Don Jehlik LfLLII SEEMS LIKE 12 days Christmas big day few days away writing first four dozen planned arti cles power systems completed am receiving letters will respond person ally print good information comes Thanks interest column Royal Kramer Allentown Pa writes disassemble engines 15 60 before running answers 1 you dont have tobut want sure maximum life performance engine thats Its like taking delivery new car checking out taking back dealer fix minor problems case buyer fixer 2 de velop wish personal skills can add enjoyment results achieve power modeling Over years Ive heard modelers remark get real satisfaction ability set up engines some competitive events winning just doesnt happen unless specialized attention paid getting specific performance engine Dr Gene Smith Stillwater OkIa writes have really enjoyed articles new engine preparation gave X40 treatment said can feel difference Gene dropped nice hint letter purchased SONAC denture ultrasonic cleaner about $15 sale locally under $10 after five minutes cleaning new engine parts bottom pan looked like panning silver said cleaning solution formula softened plastic pan cleaner Thats easily solved Take piece Saran Wrap put pan pour cleaning solution through pick up Saran Wrap bag pour solution through coffee filter ajar Seal jar tightly stor age throw wrap filter away Gene said fun Wonder thinks really silver pan keeps writing kind letters Ill send him some gold ore boys have picked up out let him separate general principle providing proper operating environment engine ap plies use put Last months column discussed some procedures en sure engine properly mounted model Now well look cooling 44 Model Aviation nroua arouna cyiinoer Improves cooling engine enclosed installation tank etc behind engine causes higher running tempera tures rear cylinder Entry shown above exit fliCturA bInw Tightly cowled engines require well-Inougni out cooling systems team racers cooling has developed fine art Top Note back air intake duct front cylinder space Middle exit duct behind cylinder bottom coolina air intakn engine Dont assume engine have designed manufacturers cool itself operate within acceptable temperature range use Lets break cooling three categories 1 air cooling 2 air/heat sink cooling 3 water cooling Air Cooling Usually confined air plane applications Air cooling ranges hang breeze carefully designed cooling systems involving cooling ducts fans etc air-cooled applications can benefit some thought Example Hang breeze pro file model Cooling air blown prop air stream over engine does flow smoothly laminar flow over entire cylinder Flow front tends laminar until air tries flow around back engine separates engine leaving area rough turbulent flow rear turbulent flow does transfer heat cool engine well laminar flow Net result front engine cooler back might say what Thats what happened test stand too since engine run way should okay flies necessarily Engines have way running too hot model test stand variety reasons may have mounted tank too close behind engine thereby enlarging area turbulent air back engine engine does run hotter rear temperature differential between front rear cylinder will great er engine will compensate condition wearing clearance tween piston sleeve Early Supertigre engines came US instruc tions printed Italian portion stated after break-in engine should mounted model flown 20-30 flights thereby settling model before maximum performance reached cases exactly what happens Example Engine enclosed stunt sport model Most frequently seen engine setting chamber air open ings front rear air circu lates through chamber cools engine usually very well results usually power losses excessive operating temperatures reduced en gine life Al Rabe problem Continued nate 99 April1978 45 Heat sink Cox 049 Cox van cools engine little cooling air available heat sink used avoid absolute peak lean settings can cause rapid burn up manufacturer incorporated extra fins rear engine en effort improve cooling hotter portion cylinder Uneven heating causes uneven wear Prior 1950 Harold deBolt developed special ducting speed engines Never improved upon preserves laminar flow about head Waterjacket really cools marine engine permitting control tem peratures settings Author sees possibility using water cooled engines aircraft cars Could interesting scale planes ments worked out using X-40 700 stroke crankshaft dis placement could reduced 357just what wanted As stroke change liner must adjusted upward de creased stroke maintain proper cy linder timing hybrid ST-36RRV performed par standard ST-G-21-35 30% nitro However ringed piston would allow us run 55% nitro still de pendable restarts Therefore able show some improvement over stand ard 35 testing done suction venturi also tried same en gine G-21-29 crank 668 stroke lowered displacement 340 limited success quickly became obvious still needed Schnuerle ports tried barstock engine designed built Henry Nelson using ST lapped piston crank ran extremely well obvi ously too costly looked OS-405R HP 40 using such good success Rat Race decided attempt destroke 40 cranks achieve 36 dis placement After about three weeks failures scrapped parts finally got HP36FR gether dramatically blew doors off everything else proceeded make both OS36RRV FV along HP 36RRV successful except OS36FV managed keep throwing crank bearings out front end turned out HPs required new stoke 667 OS 657 legal displace ments Again liners shimmed HP36FV RV essentially ran same OS performed slightly better both next step determine max imum venturi choke area could get away Initially used nominal 315 diameter stock ST spray bar going through middle tried different lengths angles eventually found 355 diameter ven turi 75 entrance angle worked about best flight testing have since stuck interesting note measured 400 500 rpm about 5-mph gain between 3 15 new 355 diameter have discussions both John Maloney World Engines Jerry Nel son Midwest HP concerning pro duction 36 engines have sup plied both engines specifica tions forward respective factories Meanwhile both Fox K&B now producing Schnuerle 36s although neither ringed dont seem re start consistently Since 1978-79 rules Slow Rat require quantity manufactured engines parts Fox K&B may have lock market least until either OS HP come out ringed-piston ball-bear ing Schnuerle-ported 36 engine found basic 8-8 fiberglass prop Bartel Kelly pitched 7 thinned down little provides best performance engines swing prop between 19200 20000 static ground rpm Whatever engine use either now future think will find Bobcat very efficient no-nonsense model capable winning performances years come Engine Technique/Jehlik continued page 45 year Nats examined engine found okay evidence overheating suggested fabricating tin can cooling shroud wrapped around back cylinder little nitro fuel overheating problem created power loss solved Example Air duct cooled engine really way go enclosed en gines Harold debolt worked up properly designed duct cooling system before 1950 really hasnt improved principle control cooling air forc ing flow laminar way around cylinder achieved nearly cooling front back really believe al enclosed engine models can should incorporate air duct cooling Air/Heat Sink Cooling Usually found helicopters RC cars picture shows heat sink Cox Van heat sink does just what says Attach mass high heat transfer material aluminum lots fins increases radi ator surface cylinder head enables engines operated environ ments dont provide high rates air flow cooling Heat sinks work pretty well care should taken run such engines absolute peak lean settings because heat sinks transfer heat rapidly effective air flow Conse quently can exceed thermal limits burn up pretty rapidly Water Cooling Usually found boat applications engine head fins re placed water jacket flattened wa ter tube cool clamp clamped around cylinder head Water cooling inter esting because provides opportunity really cool engine control opera ting temperatures power settings Ill bet well see some special water cooling ap plication planes cars near fu ture prospects controlling opera ting temperatures tuned pipe short-run maximum-power events too good pass up Some thoughts cooling 1 Dirty engines run hot let engine bake oil dirt outer sur faces cooling air wont able pick up efficiently heat off metal surfaces Clean exterior engine after flying session will stay clean 2 Hot engines run increased clear ances wear out prematurely 3 Engines have practical operating temperature envelope minimum maximum temperatures controlling factor maximum temperature oils fuel can tolerate still proper job lubrication No percen tage oil fuel really doesnt help engine runs too hot Ive never seen practical use over 20% oil providing fuel contains least 5% castor oil engine run over thermal limit April1978 99 Kraftsmanship kit processed AAMCO GOLD BALSAThis Trainer will blow apart hits ground GREATEST B/C BASIC TRAINER Design & Kit ALL TIME Ask over 25000 satisfied builders H-RAY dealers sold themSHALL WE SAY MORE Andresvs Aircraft Model Co Inc US Ete 1& North St Topstield Mass 01983 887-8541 Support AMA Price $3995 kit per dollar em too lean 4 Needle valve settings assure en gine does exceed its operating thermal limits Dont push absolute power setting unless prepared way control Operating temperatures can get completely out hand top set tings Burned pistons scored pistons sleeve multitude engine failures can occur just few seconds toolean settings 5 Observe begin flights new en gine conservative rich settings listen engine does lean out flight what needle valve setting will ensure complete run sagging CL Carrier/Perry continued page 48 87B design added folding wings tail hook Ju 87T torpedo plane also tested Hf 109 tested two forms Hf 109B used training have photo early Hf 109 probably B end run total engine run have achieve proper setting 6 I havent discussed throttles fuel pumps mufflers linkages etc get stalled engine compartments comes later columns sure accessories properly mounted function properly before flying 7 Remember can control cool ing engine achieve proper per formance Next column will fuel systems Don Jehlik 438A Schweer Dr Star Route 1 Hawthorne CA 90250 model tail hook.. addition derivative Hf 109E designated Hf 109T included tail hook en larged wings shown accompany ing drawing best description have seen Luftwaffes carrier aircraft activi ties contained German magazine Der Flieger March 1976 Its text photos cover greater list aircraft other source have encountered include catapult launch arrested land ing photos aircraft addition Hf 109 fighters already mentioned Arado Ar 197 biplane fighter used Carrier support aircraft included Arado Ar 195 Fieseler Fi 167 Heinkel 50 two-seat bomber also fitted catapult arrested landings although like Arado Fieseler aircraft biplane German carrier aircraft devel opment occurred later war would probably have fewer biplanes program monoplane help balance out set Arado Ar96 standard trainer Luftwaffe modified catapult arresting hook therefore qualifies event dont have drawings Ar 96 admit havent looked very hard Id happy hear can supply proper set three-views Although never got off deck Graf Zeppelin carrier aircraft Luftwaffe did fly provide some appealing alternatives us seek little variety Navy Carrier flying Richard L Perry 5016 Angelita Ave Dayton OH 45424 CL Scale/Gretz con tinued page 46 will undoubtedly become collectors items well showing support Scale Team price $150 three $400 postpaid Bob Underwood 4109 Concord Oake Dr St Louis MO 63128 Send wear keep Shutoff Payoff AMA Precision Scale rules currently allow additional 10 points awarded Taxi maneuver engine shutoff demonstrated far popular successful method engine shutoff throttle-equipped engine seems closing throttle completely below engines 100 Model Aviation 6 APRIL 73 & 91973 Friday9 am 6 pm Saturday9 am 6 pm Sunday9 am 330 pm presented by WEAK SIGNALS R/C CLUB PO BOX 5772 TOLEDO OHIO 43513 Kurt Kiefers profile Hawker Nimrod based Royal Navy fighter 1930s Flaps up per wing ailerons lower Would have looked batter British markings Photo Harry Higley
Edition: Model Aviation - 1978/04
Page Numbers: 44, 45, 99, 100
Don Jehlik LfLLII SEEMS LIKE 12 days Christmas big day few days away writing first four dozen planned arti cles power systems completed am receiving letters will respond person ally print good information comes Thanks interest column Royal Kramer Allentown Pa writes disassemble engines 15 60 before running answers 1 you dont have tobut want sure maximum life performance engine thats Its like taking delivery new car checking out taking back dealer fix minor problems case buyer fixer 2 de velop wish personal skills can add enjoyment results achieve power modeling Over years Ive heard modelers remark get real satisfaction ability set up engines some competitive events winning just doesnt happen unless specialized attention paid getting specific performance engine Dr Gene Smith Stillwater OkIa writes have really enjoyed articles new engine preparation gave X40 treatment said can feel difference Gene dropped nice hint letter purchased SONAC denture ultrasonic cleaner about $15 sale locally under $10 after five minutes cleaning new engine parts bottom pan looked like panning silver said cleaning solution formula softened plastic pan cleaner Thats easily solved Take piece Saran Wrap put pan pour cleaning solution through pick up Saran Wrap bag pour solution through coffee filter ajar Seal jar tightly stor age throw wrap filter away Gene said fun Wonder thinks really silver pan keeps writing kind letters Ill send him some gold ore boys have picked up out let him separate general principle providing proper operating environment engine ap plies use put Last months column discussed some procedures en sure engine properly mounted model Now well look cooling 44 Model Aviation nroua arouna cyiinoer Improves cooling engine enclosed installation tank etc behind engine causes higher running tempera tures rear cylinder Entry shown above exit fliCturA bInw Tightly cowled engines require well-Inougni out cooling systems team racers cooling has developed fine art Top Note back air intake duct front cylinder space Middle exit duct behind cylinder bottom coolina air intakn engine Dont assume engine have designed manufacturers cool itself operate within acceptable temperature range use Lets break cooling three categories 1 air cooling 2 air/heat sink cooling 3 water cooling Air Cooling Usually confined air plane applications Air cooling ranges hang breeze carefully designed cooling systems involving cooling ducts fans etc air-cooled applications can benefit some thought Example Hang breeze pro file model Cooling air blown prop air stream over engine does flow smoothly laminar flow over entire cylinder Flow front tends laminar until air tries flow around back engine separates engine leaving area rough turbulent flow rear turbulent flow does transfer heat cool engine well laminar flow Net result front engine cooler back might say what Thats what happened test stand too since engine run way should okay flies necessarily Engines have way running too hot model test stand variety reasons may have mounted tank too close behind engine thereby enlarging area turbulent air back engine engine does run hotter rear temperature differential between front rear cylinder will great er engine will compensate condition wearing clearance tween piston sleeve Early Supertigre engines came US instruc tions printed Italian portion stated after break-in engine should mounted model flown 20-30 flights thereby settling model before maximum performance reached cases exactly what happens Example Engine enclosed stunt sport model Most frequently seen engine setting chamber air open ings front rear air circu lates through chamber cools engine usually very well results usually power losses excessive operating temperatures reduced en gine life Al Rabe problem Continued nate 99 April1978 45 Heat sink Cox 049 Cox van cools engine little cooling air available heat sink used avoid absolute peak lean settings can cause rapid burn up manufacturer incorporated extra fins rear engine en effort improve cooling hotter portion cylinder Uneven heating causes uneven wear Prior 1950 Harold deBolt developed special ducting speed engines Never improved upon preserves laminar flow about head Waterjacket really cools marine engine permitting control tem peratures settings Author sees possibility using water cooled engines aircraft cars Could interesting scale planes ments worked out using X-40 700 stroke crankshaft dis placement could reduced 357just what wanted As stroke change liner must adjusted upward de creased stroke maintain proper cy linder timing hybrid ST-36RRV performed par standard ST-G-21-35 30% nitro However ringed piston would allow us run 55% nitro still de pendable restarts Therefore able show some improvement over stand ard 35 testing done suction venturi also tried same en gine G-21-29 crank 668 stroke lowered displacement 340 limited success quickly became obvious still needed Schnuerle ports tried barstock engine designed built Henry Nelson using ST lapped piston crank ran extremely well obvi ously too costly looked OS-405R HP 40 using such good success Rat Race decided attempt destroke 40 cranks achieve 36 dis placement After about three weeks failures scrapped parts finally got HP36FR gether dramatically blew doors off everything else proceeded make both OS36RRV FV along HP 36RRV successful except OS36FV managed keep throwing crank bearings out front end turned out HPs required new stoke 667 OS 657 legal displace ments Again liners shimmed HP36FV RV essentially ran same OS performed slightly better both next step determine max imum venturi choke area could get away Initially used nominal 315 diameter stock ST spray bar going through middle tried different lengths angles eventually found 355 diameter ven turi 75 entrance angle worked about best flight testing have since stuck interesting note measured 400 500 rpm about 5-mph gain between 3 15 new 355 diameter have discussions both John Maloney World Engines Jerry Nel son Midwest HP concerning pro duction 36 engines have sup plied both engines specifica tions forward respective factories Meanwhile both Fox K&B now producing Schnuerle 36s although neither ringed dont seem re start consistently Since 1978-79 rules Slow Rat require quantity manufactured engines parts Fox K&B may have lock market least until either OS HP come out ringed-piston ball-bear ing Schnuerle-ported 36 engine found basic 8-8 fiberglass prop Bartel Kelly pitched 7 thinned down little provides best performance engines swing prop between 19200 20000 static ground rpm Whatever engine use either now future think will find Bobcat very efficient no-nonsense model capable winning performances years come Engine Technique/Jehlik continued page 45 year Nats examined engine found okay evidence overheating suggested fabricating tin can cooling shroud wrapped around back cylinder little nitro fuel overheating problem created power loss solved Example Air duct cooled engine really way go enclosed en gines Harold debolt worked up properly designed duct cooling system before 1950 really hasnt improved principle control cooling air forc ing flow laminar way around cylinder achieved nearly cooling front back really believe al enclosed engine models can should incorporate air duct cooling Air/Heat Sink Cooling Usually found helicopters RC cars picture shows heat sink Cox Van heat sink does just what says Attach mass high heat transfer material aluminum lots fins increases radi ator surface cylinder head enables engines operated environ ments dont provide high rates air flow cooling Heat sinks work pretty well care should taken run such engines absolute peak lean settings because heat sinks transfer heat rapidly effective air flow Conse quently can exceed thermal limits burn up pretty rapidly Water Cooling Usually found boat applications engine head fins re placed water jacket flattened wa ter tube cool clamp clamped around cylinder head Water cooling inter esting because provides opportunity really cool engine control opera ting temperatures power settings Ill bet well see some special water cooling ap plication planes cars near fu ture prospects controlling opera ting temperatures tuned pipe short-run maximum-power events too good pass up Some thoughts cooling 1 Dirty engines run hot let engine bake oil dirt outer sur faces cooling air wont able pick up efficiently heat off metal surfaces Clean exterior engine after flying session will stay clean 2 Hot engines run increased clear ances wear out prematurely 3 Engines have practical operating temperature envelope minimum maximum temperatures controlling factor maximum temperature oils fuel can tolerate still proper job lubrication No percen tage oil fuel really doesnt help engine runs too hot Ive never seen practical use over 20% oil providing fuel contains least 5% castor oil engine run over thermal limit April1978 99 Kraftsmanship kit processed AAMCO GOLD BALSAThis Trainer will blow apart hits ground GREATEST B/C BASIC TRAINER Design & Kit ALL TIME Ask over 25000 satisfied builders H-RAY dealers sold themSHALL WE SAY MORE Andresvs Aircraft Model Co Inc US Ete 1& North St Topstield Mass 01983 887-8541 Support AMA Price $3995 kit per dollar em too lean 4 Needle valve settings assure en gine does exceed its operating thermal limits Dont push absolute power setting unless prepared way control Operating temperatures can get completely out hand top set tings Burned pistons scored pistons sleeve multitude engine failures can occur just few seconds toolean settings 5 Observe begin flights new en gine conservative rich settings listen engine does lean out flight what needle valve setting will ensure complete run sagging CL Carrier/Perry continued page 48 87B design added folding wings tail hook Ju 87T torpedo plane also tested Hf 109 tested two forms Hf 109B used training have photo early Hf 109 probably B end run total engine run have achieve proper setting 6 I havent discussed throttles fuel pumps mufflers linkages etc get stalled engine compartments comes later columns sure accessories properly mounted function properly before flying 7 Remember can control cool ing engine achieve proper per formance Next column will fuel systems Don Jehlik 438A Schweer Dr Star Route 1 Hawthorne CA 90250 model tail hook.. addition derivative Hf 109E designated Hf 109T included tail hook en larged wings shown accompany ing drawing best description have seen Luftwaffes carrier aircraft activi ties contained German magazine Der Flieger March 1976 Its text photos cover greater list aircraft other source have encountered include catapult launch arrested land ing photos aircraft addition Hf 109 fighters already mentioned Arado Ar 197 biplane fighter used Carrier support aircraft included Arado Ar 195 Fieseler Fi 167 Heinkel 50 two-seat bomber also fitted catapult arrested landings although like Arado Fieseler aircraft biplane German carrier aircraft devel opment occurred later war would probably have fewer biplanes program monoplane help balance out set Arado Ar96 standard trainer Luftwaffe modified catapult arresting hook therefore qualifies event dont have drawings Ar 96 admit havent looked very hard Id happy hear can supply proper set three-views Although never got off deck Graf Zeppelin carrier aircraft Luftwaffe did fly provide some appealing alternatives us seek little variety Navy Carrier flying Richard L Perry 5016 Angelita Ave Dayton OH 45424 CL Scale/Gretz con tinued page 46 will undoubtedly become collectors items well showing support Scale Team price $150 three $400 postpaid Bob Underwood 4109 Concord Oake Dr St Louis MO 63128 Send wear keep Shutoff Payoff AMA Precision Scale rules currently allow additional 10 points awarded Taxi maneuver engine shutoff demonstrated far popular successful method engine shutoff throttle-equipped engine seems closing throttle completely below engines 100 Model Aviation 6 APRIL 73 & 91973 Friday9 am 6 pm Saturday9 am 6 pm Sunday9 am 330 pm presented by WEAK SIGNALS R/C CLUB PO BOX 5772 TOLEDO OHIO 43513 Kurt Kiefers profile Hawker Nimrod based Royal Navy fighter 1930s Flaps up per wing ailerons lower Would have looked batter British markings Photo Harry Higley
Edition: Model Aviation - 1978/04
Page Numbers: 44, 45, 99, 100
Don Jehlik LfLLII SEEMS LIKE 12 days Christmas big day few days away writing first four dozen planned arti cles power systems completed am receiving letters will respond person ally print good information comes Thanks interest column Royal Kramer Allentown Pa writes disassemble engines 15 60 before running answers 1 you dont have tobut want sure maximum life performance engine thats Its like taking delivery new car checking out taking back dealer fix minor problems case buyer fixer 2 de velop wish personal skills can add enjoyment results achieve power modeling Over years Ive heard modelers remark get real satisfaction ability set up engines some competitive events winning just doesnt happen unless specialized attention paid getting specific performance engine Dr Gene Smith Stillwater OkIa writes have really enjoyed articles new engine preparation gave X40 treatment said can feel difference Gene dropped nice hint letter purchased SONAC denture ultrasonic cleaner about $15 sale locally under $10 after five minutes cleaning new engine parts bottom pan looked like panning silver said cleaning solution formula softened plastic pan cleaner Thats easily solved Take piece Saran Wrap put pan pour cleaning solution through pick up Saran Wrap bag pour solution through coffee filter ajar Seal jar tightly stor age throw wrap filter away Gene said fun Wonder thinks really silver pan keeps writing kind letters Ill send him some gold ore boys have picked up out let him separate general principle providing proper operating environment engine ap plies use put Last months column discussed some procedures en sure engine properly mounted model Now well look cooling 44 Model Aviation nroua arouna cyiinoer Improves cooling engine enclosed installation tank etc behind engine causes higher running tempera tures rear cylinder Entry shown above exit fliCturA bInw Tightly cowled engines require well-Inougni out cooling systems team racers cooling has developed fine art Top Note back air intake duct front cylinder space Middle exit duct behind cylinder bottom coolina air intakn engine Dont assume engine have designed manufacturers cool itself operate within acceptable temperature range use Lets break cooling three categories 1 air cooling 2 air/heat sink cooling 3 water cooling Air Cooling Usually confined air plane applications Air cooling ranges hang breeze carefully designed cooling systems involving cooling ducts fans etc air-cooled applications can benefit some thought Example Hang breeze pro file model Cooling air blown prop air stream over engine does flow smoothly laminar flow over entire cylinder Flow front tends laminar until air tries flow around back engine separates engine leaving area rough turbulent flow rear turbulent flow does transfer heat cool engine well laminar flow Net result front engine cooler back might say what Thats what happened test stand too since engine run way should okay flies necessarily Engines have way running too hot model test stand variety reasons may have mounted tank too close behind engine thereby enlarging area turbulent air back engine engine does run hotter rear temperature differential between front rear cylinder will great er engine will compensate condition wearing clearance tween piston sleeve Early Supertigre engines came US instruc tions printed Italian portion stated after break-in engine should mounted model flown 20-30 flights thereby settling model before maximum performance reached cases exactly what happens Example Engine enclosed stunt sport model Most frequently seen engine setting chamber air open ings front rear air circu lates through chamber cools engine usually very well results usually power losses excessive operating temperatures reduced en gine life Al Rabe problem Continued nate 99 April1978 45 Heat sink Cox 049 Cox van cools engine little cooling air available heat sink used avoid absolute peak lean settings can cause rapid burn up manufacturer incorporated extra fins rear engine en effort improve cooling hotter portion cylinder Uneven heating causes uneven wear Prior 1950 Harold deBolt developed special ducting speed engines Never improved upon preserves laminar flow about head Waterjacket really cools marine engine permitting control tem peratures settings Author sees possibility using water cooled engines aircraft cars Could interesting scale planes ments worked out using X-40 700 stroke crankshaft dis placement could reduced 357just what wanted As stroke change liner must adjusted upward de creased stroke maintain proper cy linder timing hybrid ST-36RRV performed par standard ST-G-21-35 30% nitro However ringed piston would allow us run 55% nitro still de pendable restarts Therefore able show some improvement over stand ard 35 testing done suction venturi also tried same en gine G-21-29 crank 668 stroke lowered displacement 340 limited success quickly became obvious still needed Schnuerle ports tried barstock engine designed built Henry Nelson using ST lapped piston crank ran extremely well obvi ously too costly looked OS-405R HP 40 using such good success Rat Race decided attempt destroke 40 cranks achieve 36 dis placement After about three weeks failures scrapped parts finally got HP36FR gether dramatically blew doors off everything else proceeded make both OS36RRV FV along HP 36RRV successful except OS36FV managed keep throwing crank bearings out front end turned out HPs required new stoke 667 OS 657 legal displace ments Again liners shimmed HP36FV RV essentially ran same OS performed slightly better both next step determine max imum venturi choke area could get away Initially used nominal 315 diameter stock ST spray bar going through middle tried different lengths angles eventually found 355 diameter ven turi 75 entrance angle worked about best flight testing have since stuck interesting note measured 400 500 rpm about 5-mph gain between 3 15 new 355 diameter have discussions both John Maloney World Engines Jerry Nel son Midwest HP concerning pro duction 36 engines have sup plied both engines specifica tions forward respective factories Meanwhile both Fox K&B now producing Schnuerle 36s although neither ringed dont seem re start consistently Since 1978-79 rules Slow Rat require quantity manufactured engines parts Fox K&B may have lock market least until either OS HP come out ringed-piston ball-bear ing Schnuerle-ported 36 engine found basic 8-8 fiberglass prop Bartel Kelly pitched 7 thinned down little provides best performance engines swing prop between 19200 20000 static ground rpm Whatever engine use either now future think will find Bobcat very efficient no-nonsense model capable winning performances years come Engine Technique/Jehlik continued page 45 year Nats examined engine found okay evidence overheating suggested fabricating tin can cooling shroud wrapped around back cylinder little nitro fuel overheating problem created power loss solved Example Air duct cooled engine really way go enclosed en gines Harold debolt worked up properly designed duct cooling system before 1950 really hasnt improved principle control cooling air forc ing flow laminar way around cylinder achieved nearly cooling front back really believe al enclosed engine models can should incorporate air duct cooling Air/Heat Sink Cooling Usually found helicopters RC cars picture shows heat sink Cox Van heat sink does just what says Attach mass high heat transfer material aluminum lots fins increases radi ator surface cylinder head enables engines operated environ ments dont provide high rates air flow cooling Heat sinks work pretty well care should taken run such engines absolute peak lean settings because heat sinks transfer heat rapidly effective air flow Conse quently can exceed thermal limits burn up pretty rapidly Water Cooling Usually found boat applications engine head fins re placed water jacket flattened wa ter tube cool clamp clamped around cylinder head Water cooling inter esting because provides opportunity really cool engine control opera ting temperatures power settings Ill bet well see some special water cooling ap plication planes cars near fu ture prospects controlling opera ting temperatures tuned pipe short-run maximum-power events too good pass up Some thoughts cooling 1 Dirty engines run hot let engine bake oil dirt outer sur faces cooling air wont able pick up efficiently heat off metal surfaces Clean exterior engine after flying session will stay clean 2 Hot engines run increased clear ances wear out prematurely 3 Engines have practical operating temperature envelope minimum maximum temperatures controlling factor maximum temperature oils fuel can tolerate still proper job lubrication No percen tage oil fuel really doesnt help engine runs too hot Ive never seen practical use over 20% oil providing fuel contains least 5% castor oil engine run over thermal limit April1978 99 Kraftsmanship kit processed AAMCO GOLD BALSAThis Trainer will blow apart hits ground GREATEST B/C BASIC TRAINER Design & Kit ALL TIME Ask over 25000 satisfied builders H-RAY dealers sold themSHALL WE SAY MORE Andresvs Aircraft Model Co Inc US Ete 1& North St Topstield Mass 01983 887-8541 Support AMA Price $3995 kit per dollar em too lean 4 Needle valve settings assure en gine does exceed its operating thermal limits Dont push absolute power setting unless prepared way control Operating temperatures can get completely out hand top set tings Burned pistons scored pistons sleeve multitude engine failures can occur just few seconds toolean settings 5 Observe begin flights new en gine conservative rich settings listen engine does lean out flight what needle valve setting will ensure complete run sagging CL Carrier/Perry continued page 48 87B design added folding wings tail hook Ju 87T torpedo plane also tested Hf 109 tested two forms Hf 109B used training have photo early Hf 109 probably B end run total engine run have achieve proper setting 6 I havent discussed throttles fuel pumps mufflers linkages etc get stalled engine compartments comes later columns sure accessories properly mounted function properly before flying 7 Remember can control cool ing engine achieve proper per formance Next column will fuel systems Don Jehlik 438A Schweer Dr Star Route 1 Hawthorne CA 90250 model tail hook.. addition derivative Hf 109E designated Hf 109T included tail hook en larged wings shown accompany ing drawing best description have seen Luftwaffes carrier aircraft activi ties contained German magazine Der Flieger March 1976 Its text photos cover greater list aircraft other source have encountered include catapult launch arrested land ing photos aircraft addition Hf 109 fighters already mentioned Arado Ar 197 biplane fighter used Carrier support aircraft included Arado Ar 195 Fieseler Fi 167 Heinkel 50 two-seat bomber also fitted catapult arrested landings although like Arado Fieseler aircraft biplane German carrier aircraft devel opment occurred later war would probably have fewer biplanes program monoplane help balance out set Arado Ar96 standard trainer Luftwaffe modified catapult arresting hook therefore qualifies event dont have drawings Ar 96 admit havent looked very hard Id happy hear can supply proper set three-views Although never got off deck Graf Zeppelin carrier aircraft Luftwaffe did fly provide some appealing alternatives us seek little variety Navy Carrier flying Richard L Perry 5016 Angelita Ave Dayton OH 45424 CL Scale/Gretz con tinued page 46 will undoubtedly become collectors items well showing support Scale Team price $150 three $400 postpaid Bob Underwood 4109 Concord Oake Dr St Louis MO 63128 Send wear keep Shutoff Payoff AMA Precision Scale rules currently allow additional 10 points awarded Taxi maneuver engine shutoff demonstrated far popular successful method engine shutoff throttle-equipped engine seems closing throttle completely below engines 100 Model Aviation 6 APRIL 73 & 91973 Friday9 am 6 pm Saturday9 am 6 pm Sunday9 am 330 pm presented by WEAK SIGNALS R/C CLUB PO BOX 5772 TOLEDO OHIO 43513 Kurt Kiefers profile Hawker Nimrod based Royal Navy fighter 1930s Flaps up per wing ailerons lower Would have looked batter British markings Photo Harry Higley
Edition: Model Aviation - 1978/04
Page Numbers: 44, 45, 99, 100
Don Jehlik LfLLII SEEMS LIKE 12 days Christmas big day few days away writing first four dozen planned arti cles power systems completed am receiving letters will respond person ally print good information comes Thanks interest column Royal Kramer Allentown Pa writes disassemble engines 15 60 before running answers 1 you dont have tobut want sure maximum life performance engine thats Its like taking delivery new car checking out taking back dealer fix minor problems case buyer fixer 2 de velop wish personal skills can add enjoyment results achieve power modeling Over years Ive heard modelers remark get real satisfaction ability set up engines some competitive events winning just doesnt happen unless specialized attention paid getting specific performance engine Dr Gene Smith Stillwater OkIa writes have really enjoyed articles new engine preparation gave X40 treatment said can feel difference Gene dropped nice hint letter purchased SONAC denture ultrasonic cleaner about $15 sale locally under $10 after five minutes cleaning new engine parts bottom pan looked like panning silver said cleaning solution formula softened plastic pan cleaner Thats easily solved Take piece Saran Wrap put pan pour cleaning solution through pick up Saran Wrap bag pour solution through coffee filter ajar Seal jar tightly stor age throw wrap filter away Gene said fun Wonder thinks really silver pan keeps writing kind letters Ill send him some gold ore boys have picked up out let him separate general principle providing proper operating environment engine ap plies use put Last months column discussed some procedures en sure engine properly mounted model Now well look cooling 44 Model Aviation nroua arouna cyiinoer Improves cooling engine enclosed installation tank etc behind engine causes higher running tempera tures rear cylinder Entry shown above exit fliCturA bInw Tightly cowled engines require well-Inougni out cooling systems team racers cooling has developed fine art Top Note back air intake duct front cylinder space Middle exit duct behind cylinder bottom coolina air intakn engine Dont assume engine have designed manufacturers cool itself operate within acceptable temperature range use Lets break cooling three categories 1 air cooling 2 air/heat sink cooling 3 water cooling Air Cooling Usually confined air plane applications Air cooling ranges hang breeze carefully designed cooling systems involving cooling ducts fans etc air-cooled applications can benefit some thought Example Hang breeze pro file model Cooling air blown prop air stream over engine does flow smoothly laminar flow over entire cylinder Flow front tends laminar until air tries flow around back engine separates engine leaving area rough turbulent flow rear turbulent flow does transfer heat cool engine well laminar flow Net result front engine cooler back might say what Thats what happened test stand too since engine run way should okay flies necessarily Engines have way running too hot model test stand variety reasons may have mounted tank too close behind engine thereby enlarging area turbulent air back engine engine does run hotter rear temperature differential between front rear cylinder will great er engine will compensate condition wearing clearance tween piston sleeve Early Supertigre engines came US instruc tions printed Italian portion stated after break-in engine should mounted model flown 20-30 flights thereby settling model before maximum performance reached cases exactly what happens Example Engine enclosed stunt sport model Most frequently seen engine setting chamber air open ings front rear air circu lates through chamber cools engine usually very well results usually power losses excessive operating temperatures reduced en gine life Al Rabe problem Continued nate 99 April1978 45 Heat sink Cox 049 Cox van cools engine little cooling air available heat sink used avoid absolute peak lean settings can cause rapid burn up manufacturer incorporated extra fins rear engine en effort improve cooling hotter portion cylinder Uneven heating causes uneven wear Prior 1950 Harold deBolt developed special ducting speed engines Never improved upon preserves laminar flow about head Waterjacket really cools marine engine permitting control tem peratures settings Author sees possibility using water cooled engines aircraft cars Could interesting scale planes ments worked out using X-40 700 stroke crankshaft dis placement could reduced 357just what wanted As stroke change liner must adjusted upward de creased stroke maintain proper cy linder timing hybrid ST-36RRV performed par standard ST-G-21-35 30% nitro However ringed piston would allow us run 55% nitro still de pendable restarts Therefore able show some improvement over stand ard 35 testing done suction venturi also tried same en gine G-21-29 crank 668 stroke lowered displacement 340 limited success quickly became obvious still needed Schnuerle ports tried barstock engine designed built Henry Nelson using ST lapped piston crank ran extremely well obvi ously too costly looked OS-405R HP 40 using such good success Rat Race decided attempt destroke 40 cranks achieve 36 dis placement After about three weeks failures scrapped parts finally got HP36FR gether dramatically blew doors off everything else proceeded make both OS36RRV FV along HP 36RRV successful except OS36FV managed keep throwing crank bearings out front end turned out HPs required new stoke 667 OS 657 legal displace ments Again liners shimmed HP36FV RV essentially ran same OS performed slightly better both next step determine max imum venturi choke area could get away Initially used nominal 315 diameter stock ST spray bar going through middle tried different lengths angles eventually found 355 diameter ven turi 75 entrance angle worked about best flight testing have since stuck interesting note measured 400 500 rpm about 5-mph gain between 3 15 new 355 diameter have discussions both John Maloney World Engines Jerry Nel son Midwest HP concerning pro duction 36 engines have sup plied both engines specifica tions forward respective factories Meanwhile both Fox K&B now producing Schnuerle 36s although neither ringed dont seem re start consistently Since 1978-79 rules Slow Rat require quantity manufactured engines parts Fox K&B may have lock market least until either OS HP come out ringed-piston ball-bear ing Schnuerle-ported 36 engine found basic 8-8 fiberglass prop Bartel Kelly pitched 7 thinned down little provides best performance engines swing prop between 19200 20000 static ground rpm Whatever engine use either now future think will find Bobcat very efficient no-nonsense model capable winning performances years come Engine Technique/Jehlik continued page 45 year Nats examined engine found okay evidence overheating suggested fabricating tin can cooling shroud wrapped around back cylinder little nitro fuel overheating problem created power loss solved Example Air duct cooled engine really way go enclosed en gines Harold debolt worked up properly designed duct cooling system before 1950 really hasnt improved principle control cooling air forc ing flow laminar way around cylinder achieved nearly cooling front back really believe al enclosed engine models can should incorporate air duct cooling Air/Heat Sink Cooling Usually found helicopters RC cars picture shows heat sink Cox Van heat sink does just what says Attach mass high heat transfer material aluminum lots fins increases radi ator surface cylinder head enables engines operated environ ments dont provide high rates air flow cooling Heat sinks work pretty well care should taken run such engines absolute peak lean settings because heat sinks transfer heat rapidly effective air flow Conse quently can exceed thermal limits burn up pretty rapidly Water Cooling Usually found boat applications engine head fins re placed water jacket flattened wa ter tube cool clamp clamped around cylinder head Water cooling inter esting because provides opportunity really cool engine control opera ting temperatures power settings Ill bet well see some special water cooling ap plication planes cars near fu ture prospects controlling opera ting temperatures tuned pipe short-run maximum-power events too good pass up Some thoughts cooling 1 Dirty engines run hot let engine bake oil dirt outer sur faces cooling air wont able pick up efficiently heat off metal surfaces Clean exterior engine after flying session will stay clean 2 Hot engines run increased clear ances wear out prematurely 3 Engines have practical operating temperature envelope minimum maximum temperatures controlling factor maximum temperature oils fuel can tolerate still proper job lubrication No percen tage oil fuel really doesnt help engine runs too hot Ive never seen practical use over 20% oil providing fuel contains least 5% castor oil engine run over thermal limit April1978 99 Kraftsmanship kit processed AAMCO GOLD BALSAThis Trainer will blow apart hits ground GREATEST B/C BASIC TRAINER Design & Kit ALL TIME Ask over 25000 satisfied builders H-RAY dealers sold themSHALL WE SAY MORE Andresvs Aircraft Model Co Inc US Ete 1& North St Topstield Mass 01983 887-8541 Support AMA Price $3995 kit per dollar em too lean 4 Needle valve settings assure en gine does exceed its operating thermal limits Dont push absolute power setting unless prepared way control Operating temperatures can get completely out hand top set tings Burned pistons scored pistons sleeve multitude engine failures can occur just few seconds toolean settings 5 Observe begin flights new en gine conservative rich settings listen engine does lean out flight what needle valve setting will ensure complete run sagging CL Carrier/Perry continued page 48 87B design added folding wings tail hook Ju 87T torpedo plane also tested Hf 109 tested two forms Hf 109B used training have photo early Hf 109 probably B end run total engine run have achieve proper setting 6 I havent discussed throttles fuel pumps mufflers linkages etc get stalled engine compartments comes later columns sure accessories properly mounted function properly before flying 7 Remember can control cool ing engine achieve proper per formance Next column will fuel systems Don Jehlik 438A Schweer Dr Star Route 1 Hawthorne CA 90250 model tail hook.. addition derivative Hf 109E designated Hf 109T included tail hook en larged wings shown accompany ing drawing best description have seen Luftwaffes carrier aircraft activi ties contained German magazine Der Flieger March 1976 Its text photos cover greater list aircraft other source have encountered include catapult launch arrested land ing photos aircraft addition Hf 109 fighters already mentioned Arado Ar 197 biplane fighter used Carrier support aircraft included Arado Ar 195 Fieseler Fi 167 Heinkel 50 two-seat bomber also fitted catapult arrested landings although like Arado Fieseler aircraft biplane German carrier aircraft devel opment occurred later war would probably have fewer biplanes program monoplane help balance out set Arado Ar96 standard trainer Luftwaffe modified catapult arresting hook therefore qualifies event dont have drawings Ar 96 admit havent looked very hard Id happy hear can supply proper set three-views Although never got off deck Graf Zeppelin carrier aircraft Luftwaffe did fly provide some appealing alternatives us seek little variety Navy Carrier flying Richard L Perry 5016 Angelita Ave Dayton OH 45424 CL Scale/Gretz con tinued page 46 will undoubtedly become collectors items well showing support Scale Team price $150 three $400 postpaid Bob Underwood 4109 Concord Oake Dr St Louis MO 63128 Send wear keep Shutoff Payoff AMA Precision Scale rules currently allow additional 10 points awarded Taxi maneuver engine shutoff demonstrated far popular successful method engine shutoff throttle-equipped engine seems closing throttle completely below engines 100 Model Aviation 6 APRIL 73 & 91973 Friday9 am 6 pm Saturday9 am 6 pm Sunday9 am 330 pm presented by WEAK SIGNALS R/C CLUB PO BOX 5772 TOLEDO OHIO 43513 Kurt Kiefers profile Hawker Nimrod based Royal Navy fighter 1930s Flaps up per wing ailerons lower Would have looked batter British markings Photo Harry Higley