bubbeguseconds Total cost gun less $10 Author uses Lux liquid soap Leit vvitn dip steady stream ot 5U-bU bubbles emitted 1-4 solution undiluted form Above Heating coil removed snout works tapes Onto side 6-volt battery RJ Dunham Bubble machines have long favorite way detecting thermals Heres simple made auto defroster HOW MANY OF YOU competi tion free-flight RC sailplane fliers have gone important contest know have best ship field intimidated some guy clunker air plane equipped latest elec tronic thermal detecting gear Worse yet might have best plane field clunker Since obviously knows taking un fair advantage rest fliers keeps detecting gear carefully screened competition makes sure inoperative taking flights Well now can get take some guesswork out thermal de tection whipping out handy port able easy use Bubblegun proceed saturate air thousands float ing soap bubbles learning action bubbles under various atmospheric condi tions can develop art can pretty accurately predict whether time has arrived put plane air watched procedure followed recently 75 Nats pro duced perfect string seven maxes FAT Power event winner method thermal detection used NO OT L~i M4o 0 CAR DEFQOSTRR MFALLiON oo& CT iPR LEL BATTRIT PLLIGATO CLs 2 ~O1 PRLE OR VASflCRK TAC WIRE COTH MAN& S4RET TJ ThCT TAV L L~Ujt SOAiV I2 yoeTT European fliers important meets such FAI FF World Champion ships present rules prohibit using stationary thermal detecting gear within designated launch area Since Bubblegun hand held portable would legal have closeby find AMA com petition bubbles used conjunc tion mylar streamer located closeby intensity lift can better evaluated bubbles alone total expense building Bubblegun less $1000 couple evenings required assemble drawing makes construction almost self explanatory few words might order key component blower made modified car window defroster case Medallion Model 62-680 available auto acces sory stores discount houses Since hot air bubbles might give errone ous action modification re quired removal heating coil located snout portion done removing three screws case allowing open down middle two wires leading coil snipped coil along sheet metal core removed discarded snipped wires folded down handle grip out air stream unit re assembled wire leads blower cut about 10 long ends fitted alligator clips J inued page 79 36 Model Aviation BURR LE G U N BY N J DUNHAM Hot Wood/Mills continued page 28 model should go straight out about 30 feet pick up speed go 30- 40degree climb model banks too steeply toward side cut small tab about 3/16 deep trailing edge wing low turn Bend tab down about 1/16 about thickness trailing edge tab will act aileron model picks up speed will hold up wing allowing model climb higher Whatever dont bend rudder correct flight path unless other adjustments fail job use very small amount rudder adjust ment models has flown right off building board very little final adjustment required models have equipped dethermalizer drop-weight-type similar type used hand-launched gliders will allow practice losing plane word caution about Jetex en gines very hot after flight dont pick up model engine until sure has cooled off B u bbleg un/Dunham continued page 36 balance construction consists sheet-metal forming wire bending used coat hanger wire easy bend removing paint soldered areas small tin can used soap reser voir ease soldering however alumi num will attachments will have epoxied can dipping wire assembled off blower epoxied place shown pop bottle cap liner removed 3/8 diameter hole drilled center cap sol dered wire dipper vertical position blowing position completed next step assemble blower 6-volt dry-cell battery 6 long piece yardstick tape though original defroster set up 12-volt operation 6-volt battery results better bubble formation slightly reducing fan speed air veloc ity use Lux liquid soap solution undiluted form possibly other soap solutions combinations might result improvement dip find steady stream bubbles will emitted about 3-4 seconds short span time 30-50 individual bubbles will wafted air have good pair lungs possible operate blow ing air inlet screen leaving battery disconnected method also serves good back-up case get meet find battery dead previous weeks outing have questions suggested improvements please let know cannot locate defroster area send $700 postage p 0 Box 7151 Tulsa OkIa 74105 December 1975 79 Greg Mills lighting fuse Jetex engine fore flight 1974 Nationals photos shot Jim Mills
Edition: Model Aviation - 1975/12
Page Numbers: 36, 79
bubbeguseconds Total cost gun less $10 Author uses Lux liquid soap Leit vvitn dip steady stream ot 5U-bU bubbles emitted 1-4 solution undiluted form Above Heating coil removed snout works tapes Onto side 6-volt battery RJ Dunham Bubble machines have long favorite way detecting thermals Heres simple made auto defroster HOW MANY OF YOU competi tion free-flight RC sailplane fliers have gone important contest know have best ship field intimidated some guy clunker air plane equipped latest elec tronic thermal detecting gear Worse yet might have best plane field clunker Since obviously knows taking un fair advantage rest fliers keeps detecting gear carefully screened competition makes sure inoperative taking flights Well now can get take some guesswork out thermal de tection whipping out handy port able easy use Bubblegun proceed saturate air thousands float ing soap bubbles learning action bubbles under various atmospheric condi tions can develop art can pretty accurately predict whether time has arrived put plane air watched procedure followed recently 75 Nats pro duced perfect string seven maxes FAT Power event winner method thermal detection used NO OT L~i M4o 0 CAR DEFQOSTRR MFALLiON oo& CT iPR LEL BATTRIT PLLIGATO CLs 2 ~O1 PRLE OR VASflCRK TAC WIRE COTH MAN& S4RET TJ ThCT TAV L L~Ujt SOAiV I2 yoeTT European fliers important meets such FAI FF World Champion ships present rules prohibit using stationary thermal detecting gear within designated launch area Since Bubblegun hand held portable would legal have closeby find AMA com petition bubbles used conjunc tion mylar streamer located closeby intensity lift can better evaluated bubbles alone total expense building Bubblegun less $1000 couple evenings required assemble drawing makes construction almost self explanatory few words might order key component blower made modified car window defroster case Medallion Model 62-680 available auto acces sory stores discount houses Since hot air bubbles might give errone ous action modification re quired removal heating coil located snout portion done removing three screws case allowing open down middle two wires leading coil snipped coil along sheet metal core removed discarded snipped wires folded down handle grip out air stream unit re assembled wire leads blower cut about 10 long ends fitted alligator clips J inued page 79 36 Model Aviation BURR LE G U N BY N J DUNHAM Hot Wood/Mills continued page 28 model should go straight out about 30 feet pick up speed go 30- 40degree climb model banks too steeply toward side cut small tab about 3/16 deep trailing edge wing low turn Bend tab down about 1/16 about thickness trailing edge tab will act aileron model picks up speed will hold up wing allowing model climb higher Whatever dont bend rudder correct flight path unless other adjustments fail job use very small amount rudder adjust ment models has flown right off building board very little final adjustment required models have equipped dethermalizer drop-weight-type similar type used hand-launched gliders will allow practice losing plane word caution about Jetex en gines very hot after flight dont pick up model engine until sure has cooled off B u bbleg un/Dunham continued page 36 balance construction consists sheet-metal forming wire bending used coat hanger wire easy bend removing paint soldered areas small tin can used soap reser voir ease soldering however alumi num will attachments will have epoxied can dipping wire assembled off blower epoxied place shown pop bottle cap liner removed 3/8 diameter hole drilled center cap sol dered wire dipper vertical position blowing position completed next step assemble blower 6-volt dry-cell battery 6 long piece yardstick tape though original defroster set up 12-volt operation 6-volt battery results better bubble formation slightly reducing fan speed air veloc ity use Lux liquid soap solution undiluted form possibly other soap solutions combinations might result improvement dip find steady stream bubbles will emitted about 3-4 seconds short span time 30-50 individual bubbles will wafted air have good pair lungs possible operate blow ing air inlet screen leaving battery disconnected method also serves good back-up case get meet find battery dead previous weeks outing have questions suggested improvements please let know cannot locate defroster area send $700 postage p 0 Box 7151 Tulsa OkIa 74105 December 1975 79 Greg Mills lighting fuse Jetex engine fore flight 1974 Nationals photos shot Jim Mills