DB Mathews Piper Skycycle Saga 25 years no column subject has generated mail responses Skycycle Im talking several dozen letters 100 months following two columns modelers wrote indicating strong interest building models prototype mentioned possibility well-known respected person dusting off prototype molds marketing h-scale Skycycle kit asked anonymity making up mind forwarded letters him can now relate potential kitter Bert Baker Everett Washington responsible design incredibly beautiful good-flying Yellow Aircraft warbirds Bert severed association company year ago considering running some limited-production kits own plugs molds Skycycle Bert developed proposal several years ago left Yellow Aircraft presumed could get back However whatever reason previous owners destroyed plugs sold out current owners As much hate report will no h-scale Skycycle kit Bert Drawings cowl canopy available h-scale 60-inch Skycycle Vintage R/C Plans 5105 Pine Hill Circle Howell MI 48843 have successfully built flown Perhaps hope lost h-scale kit old rule thumb letter sent columnist 10 never written Following line logic some manufacturer could find rather large market should choose produce Skycycle kit Because prototypes complex fuselage shape remember drop tank adapted huge canopy double compoundcurved wing fillets fiberglass fuselage would ideal other hand construction wings empennage conventional could done built-up foam form Although Skycycle rare subject Scale modeling considerable amount documentation available rare hardly obscure Hey manufacturers whole bunch modelers would stand line buy h-scale kit spend time developing another P-S 1 opportunity strange times automobiles grow smaller model airplanes grow larger Really Big KK After April 1998 column ran bunch photos Kloud Kings various sizes ranging hA nine feet Jim Halls Johnson Vermont responded letter photos biggest yet Jims Super Kloud King spans incredible 18 feet has bicycle wheels undercarriage powered Zenoah twin 445 Perhaps startling up weight no less 90 pounds Jim remission cancer following chemotherapy five flying buddies decided since hed much fun nine-foot Kloud King should build twice size during rehabilitation agreed would build would foot bill supplies quote Jim Structurally airplane strong brick outhouse /2 X /2 Sitka spruce longerons full length no splices ood extends first bay aft wing mount forward nose lots a sheeting filling gaps engine mounted inum plate turn secured er sheet absorb vibration tied other plywood combined total thickness inch wiring encased empty MonoKote tubes [Ill bet lots those] leading giant servos fuselage rear Tail 78 Model Aviation Halls friends slightly enlarged Kioud King plan 103 July 1975 ModelAviation Halls grandson refugee Gullivers Travels Lilliput normal size model Jim Halls assembles 18-foot-span Super Kioud King Notice gorgeous Vermont countryside background feathers well ailerons activated Dave Brown fiberglass pushrods Du-Bro universal joint connectors ends undercart chromoly tubing solidly brazed together no shock absorbing wheels 13-inch spoked bicycle wheels tires huge two-piece wing secured fuselage six -20 socket head cap screws running brass inserts secured two 1/2 X e wing saddle pieces anchored fore aft plywood formers amount MonoKote used incredible must have single-handedly improved Tower/Great Planes profits report its stockholders quarter no question Super KK Experimental Aircraft category will require special waiver AMAs insurance provider Crunching Some Numbers letter Jim expressed concerns about available power propeller size inquired knew source reduction gear drive unit 251 Zenoah Jim others involved project concerned Zenoah twin might sustain flight never used pet rule-of-thumb numbers such large project wondered would come out what reality model airplane remotely piloted ultralight Previously largest model tried numbers Bill Cohens Cathedral City CA 14-foot Powerhouse worked fine thought might enjoy looking through calculations educated guesses sent Jim might able apply use some time minimum can explore simplistic solution complex problem However keep mind following applies slow-flying non-acrobatic designs Im talking family sedans FerrariTM er frequently-used rule-of-thumb 250-300 square inches sq wing area 10 cubic inch cu displacement models larger 400 sq in area 441 power plant works optimally Old-Timer sportier model 1000-1200 sq same sort numerical ratio works other types models 40 cu m Pattern aireraft usually works out best 500-600 sq wing 60 cu about 700-800 sq Therefore engine-to-area ratio about 115-130 both Now get really wild stick 120 twostroke 800 sq Extra Giles ratio goes way down 66 Rule number two Old-Timers trainers wing loading weight should about 16 ounces per sq ft less first 800 sq wing area 1000 sq area will fly well roughly logarithmic progression wing loading other words 2000 sq wing should fly similarly 32 ounces per sq ft smaller will 16 ounces per sq ft etc aeronautical engineer friends tell its because something called Reynolds number larger wings lift efficiently small ones say chord influential span equation wing loading full-scale aircraft expressed pounds per sq ft ounces works out because much larger wing much efficient Two-stroke twin-cylinder engines put oufpWerUabouT85% single-cylinder two-stroke unit same displacement less smaller size twins associated additional friction extra components rubbing other Conversely twin runs smoothly singlecylinder some weight can saved mounting system sound wonderful Four-stroke single-cylinder engines figured 80% twostroke singles same displacement four-stroke twins 75% two-stroke singles Ill try apply guidelines Halls Super Kloud King project attempt predict performance Applied Numbers calculating 18-foot Kloud King chord would 3675 inches area would 54 sq ft 7900 sq 90 pounds Super Kloud King has wing loading 26 ounce/sq ft Zenoah 445 has displacement 90 cc 54 cu Just fun put numbers pet parameters calculate whether Super Kloud King will fly Zenoah needs reduction drive too heavy fly well Next month Ill follow up conclusions results Rule Sixes Again Throughout preceding number-crunching displacements converted cc cu multiplying dividing six shifting decimal left right mnemonic fact 60 cu engine also 10cc 1 cc engine 06 cu Dont get hung up zeros just move decimal make come out Fun Jim Halls interest airplanes has lifelong source enjoyment him early 1930s dad brought home rubber-powered model fifth birthday flew across room Jim hooked life grandfather architect builder encouraged Jim build fly models way focus joy learning accomplishment Winnipeg Manitoba Canada Jim spent first 10 years days Free Flight king Jims first engine OR 23 about 1940 like us younger modelers era difficulties getting run consistently because shortages 70 oil white gas dry cell batteries war going mention total lack expertise Through raw persistence us did learn run engines exception some contemporaries saved money birthdays errands odd jobs etc spent GHQs Thors rarely ran Jims first successful gas model Henry Struck-designed Berkeley Models American Ace once flew off landing Montreal Quebec top Sun Life building time tallest structure British empire Jim able retrieve model Through years Ive related some strange stories about model flyaways first time Ive ever heard anyone taking elevator recover ary1999 79 Bob McDaniels Bowie MD 1h-scale Piper PA-8 Skycycle readers interested building models Aluminum firewall backed h-inch rubber sheet absorb vibration structure one-inch thickness
Edition: Model Aviation - 1999/01
Page Numbers: 78, 79
Edition: Model Aviation - 1999/01
Page Numbers: 78, 79
DB Mathews Piper Skycycle Saga 25 years no column subject has generated mail responses Skycycle Im talking several dozen letters 100 months following two columns modelers wrote indicating strong interest building models prototype mentioned possibility well-known respected person dusting off prototype molds marketing h-scale Skycycle kit asked anonymity making up mind forwarded letters him can now relate potential kitter Bert Baker Everett Washington responsible design incredibly beautiful good-flying Yellow Aircraft warbirds Bert severed association company year ago considering running some limited-production kits own plugs molds Skycycle Bert developed proposal several years ago left Yellow Aircraft presumed could get back However whatever reason previous owners destroyed plugs sold out current owners As much hate report will no h-scale Skycycle kit Bert Drawings cowl canopy available h-scale 60-inch Skycycle Vintage R/C Plans 5105 Pine Hill Circle Howell MI 48843 have successfully built flown Perhaps hope lost h-scale kit old rule thumb letter sent columnist 10 never written Following line logic some manufacturer could find rather large market should choose produce Skycycle kit Because prototypes complex fuselage shape remember drop tank adapted huge canopy double compoundcurved wing fillets fiberglass fuselage would ideal other hand construction wings empennage conventional could done built-up foam form Although Skycycle rare subject Scale modeling considerable amount documentation available rare hardly obscure Hey manufacturers whole bunch modelers would stand line buy h-scale kit spend time developing another P-S 1 opportunity strange times automobiles grow smaller model airplanes grow larger Really Big KK After April 1998 column ran bunch photos Kloud Kings various sizes ranging hA nine feet Jim Halls Johnson Vermont responded letter photos biggest yet Jims Super Kloud King spans incredible 18 feet has bicycle wheels undercarriage powered Zenoah twin 445 Perhaps startling up weight no less 90 pounds Jim remission cancer following chemotherapy five flying buddies decided since hed much fun nine-foot Kloud King should build twice size during rehabilitation agreed would build would foot bill supplies quote Jim Structurally airplane strong brick outhouse /2 X /2 Sitka spruce longerons full length no splices ood extends first bay aft wing mount forward nose lots a sheeting filling gaps engine mounted inum plate turn secured er sheet absorb vibration tied other plywood combined total thickness inch wiring encased empty MonoKote tubes [Ill bet lots those] leading giant servos fuselage rear Tail 78 Model Aviation Halls friends slightly enlarged Kioud King plan 103 July 1975 ModelAviation Halls grandson refugee Gullivers Travels Lilliput normal size model Jim Halls assembles 18-foot-span Super Kioud King Notice gorgeous Vermont countryside background feathers well ailerons activated Dave Brown fiberglass pushrods Du-Bro universal joint connectors ends undercart chromoly tubing solidly brazed together no shock absorbing wheels 13-inch spoked bicycle wheels tires huge two-piece wing secured fuselage six -20 socket head cap screws running brass inserts secured two 1/2 X e wing saddle pieces anchored fore aft plywood formers amount MonoKote used incredible must have single-handedly improved Tower/Great Planes profits report its stockholders quarter no question Super KK Experimental Aircraft category will require special waiver AMAs insurance provider Crunching Some Numbers letter Jim expressed concerns about available power propeller size inquired knew source reduction gear drive unit 251 Zenoah Jim others involved project concerned Zenoah twin might sustain flight never used pet rule-of-thumb numbers such large project wondered would come out what reality model airplane remotely piloted ultralight Previously largest model tried numbers Bill Cohens Cathedral City CA 14-foot Powerhouse worked fine thought might enjoy looking through calculations educated guesses sent Jim might able apply use some time minimum can explore simplistic solution complex problem However keep mind following applies slow-flying non-acrobatic designs Im talking family sedans FerrariTM er frequently-used rule-of-thumb 250-300 square inches sq wing area 10 cubic inch cu displacement models larger 400 sq in area 441 power plant works optimally Old-Timer sportier model 1000-1200 sq same sort numerical ratio works other types models 40 cu m Pattern aireraft usually works out best 500-600 sq wing 60 cu about 700-800 sq Therefore engine-to-area ratio about 115-130 both Now get really wild stick 120 twostroke 800 sq Extra Giles ratio goes way down 66 Rule number two Old-Timers trainers wing loading weight should about 16 ounces per sq ft less first 800 sq wing area 1000 sq area will fly well roughly logarithmic progression wing loading other words 2000 sq wing should fly similarly 32 ounces per sq ft smaller will 16 ounces per sq ft etc aeronautical engineer friends tell its because something called Reynolds number larger wings lift efficiently small ones say chord influential span equation wing loading full-scale aircraft expressed pounds per sq ft ounces works out because much larger wing much efficient Two-stroke twin-cylinder engines put oufpWerUabouT85% single-cylinder two-stroke unit same displacement less smaller size twins associated additional friction extra components rubbing other Conversely twin runs smoothly singlecylinder some weight can saved mounting system sound wonderful Four-stroke single-cylinder engines figured 80% twostroke singles same displacement four-stroke twins 75% two-stroke singles Ill try apply guidelines Halls Super Kloud King project attempt predict performance Applied Numbers calculating 18-foot Kloud King chord would 3675 inches area would 54 sq ft 7900 sq 90 pounds Super Kloud King has wing loading 26 ounce/sq ft Zenoah 445 has displacement 90 cc 54 cu Just fun put numbers pet parameters calculate whether Super Kloud King will fly Zenoah needs reduction drive too heavy fly well Next month Ill follow up conclusions results Rule Sixes Again Throughout preceding number-crunching displacements converted cc cu multiplying dividing six shifting decimal left right mnemonic fact 60 cu engine also 10cc 1 cc engine 06 cu Dont get hung up zeros just move decimal make come out Fun Jim Halls interest airplanes has lifelong source enjoyment him early 1930s dad brought home rubber-powered model fifth birthday flew across room Jim hooked life grandfather architect builder encouraged Jim build fly models way focus joy learning accomplishment Winnipeg Manitoba Canada Jim spent first 10 years days Free Flight king Jims first engine OR 23 about 1940 like us younger modelers era difficulties getting run consistently because shortages 70 oil white gas dry cell batteries war going mention total lack expertise Through raw persistence us did learn run engines exception some contemporaries saved money birthdays errands odd jobs etc spent GHQs Thors rarely ran Jims first successful gas model Henry Struck-designed Berkeley Models American Ace once flew off landing Montreal Quebec top Sun Life building time tallest structure British empire Jim able retrieve model Through years Ive related some strange stories about model flyaways first time Ive ever heard anyone taking elevator recover ary1999 79 Bob McDaniels Bowie MD 1h-scale Piper PA-8 Skycycle readers interested building models Aluminum firewall backed h-inch rubber sheet absorb vibration structure one-inch thickness
