In age urbanization modelers take sophisti cated whole-sound approach measuring noise have edge achieving quiet flight San Diego club association won fly ing site partly doing just EJames Wilson LIKE MANY another success story grew out hard work innovation perseverance story Gopher Canyon about dedicated group RC fliers overcame local opposition secure muchneeded club flying site happened San Diego makes notable achievement large crowded city like San Diego finding flying site isnt close prox imity residential areas difficult indeed San Diego also very fast-growing city field long-term potential rare commodity Compounding challenge city surrounded mountains ocean plus side however San Diego fliers fortunate having active asso ciation flying clubs going gets tough tough get organized Spear headed Dennis Caudle local clubs banded together unified front 1986 association acts liaison county other land-controlling organizations Top picture Looking down new Gopher Canyon flying site white streaks photo methane gas collector pipes belonging methane gas generating facility shares site Above author manipulating homemade engine dynometer Cliff Bruce assisting background Note homemade test stand long rubber hose connected exhaust remove much exhaust noise possible test site August 1990 85 ian Maclaughlin ready takeoff new gravel surface proximity houses background main reason Go pher Canyon such noise-sensitIve site Table 1 Correction Noise Rating Number Primarily Applicable Residential Cases lnfiuencing FactorPossible ConditionsCorrections uncorrected N# Noise spectrumPure tone components* aracterWideband noise0 Peak factorImpulsive5 Nonimpuisive* 0 RepetitiveContinuous 1 mm* 0 character10-60 per hour5 about 10 per hour10 noise duration4-20 per day15 assumed1-4 per day20 1 per day25 Adjustment toNo previous cond* 0 exposureConsiderable cond5 Extreme conditioning10 Time dayDaytime only* seasonAt night5 Winter5 Summer* 0 Allowance forNeighborhood localRural* 5 conditionsSuburban0 Residential urban5 Urban light industry10 Industrial area15 Source 1502Total * te * indicates assumptions used Gopher Canyon number sites investigated association since its inception first report site stated unusable because meth ane gas collectors covering surface results subsequent examinations oth ers reassured modelers little tweaking runway could squeezed upwind side making weliheads minor inconvenience decided association went work Negotiations acquire site began Numerous meetings county town council local homeowners association held final hurdle flight demonstration neighbors Corrected NoiseEstImated Public Reaction Rating Number Below 40No observed reaction 40-50Sporadic complaints 45-55Widespread complaints 50-60Threats community action Above 65Vigorous community action Source 1502 city council meet ing planes used demon stration care fully tested certain met 90 dB-at-9-ft noise recommenda tion Everything went smoothly right up council meetingwhen bomb dropped first atmos phere bordering hysteria con cerned resident af ter another stood up loudly protested presence No question about shaken some us ready give up remembering first rule site search arent beat until quit rallied regrouped pushed Since first concern prospective neighbors obviously noise strategy show quiet planes actu ally Accompanied Pete n Paul Saito 45 four-stroke-equipped model fel low flier Cliff Bruce set out visit res idents door door talked people dividually demonstrated exactly quiet model airplane engine could Dealt direcfly listeners proved whole reasonablewith excep tion individual suspect still lieves world flat Collectively res idents agreed allow us stage further demonstrations quiet operation put three demonstrations using very quietest planes local clubsmostly four-strokers ex pected two ended up add ing third demo residentproba bly hoping would forget whole thingdidnt show up either break came city council mem ber attended demonstrations seeor rather listenfor herself headed straight closest house re ported couldnt hear engines further mollify neighbors Cliff came up system could follow report plane homeowners might find offensive next council meeting far re ceptive Only two persons turned up op pose usthe flat-earth proponent noshow didnt hold much weight against testimony councilwoman tended demonstration council voted grant us six months probationary period next phase securing field gan goal find out quiet beand get gain some focus just what noise limits recorded noise levels plane flown during probationary period Some us studying sound about year knew dB meter left too unanswered questions exam ple couldnt understand fourstroke engine sounded quieter twostroke yet measured louder dB ter Looking common denominator among planes produced acceptable noise levels versus sounded objec tionable sifted through information gathered during demonstrations No matter what combination multiples dB 86 Model Aviation Table 2 Public Reaction Noise Residential Districts Above modified 0S 40 FP muffler model #843 shown disassembled Inner outer tubes separated hardwood bushings Inner tube brass tubing multiple holes both ends outer tube -In brass holes back end fender washer separates rear ares separate exit chamber Gases pass outer tube back front chamber Inner tube front muffler Below left inner tube Inserted outer tube Below right fender washer shown Installed - \ N -_ Iij i S 2-Stroke IIRPM 4-Stroke 1K2K4K Mldtrequencies Octave Bands Hertz 112 108 104 -N 00 NOISE FIGURE -N40NF 96 N N N K FIgure 1 ISO Noise Rating Curves ISO2 Suburban N 2 88 500100020004000 Distance Neighbor Feet RPM NFdB@9ft cycle engines NF 9ft ngines 2000 tour-cycle e Figure 2 Allowable Noise Figure Function Distance Noise Rating Number N pm tried though seemed exception rule breakthrough came through studying article George Abbott Novem ber 1987 Model Aviation Abbott explained dB frequency relate discussed far away noise source must avoid complaints Measuring distance nearest house using mula suddenly clear some planes acceptable others Because system measurement critical success procuring site warrants detailed explanation Studies have made predict public reaction noise observing what dis tance certain predetermined responses oc cur call distance acceptabil ity accompanying graphs tables show acceptable distance deter mined Studying will provide insight Continued page 185 y Above Disassembled parts simple mod ification muffler doesnt open up has center exit consists long inner brass tube multipie holes drilled heid place nut bolt front muffler fitting tight muffier exit shorter large tube wire retaining hooks slips over muffler exit Steel wool packed between two tubes assembly should extend about 2 3 beyond exit Beiow assem bled unit ready install muffler Above modified OS 40 muffler model #743 shown disassembled easy work since screws together its center seam two tubes slide other holes opposite ends Gases pass outer tube back muffier inner tube front outside inside inner tube coated High Temp RTV outer tubs coated Inner side Below left inner tube serted outer tube Below right tubes shown installed back half muffler must noted modifications cure-ailsErratic needle valve set tings excessive pressure may occur Any muffler modification will require experimenta tion various-sized props rpm settings depending type installation used r August 1990 87 70dB 60 dB 50dB 40 dB NOISE TENSITY dO 10dB ber what rig needs done well its out everyone can see Keep tight CyA go pulling tight way Flying now youre pretty familiar Boxkite Its time give final check head Out aerodrome Correct adverse warps surfaces Trim down 8 x 4 prop fit between frames least tA -in clearance closest point its arc Balance prop best can carving and/or sand ing heaviest blade Balance Boxkite its nose-heavy first flight front elevator very sensitive model will try porpoise youre ready Practice starting procedure before ac tually fuel up Getting glow plug clips off adjusting needle valve need worked through before engine running Once youve powered up feel excessive vibra tion see loose parts shut engine down make necessary repairs adjustments Enough caveats worries Boxkite designed flying model Enjoy ready nostalgia bug bite Ken neth Munsons book chock-full other pio neer designs await talents modeler Dream Gopher Canyon/Wilson Continued page 87 understanding measuring noise Figure 1 shows series curves relate noise intensity frequency noise rating number N tables 1 2 can estimate public reaction N numbers Referring Table 2 example since de sire no public reaction select corrected noise rating less 40say 35 Table 1 find appropriate noise rating correction factor must subtracted noise rating Thats 5 case field subur ban rather rural setting would use correction factor 0 Since must re flected corrected noise rating ntlmber must use values N ural N uburban graph Figure 1 two-cycle engine speed 12000 rpm would generate exhaust fundamental frequency 200 Hz Following N 30 line 200 Hz get noise intensity 44 dB means present noise 44 dB 200 Hz neighbors property line might safely expect no reaction Assuming airplane measures 90 dB 9 ft well need reduction 46 dB According law inverse square re quires distance ratio 200 19952 pre cise distance neighbor must 9 x 200 ft Now increase rpm 18000 have fundamental frequency 300 Hz Again read ing graph Figure 1 find allowable noise intensity 38 dB 300 Hz requires drop 52 dB translates distance ra tio 400 398 exactly distance neigh bor 3600 ft other extreme reduce rpm 6000 distance acceptability drops 900 ft Note calculations based upon sound measurements taken flat C weight ing nor weighting because weighting accounted ISO curves should apparent figures practice measuring sound power dB alone fundamentally inadequate noise-sensitive field Considering frequency well dBthat Continued page 186 7e 5edtt c4za NEW CONCEPT INAERODYNAMIC DESIGN FOR LEARNING TO FLYR/CAIRCRA FT STEALTUFIAT ltoateglider incredibly light wing loading NASA lifting tiody airfoil design giies onsiirpassed slow flight capability along snperior control response STEALTHBAT made oHO polyfoam ABS High impact styrene toogh feather weight constroction Comes assembled painted THE FUN WAY TO FLY Toss control Toie up like kite release Loop dice Ili-Start launch Slope soar Strap power pod go VISA & MASTERCARD SPECIFICATIONS Wing span45 Wing area700 sq Wing loadingSoz per sq ft Weight radio27 sz Stealthbat onlg Steathbat two sticA two chan net Fututia radio inst ailed Stealthbat single stick two channel Car Cobra radio installed$27995 AVAILABLE THROUGh YOUR DEALER OR DIRECT FROM WINO MPG ordering direct send required amount along $1250 shipping tIling Mfg 306 East Simmons Gatesburg IL 61401 Illinois Residents add 7% soles tax Send $400 far cowlig last time really enjoyed building kit Stinson high quality hand cut kit lots vacuformed extras piece detailed Fiberglass Cowl Wire parts pre-bent complete hardware package included Kit requires 5 servos 7 flaps Wing Span 74 Wt 8-9 lbs Engine Sizes 60-120T FS 60-90 13 Plug Wing Panel easy transporting Go ahead Spoil Yourself Deserve $15900 Postage & Handling Color Catalog nine other quality kits $300 write Call 517-781-3000 Fax 517-781-4322 AERODROME MODELS LTD S Miller Rd naw Ml 48603 LiGHTING SYSTEMS THE #RED 01 #RED 02 #RED 03 #RED 04 #RED 05 #RED 14 #RED 16 #RED 23 ORIGINALS. Still Programmable Flashing Navigation Lights Adjustable Rate Strobe Light Landing Lights Adjustable Rate Mars Rotating Beacon Marine Navigation Lights nonflashing Big Airplane Navigation Lights Econo Landing Lights brightest Real Strobe Light true zenon strobe S SEE YOUR DEALER S SEND STAMPED ENVELOPE FOR RAM INFO II unavailable locally send check money order full credit card info coat item plus $200 $500 foreigni immediate shipment Include full address UPS Sorry no COD cRam 4736 N Milwaukee Ave ago IL 60630 Best $2495 $1995 $3995 $1995 $1095 $2495 $1995 $2995 $13995 $23995 August 1990 185 measuring sound its totalityis better realistic method measuring noise As saw above means increase rpm must reduce dB Conversely lower rpm dB can higher much higher lower find Out went back chart calcu lated effect both raising lowering rpm 6000 keeping distance ac ceptability constant case resulting change 6 dB means 1000 rpm 1 dB roughly equal ability irritate Therefore have determined field limit 90 dB 12000 rpm pilot wants fly 18000 rpm must drop 6 dB 84 dB other hand hes turning 6000 rpm gets 6 dB bonus can fly 96 dB still have same level noise simplii calculations can add dB rpm thousands together use answer field limit instance 90 dB 12000 rpm would equal 102 Any dB rpm combination adding up number less would acceptable Using criterion a~m plishes two things gives club much better noise control allows fliers use field having conform unreasonable dB level especially important anyone has low-frequency plane large two- fourstroke engine Four-stroke engines have ad vantage audio frequency onehalf rpm Thus using method four-strokes must remember calculate one-half measured rpm frequently case dB higher engines sound quieter twostrokes Gopher Canyon site set noise limit NF 96 dB plus rpm/bOO twostroke rpm/2000 four-stroke engines determined proximity neighbor about 1000 ft overfly area rural setting meet standard club set out vent new mufflers response mem bers terrific numbers designs varied inventors lot fun Den nis Caudle wrote program com puter assist designing tuned mufflers Ive found meeting noise levels use simple additional internal chambers soundabsorbing coatings Lowering rpm too essen tial surprise seem having success two-stroke engines fourstrokers As writing city council has voted unanimously give us full use field Th testing continues however Gopher Canyos has become headquarters studying sounc San Diego County latest experiments spectral analyzer have yielded some inter esting results Most clubs fly sites situated 4000 ft residential areas limit 90 dB 9 ft recommended AMA reasonable standard However urbanizatior continues residential growth closes ir around more flying fields welJ need accurate knowledge about levels 01 noise creating Measuring total sound output rather merely dB levels positive step controlling noise before causes loss flying site References Ernest J McCormick Hwnan Factors Engi neering 3rd ed New York McGraw-Hill Book Co 1970 pp 525-528 2 ISO Technical Committee 43 Acoustics Rat ing Noise Respect Hearing Conversation Speech Communication Annoyance Secretariat-189 August 1961 GF Abbott Flying Field Layout Meet Noise Criteria Model Aviation Nov 1987 pp 24-35 Editor grateful George F Abbott checking manuscript Gopher Canyon article offering several suggestions incorporated Embry-omatic/De Loach Continued page 58 grain tissue must run lengthwise structure being covered parts covered its time shrink tissue tight moistening Again start fuselage Thoroughly moisten covering water alcohol Dont worry about getting too wet structure wont warp Set fuse lage aside dry wing empennage another matter Shrinking tissue structures must done very carefully since will warp quite easily have airbrush mist surfaces lightly tiny amount water alcohol Without airbrush task little dif ficult case best lightly sprink ling fingertips warps occur can steamed Out over teakettle before Continued page 190 186 Model Aviation Fly Mc Daniel Power New Solid State On-Board Glow-Plug Drivers Now can drive 1 2 glow plugs efficiently automatically new McDaniel On-Board Glow-Plug Drivers engine 2 4 stroke glow has 1 2 cylinders Model 471 472 On-Board Glow-Plug Driver will ease jobs starting maintaining idle during taxiing power down flight maneuvers FEATURES INCLUDE Servo Reversing Optically Coupled Circuitry No RFI Automatic Shutdown Via TX RX Connector Plug Battery Pack Remote Glow Plug Indicator Panels Available Separately Battery Pack AC Charger NOT Included Available Separately See Year Local Hobby Dealer Contact McDaniel R/C IncVisa MC accepted 1654 Crofton Blvd Suite 4 Crofton MD 21114 e 301721-6303 301721-6306 II V flULUUI Made ot White Laminating Epoxy & Fiberglass Strong Lightweight No Pin Holes tle e Construction dor I
Edition: Model Aviation - 1990/08
Page Numbers: 85, 86, 87, 185, 186
In age urbanization modelers take sophisti cated whole-sound approach measuring noise have edge achieving quiet flight San Diego club association won fly ing site partly doing just EJames Wilson LIKE MANY another success story grew out hard work innovation perseverance story Gopher Canyon about dedicated group RC fliers overcame local opposition secure muchneeded club flying site happened San Diego makes notable achievement large crowded city like San Diego finding flying site isnt close prox imity residential areas difficult indeed San Diego also very fast-growing city field long-term potential rare commodity Compounding challenge city surrounded mountains ocean plus side however San Diego fliers fortunate having active asso ciation flying clubs going gets tough tough get organized Spear headed Dennis Caudle local clubs banded together unified front 1986 association acts liaison county other land-controlling organizations Top picture Looking down new Gopher Canyon flying site white streaks photo methane gas collector pipes belonging methane gas generating facility shares site Above author manipulating homemade engine dynometer Cliff Bruce assisting background Note homemade test stand long rubber hose connected exhaust remove much exhaust noise possible test site August 1990 85 ian Maclaughlin ready takeoff new gravel surface proximity houses background main reason Go pher Canyon such noise-sensitIve site Table 1 Correction Noise Rating Number Primarily Applicable Residential Cases lnfiuencing FactorPossible ConditionsCorrections uncorrected N# Noise spectrumPure tone components* aracterWideband noise0 Peak factorImpulsive5 Nonimpuisive* 0 RepetitiveContinuous 1 mm* 0 character10-60 per hour5 about 10 per hour10 noise duration4-20 per day15 assumed1-4 per day20 1 per day25 Adjustment toNo previous cond* 0 exposureConsiderable cond5 Extreme conditioning10 Time dayDaytime only* seasonAt night5 Winter5 Summer* 0 Allowance forNeighborhood localRural* 5 conditionsSuburban0 Residential urban5 Urban light industry10 Industrial area15 Source 1502Total * te * indicates assumptions used Gopher Canyon number sites investigated association since its inception first report site stated unusable because meth ane gas collectors covering surface results subsequent examinations oth ers reassured modelers little tweaking runway could squeezed upwind side making weliheads minor inconvenience decided association went work Negotiations acquire site began Numerous meetings county town council local homeowners association held final hurdle flight demonstration neighbors Corrected NoiseEstImated Public Reaction Rating Number Below 40No observed reaction 40-50Sporadic complaints 45-55Widespread complaints 50-60Threats community action Above 65Vigorous community action Source 1502 city council meet ing planes used demon stration care fully tested certain met 90 dB-at-9-ft noise recommenda tion Everything went smoothly right up council meetingwhen bomb dropped first atmos phere bordering hysteria con cerned resident af ter another stood up loudly protested presence No question about shaken some us ready give up remembering first rule site search arent beat until quit rallied regrouped pushed Since first concern prospective neighbors obviously noise strategy show quiet planes actu ally Accompanied Pete n Paul Saito 45 four-stroke-equipped model fel low flier Cliff Bruce set out visit res idents door door talked people dividually demonstrated exactly quiet model airplane engine could Dealt direcfly listeners proved whole reasonablewith excep tion individual suspect still lieves world flat Collectively res idents agreed allow us stage further demonstrations quiet operation put three demonstrations using very quietest planes local clubsmostly four-strokers ex pected two ended up add ing third demo residentproba bly hoping would forget whole thingdidnt show up either break came city council mem ber attended demonstrations seeor rather listenfor herself headed straight closest house re ported couldnt hear engines further mollify neighbors Cliff came up system could follow report plane homeowners might find offensive next council meeting far re ceptive Only two persons turned up op pose usthe flat-earth proponent noshow didnt hold much weight against testimony councilwoman tended demonstration council voted grant us six months probationary period next phase securing field gan goal find out quiet beand get gain some focus just what noise limits recorded noise levels plane flown during probationary period Some us studying sound about year knew dB meter left too unanswered questions exam ple couldnt understand fourstroke engine sounded quieter twostroke yet measured louder dB ter Looking common denominator among planes produced acceptable noise levels versus sounded objec tionable sifted through information gathered during demonstrations No matter what combination multiples dB 86 Model Aviation Table 2 Public Reaction Noise Residential Districts Above modified 0S 40 FP muffler model #843 shown disassembled Inner outer tubes separated hardwood bushings Inner tube brass tubing multiple holes both ends outer tube -In brass holes back end fender washer separates rear ares separate exit chamber Gases pass outer tube back front chamber Inner tube front muffler Below left inner tube Inserted outer tube Below right fender washer shown Installed - \ N -_ Iij i S 2-Stroke IIRPM 4-Stroke 1K2K4K Mldtrequencies Octave Bands Hertz 112 108 104 -N 00 NOISE FIGURE -N40NF 96 N N N K FIgure 1 ISO Noise Rating Curves ISO2 Suburban N 2 88 500100020004000 Distance Neighbor Feet RPM NFdB@9ft cycle engines NF 9ft ngines 2000 tour-cycle e Figure 2 Allowable Noise Figure Function Distance Noise Rating Number N pm tried though seemed exception rule breakthrough came through studying article George Abbott Novem ber 1987 Model Aviation Abbott explained dB frequency relate discussed far away noise source must avoid complaints Measuring distance nearest house using mula suddenly clear some planes acceptable others Because system measurement critical success procuring site warrants detailed explanation Studies have made predict public reaction noise observing what dis tance certain predetermined responses oc cur call distance acceptabil ity accompanying graphs tables show acceptable distance deter mined Studying will provide insight Continued page 185 y Above Disassembled parts simple mod ification muffler doesnt open up has center exit consists long inner brass tube multipie holes drilled heid place nut bolt front muffler fitting tight muffier exit shorter large tube wire retaining hooks slips over muffler exit Steel wool packed between two tubes assembly should extend about 2 3 beyond exit Beiow assem bled unit ready install muffler Above modified OS 40 muffler model #743 shown disassembled easy work since screws together its center seam two tubes slide other holes opposite ends Gases pass outer tube back muffier inner tube front outside inside inner tube coated High Temp RTV outer tubs coated Inner side Below left inner tube serted outer tube Below right tubes shown installed back half muffler must noted modifications cure-ailsErratic needle valve set tings excessive pressure may occur Any muffler modification will require experimenta tion various-sized props rpm settings depending type installation used r August 1990 87 70dB 60 dB 50dB 40 dB NOISE TENSITY dO 10dB ber what rig needs done well its out everyone can see Keep tight CyA go pulling tight way Flying now youre pretty familiar Boxkite Its time give final check head Out aerodrome Correct adverse warps surfaces Trim down 8 x 4 prop fit between frames least tA -in clearance closest point its arc Balance prop best can carving and/or sand ing heaviest blade Balance Boxkite its nose-heavy first flight front elevator very sensitive model will try porpoise youre ready Practice starting procedure before ac tually fuel up Getting glow plug clips off adjusting needle valve need worked through before engine running Once youve powered up feel excessive vibra tion see loose parts shut engine down make necessary repairs adjustments Enough caveats worries Boxkite designed flying model Enjoy ready nostalgia bug bite Ken neth Munsons book chock-full other pio neer designs await talents modeler Dream Gopher Canyon/Wilson Continued page 87 understanding measuring noise Figure 1 shows series curves relate noise intensity frequency noise rating number N tables 1 2 can estimate public reaction N numbers Referring Table 2 example since de sire no public reaction select corrected noise rating less 40say 35 Table 1 find appropriate noise rating correction factor must subtracted noise rating Thats 5 case field subur ban rather rural setting would use correction factor 0 Since must re flected corrected noise rating ntlmber must use values N ural N uburban graph Figure 1 two-cycle engine speed 12000 rpm would generate exhaust fundamental frequency 200 Hz Following N 30 line 200 Hz get noise intensity 44 dB means present noise 44 dB 200 Hz neighbors property line might safely expect no reaction Assuming airplane measures 90 dB 9 ft well need reduction 46 dB According law inverse square re quires distance ratio 200 19952 pre cise distance neighbor must 9 x 200 ft Now increase rpm 18000 have fundamental frequency 300 Hz Again read ing graph Figure 1 find allowable noise intensity 38 dB 300 Hz requires drop 52 dB translates distance ra tio 400 398 exactly distance neigh bor 3600 ft other extreme reduce rpm 6000 distance acceptability drops 900 ft Note calculations based upon sound measurements taken flat C weight ing nor weighting because weighting accounted ISO curves should apparent figures practice measuring sound power dB alone fundamentally inadequate noise-sensitive field Considering frequency well dBthat Continued page 186 7e 5edtt c4za NEW CONCEPT INAERODYNAMIC DESIGN FOR LEARNING TO FLYR/CAIRCRA FT STEALTUFIAT ltoateglider incredibly light wing loading NASA lifting tiody airfoil design giies onsiirpassed slow flight capability along snperior control response STEALTHBAT made oHO polyfoam ABS High impact styrene toogh feather weight constroction Comes assembled painted THE FUN WAY TO FLY Toss control Toie up like kite release Loop dice Ili-Start launch Slope soar Strap power pod go VISA & MASTERCARD SPECIFICATIONS Wing span45 Wing area700 sq Wing loadingSoz per sq ft Weight radio27 sz Stealthbat onlg Steathbat two sticA two chan net Fututia radio inst ailed Stealthbat single stick two channel Car Cobra radio installed$27995 AVAILABLE THROUGh YOUR DEALER OR DIRECT FROM WINO MPG ordering direct send required amount along $1250 shipping tIling Mfg 306 East Simmons Gatesburg IL 61401 Illinois Residents add 7% soles tax Send $400 far cowlig last time really enjoyed building kit Stinson high quality hand cut kit lots vacuformed extras piece detailed Fiberglass Cowl Wire parts pre-bent complete hardware package included Kit requires 5 servos 7 flaps Wing Span 74 Wt 8-9 lbs Engine Sizes 60-120T FS 60-90 13 Plug Wing Panel easy transporting Go ahead Spoil Yourself Deserve $15900 Postage & Handling Color Catalog nine other quality kits $300 write Call 517-781-3000 Fax 517-781-4322 AERODROME MODELS LTD S Miller Rd naw Ml 48603 LiGHTING SYSTEMS THE #RED 01 #RED 02 #RED 03 #RED 04 #RED 05 #RED 14 #RED 16 #RED 23 ORIGINALS. Still Programmable Flashing Navigation Lights Adjustable Rate Strobe Light Landing Lights Adjustable Rate Mars Rotating Beacon Marine Navigation Lights nonflashing Big Airplane Navigation Lights Econo Landing Lights brightest Real Strobe Light true zenon strobe S SEE YOUR DEALER S SEND STAMPED ENVELOPE FOR RAM INFO II unavailable locally send check money order full credit card info coat item plus $200 $500 foreigni immediate shipment Include full address UPS Sorry no COD cRam 4736 N Milwaukee Ave ago IL 60630 Best $2495 $1995 $3995 $1995 $1095 $2495 $1995 $2995 $13995 $23995 August 1990 185 measuring sound its totalityis better realistic method measuring noise As saw above means increase rpm must reduce dB Conversely lower rpm dB can higher much higher lower find Out went back chart calcu lated effect both raising lowering rpm 6000 keeping distance ac ceptability constant case resulting change 6 dB means 1000 rpm 1 dB roughly equal ability irritate Therefore have determined field limit 90 dB 12000 rpm pilot wants fly 18000 rpm must drop 6 dB 84 dB other hand hes turning 6000 rpm gets 6 dB bonus can fly 96 dB still have same level noise simplii calculations can add dB rpm thousands together use answer field limit instance 90 dB 12000 rpm would equal 102 Any dB rpm combination adding up number less would acceptable Using criterion a~m plishes two things gives club much better noise control allows fliers use field having conform unreasonable dB level especially important anyone has low-frequency plane large two- fourstroke engine Four-stroke engines have ad vantage audio frequency onehalf rpm Thus using method four-strokes must remember calculate one-half measured rpm frequently case dB higher engines sound quieter twostrokes Gopher Canyon site set noise limit NF 96 dB plus rpm/bOO twostroke rpm/2000 four-stroke engines determined proximity neighbor about 1000 ft overfly area rural setting meet standard club set out vent new mufflers response mem bers terrific numbers designs varied inventors lot fun Den nis Caudle wrote program com puter assist designing tuned mufflers Ive found meeting noise levels use simple additional internal chambers soundabsorbing coatings Lowering rpm too essen tial surprise seem having success two-stroke engines fourstrokers As writing city council has voted unanimously give us full use field Th testing continues however Gopher Canyos has become headquarters studying sounc San Diego County latest experiments spectral analyzer have yielded some inter esting results Most clubs fly sites situated 4000 ft residential areas limit 90 dB 9 ft recommended AMA reasonable standard However urbanizatior continues residential growth closes ir around more flying fields welJ need accurate knowledge about levels 01 noise creating Measuring total sound output rather merely dB levels positive step controlling noise before causes loss flying site References Ernest J McCormick Hwnan Factors Engi neering 3rd ed New York McGraw-Hill Book Co 1970 pp 525-528 2 ISO Technical Committee 43 Acoustics Rat ing Noise Respect Hearing Conversation Speech Communication Annoyance Secretariat-189 August 1961 GF Abbott Flying Field Layout Meet Noise Criteria Model Aviation Nov 1987 pp 24-35 Editor grateful George F Abbott checking manuscript Gopher Canyon article offering several suggestions incorporated Embry-omatic/De Loach Continued page 58 grain tissue must run lengthwise structure being covered parts covered its time shrink tissue tight moistening Again start fuselage Thoroughly moisten covering water alcohol Dont worry about getting too wet structure wont warp Set fuse lage aside dry wing empennage another matter Shrinking tissue structures must done very carefully since will warp quite easily have airbrush mist surfaces lightly tiny amount water alcohol Without airbrush task little dif ficult case best lightly sprink ling fingertips warps occur can steamed Out over teakettle before Continued page 190 186 Model Aviation Fly Mc Daniel Power New Solid State On-Board Glow-Plug Drivers Now can drive 1 2 glow plugs efficiently automatically new McDaniel On-Board Glow-Plug Drivers engine 2 4 stroke glow has 1 2 cylinders Model 471 472 On-Board Glow-Plug Driver will ease jobs starting maintaining idle during taxiing power down flight maneuvers FEATURES INCLUDE Servo Reversing Optically Coupled Circuitry No RFI Automatic Shutdown Via TX RX Connector Plug Battery Pack Remote Glow Plug Indicator Panels Available Separately Battery Pack AC Charger NOT Included Available Separately See Year Local Hobby Dealer Contact McDaniel R/C IncVisa MC accepted 1654 Crofton Blvd Suite 4 Crofton MD 21114 e 301721-6303 301721-6306 II V flULUUI Made ot White Laminating Epoxy & Fiberglass Strong Lightweight No Pin Holes tle e Construction dor I
Edition: Model Aviation - 1990/08
Page Numbers: 85, 86, 87, 185, 186
In age urbanization modelers take sophisti cated whole-sound approach measuring noise have edge achieving quiet flight San Diego club association won fly ing site partly doing just EJames Wilson LIKE MANY another success story grew out hard work innovation perseverance story Gopher Canyon about dedicated group RC fliers overcame local opposition secure muchneeded club flying site happened San Diego makes notable achievement large crowded city like San Diego finding flying site isnt close prox imity residential areas difficult indeed San Diego also very fast-growing city field long-term potential rare commodity Compounding challenge city surrounded mountains ocean plus side however San Diego fliers fortunate having active asso ciation flying clubs going gets tough tough get organized Spear headed Dennis Caudle local clubs banded together unified front 1986 association acts liaison county other land-controlling organizations Top picture Looking down new Gopher Canyon flying site white streaks photo methane gas collector pipes belonging methane gas generating facility shares site Above author manipulating homemade engine dynometer Cliff Bruce assisting background Note homemade test stand long rubber hose connected exhaust remove much exhaust noise possible test site August 1990 85 ian Maclaughlin ready takeoff new gravel surface proximity houses background main reason Go pher Canyon such noise-sensitIve site Table 1 Correction Noise Rating Number Primarily Applicable Residential Cases lnfiuencing FactorPossible ConditionsCorrections uncorrected N# Noise spectrumPure tone components* aracterWideband noise0 Peak factorImpulsive5 Nonimpuisive* 0 RepetitiveContinuous 1 mm* 0 character10-60 per hour5 about 10 per hour10 noise duration4-20 per day15 assumed1-4 per day20 1 per day25 Adjustment toNo previous cond* 0 exposureConsiderable cond5 Extreme conditioning10 Time dayDaytime only* seasonAt night5 Winter5 Summer* 0 Allowance forNeighborhood localRural* 5 conditionsSuburban0 Residential urban5 Urban light industry10 Industrial area15 Source 1502Total * te * indicates assumptions used Gopher Canyon number sites investigated association since its inception first report site stated unusable because meth ane gas collectors covering surface results subsequent examinations oth ers reassured modelers little tweaking runway could squeezed upwind side making weliheads minor inconvenience decided association went work Negotiations acquire site began Numerous meetings county town council local homeowners association held final hurdle flight demonstration neighbors Corrected NoiseEstImated Public Reaction Rating Number Below 40No observed reaction 40-50Sporadic complaints 45-55Widespread complaints 50-60Threats community action Above 65Vigorous community action Source 1502 city council meet ing planes used demon stration care fully tested certain met 90 dB-at-9-ft noise recommenda tion Everything went smoothly right up council meetingwhen bomb dropped first atmos phere bordering hysteria con cerned resident af ter another stood up loudly protested presence No question about shaken some us ready give up remembering first rule site search arent beat until quit rallied regrouped pushed Since first concern prospective neighbors obviously noise strategy show quiet planes actu ally Accompanied Pete n Paul Saito 45 four-stroke-equipped model fel low flier Cliff Bruce set out visit res idents door door talked people dividually demonstrated exactly quiet model airplane engine could Dealt direcfly listeners proved whole reasonablewith excep tion individual suspect still lieves world flat Collectively res idents agreed allow us stage further demonstrations quiet operation put three demonstrations using very quietest planes local clubsmostly four-strokers ex pected two ended up add ing third demo residentproba bly hoping would forget whole thingdidnt show up either break came city council mem ber attended demonstrations seeor rather listenfor herself headed straight closest house re ported couldnt hear engines further mollify neighbors Cliff came up system could follow report plane homeowners might find offensive next council meeting far re ceptive Only two persons turned up op pose usthe flat-earth proponent noshow didnt hold much weight against testimony councilwoman tended demonstration council voted grant us six months probationary period next phase securing field gan goal find out quiet beand get gain some focus just what noise limits recorded noise levels plane flown during probationary period Some us studying sound about year knew dB meter left too unanswered questions exam ple couldnt understand fourstroke engine sounded quieter twostroke yet measured louder dB ter Looking common denominator among planes produced acceptable noise levels versus sounded objec tionable sifted through information gathered during demonstrations No matter what combination multiples dB 86 Model Aviation Table 2 Public Reaction Noise Residential Districts Above modified 0S 40 FP muffler model #843 shown disassembled Inner outer tubes separated hardwood bushings Inner tube brass tubing multiple holes both ends outer tube -In brass holes back end fender washer separates rear ares separate exit chamber Gases pass outer tube back front chamber Inner tube front muffler Below left inner tube Inserted outer tube Below right fender washer shown Installed - \ N -_ Iij i S 2-Stroke IIRPM 4-Stroke 1K2K4K Mldtrequencies Octave Bands Hertz 112 108 104 -N 00 NOISE FIGURE -N40NF 96 N N N K FIgure 1 ISO Noise Rating Curves ISO2 Suburban N 2 88 500100020004000 Distance Neighbor Feet RPM NFdB@9ft cycle engines NF 9ft ngines 2000 tour-cycle e Figure 2 Allowable Noise Figure Function Distance Noise Rating Number N pm tried though seemed exception rule breakthrough came through studying article George Abbott Novem ber 1987 Model Aviation Abbott explained dB frequency relate discussed far away noise source must avoid complaints Measuring distance nearest house using mula suddenly clear some planes acceptable others Because system measurement critical success procuring site warrants detailed explanation Studies have made predict public reaction noise observing what dis tance certain predetermined responses oc cur call distance acceptabil ity accompanying graphs tables show acceptable distance deter mined Studying will provide insight Continued page 185 y Above Disassembled parts simple mod ification muffler doesnt open up has center exit consists long inner brass tube multipie holes drilled heid place nut bolt front muffler fitting tight muffier exit shorter large tube wire retaining hooks slips over muffler exit Steel wool packed between two tubes assembly should extend about 2 3 beyond exit Beiow assem bled unit ready install muffler Above modified OS 40 muffler model #743 shown disassembled easy work since screws together its center seam two tubes slide other holes opposite ends Gases pass outer tube back muffier inner tube front outside inside inner tube coated High Temp RTV outer tubs coated Inner side Below left inner tube serted outer tube Below right tubes shown installed back half muffler must noted modifications cure-ailsErratic needle valve set tings excessive pressure may occur Any muffler modification will require experimenta tion various-sized props rpm settings depending type installation used r August 1990 87 70dB 60 dB 50dB 40 dB NOISE TENSITY dO 10dB ber what rig needs done well its out everyone can see Keep tight CyA go pulling tight way Flying now youre pretty familiar Boxkite Its time give final check head Out aerodrome Correct adverse warps surfaces Trim down 8 x 4 prop fit between frames least tA -in clearance closest point its arc Balance prop best can carving and/or sand ing heaviest blade Balance Boxkite its nose-heavy first flight front elevator very sensitive model will try porpoise youre ready Practice starting procedure before ac tually fuel up Getting glow plug clips off adjusting needle valve need worked through before engine running Once youve powered up feel excessive vibra tion see loose parts shut engine down make necessary repairs adjustments Enough caveats worries Boxkite designed flying model Enjoy ready nostalgia bug bite Ken neth Munsons book chock-full other pio neer designs await talents modeler Dream Gopher Canyon/Wilson Continued page 87 understanding measuring noise Figure 1 shows series curves relate noise intensity frequency noise rating number N tables 1 2 can estimate public reaction N numbers Referring Table 2 example since de sire no public reaction select corrected noise rating less 40say 35 Table 1 find appropriate noise rating correction factor must subtracted noise rating Thats 5 case field subur ban rather rural setting would use correction factor 0 Since must re flected corrected noise rating ntlmber must use values N ural N uburban graph Figure 1 two-cycle engine speed 12000 rpm would generate exhaust fundamental frequency 200 Hz Following N 30 line 200 Hz get noise intensity 44 dB means present noise 44 dB 200 Hz neighbors property line might safely expect no reaction Assuming airplane measures 90 dB 9 ft well need reduction 46 dB According law inverse square re quires distance ratio 200 19952 pre cise distance neighbor must 9 x 200 ft Now increase rpm 18000 have fundamental frequency 300 Hz Again read ing graph Figure 1 find allowable noise intensity 38 dB 300 Hz requires drop 52 dB translates distance ra tio 400 398 exactly distance neigh bor 3600 ft other extreme reduce rpm 6000 distance acceptability drops 900 ft Note calculations based upon sound measurements taken flat C weight ing nor weighting because weighting accounted ISO curves should apparent figures practice measuring sound power dB alone fundamentally inadequate noise-sensitive field Considering frequency well dBthat Continued page 186 7e 5edtt c4za NEW CONCEPT INAERODYNAMIC DESIGN FOR LEARNING TO FLYR/CAIRCRA FT STEALTUFIAT ltoateglider incredibly light wing loading NASA lifting tiody airfoil design giies onsiirpassed slow flight capability along snperior control response STEALTHBAT made oHO polyfoam ABS High impact styrene toogh feather weight constroction Comes assembled painted THE FUN WAY TO FLY Toss control Toie up like kite release Loop dice Ili-Start launch Slope soar Strap power pod go VISA & MASTERCARD SPECIFICATIONS Wing span45 Wing area700 sq Wing loadingSoz per sq ft Weight radio27 sz Stealthbat onlg Steathbat two sticA two chan net Fututia radio inst ailed Stealthbat single stick two channel Car Cobra radio installed$27995 AVAILABLE THROUGh YOUR DEALER OR DIRECT FROM WINO MPG ordering direct send required amount along $1250 shipping tIling Mfg 306 East Simmons Gatesburg IL 61401 Illinois Residents add 7% soles tax Send $400 far cowlig last time really enjoyed building kit Stinson high quality hand cut kit lots vacuformed extras piece detailed Fiberglass Cowl Wire parts pre-bent complete hardware package included Kit requires 5 servos 7 flaps Wing Span 74 Wt 8-9 lbs Engine Sizes 60-120T FS 60-90 13 Plug Wing Panel easy transporting Go ahead Spoil Yourself Deserve $15900 Postage & Handling Color Catalog nine other quality kits $300 write Call 517-781-3000 Fax 517-781-4322 AERODROME MODELS LTD S Miller Rd naw Ml 48603 LiGHTING SYSTEMS THE #RED 01 #RED 02 #RED 03 #RED 04 #RED 05 #RED 14 #RED 16 #RED 23 ORIGINALS. Still Programmable Flashing Navigation Lights Adjustable Rate Strobe Light Landing Lights Adjustable Rate Mars Rotating Beacon Marine Navigation Lights nonflashing Big Airplane Navigation Lights Econo Landing Lights brightest Real Strobe Light true zenon strobe S SEE YOUR DEALER S SEND STAMPED ENVELOPE FOR RAM INFO II unavailable locally send check money order full credit card info coat item plus $200 $500 foreigni immediate shipment Include full address UPS Sorry no COD cRam 4736 N Milwaukee Ave ago IL 60630 Best $2495 $1995 $3995 $1995 $1095 $2495 $1995 $2995 $13995 $23995 August 1990 185 measuring sound its totalityis better realistic method measuring noise As saw above means increase rpm must reduce dB Conversely lower rpm dB can higher much higher lower find Out went back chart calcu lated effect both raising lowering rpm 6000 keeping distance ac ceptability constant case resulting change 6 dB means 1000 rpm 1 dB roughly equal ability irritate Therefore have determined field limit 90 dB 12000 rpm pilot wants fly 18000 rpm must drop 6 dB 84 dB other hand hes turning 6000 rpm gets 6 dB bonus can fly 96 dB still have same level noise simplii calculations can add dB rpm thousands together use answer field limit instance 90 dB 12000 rpm would equal 102 Any dB rpm combination adding up number less would acceptable Using criterion a~m plishes two things gives club much better noise control allows fliers use field having conform unreasonable dB level especially important anyone has low-frequency plane large two- fourstroke engine Four-stroke engines have ad vantage audio frequency onehalf rpm Thus using method four-strokes must remember calculate one-half measured rpm frequently case dB higher engines sound quieter twostrokes Gopher Canyon site set noise limit NF 96 dB plus rpm/bOO twostroke rpm/2000 four-stroke engines determined proximity neighbor about 1000 ft overfly area rural setting meet standard club set out vent new mufflers response mem bers terrific numbers designs varied inventors lot fun Den nis Caudle wrote program com puter assist designing tuned mufflers Ive found meeting noise levels use simple additional internal chambers soundabsorbing coatings Lowering rpm too essen tial surprise seem having success two-stroke engines fourstrokers As writing city council has voted unanimously give us full use field Th testing continues however Gopher Canyos has become headquarters studying sounc San Diego County latest experiments spectral analyzer have yielded some inter esting results Most clubs fly sites situated 4000 ft residential areas limit 90 dB 9 ft recommended AMA reasonable standard However urbanizatior continues residential growth closes ir around more flying fields welJ need accurate knowledge about levels 01 noise creating Measuring total sound output rather merely dB levels positive step controlling noise before causes loss flying site References Ernest J McCormick Hwnan Factors Engi neering 3rd ed New York McGraw-Hill Book Co 1970 pp 525-528 2 ISO Technical Committee 43 Acoustics Rat ing Noise Respect Hearing Conversation Speech Communication Annoyance Secretariat-189 August 1961 GF Abbott Flying Field Layout Meet Noise Criteria Model Aviation Nov 1987 pp 24-35 Editor grateful George F Abbott checking manuscript Gopher Canyon article offering several suggestions incorporated Embry-omatic/De Loach Continued page 58 grain tissue must run lengthwise structure being covered parts covered its time shrink tissue tight moistening Again start fuselage Thoroughly moisten covering water alcohol Dont worry about getting too wet structure wont warp Set fuse lage aside dry wing empennage another matter Shrinking tissue structures must done very carefully since will warp quite easily have airbrush mist surfaces lightly tiny amount water alcohol Without airbrush task little dif ficult case best lightly sprink ling fingertips warps occur can steamed Out over teakettle before Continued page 190 186 Model Aviation Fly Mc Daniel Power New Solid State On-Board Glow-Plug Drivers Now can drive 1 2 glow plugs efficiently automatically new McDaniel On-Board Glow-Plug Drivers engine 2 4 stroke glow has 1 2 cylinders Model 471 472 On-Board Glow-Plug Driver will ease jobs starting maintaining idle during taxiing power down flight maneuvers FEATURES INCLUDE Servo Reversing Optically Coupled Circuitry No RFI Automatic Shutdown Via TX RX Connector Plug Battery Pack Remote Glow Plug Indicator Panels Available Separately Battery Pack AC Charger NOT Included Available Separately See Year Local Hobby Dealer Contact McDaniel R/C IncVisa MC accepted 1654 Crofton Blvd Suite 4 Crofton MD 21114 e 301721-6303 301721-6306 II V flULUUI Made ot White Laminating Epoxy & Fiberglass Strong Lightweight No Pin Holes tle e Construction dor I
Edition: Model Aviation - 1990/08
Page Numbers: 85, 86, 87, 185, 186
In age urbanization modelers take sophisti cated whole-sound approach measuring noise have edge achieving quiet flight San Diego club association won fly ing site partly doing just EJames Wilson LIKE MANY another success story grew out hard work innovation perseverance story Gopher Canyon about dedicated group RC fliers overcame local opposition secure muchneeded club flying site happened San Diego makes notable achievement large crowded city like San Diego finding flying site isnt close prox imity residential areas difficult indeed San Diego also very fast-growing city field long-term potential rare commodity Compounding challenge city surrounded mountains ocean plus side however San Diego fliers fortunate having active asso ciation flying clubs going gets tough tough get organized Spear headed Dennis Caudle local clubs banded together unified front 1986 association acts liaison county other land-controlling organizations Top picture Looking down new Gopher Canyon flying site white streaks photo methane gas collector pipes belonging methane gas generating facility shares site Above author manipulating homemade engine dynometer Cliff Bruce assisting background Note homemade test stand long rubber hose connected exhaust remove much exhaust noise possible test site August 1990 85 ian Maclaughlin ready takeoff new gravel surface proximity houses background main reason Go pher Canyon such noise-sensitIve site Table 1 Correction Noise Rating Number Primarily Applicable Residential Cases lnfiuencing FactorPossible ConditionsCorrections uncorrected N# Noise spectrumPure tone components* aracterWideband noise0 Peak factorImpulsive5 Nonimpuisive* 0 RepetitiveContinuous 1 mm* 0 character10-60 per hour5 about 10 per hour10 noise duration4-20 per day15 assumed1-4 per day20 1 per day25 Adjustment toNo previous cond* 0 exposureConsiderable cond5 Extreme conditioning10 Time dayDaytime only* seasonAt night5 Winter5 Summer* 0 Allowance forNeighborhood localRural* 5 conditionsSuburban0 Residential urban5 Urban light industry10 Industrial area15 Source 1502Total * te * indicates assumptions used Gopher Canyon number sites investigated association since its inception first report site stated unusable because meth ane gas collectors covering surface results subsequent examinations oth ers reassured modelers little tweaking runway could squeezed upwind side making weliheads minor inconvenience decided association went work Negotiations acquire site began Numerous meetings county town council local homeowners association held final hurdle flight demonstration neighbors Corrected NoiseEstImated Public Reaction Rating Number Below 40No observed reaction 40-50Sporadic complaints 45-55Widespread complaints 50-60Threats community action Above 65Vigorous community action Source 1502 city council meet ing planes used demon stration care fully tested certain met 90 dB-at-9-ft noise recommenda tion Everything went smoothly right up council meetingwhen bomb dropped first atmos phere bordering hysteria con cerned resident af ter another stood up loudly protested presence No question about shaken some us ready give up remembering first rule site search arent beat until quit rallied regrouped pushed Since first concern prospective neighbors obviously noise strategy show quiet planes actu ally Accompanied Pete n Paul Saito 45 four-stroke-equipped model fel low flier Cliff Bruce set out visit res idents door door talked people dividually demonstrated exactly quiet model airplane engine could Dealt direcfly listeners proved whole reasonablewith excep tion individual suspect still lieves world flat Collectively res idents agreed allow us stage further demonstrations quiet operation put three demonstrations using very quietest planes local clubsmostly four-strokers ex pected two ended up add ing third demo residentproba bly hoping would forget whole thingdidnt show up either break came city council mem ber attended demonstrations seeor rather listenfor herself headed straight closest house re ported couldnt hear engines further mollify neighbors Cliff came up system could follow report plane homeowners might find offensive next council meeting far re ceptive Only two persons turned up op pose usthe flat-earth proponent noshow didnt hold much weight against testimony councilwoman tended demonstration council voted grant us six months probationary period next phase securing field gan goal find out quiet beand get gain some focus just what noise limits recorded noise levels plane flown during probationary period Some us studying sound about year knew dB meter left too unanswered questions exam ple couldnt understand fourstroke engine sounded quieter twostroke yet measured louder dB ter Looking common denominator among planes produced acceptable noise levels versus sounded objec tionable sifted through information gathered during demonstrations No matter what combination multiples dB 86 Model Aviation Table 2 Public Reaction Noise Residential Districts Above modified 0S 40 FP muffler model #843 shown disassembled Inner outer tubes separated hardwood bushings Inner tube brass tubing multiple holes both ends outer tube -In brass holes back end fender washer separates rear ares separate exit chamber Gases pass outer tube back front chamber Inner tube front muffler Below left inner tube Inserted outer tube Below right fender washer shown Installed - \ N -_ Iij i S 2-Stroke IIRPM 4-Stroke 1K2K4K Mldtrequencies Octave Bands Hertz 112 108 104 -N 00 NOISE FIGURE -N40NF 96 N N N K FIgure 1 ISO Noise Rating Curves ISO2 Suburban N 2 88 500100020004000 Distance Neighbor Feet RPM NFdB@9ft cycle engines NF 9ft ngines 2000 tour-cycle e Figure 2 Allowable Noise Figure Function Distance Noise Rating Number N pm tried though seemed exception rule breakthrough came through studying article George Abbott Novem ber 1987 Model Aviation Abbott explained dB frequency relate discussed far away noise source must avoid complaints Measuring distance nearest house using mula suddenly clear some planes acceptable others Because system measurement critical success procuring site warrants detailed explanation Studies have made predict public reaction noise observing what dis tance certain predetermined responses oc cur call distance acceptabil ity accompanying graphs tables show acceptable distance deter mined Studying will provide insight Continued page 185 y Above Disassembled parts simple mod ification muffler doesnt open up has center exit consists long inner brass tube multipie holes drilled heid place nut bolt front muffler fitting tight muffier exit shorter large tube wire retaining hooks slips over muffler exit Steel wool packed between two tubes assembly should extend about 2 3 beyond exit Beiow assem bled unit ready install muffler Above modified OS 40 muffler model #743 shown disassembled easy work since screws together its center seam two tubes slide other holes opposite ends Gases pass outer tube back muffier inner tube front outside inside inner tube coated High Temp RTV outer tubs coated Inner side Below left inner tube serted outer tube Below right tubes shown installed back half muffler must noted modifications cure-ailsErratic needle valve set tings excessive pressure may occur Any muffler modification will require experimenta tion various-sized props rpm settings depending type installation used r August 1990 87 70dB 60 dB 50dB 40 dB NOISE TENSITY dO 10dB ber what rig needs done well its out everyone can see Keep tight CyA go pulling tight way Flying now youre pretty familiar Boxkite Its time give final check head Out aerodrome Correct adverse warps surfaces Trim down 8 x 4 prop fit between frames least tA -in clearance closest point its arc Balance prop best can carving and/or sand ing heaviest blade Balance Boxkite its nose-heavy first flight front elevator very sensitive model will try porpoise youre ready Practice starting procedure before ac tually fuel up Getting glow plug clips off adjusting needle valve need worked through before engine running Once youve powered up feel excessive vibra tion see loose parts shut engine down make necessary repairs adjustments Enough caveats worries Boxkite designed flying model Enjoy ready nostalgia bug bite Ken neth Munsons book chock-full other pio neer designs await talents modeler Dream Gopher Canyon/Wilson Continued page 87 understanding measuring noise Figure 1 shows series curves relate noise intensity frequency noise rating number N tables 1 2 can estimate public reaction N numbers Referring Table 2 example since de sire no public reaction select corrected noise rating less 40say 35 Table 1 find appropriate noise rating correction factor must subtracted noise rating Thats 5 case field subur ban rather rural setting would use correction factor 0 Since must re flected corrected noise rating ntlmber must use values N ural N uburban graph Figure 1 two-cycle engine speed 12000 rpm would generate exhaust fundamental frequency 200 Hz Following N 30 line 200 Hz get noise intensity 44 dB means present noise 44 dB 200 Hz neighbors property line might safely expect no reaction Assuming airplane measures 90 dB 9 ft well need reduction 46 dB According law inverse square re quires distance ratio 200 19952 pre cise distance neighbor must 9 x 200 ft Now increase rpm 18000 have fundamental frequency 300 Hz Again read ing graph Figure 1 find allowable noise intensity 38 dB 300 Hz requires drop 52 dB translates distance ra tio 400 398 exactly distance neigh bor 3600 ft other extreme reduce rpm 6000 distance acceptability drops 900 ft Note calculations based upon sound measurements taken flat C weight ing nor weighting because weighting accounted ISO curves should apparent figures practice measuring sound power dB alone fundamentally inadequate noise-sensitive field Considering frequency well dBthat Continued page 186 7e 5edtt c4za NEW CONCEPT INAERODYNAMIC DESIGN FOR LEARNING TO FLYR/CAIRCRA FT STEALTUFIAT ltoateglider incredibly light wing loading NASA lifting tiody airfoil design giies onsiirpassed slow flight capability along snperior control response STEALTHBAT made oHO polyfoam ABS High impact styrene toogh feather weight constroction Comes assembled painted THE FUN WAY TO FLY Toss control Toie up like kite release Loop dice Ili-Start launch Slope soar Strap power pod go VISA & MASTERCARD SPECIFICATIONS Wing span45 Wing area700 sq Wing loadingSoz per sq ft Weight radio27 sz Stealthbat onlg Steathbat two sticA two chan net Fututia radio inst ailed Stealthbat single stick two channel Car Cobra radio installed$27995 AVAILABLE THROUGh YOUR DEALER OR DIRECT FROM WINO MPG ordering direct send required amount along $1250 shipping tIling Mfg 306 East Simmons Gatesburg IL 61401 Illinois Residents add 7% soles tax Send $400 far cowlig last time really enjoyed building kit Stinson high quality hand cut kit lots vacuformed extras piece detailed Fiberglass Cowl Wire parts pre-bent complete hardware package included Kit requires 5 servos 7 flaps Wing Span 74 Wt 8-9 lbs Engine Sizes 60-120T FS 60-90 13 Plug Wing Panel easy transporting Go ahead Spoil Yourself Deserve $15900 Postage & Handling Color Catalog nine other quality kits $300 write Call 517-781-3000 Fax 517-781-4322 AERODROME MODELS LTD S Miller Rd naw Ml 48603 LiGHTING SYSTEMS THE #RED 01 #RED 02 #RED 03 #RED 04 #RED 05 #RED 14 #RED 16 #RED 23 ORIGINALS. Still Programmable Flashing Navigation Lights Adjustable Rate Strobe Light Landing Lights Adjustable Rate Mars Rotating Beacon Marine Navigation Lights nonflashing Big Airplane Navigation Lights Econo Landing Lights brightest Real Strobe Light true zenon strobe S SEE YOUR DEALER S SEND STAMPED ENVELOPE FOR RAM INFO II unavailable locally send check money order full credit card info coat item plus $200 $500 foreigni immediate shipment Include full address UPS Sorry no COD cRam 4736 N Milwaukee Ave ago IL 60630 Best $2495 $1995 $3995 $1995 $1095 $2495 $1995 $2995 $13995 $23995 August 1990 185 measuring sound its totalityis better realistic method measuring noise As saw above means increase rpm must reduce dB Conversely lower rpm dB can higher much higher lower find Out went back chart calcu lated effect both raising lowering rpm 6000 keeping distance ac ceptability constant case resulting change 6 dB means 1000 rpm 1 dB roughly equal ability irritate Therefore have determined field limit 90 dB 12000 rpm pilot wants fly 18000 rpm must drop 6 dB 84 dB other hand hes turning 6000 rpm gets 6 dB bonus can fly 96 dB still have same level noise simplii calculations can add dB rpm thousands together use answer field limit instance 90 dB 12000 rpm would equal 102 Any dB rpm combination adding up number less would acceptable Using criterion a~m plishes two things gives club much better noise control allows fliers use field having conform unreasonable dB level especially important anyone has low-frequency plane large two- fourstroke engine Four-stroke engines have ad vantage audio frequency onehalf rpm Thus using method four-strokes must remember calculate one-half measured rpm frequently case dB higher engines sound quieter twostrokes Gopher Canyon site set noise limit NF 96 dB plus rpm/bOO twostroke rpm/2000 four-stroke engines determined proximity neighbor about 1000 ft overfly area rural setting meet standard club set out vent new mufflers response mem bers terrific numbers designs varied inventors lot fun Den nis Caudle wrote program com puter assist designing tuned mufflers Ive found meeting noise levels use simple additional internal chambers soundabsorbing coatings Lowering rpm too essen tial surprise seem having success two-stroke engines fourstrokers As writing city council has voted unanimously give us full use field Th testing continues however Gopher Canyos has become headquarters studying sounc San Diego County latest experiments spectral analyzer have yielded some inter esting results Most clubs fly sites situated 4000 ft residential areas limit 90 dB 9 ft recommended AMA reasonable standard However urbanizatior continues residential growth closes ir around more flying fields welJ need accurate knowledge about levels 01 noise creating Measuring total sound output rather merely dB levels positive step controlling noise before causes loss flying site References Ernest J McCormick Hwnan Factors Engi neering 3rd ed New York McGraw-Hill Book Co 1970 pp 525-528 2 ISO Technical Committee 43 Acoustics Rat ing Noise Respect Hearing Conversation Speech Communication Annoyance Secretariat-189 August 1961 GF Abbott Flying Field Layout Meet Noise Criteria Model Aviation Nov 1987 pp 24-35 Editor grateful George F Abbott checking manuscript Gopher Canyon article offering several suggestions incorporated Embry-omatic/De Loach Continued page 58 grain tissue must run lengthwise structure being covered parts covered its time shrink tissue tight moistening Again start fuselage Thoroughly moisten covering water alcohol Dont worry about getting too wet structure wont warp Set fuse lage aside dry wing empennage another matter Shrinking tissue structures must done very carefully since will warp quite easily have airbrush mist surfaces lightly tiny amount water alcohol Without airbrush task little dif ficult case best lightly sprink ling fingertips warps occur can steamed Out over teakettle before Continued page 190 186 Model Aviation Fly Mc Daniel Power New Solid State On-Board Glow-Plug Drivers Now can drive 1 2 glow plugs efficiently automatically new McDaniel On-Board Glow-Plug Drivers engine 2 4 stroke glow has 1 2 cylinders Model 471 472 On-Board Glow-Plug Driver will ease jobs starting maintaining idle during taxiing power down flight maneuvers FEATURES INCLUDE Servo Reversing Optically Coupled Circuitry No RFI Automatic Shutdown Via TX RX Connector Plug Battery Pack Remote Glow Plug Indicator Panels Available Separately Battery Pack AC Charger NOT Included Available Separately See Year Local Hobby Dealer Contact McDaniel R/C IncVisa MC accepted 1654 Crofton Blvd Suite 4 Crofton MD 21114 e 301721-6303 301721-6306 II V flULUUI Made ot White Laminating Epoxy & Fiberglass Strong Lightweight No Pin Holes tle e Construction dor I
Edition: Model Aviation - 1990/08
Page Numbers: 85, 86, 87, 185, 186
In age urbanization modelers take sophisti cated whole-sound approach measuring noise have edge achieving quiet flight San Diego club association won fly ing site partly doing just EJames Wilson LIKE MANY another success story grew out hard work innovation perseverance story Gopher Canyon about dedicated group RC fliers overcame local opposition secure muchneeded club flying site happened San Diego makes notable achievement large crowded city like San Diego finding flying site isnt close prox imity residential areas difficult indeed San Diego also very fast-growing city field long-term potential rare commodity Compounding challenge city surrounded mountains ocean plus side however San Diego fliers fortunate having active asso ciation flying clubs going gets tough tough get organized Spear headed Dennis Caudle local clubs banded together unified front 1986 association acts liaison county other land-controlling organizations Top picture Looking down new Gopher Canyon flying site white streaks photo methane gas collector pipes belonging methane gas generating facility shares site Above author manipulating homemade engine dynometer Cliff Bruce assisting background Note homemade test stand long rubber hose connected exhaust remove much exhaust noise possible test site August 1990 85 ian Maclaughlin ready takeoff new gravel surface proximity houses background main reason Go pher Canyon such noise-sensitIve site Table 1 Correction Noise Rating Number Primarily Applicable Residential Cases lnfiuencing FactorPossible ConditionsCorrections uncorrected N# Noise spectrumPure tone components* aracterWideband noise0 Peak factorImpulsive5 Nonimpuisive* 0 RepetitiveContinuous 1 mm* 0 character10-60 per hour5 about 10 per hour10 noise duration4-20 per day15 assumed1-4 per day20 1 per day25 Adjustment toNo previous cond* 0 exposureConsiderable cond5 Extreme conditioning10 Time dayDaytime only* seasonAt night5 Winter5 Summer* 0 Allowance forNeighborhood localRural* 5 conditionsSuburban0 Residential urban5 Urban light industry10 Industrial area15 Source 1502Total * te * indicates assumptions used Gopher Canyon number sites investigated association since its inception first report site stated unusable because meth ane gas collectors covering surface results subsequent examinations oth ers reassured modelers little tweaking runway could squeezed upwind side making weliheads minor inconvenience decided association went work Negotiations acquire site began Numerous meetings county town council local homeowners association held final hurdle flight demonstration neighbors Corrected NoiseEstImated Public Reaction Rating Number Below 40No observed reaction 40-50Sporadic complaints 45-55Widespread complaints 50-60Threats community action Above 65Vigorous community action Source 1502 city council meet ing planes used demon stration care fully tested certain met 90 dB-at-9-ft noise recommenda tion Everything went smoothly right up council meetingwhen bomb dropped first atmos phere bordering hysteria con cerned resident af ter another stood up loudly protested presence No question about shaken some us ready give up remembering first rule site search arent beat until quit rallied regrouped pushed Since first concern prospective neighbors obviously noise strategy show quiet planes actu ally Accompanied Pete n Paul Saito 45 four-stroke-equipped model fel low flier Cliff Bruce set out visit res idents door door talked people dividually demonstrated exactly quiet model airplane engine could Dealt direcfly listeners proved whole reasonablewith excep tion individual suspect still lieves world flat Collectively res idents agreed allow us stage further demonstrations quiet operation put three demonstrations using very quietest planes local clubsmostly four-strokers ex pected two ended up add ing third demo residentproba bly hoping would forget whole thingdidnt show up either break came city council mem ber attended demonstrations seeor rather listenfor herself headed straight closest house re ported couldnt hear engines further mollify neighbors Cliff came up system could follow report plane homeowners might find offensive next council meeting far re ceptive Only two persons turned up op pose usthe flat-earth proponent noshow didnt hold much weight against testimony councilwoman tended demonstration council voted grant us six months probationary period next phase securing field gan goal find out quiet beand get gain some focus just what noise limits recorded noise levels plane flown during probationary period Some us studying sound about year knew dB meter left too unanswered questions exam ple couldnt understand fourstroke engine sounded quieter twostroke yet measured louder dB ter Looking common denominator among planes produced acceptable noise levels versus sounded objec tionable sifted through information gathered during demonstrations No matter what combination multiples dB 86 Model Aviation Table 2 Public Reaction Noise Residential Districts Above modified 0S 40 FP muffler model #843 shown disassembled Inner outer tubes separated hardwood bushings Inner tube brass tubing multiple holes both ends outer tube -In brass holes back end fender washer separates rear ares separate exit chamber Gases pass outer tube back front chamber Inner tube front muffler Below left inner tube Inserted outer tube Below right fender washer shown Installed - \ N -_ Iij i S 2-Stroke IIRPM 4-Stroke 1K2K4K Mldtrequencies Octave Bands Hertz 112 108 104 -N 00 NOISE FIGURE -N40NF 96 N N N K FIgure 1 ISO Noise Rating Curves ISO2 Suburban N 2 88 500100020004000 Distance Neighbor Feet RPM NFdB@9ft cycle engines NF 9ft ngines 2000 tour-cycle e Figure 2 Allowable Noise Figure Function Distance Noise Rating Number N pm tried though seemed exception rule breakthrough came through studying article George Abbott Novem ber 1987 Model Aviation Abbott explained dB frequency relate discussed far away noise source must avoid complaints Measuring distance nearest house using mula suddenly clear some planes acceptable others Because system measurement critical success procuring site warrants detailed explanation Studies have made predict public reaction noise observing what dis tance certain predetermined responses oc cur call distance acceptabil ity accompanying graphs tables show acceptable distance deter mined Studying will provide insight Continued page 185 y Above Disassembled parts simple mod ification muffler doesnt open up has center exit consists long inner brass tube multipie holes drilled heid place nut bolt front muffler fitting tight muffier exit shorter large tube wire retaining hooks slips over muffler exit Steel wool packed between two tubes assembly should extend about 2 3 beyond exit Beiow assem bled unit ready install muffler Above modified OS 40 muffler model #743 shown disassembled easy work since screws together its center seam two tubes slide other holes opposite ends Gases pass outer tube back muffier inner tube front outside inside inner tube coated High Temp RTV outer tubs coated Inner side Below left inner tube serted outer tube Below right tubes shown installed back half muffler must noted modifications cure-ailsErratic needle valve set tings excessive pressure may occur Any muffler modification will require experimenta tion various-sized props rpm settings depending type installation used r August 1990 87 70dB 60 dB 50dB 40 dB NOISE TENSITY dO 10dB ber what rig needs done well its out everyone can see Keep tight CyA go pulling tight way Flying now youre pretty familiar Boxkite Its time give final check head Out aerodrome Correct adverse warps surfaces Trim down 8 x 4 prop fit between frames least tA -in clearance closest point its arc Balance prop best can carving and/or sand ing heaviest blade Balance Boxkite its nose-heavy first flight front elevator very sensitive model will try porpoise youre ready Practice starting procedure before ac tually fuel up Getting glow plug clips off adjusting needle valve need worked through before engine running Once youve powered up feel excessive vibra tion see loose parts shut engine down make necessary repairs adjustments Enough caveats worries Boxkite designed flying model Enjoy ready nostalgia bug bite Ken neth Munsons book chock-full other pio neer designs await talents modeler Dream Gopher Canyon/Wilson Continued page 87 understanding measuring noise Figure 1 shows series curves relate noise intensity frequency noise rating number N tables 1 2 can estimate public reaction N numbers Referring Table 2 example since de sire no public reaction select corrected noise rating less 40say 35 Table 1 find appropriate noise rating correction factor must subtracted noise rating Thats 5 case field subur ban rather rural setting would use correction factor 0 Since must re flected corrected noise rating ntlmber must use values N ural N uburban graph Figure 1 two-cycle engine speed 12000 rpm would generate exhaust fundamental frequency 200 Hz Following N 30 line 200 Hz get noise intensity 44 dB means present noise 44 dB 200 Hz neighbors property line might safely expect no reaction Assuming airplane measures 90 dB 9 ft well need reduction 46 dB According law inverse square re quires distance ratio 200 19952 pre cise distance neighbor must 9 x 200 ft Now increase rpm 18000 have fundamental frequency 300 Hz Again read ing graph Figure 1 find allowable noise intensity 38 dB 300 Hz requires drop 52 dB translates distance ra tio 400 398 exactly distance neigh bor 3600 ft other extreme reduce rpm 6000 distance acceptability drops 900 ft Note calculations based upon sound measurements taken flat C weight ing nor weighting because weighting accounted ISO curves should apparent figures practice measuring sound power dB alone fundamentally inadequate noise-sensitive field Considering frequency well dBthat Continued page 186 7e 5edtt c4za NEW CONCEPT INAERODYNAMIC DESIGN FOR LEARNING TO FLYR/CAIRCRA FT STEALTUFIAT ltoateglider incredibly light wing loading NASA lifting tiody airfoil design giies onsiirpassed slow flight capability along snperior control response STEALTHBAT made oHO polyfoam ABS High impact styrene toogh feather weight constroction Comes assembled painted THE FUN WAY TO FLY Toss control Toie up like kite release Loop dice Ili-Start launch Slope soar Strap power pod go VISA & MASTERCARD SPECIFICATIONS Wing span45 Wing area700 sq Wing loadingSoz per sq ft Weight radio27 sz Stealthbat onlg Steathbat two sticA two chan net Fututia radio inst ailed Stealthbat single stick two channel Car Cobra radio installed$27995 AVAILABLE THROUGh YOUR DEALER OR DIRECT FROM WINO MPG ordering direct send required amount along $1250 shipping tIling Mfg 306 East Simmons Gatesburg IL 61401 Illinois Residents add 7% soles tax Send $400 far cowlig last time really enjoyed building kit Stinson high quality hand cut kit lots vacuformed extras piece detailed Fiberglass Cowl Wire parts pre-bent complete hardware package included Kit requires 5 servos 7 flaps Wing Span 74 Wt 8-9 lbs Engine Sizes 60-120T FS 60-90 13 Plug Wing Panel easy transporting Go ahead Spoil Yourself Deserve $15900 Postage & Handling Color Catalog nine other quality kits $300 write Call 517-781-3000 Fax 517-781-4322 AERODROME MODELS LTD S Miller Rd naw Ml 48603 LiGHTING SYSTEMS THE #RED 01 #RED 02 #RED 03 #RED 04 #RED 05 #RED 14 #RED 16 #RED 23 ORIGINALS. Still Programmable Flashing Navigation Lights Adjustable Rate Strobe Light Landing Lights Adjustable Rate Mars Rotating Beacon Marine Navigation Lights nonflashing Big Airplane Navigation Lights Econo Landing Lights brightest Real Strobe Light true zenon strobe S SEE YOUR DEALER S SEND STAMPED ENVELOPE FOR RAM INFO II unavailable locally send check money order full credit card info coat item plus $200 $500 foreigni immediate shipment Include full address UPS Sorry no COD cRam 4736 N Milwaukee Ave ago IL 60630 Best $2495 $1995 $3995 $1995 $1095 $2495 $1995 $2995 $13995 $23995 August 1990 185 measuring sound its totalityis better realistic method measuring noise As saw above means increase rpm must reduce dB Conversely lower rpm dB can higher much higher lower find Out went back chart calcu lated effect both raising lowering rpm 6000 keeping distance ac ceptability constant case resulting change 6 dB means 1000 rpm 1 dB roughly equal ability irritate Therefore have determined field limit 90 dB 12000 rpm pilot wants fly 18000 rpm must drop 6 dB 84 dB other hand hes turning 6000 rpm gets 6 dB bonus can fly 96 dB still have same level noise simplii calculations can add dB rpm thousands together use answer field limit instance 90 dB 12000 rpm would equal 102 Any dB rpm combination adding up number less would acceptable Using criterion a~m plishes two things gives club much better noise control allows fliers use field having conform unreasonable dB level especially important anyone has low-frequency plane large two- fourstroke engine Four-stroke engines have ad vantage audio frequency onehalf rpm Thus using method four-strokes must remember calculate one-half measured rpm frequently case dB higher engines sound quieter twostrokes Gopher Canyon site set noise limit NF 96 dB plus rpm/bOO twostroke rpm/2000 four-stroke engines determined proximity neighbor about 1000 ft overfly area rural setting meet standard club set out vent new mufflers response mem bers terrific numbers designs varied inventors lot fun Den nis Caudle wrote program com puter assist designing tuned mufflers Ive found meeting noise levels use simple additional internal chambers soundabsorbing coatings Lowering rpm too essen tial surprise seem having success two-stroke engines fourstrokers As writing city council has voted unanimously give us full use field Th testing continues however Gopher Canyos has become headquarters studying sounc San Diego County latest experiments spectral analyzer have yielded some inter esting results Most clubs fly sites situated 4000 ft residential areas limit 90 dB 9 ft recommended AMA reasonable standard However urbanizatior continues residential growth closes ir around more flying fields welJ need accurate knowledge about levels 01 noise creating Measuring total sound output rather merely dB levels positive step controlling noise before causes loss flying site References Ernest J McCormick Hwnan Factors Engi neering 3rd ed New York McGraw-Hill Book Co 1970 pp 525-528 2 ISO Technical Committee 43 Acoustics Rat ing Noise Respect Hearing Conversation Speech Communication Annoyance Secretariat-189 August 1961 GF Abbott Flying Field Layout Meet Noise Criteria Model Aviation Nov 1987 pp 24-35 Editor grateful George F Abbott checking manuscript Gopher Canyon article offering several suggestions incorporated Embry-omatic/De Loach Continued page 58 grain tissue must run lengthwise structure being covered parts covered its time shrink tissue tight moistening Again start fuselage Thoroughly moisten covering water alcohol Dont worry about getting too wet structure wont warp Set fuse lage aside dry wing empennage another matter Shrinking tissue structures must done very carefully since will warp quite easily have airbrush mist surfaces lightly tiny amount water alcohol Without airbrush task little dif ficult case best lightly sprink ling fingertips warps occur can steamed Out over teakettle before Continued page 190 186 Model Aviation Fly Mc Daniel Power New Solid State On-Board Glow-Plug Drivers Now can drive 1 2 glow plugs efficiently automatically new McDaniel On-Board Glow-Plug Drivers engine 2 4 stroke glow has 1 2 cylinders Model 471 472 On-Board Glow-Plug Driver will ease jobs starting maintaining idle during taxiing power down flight maneuvers FEATURES INCLUDE Servo Reversing Optically Coupled Circuitry No RFI Automatic Shutdown Via TX RX Connector Plug Battery Pack Remote Glow Plug Indicator Panels Available Separately Battery Pack AC Charger NOT Included Available Separately See Year Local Hobby Dealer Contact McDaniel R/C IncVisa MC accepted 1654 Crofton Blvd Suite 4 Crofton MD 21114 e 301721-6303 301721-6306 II V flULUUI Made ot White Laminating Epoxy & Fiberglass Strong Lightweight No Pin Holes tle e Construction dor I