Control Line SPEED Gene Hem pet THIS MONTH concludes Jerry Rautlos propeller discussion begun May issue want thank Jerry sharing thoughts ideas about propeller design us invitation extended read CL Speed column express opin ions ideas share helpful construc tion techniques Continuing May issue Two additional examples calculated time airspeed 170 mph other five examples 165 mph sixth example three-bladed pro peller designed give 170 mph engine turning 35000 rpm delivering enough brake horsepower give 1235 thrust horsepower Examples equa tions used calculations involved THRUST HP REQUIRED FOR CONTROL LINES C RPS Formulas Calculations RPS 165 mph 242 fP5217 522344 59 2 ST Rn Ft/Sec Vfps Vmph 667 Miles Per Hour D l Vmphl 2 Drag Single Control Line Lbs/Ft 1001 d 5 Control Line Diameter Inches Resistance Two Lines Drag Variation Due Line Skewing Resistance Line DT D Drag Lbs Two Skewed Control Lines THP — DT x Vmph Thrust HP Required 375 May issue con clusion engine would have produce 21 brake horse power propeller would have diameter 627 pitch 5834 Prop tip speed wa 989 ft/sec giving efficien cy correction factor tip speed 0758 Overall propulsive efficiency 05 899 59% seventh example two bladed prop same airspeed rpm thrust horsepower required conclusion engine would have produce 237 brake horsepower propeller would have diameter 7045 pitch 6008 Prop tip speed 1104 ft/sec resulting efficiency correction factor 06628 overall propulsive efficiency 052 16 52% sum up theoretical propulsion unit requirements must hope get engine power output 19 21 brake horsepower 35000 rpm can get three bladed propeller diameter 6169 6301 would desirable two bladed prop used its maximum diameter should 6895 three-blader actually efficient will probably considerably smoother circular flight results six examples calculated exercise summarized tables Without exact brake horsepower/rpm torque/rpm curves engine/tunedpipe assembly no guarantee can given calculations have given us ab solute delineation propeller searching represent quite accu Continued page 164 Table 1 THRUST HP REQUIRED FOR CONTROL LINES Red & Die No AIRPLANE SPECIFICATIONS & THRUST HP REQUIRED CDf CD CDp0077 CD F uselage Stabilizer CL SPEED AIRPLANE ASVMMETRIC Wing Area78 sq in05416 sq ft Semi-Span24 in2000 ft Stab Area2475 sq in01 719 sq ft Stab Semi-Spen9 in075 ft Fuse CrossSect375 sq in0026 sq ft Weight1765 oz1103 lb Control Lines 2001575 die DRAG & THRUST HP REQUIREMENTS AT 165 MPH LbsTHPr 1686074 0880 2929 0227 22227 27949 039 129 010 978 1230 Average 11 34 Clean Df 2 Af V2 Ds CD5 2 A5V2 Wing ProfileDp 2 Aw V2 Wing InducedDL CDl 2 AwV2 Control LinesSee Table 1 Total Thrust HP Required Note Hempel estimate Total THPr See Model Aviation July September 1982 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 44 49 50 497344 487344 477344 467344 457344 447344 437344 427344 417344 407344 397344 387344 377344 367344 357344 347344 337344 327344 317344 307344 297344 287344 277344 267344 257344 247344 237344 227344 217344 207344 197 344 187344 177344 167344 157344 147344 137344 127344 117344 10 7344 97344 87344 77344 67344 57344 47 344 37344 27344 07344 2 Rn 3124904 3062072 2989240 2936408 2873577 2810745 2747913 2685081 2622249 2559417 2496585 2433754 2370922 2308090 2245258 2182426 2119594 2056783 1993931 1931099 1868267 1805435 1742803 1879771 1616940 1554108 1491 276 1428444 13658 12 1302780 1239948 1177117 1114285 1051 453 988621 925789 862957 800125 737294 674462 611 630 548798 485966 423 134 360302 297471 234639 171807 108975 46143 VfpsVmphDrDrTHPr 23041761571029099511413930583 2257846153944009555147514090578 221156715078520916715514200570 2165187147626308787182514270561 21188571444675004151714300550 2072528141308708051177514290538 202619813814980769518514230524 1979869134991007347192514140509 19335391318322070072014010492 166720912867330667513350458 184088012551450635112700425 17945501223556003612070393 174822011919680572811450363 170189111603800542910850335 165556111287910513710270309 160923110972030485309700283 156290210656140457809150260 151657210340260431108620237 147024310024380405108100216 14239139708490380007800196 13775839392610355707110178 13312549076730332106640180 12849248760840309406180144 12385948444960287505750129 11922658129070266405320115 11459357813190246104920102 10996067497310226604530090 10532767181420207904150079 10060466665540190003800069 9606176549660172903450080 9142876233770156603130052 8679575917890141202820044 8216285602000126502530037 7752985286120112602250032 7289664970240099601990026 6826394654350087301740022 6363094338470075801510017 5899804022590065201300014 5436503706700055301100011 49732033908200463009200083 45099130749300381007600062 40466127590500306006100045 35833124431700240004800031 31200221272800182003600020 26567218114000132002600013 21934314955200090001800007 173013117963000560011000035 12666386375000300006000014 8035454786000120002000003 34024231980000220000040000002 THRUST HP REQUIRED FOR LINES9787622 66 Model Aviation R 522344- 1I 50 R 497344p95705 O3D1 performance certainly strengthens frontal area pan considerably California Racing under adverse condi tions just received photograph Cal ifornia showing Bob Kerr just turned new WAM record time 50001 using muffler-equipped Rat Racer Mufflers required WAM rules picture can sec muffler protruding out area mini-pipe usually exits addi tion can see racing circles over lap speed bump parking lot guess can say racing under ad verse conditions' comments suggestions al ways appreciated John C Ballard 10102 Kimblewick Dr Louisville KY 40223 CL Speed/Hempel Continued page 66 rately however propellers required particular assumed brake horsepower rpm speed thrust horsepower required standard sea level atmospheric conditions study summaries points out tiny changes diameter pitch affect power requirement speed course propellers must have true helical pitch least 30%-radius point blade tips pitch/diameter ratio should di minish towards hub two-blade pro pellers suffer high tip-speed efficiency-loss requires greater en gine power Ditto one-blader although studied specifically Three bladed props appear provide power required minimum brake horsepower arid tip-speed efficiency-loss Three-blade smoothness circular flight may also plus So study FAI CL Speed airplane warts hope might reveal something useful different per spective o new idea stranger competition class Id happy receive Proxy/Hannan Continued page 69 can also soak up hours almost alarming fashion Allow adequate time shipping too air mail delays can occur models have known miss contests little day account Additional hang ups have encountered via postal strikes over-zealous customs officers hap pily such incidents have infrequent Careful packing must models transported safely unrealistic ex pect Fragile Side Up notices much protecting delicate models Rather should strive bullet-proof con tainer withstand anticipated stresses Small suitcases metal boxes wooden boxes reinforced cardboard cartons have successfully employed Some builders prefer box-within-a-box con cept may help isolate contents outside pressure shocks Continued page 165 comments critique findings best regards Jerry Rautio 18 Highland Ct Fitchburg MA 01420 Well fellow Speed fliers what think can write Jerry directly course Id like know what com ments too Remember Jerrys work based directly proven full-scale propeller-design science very difficult know what correction factors must applied model prac tices use very high rpms propblade airfoils almost microscopic com pared full-scale ones brings kinds air-property effects scaleinduced effects picture Yet various coefficients efficiency correc tion factors still exist us though may different imagined Jerrys investigation Its place start Gene Hempel 301 N Yale Dr. Garland TX 75042 Table 2 ENGINE/PROPELLER SuMMARIEs FOR CLEAN AIRPLANE THP 165 nel No BIadm 3 2 liochosi PlO BI-IP RPM MPH 6169c5667 918 19 39000 165 6895 58658902135000165 THP0 ToTCp 5971135257944980916 9401134257 745770390 FOR CLEAR AIRPLANE THP 170 mph 362 70 5834930 21 35000170 27045 6008852 237 35000170 8991238273047260913 5211236272649670286 FOR AvERAGE AIRPLANE THPr 165 mph 36301 5699904 21 39000165 27081 5801818 239 35000165 9861230279548150928 5151230279550690395 Propulsive efficiency maw elm airspeed THP0 Thesat HP available maw elm aiesoeod Ta Thrast lb available may dee airapead Ta ic thraso Est V 0 C0 Power CanffieientBHP 590 P an3 CT fivieet tftraat P 00239 tao-leeel nRPM/6Q 0Ojam. Pt KTipSpeecl Carrection Poelor 164 Model Aviation HOt*iy H am Wieg Span -789 9mg Area 550 Sq SENSOAR glider HOBBY HORN Eaclasivel HOBBY HORN Kit SENSOAR Glider kit high qaality kit Machine catsanded parts Select quality balsa spruce Detailed plans written restructrons Far THERMAL yr SLOPE yr 115 ELECTRIC POWER VALUE PRICED a1 51600 OLLI TItR ICflS butt Partial Ktts P & W Semi-Kilt Cacibined seilh full atripeOOd plan Nose bscl Wire Windose etc Mat Ncles may purchased Just semi kits sr seith plans- serite sr call prices i93f Baceaneerf4$Si 1936 Cilpiser MR i-72-$39 1937 Dollaire SptaertS5$ft 1940 Ravger-40 $27 1939 Mercury72$Sf 1935 MIss Ametitaf4559 1941 Playboy Jr-54-$29 1941 Playbsy Sr-fO$46 iS3f Power Hsasef4--$43 1940 Sailpiane-7f-- $74 1940 So Long-St$2f 1939 Trentsn Terror-72-$32 i939 ZipperS4--$49 i925 Ksrda Wokelield-44 $17 MIDtflAP MODEL CO Sems-kttS Combined u/strip 11311 Flying Qaaker-f4-$49 1937 Qualcer Flssh-07535 1937 Long Cabin79$42 1937 Air Cbieffl$40 STRUCKS 1940 79 Span 935 Sq uiOW ruler SEMI KIT Plan inclj $3300 Combo Pull Kit 56300 SCALE PLANS ond DRAWINGS SSO HEINKEL HEiSSO 02 SOs $1000 SHiPPINO AND HANDLiNO sge TALOGUE Up $900 sdd $150 $290 PP/lsl Class $501 $2990 add $225 copy mill sent $2001 $4509 add $300 free--when requested$45 01 $7009 add $350 order aver $7000 add $400 HOBBY HORN CA Addressees add 6% tax vahobby specialliesac Send 510 visa/MC#Eap 15173 Maran Street tAl Check allow up tO 30 PO Boa 2212 days check clearance Westminster Ca 92693 CDDEsact CharKes 719 893 8311 Fidi Cash OnlyliAll UPS 7t9 8901203 AIRCRAFT OUALITV ALLEN SCREW SETS FOR ALL BRAND ENGINES Screw Sets come complete Allen Wrench available American metric sizes Write Call free price list RJL INDUSTRIES PO BOX 5654 PASADENA CA 91107 213 359-0016 795-9821 30 PACIFIC ACE complete kit includes printwood stripwood wheels rubber propeller real Japanese tissue Price $750 Plus $150 5&H SEAGLEN MODEL CO Box 123 Plympton Ma 02367
Edition: Model Aviation - 1983/07
Page Numbers: 66, 164
Control Line SPEED Gene Hem pet THIS MONTH concludes Jerry Rautlos propeller discussion begun May issue want thank Jerry sharing thoughts ideas about propeller design us invitation extended read CL Speed column express opin ions ideas share helpful construc tion techniques Continuing May issue Two additional examples calculated time airspeed 170 mph other five examples 165 mph sixth example three-bladed pro peller designed give 170 mph engine turning 35000 rpm delivering enough brake horsepower give 1235 thrust horsepower Examples equa tions used calculations involved THRUST HP REQUIRED FOR CONTROL LINES C RPS Formulas Calculations RPS 165 mph 242 fP5217 522344 59 2 ST Rn Ft/Sec Vfps Vmph 667 Miles Per Hour D l Vmphl 2 Drag Single Control Line Lbs/Ft 1001 d 5 Control Line Diameter Inches Resistance Two Lines Drag Variation Due Line Skewing Resistance Line DT D Drag Lbs Two Skewed Control Lines THP — DT x Vmph Thrust HP Required 375 May issue con clusion engine would have produce 21 brake horse power propeller would have diameter 627 pitch 5834 Prop tip speed wa 989 ft/sec giving efficien cy correction factor tip speed 0758 Overall propulsive efficiency 05 899 59% seventh example two bladed prop same airspeed rpm thrust horsepower required conclusion engine would have produce 237 brake horsepower propeller would have diameter 7045 pitch 6008 Prop tip speed 1104 ft/sec resulting efficiency correction factor 06628 overall propulsive efficiency 052 16 52% sum up theoretical propulsion unit requirements must hope get engine power output 19 21 brake horsepower 35000 rpm can get three bladed propeller diameter 6169 6301 would desirable two bladed prop used its maximum diameter should 6895 three-blader actually efficient will probably considerably smoother circular flight results six examples calculated exercise summarized tables Without exact brake horsepower/rpm torque/rpm curves engine/tunedpipe assembly no guarantee can given calculations have given us ab solute delineation propeller searching represent quite accu Continued page 164 Table 1 THRUST HP REQUIRED FOR CONTROL LINES Red & Die No AIRPLANE SPECIFICATIONS & THRUST HP REQUIRED CDf CD CDp0077 CD F uselage Stabilizer CL SPEED AIRPLANE ASVMMETRIC Wing Area78 sq in05416 sq ft Semi-Span24 in2000 ft Stab Area2475 sq in01 719 sq ft Stab Semi-Spen9 in075 ft Fuse CrossSect375 sq in0026 sq ft Weight1765 oz1103 lb Control Lines 2001575 die DRAG & THRUST HP REQUIREMENTS AT 165 MPH LbsTHPr 1686074 0880 2929 0227 22227 27949 039 129 010 978 1230 Average 11 34 Clean Df 2 Af V2 Ds CD5 2 A5V2 Wing ProfileDp 2 Aw V2 Wing InducedDL CDl 2 AwV2 Control LinesSee Table 1 Total Thrust HP Required Note Hempel estimate Total THPr See Model Aviation July September 1982 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 44 49 50 497344 487344 477344 467344 457344 447344 437344 427344 417344 407344 397344 387344 377344 367344 357344 347344 337344 327344 317344 307344 297344 287344 277344 267344 257344 247344 237344 227344 217344 207344 197 344 187344 177344 167344 157344 147344 137344 127344 117344 10 7344 97344 87344 77344 67344 57344 47 344 37344 27344 07344 2 Rn 3124904 3062072 2989240 2936408 2873577 2810745 2747913 2685081 2622249 2559417 2496585 2433754 2370922 2308090 2245258 2182426 2119594 2056783 1993931 1931099 1868267 1805435 1742803 1879771 1616940 1554108 1491 276 1428444 13658 12 1302780 1239948 1177117 1114285 1051 453 988621 925789 862957 800125 737294 674462 611 630 548798 485966 423 134 360302 297471 234639 171807 108975 46143 VfpsVmphDrDrTHPr 23041761571029099511413930583 2257846153944009555147514090578 221156715078520916715514200570 2165187147626308787182514270561 21188571444675004151714300550 2072528141308708051177514290538 202619813814980769518514230524 1979869134991007347192514140509 19335391318322070072014010492 166720912867330667513350458 184088012551450635112700425 17945501223556003612070393 174822011919680572811450363 170189111603800542910850335 165556111287910513710270309 160923110972030485309700283 156290210656140457809150260 151657210340260431108620237 147024310024380405108100216 14239139708490380007800196 13775839392610355707110178 13312549076730332106640180 12849248760840309406180144 12385948444960287505750129 11922658129070266405320115 11459357813190246104920102 10996067497310226604530090 10532767181420207904150079 10060466665540190003800069 9606176549660172903450080 9142876233770156603130052 8679575917890141202820044 8216285602000126502530037 7752985286120112602250032 7289664970240099601990026 6826394654350087301740022 6363094338470075801510017 5899804022590065201300014 5436503706700055301100011 49732033908200463009200083 45099130749300381007600062 40466127590500306006100045 35833124431700240004800031 31200221272800182003600020 26567218114000132002600013 21934314955200090001800007 173013117963000560011000035 12666386375000300006000014 8035454786000120002000003 34024231980000220000040000002 THRUST HP REQUIRED FOR LINES9787622 66 Model Aviation R 522344- 1I 50 R 497344p95705 O3D1 performance certainly strengthens frontal area pan considerably California Racing under adverse condi tions just received photograph Cal ifornia showing Bob Kerr just turned new WAM record time 50001 using muffler-equipped Rat Racer Mufflers required WAM rules picture can sec muffler protruding out area mini-pipe usually exits addi tion can see racing circles over lap speed bump parking lot guess can say racing under ad verse conditions' comments suggestions al ways appreciated John C Ballard 10102 Kimblewick Dr Louisville KY 40223 CL Speed/Hempel Continued page 66 rately however propellers required particular assumed brake horsepower rpm speed thrust horsepower required standard sea level atmospheric conditions study summaries points out tiny changes diameter pitch affect power requirement speed course propellers must have true helical pitch least 30%-radius point blade tips pitch/diameter ratio should di minish towards hub two-blade pro pellers suffer high tip-speed efficiency-loss requires greater en gine power Ditto one-blader although studied specifically Three bladed props appear provide power required minimum brake horsepower arid tip-speed efficiency-loss Three-blade smoothness circular flight may also plus So study FAI CL Speed airplane warts hope might reveal something useful different per spective o new idea stranger competition class Id happy receive Proxy/Hannan Continued page 69 can also soak up hours almost alarming fashion Allow adequate time shipping too air mail delays can occur models have known miss contests little day account Additional hang ups have encountered via postal strikes over-zealous customs officers hap pily such incidents have infrequent Careful packing must models transported safely unrealistic ex pect Fragile Side Up notices much protecting delicate models Rather should strive bullet-proof con tainer withstand anticipated stresses Small suitcases metal boxes wooden boxes reinforced cardboard cartons have successfully employed Some builders prefer box-within-a-box con cept may help isolate contents outside pressure shocks Continued page 165 comments critique findings best regards Jerry Rautio 18 Highland Ct Fitchburg MA 01420 Well fellow Speed fliers what think can write Jerry directly course Id like know what com ments too Remember Jerrys work based directly proven full-scale propeller-design science very difficult know what correction factors must applied model prac tices use very high rpms propblade airfoils almost microscopic com pared full-scale ones brings kinds air-property effects scaleinduced effects picture Yet various coefficients efficiency correc tion factors still exist us though may different imagined Jerrys investigation Its place start Gene Hempel 301 N Yale Dr. Garland TX 75042 Table 2 ENGINE/PROPELLER SuMMARIEs FOR CLEAN AIRPLANE THP 165 nel No BIadm 3 2 liochosi PlO BI-IP RPM MPH 6169c5667 918 19 39000 165 6895 58658902135000165 THP0 ToTCp 5971135257944980916 9401134257 745770390 FOR CLEAR AIRPLANE THP 170 mph 362 70 5834930 21 35000170 27045 6008852 237 35000170 8991238273047260913 5211236272649670286 FOR AvERAGE AIRPLANE THPr 165 mph 36301 5699904 21 39000165 27081 5801818 239 35000165 9861230279548150928 5151230279550690395 Propulsive efficiency maw elm airspeed THP0 Thesat HP available maw elm aiesoeod Ta Thrast lb available may dee airapead Ta ic thraso Est V 0 C0 Power CanffieientBHP 590 P an3 CT fivieet tftraat P 00239 tao-leeel nRPM/6Q 0Ojam. Pt KTipSpeecl Carrection Poelor 164 Model Aviation HOt*iy H am Wieg Span -789 9mg Area 550 Sq SENSOAR glider HOBBY HORN Eaclasivel HOBBY HORN Kit SENSOAR Glider kit high qaality kit Machine catsanded parts Select quality balsa spruce Detailed plans written restructrons Far THERMAL yr SLOPE yr 115 ELECTRIC POWER VALUE PRICED a1 51600 OLLI TItR ICflS butt Partial Ktts P & W Semi-Kilt Cacibined seilh full atripeOOd plan Nose bscl Wire Windose etc Mat Ncles may purchased Just semi kits sr seith plans- serite sr call prices i93f Baceaneerf4$Si 1936 Cilpiser MR i-72-$39 1937 Dollaire SptaertS5$ft 1940 Ravger-40 $27 1939 Mercury72$Sf 1935 MIss Ametitaf4559 1941 Playboy Jr-54-$29 1941 Playbsy Sr-fO$46 iS3f Power Hsasef4--$43 1940 Sailpiane-7f-- $74 1940 So Long-St$2f 1939 Trentsn Terror-72-$32 i939 ZipperS4--$49 i925 Ksrda Wokelield-44 $17 MIDtflAP MODEL CO Sems-kttS Combined u/strip 11311 Flying Qaaker-f4-$49 1937 Qualcer Flssh-07535 1937 Long Cabin79$42 1937 Air Cbieffl$40 STRUCKS 1940 79 Span 935 Sq uiOW ruler SEMI KIT Plan inclj $3300 Combo Pull Kit 56300 SCALE PLANS ond DRAWINGS SSO HEINKEL HEiSSO 02 SOs $1000 SHiPPINO AND HANDLiNO sge TALOGUE Up $900 sdd $150 $290 PP/lsl Class $501 $2990 add $225 copy mill sent $2001 $4509 add $300 free--when requested$45 01 $7009 add $350 order aver $7000 add $400 HOBBY HORN CA Addressees add 6% tax vahobby specialliesac Send 510 visa/MC#Eap 15173 Maran Street tAl Check allow up tO 30 PO Boa 2212 days check clearance Westminster Ca 92693 CDDEsact CharKes 719 893 8311 Fidi Cash OnlyliAll UPS 7t9 8901203 AIRCRAFT OUALITV ALLEN SCREW SETS FOR ALL BRAND ENGINES Screw Sets come complete Allen Wrench available American metric sizes Write Call free price list RJL INDUSTRIES PO BOX 5654 PASADENA CA 91107 213 359-0016 795-9821 30 PACIFIC ACE complete kit includes printwood stripwood wheels rubber propeller real Japanese tissue Price $750 Plus $150 5&H SEAGLEN MODEL CO Box 123 Plympton Ma 02367