Piper J3 Cob 90 98 look Hodoon snob 038 117 Bo 43 Gonr 969 Helloot $38 68 55 Hooth Boby Bolt 024 54 C SoI4 Thro toolerFri0 Am, rotc oootroeo Qrjor OoerlAOO l4ore 500 Op 612 A44 tE% oil ordero Oo oh USA Con & 140 EIoooher 15% 125% lby oiI Potonol ooolog $2 00 Inolode Froce Loot Frioe loot * 00100 olon 81 0$ oo toregn odd 8100 LEVELAND MODEL & SUPPLY Co0 o,oWor 100050 t PAoo*OooIotrOoo Efl MOEOoOOOOoOFOCO* oOo008000000pOOo 183078 DETROIT AVE CLEVBLAND OHIO 44102 oonoooooooHooOooo ne 515 PM9ST 0221-12 161 9613600 E0noOOr 9 Prepare epoxy resin Wearing pro tective gloves using accurate scale carefully weigh out predetermined quan tity EPON 815 Dont forget record weight empty container can determine net amount resin amount TETA catalyst should range 15-20% resin weight 17% being about ideal example assume 8-in-dia prop will require 22 grams EPON amount TETA needed will additional 375 grams giving total liquid weight 25 75 grams Mix resin catalyst thoroughly allow settle about 10 min permit bubbles clear Because way mold con structed bottom half natural reser voir ideal trough lay-up prop Start giving trough area heavy coat epoxy resin lay longest rovings arranging straddle center post Always keep strands centered lengthwise mold assist equalizing blade balance Use small stick x smoothed rounded end spread out filaments cover much blade area possible Add resin progress shorter lengths using stick maneuver strands work out bubbles might trapped hub area can filled 1-in shorter clippings keeping whole mass wet resin Keep filaments confined blade area let slide closing faces will notice rovings begin take silver translucent appearance some seeming disappear entirely sign good wetting necessary resin penetration occurring glass place trough filled resin coat top mold face resin slide down onto center post Check make sure mold match marks correspond because mold closed reversed ends will never able reopen mold salvage what have done point Manually bring top mold down within about ing position four clamps shown pictures clamps should very slowly evenly tightened until faces close tightly will some loss glass lot oozing resin between faces normal Too much glass loss indicates either overstuffed mold closed too rapidly Cleaning up can accom plished acetone epoxy thinner Lay mold aside making sure level something underneath catch cascading drips normal room tem perature prop will take five six hours hardenconsiderably less left direct sun warm oven Check stiffness end spears doubt convinced epoxy firm loosen clamps use vice-grip pliers remove center post twisting pull advisable trim away washed-out rovings have formed long sides since will interfere opening mold Leave end spears untouched time five-minute soaking mold very hot water can sometimes wonders getting come apart Insert sharp knife screwdriver several places along parting line two halves should separate free prop again immerse hot water lift flashing flaps loosen grip especially hub area pull up end spears prop should snap free mold point should holding molded prop attached rectangle thin flashing Most flashing can cut away scissorsup within line sharp flat medium-coarse file used remove last ng along cleft line between flash prop Just few strokes will job nicely area around hub can best removed X-Acto knife file end spears cut away scissors after first filing groove across tongue sharp edge file Balancing prop acoomplished file and/or sandpaper progressing No 150 No 300 final polish Restrict balancing work top curved surface otherwise stand good chance altering blade pitch need help locating supplies cannot purchase small lots please contact Bob Dunham 4730 So Yorktown Tulsa OK 74105 starter kit consisting auto body filler PVA EPON 815 TETA vinyl gloves fiberglass rovings can furnished $60 postpaid US kit contains enough filler fiberglass other liquids make couple molds 20 25 medium-size props Material Sources Auto body filler CUZ NAPA Auto motive Stores White Knight K-Mart Wal Mart auto supply parts stores Steel-filled epoxy 1 qt kit EPOCAST #1 iB #9812 hardener EV Roberts & Assoc Box 868 Culver City CA 90232 phone 1-800-421-0824 Epoxy resin Shell Chemical EPON 815 EV Roberts & Assoc Epoxy catalyst TETA EV Roberts & Assoc Polyester resin K&B Manufacturing hobby shops Fiberglass rovings Owens-Corning Product #447-211 #352-211 CertainTeed Product #282-Bi See Yellow Pages under Fiberglass Materials Carbon fiber tows Gougeon Bros Box X908 Bay City MI 48707 NFFS Supplies 12 Cook St Rowayton CT 06853 RC History/Good Continued page 60 throttle offone time Panel lights indicated airborne pilot control signal being transmitted Continued page 126 March 1986 123 Will OPS 000 Sa#uoc4 specialists High Performance Model Airplane Engines stock parts back up will like doing business us See local hoppy shop P arts Peo pie Box 26247 New Orleans LA 70186 242-5967
Edition: Model Aviation - 1986/03
Page Numbers: 42, 43, 44, 45, 122, 123
How Mold FalansentReinforced Props taking time cast own props may seem like lot trouble equates tailor-made suit compared off rack Nothing can fit specific needs better EBob Dunham USING PROCEDURES developed serious Control Line Free Flight fliers description make rein forced plastic propellers using split mold procedure has refined recent years point consistent reliable results can produced great dif ficulty propeller tip-to-tip fiberglass carbon fiber hereinafter referred FG/CF rovings tows almost neces sity using high-revving Schnuerle-ported engines turning speed approaching excess 28000 rpm important maintain both blade pitch efficiency structural integrity safety lower rpm forces blade some propellersin both outward twisting directionscan cause blade shedding failure usually oc curring hub area can endanger operator others within 30-ft radius FG/CF other blade reinforcement material prop unexpected blade separation can still some times occur always good practice use protective eye gear check prop carefully after flight obscure landing damage over-stressing previous flight several advantages making own FG/CF props model interests mainstream popu larity already have found model shops simply stock props suitable high-revving engines leaves choices substituting less-de sirable prop writing manufacturer cottage industry molder possibly wait ing several weeks delivery Also like original can carve prop own specifications reproduce FG/CF over over Similarly ex 42 Model Aviation isting prop can thinned repitched re shaped generally reworked close relative can molded new prop produced incorporating modifica tions mold presented satisfactory use reinforcing materials fiber glass carbon fiber combination Making mold first step both Keviar has also used have no experience application Materials produce several molds enough epoxy resin strand material make 30 40 props will cost neighborhood $75 Above Lineup principal Ingredients will used make mold Below Ma terials used produce reinforced prop Source list end text contains addresses contact special materials may able find locally Pattern prop mounted base piate shaft place Smooth-flowing clay lines desirable Take special note 150 parting line hub tip treatment difficult part project done care will reward quality product can used times over molding matrix can either auto body filler polyester base steelfilled epoxy resin first attempt please try body filler easily obtained will produce very satisfactory mold steel-filled epoxy harder durable does shrink however expensive delivery listed source slow main disadvantages auto body filler produces somewhat softer mold prone wear chipping shrinks slightly cured makes copy prop slightly diminished size original enough cause problem Construction mold same regardless matrix choose will need polyester resin thinning purposes polyvinyl alcohol PVA re lease agent PVA vital its importance will become apparent read along green-tinted water-soluble liquid applied brush has consistency thin dope dries rapidly metal base plate needed should approximately -in thick absolutely flat smooth since shapes mold parting line base plate should least 2 wide 12 long Using care drill press position hole midpoint match prop shaft diameter best hole tight fit 3-in length steel rod mold side frames can cut plywood awidthof 1 4 Lengths wooden yardstick make very suitable substitute will need two long sides about 1 longer prop diameter two end pieces about 1 long mold frames should given two coats clear epoxy paint side allowed cure Choose prop wish reproduce varnished wood variety finish must removed sanding washing acetone suggest further thin prop blades sanding about five thousandths away top curved side makes allowance strand interference between mold faces two coats epoxy paint applied prop seal grain prevent absorbing liquids Spraying preferred over brushing minimize thickness build-up molding fiberglass nylon plastic prop go through same blade-thinning operation paint epoxy Check finished prop wish reproduce has no nicks scratches slightest imperfection wood grain brush marks will reproduced real business matter Mount pattern prop base plate top camber facing up center post inserted drilled hole aligned perpendicular plate directions Both blade tips should same distance above surface plate Make worms hand-warmed clay fill area underneath blades take care deform bend blades process Using tool such back edge single-edge razor blade carefully mold clay parting draft angle about 15 formed angle necessary get poured mold release properly hub area takes slightly different treatment can best shown photos tips leave tongue area extends about nd prop tip maintaining general slope con tour blade may take several tries resculpting attempts get things looking just right will soon get hang wet finger helpful obtain desired smoothness March 1986 43 PVA release agent applied surfaces retainer box absolute must order retrieve prop molding matrix C-clamps secure box sides base plate Auto body filler recommended first attempts making mold Instance though steel-filled epoxy being poured over clayed-up prop produce bottom half Actually procedure same whether body filler steel-filled epoxy used Once bottom half mold has cured isturned overand used asthe baseforpouring top half mold Secure box C-clamps again coat insides PVA black gunk being poured produce top half mold messy prepared lots rags newspapers drop cloth catch Inevitable drips refrain repeatedly going over area things seem get worse finished wash oil clay smears plate acetone Assemble mold frames rec tangular box joining 5-min epoxy sides box already painted epoxy should face inward end pieces located just barely enclose clay tongues Place box over clayed up prop secure base Cclamps done coat inside surfaces box well post prop clay two coats PVA applied soft brush After coating careful break disturb green PVA skinwhich will give good visual indication parts coated Allow PVA dry thoroughly During mixing pouring opera tions follow disposable vinyl gloves protective glasses should worn work area should well-ventilated Always read heed caution labels materials familiar know what accident should occur Pouring mold matrix next will describe use body filler though procedure steel-filled epoxy essen tially same personal preferences brands available CUZ White Knight both easily obtained An 8-in-dia prop mold will require about 7 oz 200 grams filler mixed about 1 oz 28 grams polyester resin milkshake-like con sistency amount thinning resin required will vary between brands Discard catalyst accompanied body filler use polyester resin catalyst instead liquid catalyst clear squeeze bottle easier measure control paste catalyst supplied filler amount thinned Before beginning lay-up rovings cutand arranged man orderlyfashion nearby wilt handy Longest rovings laid first Straddle center post center extend out both ends Proceed tothe shorter rovings 1-in steps Relieve ends mold producethis small gap will allow glass rovings run full length blade give additional strength Key markings mold ends prevent accidental disas trous reversing mold reassembly jreat definItion has attained mold produced auto body filler bottom half natural reservoIr will hold epoxy reinforcing strands during lay-up Note mold tip relieving does extend inward past edge mark left bythe prop Two coats applied surfaces before beginning lay-up e release agent must get mold halves apart Use care green skin forms easily broken Pack critical hub area blade sep aration Ia moat likely Occur short giass clippingeto firm up Watch see glass changes ocior good wetting body filler use thoroughly mix about 2 drops catalyst matrix slowly poured mold box using lengthwise back-and-forth motion pro duce build-up andto avoid bubbles After matrix has become firm 2-3 hr still pliable centerpost can removed exerting twisting pulling tug pliers C-clamps loos ened should able lift slide complete assembly plate Dis mantle wooden sides remove much clay possible fingers give access pattern prop Without marring mold face angled sides exposed gently lift prop using reasonable persuasion pop prop out mold Tag corresponding ends mold prop later reassembly can accomplished prop removed mold may still flexible re-clamp plate curing another couple hours until stiff complete part mold remove PVA clay residue washing soap water Pouring top half mold next first step give entire bottom half loose prop ooat PVA dry return prop bottom mold making sure orientation corresponds markings Insert center post assemble wooden frame around mold maintain tight fit C-clamps assure easy release later apply final coat PVA prop mold face center post inside sur faces frame Mix auto body matrix before Pour enclosure filling thickness about w top matrix set few hours remove side frames pull out center post may necessary trim away thin layer matrix has tendency seep past Continued page 122 ciosing act ideai viscosity EPON 815 resin controis overfiow ends though mold fuli brim close mold hand bringing two halves together too quickiy wiii wash too much roving out maid weaken prop C-ciamps used controi ciosing speed moid secure two haives gether once have mated Gioves must some may aiiergic resin Afterthe prop cures rod puiled outwith visegrips andthe mold can separated see text detaiis End spearsthatwere formed provide handiesto help removethe prop Lineup some props author has produced using methods Au combi nations giass carbon fiber possi bie Experiment best suits New Sensation Towing Friends Glider created first Big modified Clark-Y airfoil realistic docile flying STOL capabilities ideal Quadra precut firewall flies also well 90 Two-Stroke 120 Four-Stroke realistic spring-loaded telescopic landing gear - Flying Weight 18 lbs Weight 6 lbs 702 Functions Full House plus Optionals Optionals Fiaps mixed ailerons own discre tion Releasable tow-hook extra cost own discretion Engine Quadra Irecommended towingi Other Models Also Available Call Write Information IKAROS INTERNA TIONAL 7035 LAWN WOOD LANE HOUSTON TEXAS 77086 893-1418 Make Towfl torque twists out outsidesso far dont use choke starting quick starter though gross well over 8 lb no apparent need bigger Enyn 80 basically rebored 60 3 oz lighter Maybe hotshots 60 14-6 ship goes airborne during moderately fast taxi upon hitting slightest bump Dont ask plans Rosenstock sells plans authentic 1 960s version thing fourstroke engine necessary place 1000 mAh pack above CG instead nose word caution engine has front plug use remote booster hookup just seven flights two guys have nicked fingers Certain props size could easily remove finger though user responsibility now hold cylinder head same hand takes care detaching battery clip never locked really need metered glow driver sure dont load up engine due no battery contact loosens prop Don t count smart Bill Winter 4432 Altura Ct Fajifax VA 22030 Props/Dunham Continued page 45 framing edges reveal parting line sharp-edged tool deliver few tentative pecking-type blows ham mer several places along parting line mold halves should split apart cleanly trouble encountered getting mold halves separate let matrix cure another hour try again prop exposed halves parted should carefully pried loose removed Assemble halves together again reclamp allowing mold cure fully clamping cured bottom half bowing alignment prob lems top half will straighten out Wash mold remove traces PVA relieve ends tongue area sharp knife gap should approximately Y$2 just enough glass carbon strands extend beyond ends still allowing mold close tightly cutting down part go flush blade surface Leave slight ridge provide outline blade shape removing molding flash mold completed have marked corresponding ends assure correct assembly later Making prop epoxy resin chosen has proven very satisfactory application made Shell Chemical sold under trade name EPON 815 clear syrupy liquid mixed catalyst having tongue-twisting chemical name Tn ethylenetetramine TETA nicely wets FG/CF strands cures produce strong stiff yet too brittle struc tore Usable pot life about 1 hr room temperature ample viscosity sufficiently low permit FG/CF strands easily maneuvered high enough resin stay mold Fiberglass reinforcement rovings bun dle form resembling coarse twine easily handled bundle consists about 30-40 individual glass filaments CertainTeed Owens-Corning just two firms market form strand known gun roving descrip tive process after being chopped small lengths shot under pressure sprayed stream resin Familiar objects such hot tubs shower stalls boat hulls camper tops made using technique Any glass strand form choose unraveled cloth should chrome/silane sized improve wetting resin-compatibility character istics Carbon fiber commonly used alternate fiberglass combination FG same lay-up CF imparts great strength rigidity lighter weight adds color preferred some However CF brittle prone break age landing CF also expensive opinion bit difficult work imply CF desirable choice fact preferred users good quality beam-type scale almost necessity weighing resin catalyst strands As will dealing quantities weighing no 2 oz little small fraction ounce accuracy needed Guessing will get job done necessary build borrow scale better yet buy good such made Ohaus Other items required PVA release agent mixing containers clamps disposable brushes lots paper towels Again word warning about handling epoxies catalysts have history alergies working resins go further project others should take precautions using gloves face mask guard against toxicity materials Adequate ven tilation wash-up after skin contact recommended Cut reinforcing strands length before fingers become sticky resin difficult describe will vary prop size shape general always cut strands pairs starting longest lengths should least 1 longer mold extend well past end relief slots Prepare progressively shorter lengths 1-in increments until get some near half props diameter hub area can stuffed short clippings filling imparting hardness pos sible ratio resin weight roving weight should least 6040 weight strand material required attain ratio hard determine first try corrections can made later attempts 122Model Aviation CLEVIILAND GIANTS 78 onool Cot PSYSA $42621o JN4 Jenny$28 104 Co, Cot FBY5A$5660 V05 Co 945$25 96W gh Nooy8ooe $48 OOVogtCo F40$69 52W W,r0121 RodL$26SASODorrroooIeSI$4B 77WWnro21561$4872Co0251/4LbS045 84 Foblo 07 F52962 Hoooo 6 Rooo lb $46 60 Honoord F Boo 23377 8oe o B hG Fo $25 70 soylco G-5o $22 102 817G Fort $55 -60 Sopornronn 068 $24 68 toog O-46A Dl, $22 89 Soprr~orin 568 $22 108 Sikor 2-38 Aoph 049 * 62 Cort Honob F6E $42 OSBoc 10$ Sport . $26 94 CorOok P6E F, 95490 8oo 100 Spot . $49 02 Lookkeod Vogo 024 90 StinoAtono WI,0 $56 76 SooIrrlo GB 11 $40 8$ Mortir 7424141 $29 95 Monoooopo Sport $26 75 HFoo 5400 Bomb $25 80 BoIl Spr Soildog $42 100 8-Foe 0400 Born $49 107 Aeronoo C3 $pr $32 60 8Eooomoo VToil $29 -41 Doogloo 030 Ok $32 77 Loooonrbo Sodorr $25 * 122 Dooglo 030 0k04F 72NA Miroh Bonrb $49 94 Fog Cort Oooer $45- 65 TMMorooder 826 049 71 Morn 510 Bonb $29 81 80 Mooqoiro Sb $42 78 Torn, WW 80002510808 MoosoOoorb $55 64 Cor Goobk Fl tC2 842 90 Stoor FTl7toydet $56P4tor Gooblo FtIC2 $54 9NBlb Widomo 961 849 66 DeHoS Cooot Boo $24 71 Boog OC3 Torr $32. 52 floooMrMoIllgon 835 95 Looo tC3 Tron 055 * 94 KooM Molligoo $45r 06 Ho,k Yooooo 12 $29 63 Booing p38A FIr $36 108 CorOSO 1/4 L&$ $56r 84 Boeing P-26A Ftr $48 60 loo9loo 142 Moil $34 49 Wooo C4 Cobio $36 68 Briotol Boildog Fr $30 64 Beeoh C17B Stog $38 SF BrooonRooeMoLA $54r96 Beeoh C17B Stog $49 1070 Boo otFOF 854 55 Look 11 Eleotro 030 73 Troonl 6000 034 83 Look 11 Elootro $40 lO7Mo t MB 1 Boor $44 42 S8noon T/W S07 $16 91 Lodbergo NO211 81 Stlnoon 2/W $87 024 100 FoirohPT19 5 $29i 122 Stinoon 5/W SB7 038 90Wp W 0039 59 8ritol Fr 935 020 75 W4o 4 $32 78 Briotol Fr 93-B 032 100W4 4 110 Briotol FtrF2B $45 379 4rn 74TL Peooo Opeo 045769 4roA 3Sbyrook 59SF-I $24 1144noA $59 56 Cor Worbk 948 034 048 5 $56 8 Look Ligbog 938 050 93 $6 Sop Sco-Bee A, 024 58 G 4 BepSooB Anph 039 78 0 106 Piper J3 Cob 90 98 look Hodoon snob 038 117 Bo 43 Gonr 969 Helloot $38 68 55 Hooth Boby Bolt 024 54 C SoI4 Thro toolerFri0 Am, rotc oootroeo Qrjor OoerlAOO l4ore 500 Op 612 A44 tE% oil ordero Oo oh USA Con & 140 EIoooher 15% 125% lby oiI Potonol ooolog $2 00 Inolode Froce Loot Frioe loot * 00100 olon 81 0$ oo toregn odd 8100 LEVELAND MODEL & SUPPLY Co0 o,oWor 100050 t PAoo*OooIotrOoo Efl MOEOoOOOOoOFOCO* oOo008000000pOOo 183078 DETROIT AVE CLEVBLAND OHIO 44102 oonoooooooHooOooo ne 515 PM9ST 0221-12 161 9613600 E0noOOr 9 Prepare epoxy resin Wearing pro tective gloves using accurate scale carefully weigh out predetermined quan tity EPON 815 Dont forget record weight empty container can determine net amount resin amount TETA catalyst should range 15-20% resin weight 17% being about ideal example assume 8-in-dia prop will require 22 grams EPON amount TETA needed will additional 375 grams giving total liquid weight 25 75 grams Mix resin catalyst thoroughly allow settle about 10 min permit bubbles clear Because way mold con structed bottom half natural reser voir ideal trough lay-up prop Start giving trough area heavy coat epoxy resin lay longest rovings arranging straddle center post Always keep strands centered lengthwise mold assist equalizing blade balance Use small stick x smoothed rounded end spread out filaments cover much blade area possible Add resin progress shorter lengths using stick maneuver strands work out bubbles might trapped hub area can filled 1-in shorter clippings keeping whole mass wet resin Keep filaments confined blade area let slide closing faces will notice rovings begin take silver translucent appearance some seeming disappear entirely sign good wetting necessary resin penetration occurring glass place trough filled resin coat top mold face resin slide down onto center post Check make sure mold match marks correspond because mold closed reversed ends will never able reopen mold salvage what have done point Manually bring top mold down within about ing position four clamps shown pictures clamps should very slowly evenly tightened until faces close tightly will some loss glass lot oozing resin between faces normal Too much glass loss indicates either overstuffed mold closed too rapidly Cleaning up can accom plished acetone epoxy thinner Lay mold aside making sure level something underneath catch cascading drips normal room tem perature prop will take five six hours hardenconsiderably less left direct sun warm oven Check stiffness end spears doubt convinced epoxy firm loosen clamps use vice-grip pliers remove center post twisting pull advisable trim away washed-out rovings have formed long sides since will interfere opening mold Leave end spears untouched time five-minute soaking mold very hot water can sometimes wonders getting come apart Insert sharp knife screwdriver several places along parting line two halves should separate free prop again immerse hot water lift flashing flaps loosen grip especially hub area pull up end spears prop should snap free mold point should holding molded prop attached rectangle thin flashing Most flashing can cut away scissorsup within line sharp flat medium-coarse file used remove last ng along cleft line between flash prop Just few strokes will job nicely area around hub can best removed X-Acto knife file end spears cut away scissors after first filing groove across tongue sharp edge file Balancing prop acoomplished file and/or sandpaper progressing No 150 No 300 final polish Restrict balancing work top curved surface otherwise stand good chance altering blade pitch need help locating supplies cannot purchase small lots please contact Bob Dunham 4730 So Yorktown Tulsa OK 74105 starter kit consisting auto body filler PVA EPON 815 TETA vinyl gloves fiberglass rovings can furnished $60 postpaid US kit contains enough filler fiberglass other liquids make couple molds 20 25 medium-size props Material Sources Auto body filler CUZ NAPA Auto motive Stores White Knight K-Mart Wal Mart auto supply parts stores Steel-filled epoxy 1 qt kit EPOCAST #1 iB #9812 hardener EV Roberts & Assoc Box 868 Culver City CA 90232 phone 1-800-421-0824 Epoxy resin Shell Chemical EPON 815 EV Roberts & Assoc Epoxy catalyst TETA EV Roberts & Assoc Polyester resin K&B Manufacturing hobby shops Fiberglass rovings Owens-Corning Product #447-211 #352-211 CertainTeed Product #282-Bi See Yellow Pages under Fiberglass Materials Carbon fiber tows Gougeon Bros Box X908 Bay City MI 48707 NFFS Supplies 12 Cook St Rowayton CT 06853 RC History/Good Continued page 60 throttle offone time Panel lights indicated airborne pilot control signal being transmitted Continued page 126 March 1986 123 Will OPS 000 Sa#uoc4 specialists High Performance Model Airplane Engines stock parts back up will like doing business us See local hoppy shop P arts Peo pie Box 26247 New Orleans LA 70186 242-5967
Edition: Model Aviation - 1986/03
Page Numbers: 42, 43, 44, 45, 122, 123
How Mold FalansentReinforced Props taking time cast own props may seem like lot trouble equates tailor-made suit compared off rack Nothing can fit specific needs better EBob Dunham USING PROCEDURES developed serious Control Line Free Flight fliers description make rein forced plastic propellers using split mold procedure has refined recent years point consistent reliable results can produced great dif ficulty propeller tip-to-tip fiberglass carbon fiber hereinafter referred FG/CF rovings tows almost neces sity using high-revving Schnuerle-ported engines turning speed approaching excess 28000 rpm important maintain both blade pitch efficiency structural integrity safety lower rpm forces blade some propellersin both outward twisting directionscan cause blade shedding failure usually oc curring hub area can endanger operator others within 30-ft radius FG/CF other blade reinforcement material prop unexpected blade separation can still some times occur always good practice use protective eye gear check prop carefully after flight obscure landing damage over-stressing previous flight several advantages making own FG/CF props model interests mainstream popu larity already have found model shops simply stock props suitable high-revving engines leaves choices substituting less-de sirable prop writing manufacturer cottage industry molder possibly wait ing several weeks delivery Also like original can carve prop own specifications reproduce FG/CF over over Similarly ex 42 Model Aviation isting prop can thinned repitched re shaped generally reworked close relative can molded new prop produced incorporating modifica tions mold presented satisfactory use reinforcing materials fiber glass carbon fiber combination Making mold first step both Keviar has also used have no experience application Materials produce several molds enough epoxy resin strand material make 30 40 props will cost neighborhood $75 Above Lineup principal Ingredients will used make mold Below Ma terials used produce reinforced prop Source list end text contains addresses contact special materials may able find locally Pattern prop mounted base piate shaft place Smooth-flowing clay lines desirable Take special note 150 parting line hub tip treatment difficult part project done care will reward quality product can used times over molding matrix can either auto body filler polyester base steelfilled epoxy resin first attempt please try body filler easily obtained will produce very satisfactory mold steel-filled epoxy harder durable does shrink however expensive delivery listed source slow main disadvantages auto body filler produces somewhat softer mold prone wear chipping shrinks slightly cured makes copy prop slightly diminished size original enough cause problem Construction mold same regardless matrix choose will need polyester resin thinning purposes polyvinyl alcohol PVA re lease agent PVA vital its importance will become apparent read along green-tinted water-soluble liquid applied brush has consistency thin dope dries rapidly metal base plate needed should approximately -in thick absolutely flat smooth since shapes mold parting line base plate should least 2 wide 12 long Using care drill press position hole midpoint match prop shaft diameter best hole tight fit 3-in length steel rod mold side frames can cut plywood awidthof 1 4 Lengths wooden yardstick make very suitable substitute will need two long sides about 1 longer prop diameter two end pieces about 1 long mold frames should given two coats clear epoxy paint side allowed cure Choose prop wish reproduce varnished wood variety finish must removed sanding washing acetone suggest further thin prop blades sanding about five thousandths away top curved side makes allowance strand interference between mold faces two coats epoxy paint applied prop seal grain prevent absorbing liquids Spraying preferred over brushing minimize thickness build-up molding fiberglass nylon plastic prop go through same blade-thinning operation paint epoxy Check finished prop wish reproduce has no nicks scratches slightest imperfection wood grain brush marks will reproduced real business matter Mount pattern prop base plate top camber facing up center post inserted drilled hole aligned perpendicular plate directions Both blade tips should same distance above surface plate Make worms hand-warmed clay fill area underneath blades take care deform bend blades process Using tool such back edge single-edge razor blade carefully mold clay parting draft angle about 15 formed angle necessary get poured mold release properly hub area takes slightly different treatment can best shown photos tips leave tongue area extends about nd prop tip maintaining general slope con tour blade may take several tries resculpting attempts get things looking just right will soon get hang wet finger helpful obtain desired smoothness March 1986 43 PVA release agent applied surfaces retainer box absolute must order retrieve prop molding matrix C-clamps secure box sides base plate Auto body filler recommended first attempts making mold Instance though steel-filled epoxy being poured over clayed-up prop produce bottom half Actually procedure same whether body filler steel-filled epoxy used Once bottom half mold has cured isturned overand used asthe baseforpouring top half mold Secure box C-clamps again coat insides PVA black gunk being poured produce top half mold messy prepared lots rags newspapers drop cloth catch Inevitable drips refrain repeatedly going over area things seem get worse finished wash oil clay smears plate acetone Assemble mold frames rec tangular box joining 5-min epoxy sides box already painted epoxy should face inward end pieces located just barely enclose clay tongues Place box over clayed up prop secure base Cclamps done coat inside surfaces box well post prop clay two coats PVA applied soft brush After coating careful break disturb green PVA skinwhich will give good visual indication parts coated Allow PVA dry thoroughly During mixing pouring opera tions follow disposable vinyl gloves protective glasses should worn work area should well-ventilated Always read heed caution labels materials familiar know what accident should occur Pouring mold matrix next will describe use body filler though procedure steel-filled epoxy essen tially same personal preferences brands available CUZ White Knight both easily obtained An 8-in-dia prop mold will require about 7 oz 200 grams filler mixed about 1 oz 28 grams polyester resin milkshake-like con sistency amount thinning resin required will vary between brands Discard catalyst accompanied body filler use polyester resin catalyst instead liquid catalyst clear squeeze bottle easier measure control paste catalyst supplied filler amount thinned Before beginning lay-up rovings cutand arranged man orderlyfashion nearby wilt handy Longest rovings laid first Straddle center post center extend out both ends Proceed tothe shorter rovings 1-in steps Relieve ends mold producethis small gap will allow glass rovings run full length blade give additional strength Key markings mold ends prevent accidental disas trous reversing mold reassembly jreat definItion has attained mold produced auto body filler bottom half natural reservoIr will hold epoxy reinforcing strands during lay-up Note mold tip relieving does extend inward past edge mark left bythe prop Two coats applied surfaces before beginning lay-up e release agent must get mold halves apart Use care green skin forms easily broken Pack critical hub area blade sep aration Ia moat likely Occur short giass clippingeto firm up Watch see glass changes ocior good wetting body filler use thoroughly mix about 2 drops catalyst matrix slowly poured mold box using lengthwise back-and-forth motion pro duce build-up andto avoid bubbles After matrix has become firm 2-3 hr still pliable centerpost can removed exerting twisting pulling tug pliers C-clamps loos ened should able lift slide complete assembly plate Dis mantle wooden sides remove much clay possible fingers give access pattern prop Without marring mold face angled sides exposed gently lift prop using reasonable persuasion pop prop out mold Tag corresponding ends mold prop later reassembly can accomplished prop removed mold may still flexible re-clamp plate curing another couple hours until stiff complete part mold remove PVA clay residue washing soap water Pouring top half mold next first step give entire bottom half loose prop ooat PVA dry return prop bottom mold making sure orientation corresponds markings Insert center post assemble wooden frame around mold maintain tight fit C-clamps assure easy release later apply final coat PVA prop mold face center post inside sur faces frame Mix auto body matrix before Pour enclosure filling thickness about w top matrix set few hours remove side frames pull out center post may necessary trim away thin layer matrix has tendency seep past Continued page 122 ciosing act ideai viscosity EPON 815 resin controis overfiow ends though mold fuli brim close mold hand bringing two halves together too quickiy wiii wash too much roving out maid weaken prop C-ciamps used controi ciosing speed moid secure two haives gether once have mated Gioves must some may aiiergic resin Afterthe prop cures rod puiled outwith visegrips andthe mold can separated see text detaiis End spearsthatwere formed provide handiesto help removethe prop Lineup some props author has produced using methods Au combi nations giass carbon fiber possi bie Experiment best suits New Sensation Towing Friends Glider created first Big modified Clark-Y airfoil realistic docile flying STOL capabilities ideal Quadra precut firewall flies also well 90 Two-Stroke 120 Four-Stroke realistic spring-loaded telescopic landing gear - Flying Weight 18 lbs Weight 6 lbs 702 Functions Full House plus Optionals Optionals Fiaps mixed ailerons own discre tion Releasable tow-hook extra cost own discretion Engine Quadra Irecommended towingi Other Models Also Available Call Write Information IKAROS INTERNA TIONAL 7035 LAWN WOOD LANE HOUSTON TEXAS 77086 893-1418 Make Towfl torque twists out outsidesso far dont use choke starting quick starter though gross well over 8 lb no apparent need bigger Enyn 80 basically rebored 60 3 oz lighter Maybe hotshots 60 14-6 ship goes airborne during moderately fast taxi upon hitting slightest bump Dont ask plans Rosenstock sells plans authentic 1 960s version thing fourstroke engine necessary place 1000 mAh pack above CG instead nose word caution engine has front plug use remote booster hookup just seven flights two guys have nicked fingers Certain props size could easily remove finger though user responsibility now hold cylinder head same hand takes care detaching battery clip never locked really need metered glow driver sure dont load up engine due no battery contact loosens prop Don t count smart Bill Winter 4432 Altura Ct Fajifax VA 22030 Props/Dunham Continued page 45 framing edges reveal parting line sharp-edged tool deliver few tentative pecking-type blows ham mer several places along parting line mold halves should split apart cleanly trouble encountered getting mold halves separate let matrix cure another hour try again prop exposed halves parted should carefully pried loose removed Assemble halves together again reclamp allowing mold cure fully clamping cured bottom half bowing alignment prob lems top half will straighten out Wash mold remove traces PVA relieve ends tongue area sharp knife gap should approximately Y$2 just enough glass carbon strands extend beyond ends still allowing mold close tightly cutting down part go flush blade surface Leave slight ridge provide outline blade shape removing molding flash mold completed have marked corresponding ends assure correct assembly later Making prop epoxy resin chosen has proven very satisfactory application made Shell Chemical sold under trade name EPON 815 clear syrupy liquid mixed catalyst having tongue-twisting chemical name Tn ethylenetetramine TETA nicely wets FG/CF strands cures produce strong stiff yet too brittle struc tore Usable pot life about 1 hr room temperature ample viscosity sufficiently low permit FG/CF strands easily maneuvered high enough resin stay mold Fiberglass reinforcement rovings bun dle form resembling coarse twine easily handled bundle consists about 30-40 individual glass filaments CertainTeed Owens-Corning just two firms market form strand known gun roving descrip tive process after being chopped small lengths shot under pressure sprayed stream resin Familiar objects such hot tubs shower stalls boat hulls camper tops made using technique Any glass strand form choose unraveled cloth should chrome/silane sized improve wetting resin-compatibility character istics Carbon fiber commonly used alternate fiberglass combination FG same lay-up CF imparts great strength rigidity lighter weight adds color preferred some However CF brittle prone break age landing CF also expensive opinion bit difficult work imply CF desirable choice fact preferred users good quality beam-type scale almost necessity weighing resin catalyst strands As will dealing quantities weighing no 2 oz little small fraction ounce accuracy needed Guessing will get job done necessary build borrow scale better yet buy good such made Ohaus Other items required PVA release agent mixing containers clamps disposable brushes lots paper towels Again word warning about handling epoxies catalysts have history alergies working resins go further project others should take precautions using gloves face mask guard against toxicity materials Adequate ven tilation wash-up after skin contact recommended Cut reinforcing strands length before fingers become sticky resin difficult describe will vary prop size shape general always cut strands pairs starting longest lengths should least 1 longer mold extend well past end relief slots Prepare progressively shorter lengths 1-in increments until get some near half props diameter hub area can stuffed short clippings filling imparting hardness pos sible ratio resin weight roving weight should least 6040 weight strand material required attain ratio hard determine first try corrections can made later attempts 122Model Aviation CLEVIILAND GIANTS 78 onool Cot PSYSA $42621o JN4 Jenny$28 104 Co, Cot FBY5A$5660 V05 Co 945$25 96W gh Nooy8ooe $48 OOVogtCo F40$69 52W W,r0121 RodL$26SASODorrroooIeSI$4B 77WWnro21561$4872Co0251/4LbS045 84 Foblo 07 F52962 Hoooo 6 Rooo lb $46 60 Honoord F Boo 23377 8oe o B hG Fo $25 70 soylco G-5o $22 102 817G Fort $55 -60 Sopornronn 068 $24 68 toog O-46A Dl, $22 89 Soprr~orin 568 $22 108 Sikor 2-38 Aoph 049 * 62 Cort Honob F6E $42 OSBoc 10$ Sport . $26 94 CorOok P6E F, 95490 8oo 100 Spot . $49 02 Lookkeod Vogo 024 90 StinoAtono WI,0 $56 76 SooIrrlo GB 11 $40 8$ Mortir 7424141 $29 95 Monoooopo Sport $26 75 HFoo 5400 Bomb $25 80 BoIl Spr Soildog $42 100 8-Foe 0400 Born $49 107 Aeronoo C3 $pr $32 60 8Eooomoo VToil $29 -41 Doogloo 030 Ok $32 77 Loooonrbo Sodorr $25 * 122 Dooglo 030 0k04F 72NA Miroh Bonrb $49 94 Fog Cort Oooer $45- 65 TMMorooder 826 049 71 Morn 510 Bonb $29 81 80 Mooqoiro Sb $42 78 Torn, WW 80002510808 MoosoOoorb $55 64 Cor Goobk Fl tC2 842 90 Stoor FTl7toydet $56P4tor Gooblo FtIC2 $54 9NBlb Widomo 961 849 66 DeHoS Cooot Boo $24 71 Boog OC3 Torr $32. 52 floooMrMoIllgon 835 95 Looo tC3 Tron 055 * 94 KooM Molligoo $45r 06 Ho,k Yooooo 12 $29 63 Booing p38A FIr $36 108 CorOSO 1/4 L&$ $56r 84 Boeing P-26A Ftr $48 60 loo9loo 142 Moil $34 49 Wooo C4 Cobio $36 68 Briotol Boildog Fr $30 64 Beeoh C17B Stog $38 SF BrooonRooeMoLA $54r96 Beeoh C17B Stog $49 1070 Boo otFOF 854 55 Look 11 Eleotro 030 73 Troonl 6000 034 83 Look 11 Elootro $40 lO7Mo t MB 1 Boor $44 42 S8noon T/W S07 $16 91 Lodbergo NO211 81 Stlnoon 2/W $87 024 100 FoirohPT19 5 $29i 122 Stinoon 5/W SB7 038 90Wp W 0039 59 8ritol Fr 935 020 75 W4o 4 $32 78 Briotol Fr 93-B 032 100W4 4 110 Briotol FtrF2B $45 379 4rn 74TL Peooo Opeo 045769 4roA 3Sbyrook 59SF-I $24 1144noA $59 56 Cor Worbk 948 034 048 5 $56 8 Look Ligbog 938 050 93 $6 Sop Sco-Bee A, 024 58 G 4 BepSooB Anph 039 78 0 106 Piper J3 Cob 90 98 look Hodoon snob 038 117 Bo 43 Gonr 969 Helloot $38 68 55 Hooth Boby Bolt 024 54 C SoI4 Thro toolerFri0 Am, rotc oootroeo Qrjor OoerlAOO l4ore 500 Op 612 A44 tE% oil ordero Oo oh USA Con & 140 EIoooher 15% 125% lby oiI Potonol ooolog $2 00 Inolode Froce Loot Frioe loot * 00100 olon 81 0$ oo toregn odd 8100 LEVELAND MODEL & SUPPLY Co0 o,oWor 100050 t PAoo*OooIotrOoo Efl MOEOoOOOOoOFOCO* oOo008000000pOOo 183078 DETROIT AVE CLEVBLAND OHIO 44102 oonoooooooHooOooo ne 515 PM9ST 0221-12 161 9613600 E0noOOr 9 Prepare epoxy resin Wearing pro tective gloves using accurate scale carefully weigh out predetermined quan tity EPON 815 Dont forget record weight empty container can determine net amount resin amount TETA catalyst should range 15-20% resin weight 17% being about ideal example assume 8-in-dia prop will require 22 grams EPON amount TETA needed will additional 375 grams giving total liquid weight 25 75 grams Mix resin catalyst thoroughly allow settle about 10 min permit bubbles clear Because way mold con structed bottom half natural reser voir ideal trough lay-up prop Start giving trough area heavy coat epoxy resin lay longest rovings arranging straddle center post Always keep strands centered lengthwise mold assist equalizing blade balance Use small stick x smoothed rounded end spread out filaments cover much blade area possible Add resin progress shorter lengths using stick maneuver strands work out bubbles might trapped hub area can filled 1-in shorter clippings keeping whole mass wet resin Keep filaments confined blade area let slide closing faces will notice rovings begin take silver translucent appearance some seeming disappear entirely sign good wetting necessary resin penetration occurring glass place trough filled resin coat top mold face resin slide down onto center post Check make sure mold match marks correspond because mold closed reversed ends will never able reopen mold salvage what have done point Manually bring top mold down within about ing position four clamps shown pictures clamps should very slowly evenly tightened until faces close tightly will some loss glass lot oozing resin between faces normal Too much glass loss indicates either overstuffed mold closed too rapidly Cleaning up can accom plished acetone epoxy thinner Lay mold aside making sure level something underneath catch cascading drips normal room tem perature prop will take five six hours hardenconsiderably less left direct sun warm oven Check stiffness end spears doubt convinced epoxy firm loosen clamps use vice-grip pliers remove center post twisting pull advisable trim away washed-out rovings have formed long sides since will interfere opening mold Leave end spears untouched time five-minute soaking mold very hot water can sometimes wonders getting come apart Insert sharp knife screwdriver several places along parting line two halves should separate free prop again immerse hot water lift flashing flaps loosen grip especially hub area pull up end spears prop should snap free mold point should holding molded prop attached rectangle thin flashing Most flashing can cut away scissorsup within line sharp flat medium-coarse file used remove last ng along cleft line between flash prop Just few strokes will job nicely area around hub can best removed X-Acto knife file end spears cut away scissors after first filing groove across tongue sharp edge file Balancing prop acoomplished file and/or sandpaper progressing No 150 No 300 final polish Restrict balancing work top curved surface otherwise stand good chance altering blade pitch need help locating supplies cannot purchase small lots please contact Bob Dunham 4730 So Yorktown Tulsa OK 74105 starter kit consisting auto body filler PVA EPON 815 TETA vinyl gloves fiberglass rovings can furnished $60 postpaid US kit contains enough filler fiberglass other liquids make couple molds 20 25 medium-size props Material Sources Auto body filler CUZ NAPA Auto motive Stores White Knight K-Mart Wal Mart auto supply parts stores Steel-filled epoxy 1 qt kit EPOCAST #1 iB #9812 hardener EV Roberts & Assoc Box 868 Culver City CA 90232 phone 1-800-421-0824 Epoxy resin Shell Chemical EPON 815 EV Roberts & Assoc Epoxy catalyst TETA EV Roberts & Assoc Polyester resin K&B Manufacturing hobby shops Fiberglass rovings Owens-Corning Product #447-211 #352-211 CertainTeed Product #282-Bi See Yellow Pages under Fiberglass Materials Carbon fiber tows Gougeon Bros Box X908 Bay City MI 48707 NFFS Supplies 12 Cook St Rowayton CT 06853 RC History/Good Continued page 60 throttle offone time Panel lights indicated airborne pilot control signal being transmitted Continued page 126 March 1986 123 Will OPS 000 Sa#uoc4 specialists High Performance Model Airplane Engines stock parts back up will like doing business us See local hoppy shop P arts Peo pie Box 26247 New Orleans LA 70186 242-5967
Edition: Model Aviation - 1986/03
Page Numbers: 42, 43, 44, 45, 122, 123
How Mold FalansentReinforced Props taking time cast own props may seem like lot trouble equates tailor-made suit compared off rack Nothing can fit specific needs better EBob Dunham USING PROCEDURES developed serious Control Line Free Flight fliers description make rein forced plastic propellers using split mold procedure has refined recent years point consistent reliable results can produced great dif ficulty propeller tip-to-tip fiberglass carbon fiber hereinafter referred FG/CF rovings tows almost neces sity using high-revving Schnuerle-ported engines turning speed approaching excess 28000 rpm important maintain both blade pitch efficiency structural integrity safety lower rpm forces blade some propellersin both outward twisting directionscan cause blade shedding failure usually oc curring hub area can endanger operator others within 30-ft radius FG/CF other blade reinforcement material prop unexpected blade separation can still some times occur always good practice use protective eye gear check prop carefully after flight obscure landing damage over-stressing previous flight several advantages making own FG/CF props model interests mainstream popu larity already have found model shops simply stock props suitable high-revving engines leaves choices substituting less-de sirable prop writing manufacturer cottage industry molder possibly wait ing several weeks delivery Also like original can carve prop own specifications reproduce FG/CF over over Similarly ex 42 Model Aviation isting prop can thinned repitched re shaped generally reworked close relative can molded new prop produced incorporating modifica tions mold presented satisfactory use reinforcing materials fiber glass carbon fiber combination Making mold first step both Keviar has also used have no experience application Materials produce several molds enough epoxy resin strand material make 30 40 props will cost neighborhood $75 Above Lineup principal Ingredients will used make mold Below Ma terials used produce reinforced prop Source list end text contains addresses contact special materials may able find locally Pattern prop mounted base piate shaft place Smooth-flowing clay lines desirable Take special note 150 parting line hub tip treatment difficult part project done care will reward quality product can used times over molding matrix can either auto body filler polyester base steelfilled epoxy resin first attempt please try body filler easily obtained will produce very satisfactory mold steel-filled epoxy harder durable does shrink however expensive delivery listed source slow main disadvantages auto body filler produces somewhat softer mold prone wear chipping shrinks slightly cured makes copy prop slightly diminished size original enough cause problem Construction mold same regardless matrix choose will need polyester resin thinning purposes polyvinyl alcohol PVA re lease agent PVA vital its importance will become apparent read along green-tinted water-soluble liquid applied brush has consistency thin dope dries rapidly metal base plate needed should approximately -in thick absolutely flat smooth since shapes mold parting line base plate should least 2 wide 12 long Using care drill press position hole midpoint match prop shaft diameter best hole tight fit 3-in length steel rod mold side frames can cut plywood awidthof 1 4 Lengths wooden yardstick make very suitable substitute will need two long sides about 1 longer prop diameter two end pieces about 1 long mold frames should given two coats clear epoxy paint side allowed cure Choose prop wish reproduce varnished wood variety finish must removed sanding washing acetone suggest further thin prop blades sanding about five thousandths away top curved side makes allowance strand interference between mold faces two coats epoxy paint applied prop seal grain prevent absorbing liquids Spraying preferred over brushing minimize thickness build-up molding fiberglass nylon plastic prop go through same blade-thinning operation paint epoxy Check finished prop wish reproduce has no nicks scratches slightest imperfection wood grain brush marks will reproduced real business matter Mount pattern prop base plate top camber facing up center post inserted drilled hole aligned perpendicular plate directions Both blade tips should same distance above surface plate Make worms hand-warmed clay fill area underneath blades take care deform bend blades process Using tool such back edge single-edge razor blade carefully mold clay parting draft angle about 15 formed angle necessary get poured mold release properly hub area takes slightly different treatment can best shown photos tips leave tongue area extends about nd prop tip maintaining general slope con tour blade may take several tries resculpting attempts get things looking just right will soon get hang wet finger helpful obtain desired smoothness March 1986 43 PVA release agent applied surfaces retainer box absolute must order retrieve prop molding matrix C-clamps secure box sides base plate Auto body filler recommended first attempts making mold Instance though steel-filled epoxy being poured over clayed-up prop produce bottom half Actually procedure same whether body filler steel-filled epoxy used Once bottom half mold has cured isturned overand used asthe baseforpouring top half mold Secure box C-clamps again coat insides PVA black gunk being poured produce top half mold messy prepared lots rags newspapers drop cloth catch Inevitable drips refrain repeatedly going over area things seem get worse finished wash oil clay smears plate acetone Assemble mold frames rec tangular box joining 5-min epoxy sides box already painted epoxy should face inward end pieces located just barely enclose clay tongues Place box over clayed up prop secure base Cclamps done coat inside surfaces box well post prop clay two coats PVA applied soft brush After coating careful break disturb green PVA skinwhich will give good visual indication parts coated Allow PVA dry thoroughly During mixing pouring opera tions follow disposable vinyl gloves protective glasses should worn work area should well-ventilated Always read heed caution labels materials familiar know what accident should occur Pouring mold matrix next will describe use body filler though procedure steel-filled epoxy essen tially same personal preferences brands available CUZ White Knight both easily obtained An 8-in-dia prop mold will require about 7 oz 200 grams filler mixed about 1 oz 28 grams polyester resin milkshake-like con sistency amount thinning resin required will vary between brands Discard catalyst accompanied body filler use polyester resin catalyst instead liquid catalyst clear squeeze bottle easier measure control paste catalyst supplied filler amount thinned Before beginning lay-up rovings cutand arranged man orderlyfashion nearby wilt handy Longest rovings laid first Straddle center post center extend out both ends Proceed tothe shorter rovings 1-in steps Relieve ends mold producethis small gap will allow glass rovings run full length blade give additional strength Key markings mold ends prevent accidental disas trous reversing mold reassembly jreat definItion has attained mold produced auto body filler bottom half natural reservoIr will hold epoxy reinforcing strands during lay-up Note mold tip relieving does extend inward past edge mark left bythe prop Two coats applied surfaces before beginning lay-up e release agent must get mold halves apart Use care green skin forms easily broken Pack critical hub area blade sep aration Ia moat likely Occur short giass clippingeto firm up Watch see glass changes ocior good wetting body filler use thoroughly mix about 2 drops catalyst matrix slowly poured mold box using lengthwise back-and-forth motion pro duce build-up andto avoid bubbles After matrix has become firm 2-3 hr still pliable centerpost can removed exerting twisting pulling tug pliers C-clamps loos ened should able lift slide complete assembly plate Dis mantle wooden sides remove much clay possible fingers give access pattern prop Without marring mold face angled sides exposed gently lift prop using reasonable persuasion pop prop out mold Tag corresponding ends mold prop later reassembly can accomplished prop removed mold may still flexible re-clamp plate curing another couple hours until stiff complete part mold remove PVA clay residue washing soap water Pouring top half mold next first step give entire bottom half loose prop ooat PVA dry return prop bottom mold making sure orientation corresponds markings Insert center post assemble wooden frame around mold maintain tight fit C-clamps assure easy release later apply final coat PVA prop mold face center post inside sur faces frame Mix auto body matrix before Pour enclosure filling thickness about w top matrix set few hours remove side frames pull out center post may necessary trim away thin layer matrix has tendency seep past Continued page 122 ciosing act ideai viscosity EPON 815 resin controis overfiow ends though mold fuli brim close mold hand bringing two halves together too quickiy wiii wash too much roving out maid weaken prop C-ciamps used controi ciosing speed moid secure two haives gether once have mated Gioves must some may aiiergic resin Afterthe prop cures rod puiled outwith visegrips andthe mold can separated see text detaiis End spearsthatwere formed provide handiesto help removethe prop Lineup some props author has produced using methods Au combi nations giass carbon fiber possi bie Experiment best suits New Sensation Towing Friends Glider created first Big modified Clark-Y airfoil realistic docile flying STOL capabilities ideal Quadra precut firewall flies also well 90 Two-Stroke 120 Four-Stroke realistic spring-loaded telescopic landing gear - Flying Weight 18 lbs Weight 6 lbs 702 Functions Full House plus Optionals Optionals Fiaps mixed ailerons own discre tion Releasable tow-hook extra cost own discretion Engine Quadra Irecommended towingi Other Models Also Available Call Write Information IKAROS INTERNA TIONAL 7035 LAWN WOOD LANE HOUSTON TEXAS 77086 893-1418 Make Towfl torque twists out outsidesso far dont use choke starting quick starter though gross well over 8 lb no apparent need bigger Enyn 80 basically rebored 60 3 oz lighter Maybe hotshots 60 14-6 ship goes airborne during moderately fast taxi upon hitting slightest bump Dont ask plans Rosenstock sells plans authentic 1 960s version thing fourstroke engine necessary place 1000 mAh pack above CG instead nose word caution engine has front plug use remote booster hookup just seven flights two guys have nicked fingers Certain props size could easily remove finger though user responsibility now hold cylinder head same hand takes care detaching battery clip never locked really need metered glow driver sure dont load up engine due no battery contact loosens prop Don t count smart Bill Winter 4432 Altura Ct Fajifax VA 22030 Props/Dunham Continued page 45 framing edges reveal parting line sharp-edged tool deliver few tentative pecking-type blows ham mer several places along parting line mold halves should split apart cleanly trouble encountered getting mold halves separate let matrix cure another hour try again prop exposed halves parted should carefully pried loose removed Assemble halves together again reclamp allowing mold cure fully clamping cured bottom half bowing alignment prob lems top half will straighten out Wash mold remove traces PVA relieve ends tongue area sharp knife gap should approximately Y$2 just enough glass carbon strands extend beyond ends still allowing mold close tightly cutting down part go flush blade surface Leave slight ridge provide outline blade shape removing molding flash mold completed have marked corresponding ends assure correct assembly later Making prop epoxy resin chosen has proven very satisfactory application made Shell Chemical sold under trade name EPON 815 clear syrupy liquid mixed catalyst having tongue-twisting chemical name Tn ethylenetetramine TETA nicely wets FG/CF strands cures produce strong stiff yet too brittle struc tore Usable pot life about 1 hr room temperature ample viscosity sufficiently low permit FG/CF strands easily maneuvered high enough resin stay mold Fiberglass reinforcement rovings bun dle form resembling coarse twine easily handled bundle consists about 30-40 individual glass filaments CertainTeed Owens-Corning just two firms market form strand known gun roving descrip tive process after being chopped small lengths shot under pressure sprayed stream resin Familiar objects such hot tubs shower stalls boat hulls camper tops made using technique Any glass strand form choose unraveled cloth should chrome/silane sized improve wetting resin-compatibility character istics Carbon fiber commonly used alternate fiberglass combination FG same lay-up CF imparts great strength rigidity lighter weight adds color preferred some However CF brittle prone break age landing CF also expensive opinion bit difficult work imply CF desirable choice fact preferred users good quality beam-type scale almost necessity weighing resin catalyst strands As will dealing quantities weighing no 2 oz little small fraction ounce accuracy needed Guessing will get job done necessary build borrow scale better yet buy good such made Ohaus Other items required PVA release agent mixing containers clamps disposable brushes lots paper towels Again word warning about handling epoxies catalysts have history alergies working resins go further project others should take precautions using gloves face mask guard against toxicity materials Adequate ven tilation wash-up after skin contact recommended Cut reinforcing strands length before fingers become sticky resin difficult describe will vary prop size shape general always cut strands pairs starting longest lengths should least 1 longer mold extend well past end relief slots Prepare progressively shorter lengths 1-in increments until get some near half props diameter hub area can stuffed short clippings filling imparting hardness pos sible ratio resin weight roving weight should least 6040 weight strand material required attain ratio hard determine first try corrections can made later attempts 122Model Aviation CLEVIILAND GIANTS 78 onool Cot PSYSA $42621o JN4 Jenny$28 104 Co, Cot FBY5A$5660 V05 Co 945$25 96W gh Nooy8ooe $48 OOVogtCo F40$69 52W W,r0121 RodL$26SASODorrroooIeSI$4B 77WWnro21561$4872Co0251/4LbS045 84 Foblo 07 F52962 Hoooo 6 Rooo lb $46 60 Honoord F Boo 23377 8oe o B hG Fo $25 70 soylco G-5o $22 102 817G Fort $55 -60 Sopornronn 068 $24 68 toog O-46A Dl, $22 89 Soprr~orin 568 $22 108 Sikor 2-38 Aoph 049 * 62 Cort Honob F6E $42 OSBoc 10$ Sport . $26 94 CorOok P6E F, 95490 8oo 100 Spot . $49 02 Lookkeod Vogo 024 90 StinoAtono WI,0 $56 76 SooIrrlo GB 11 $40 8$ Mortir 7424141 $29 95 Monoooopo Sport $26 75 HFoo 5400 Bomb $25 80 BoIl Spr Soildog $42 100 8-Foe 0400 Born $49 107 Aeronoo C3 $pr $32 60 8Eooomoo VToil $29 -41 Doogloo 030 Ok $32 77 Loooonrbo Sodorr $25 * 122 Dooglo 030 0k04F 72NA Miroh Bonrb $49 94 Fog Cort Oooer $45- 65 TMMorooder 826 049 71 Morn 510 Bonb $29 81 80 Mooqoiro Sb $42 78 Torn, WW 80002510808 MoosoOoorb $55 64 Cor Goobk Fl tC2 842 90 Stoor FTl7toydet $56P4tor Gooblo FtIC2 $54 9NBlb Widomo 961 849 66 DeHoS Cooot Boo $24 71 Boog OC3 Torr $32. 52 floooMrMoIllgon 835 95 Looo tC3 Tron 055 * 94 KooM Molligoo $45r 06 Ho,k Yooooo 12 $29 63 Booing p38A FIr $36 108 CorOSO 1/4 L&$ $56r 84 Boeing P-26A Ftr $48 60 loo9loo 142 Moil $34 49 Wooo C4 Cobio $36 68 Briotol Boildog Fr $30 64 Beeoh C17B Stog $38 SF BrooonRooeMoLA $54r96 Beeoh C17B Stog $49 1070 Boo otFOF 854 55 Look 11 Eleotro 030 73 Troonl 6000 034 83 Look 11 Elootro $40 lO7Mo t MB 1 Boor $44 42 S8noon T/W S07 $16 91 Lodbergo NO211 81 Stlnoon 2/W $87 024 100 FoirohPT19 5 $29i 122 Stinoon 5/W SB7 038 90Wp W 0039 59 8ritol Fr 935 020 75 W4o 4 $32 78 Briotol Fr 93-B 032 100W4 4 110 Briotol FtrF2B $45 379 4rn 74TL Peooo Opeo 045769 4roA 3Sbyrook 59SF-I $24 1144noA $59 56 Cor Worbk 948 034 048 5 $56 8 Look Ligbog 938 050 93 $6 Sop Sco-Bee A, 024 58 G 4 BepSooB Anph 039 78 0 106 Piper J3 Cob 90 98 look Hodoon snob 038 117 Bo 43 Gonr 969 Helloot $38 68 55 Hooth Boby Bolt 024 54 C SoI4 Thro toolerFri0 Am, rotc oootroeo Qrjor OoerlAOO l4ore 500 Op 612 A44 tE% oil ordero Oo oh USA Con & 140 EIoooher 15% 125% lby oiI Potonol ooolog $2 00 Inolode Froce Loot Frioe loot * 00100 olon 81 0$ oo toregn odd 8100 LEVELAND MODEL & SUPPLY Co0 o,oWor 100050 t PAoo*OooIotrOoo Efl MOEOoOOOOoOFOCO* oOo008000000pOOo 183078 DETROIT AVE CLEVBLAND OHIO 44102 oonoooooooHooOooo ne 515 PM9ST 0221-12 161 9613600 E0noOOr 9 Prepare epoxy resin Wearing pro tective gloves using accurate scale carefully weigh out predetermined quan tity EPON 815 Dont forget record weight empty container can determine net amount resin amount TETA catalyst should range 15-20% resin weight 17% being about ideal example assume 8-in-dia prop will require 22 grams EPON amount TETA needed will additional 375 grams giving total liquid weight 25 75 grams Mix resin catalyst thoroughly allow settle about 10 min permit bubbles clear Because way mold con structed bottom half natural reser voir ideal trough lay-up prop Start giving trough area heavy coat epoxy resin lay longest rovings arranging straddle center post Always keep strands centered lengthwise mold assist equalizing blade balance Use small stick x smoothed rounded end spread out filaments cover much blade area possible Add resin progress shorter lengths using stick maneuver strands work out bubbles might trapped hub area can filled 1-in shorter clippings keeping whole mass wet resin Keep filaments confined blade area let slide closing faces will notice rovings begin take silver translucent appearance some seeming disappear entirely sign good wetting necessary resin penetration occurring glass place trough filled resin coat top mold face resin slide down onto center post Check make sure mold match marks correspond because mold closed reversed ends will never able reopen mold salvage what have done point Manually bring top mold down within about ing position four clamps shown pictures clamps should very slowly evenly tightened until faces close tightly will some loss glass lot oozing resin between faces normal Too much glass loss indicates either overstuffed mold closed too rapidly Cleaning up can accom plished acetone epoxy thinner Lay mold aside making sure level something underneath catch cascading drips normal room tem perature prop will take five six hours hardenconsiderably less left direct sun warm oven Check stiffness end spears doubt convinced epoxy firm loosen clamps use vice-grip pliers remove center post twisting pull advisable trim away washed-out rovings have formed long sides since will interfere opening mold Leave end spears untouched time five-minute soaking mold very hot water can sometimes wonders getting come apart Insert sharp knife screwdriver several places along parting line two halves should separate free prop again immerse hot water lift flashing flaps loosen grip especially hub area pull up end spears prop should snap free mold point should holding molded prop attached rectangle thin flashing Most flashing can cut away scissorsup within line sharp flat medium-coarse file used remove last ng along cleft line between flash prop Just few strokes will job nicely area around hub can best removed X-Acto knife file end spears cut away scissors after first filing groove across tongue sharp edge file Balancing prop acoomplished file and/or sandpaper progressing No 150 No 300 final polish Restrict balancing work top curved surface otherwise stand good chance altering blade pitch need help locating supplies cannot purchase small lots please contact Bob Dunham 4730 So Yorktown Tulsa OK 74105 starter kit consisting auto body filler PVA EPON 815 TETA vinyl gloves fiberglass rovings can furnished $60 postpaid US kit contains enough filler fiberglass other liquids make couple molds 20 25 medium-size props Material Sources Auto body filler CUZ NAPA Auto motive Stores White Knight K-Mart Wal Mart auto supply parts stores Steel-filled epoxy 1 qt kit EPOCAST #1 iB #9812 hardener EV Roberts & Assoc Box 868 Culver City CA 90232 phone 1-800-421-0824 Epoxy resin Shell Chemical EPON 815 EV Roberts & Assoc Epoxy catalyst TETA EV Roberts & Assoc Polyester resin K&B Manufacturing hobby shops Fiberglass rovings Owens-Corning Product #447-211 #352-211 CertainTeed Product #282-Bi See Yellow Pages under Fiberglass Materials Carbon fiber tows Gougeon Bros Box X908 Bay City MI 48707 NFFS Supplies 12 Cook St Rowayton CT 06853 RC History/Good Continued page 60 throttle offone time Panel lights indicated airborne pilot control signal being transmitted Continued page 126 March 1986 123 Will OPS 000 Sa#uoc4 specialists High Performance Model Airplane Engines stock parts back up will like doing business us See local hoppy shop P arts Peo pie Box 26247 New Orleans LA 70186 242-5967