U Bob Underwood 5P74 Y@KU MODELING IS LIKE other activity involves technically oriented products breed undergoes continuous evolution refinement find new approaches older established methods tweaked make better Sometimes better just tad ten tads over few years adds up great glob course technical terms An excellent example propulsion unitsengines motorswhatever used make powered models fly providing thrust recent addition power mode true jet engine several thousand dollars pop its level sophistication its NewComer issue illustrates point regarding development Within standard engine forms old two-strokes dating early 1900s underwent constant subtle changes Power levels rpm increased steadily through improvements materials experimentation timing porting etc Four-strokes converted chain-saw gasoline engines made appearance modeler suddenly armed multitude weapons wage power battle task became complicated advent propeller research Prompted desire reduce sound noise revolution pun intended props has very helpful use highly refined high-pitch props RC Pattern airplanes has produced power sound ratio fantastic ramifications progress through competition has rippled through model community Unfortunately NewComer task getting started has become complicated choices greater So what use guideline Manufacturers dealers generally attempt provide some help tendency equate model size weight wingspan etc engine size size range two schools thought regarding size range club expert will tell hug low end displacement range keep out trouble having too much power other club expert will tell bang top end range sometimes go larger can always throttle back youll have extra power need can pitfalls approach started flying RC 1967 chose Falcon 56 56-inch wingspan 19 two-stroke engine standard combination time model flew nicely Now model 50-60-inch span considered 40-sized model Thats spite fact modern sport 40 usually whale lot powerful 23 years ago own observations relative getting started Stay within power/size range recommended manufacturer tendency lean toward top end larger size suggested several reasons use smaller-size engine may have wring out rpm make model fly well always run risk leaning out engine too far too little fuel fueL/air mixture frying short order always possible underprop use lower-pitch prop manage excess power can also run engine richer fuel/air mixture Since early models built tend tailheavy little extra engine ballast may bad other considerations selecting size range starting model general rule suggests smaller models difficult fly sensitive overweight conditions generally control-sensitive other hand larger can equate expensive true initial expense model finishing material engine also overall upkeep Check cost fuel instance As result factors will notice trainers 4060 size range RC 40-and-slightlybelow Control Line produces reasonably sized model flies well easy transport doesnt bend pocketbook other factor may affect selection have thought ahead stage two aeromodeling growth may engine size etc dictated future model choices would shame have perfectly good engine isnt usable future project RC same true radio systems previous column suggested minimum five channels though trainer may utilize three throttle rudder elevator Yes know basic functions take four channels really U May1996 27 retracts other stuff Another difficult decision whether use two-stroke four-stroke engine Some considerations Cost Four-strokes generally expensive However use less fuel theyve got parts wear Fun huh Sound unmuffled four-strokes tend quieter least engine note harshness less objectionable Does club have restriction Weight rpm As general rule fourstrokes heavier operate lower rpm two-strokes However will often swing bigger prop creating much thrust During last few years significant strides have made closing gap between two- four-strokes long time least efficient parts power system prop true regarding power sound reduction As modelers tended complicate issue having relatively closed minds about engine/prop size correlation onetime charts said 40 lOx 6 6011 x 7 Well props have gotten much better modelers much wiser selecting proper diameter pitch specific application engine has power curve dictated various factors model due its configuration potential use has specific prop/engine needs job link up Fortunately trainer applications adaptability covers wide range stick somewhere middle engine manufacturers diameter/pitch range should have no problem doesnt hurt experiment little just dont lug engine down too far field competition communities have very helpful spurring development Youve probably noticed cost engines given size covers wide range subscribe theory espoused mother-in-law youll select expensive engine based concept premise should buy best served well indeed furniture owned would wear forever style didnt beware following philosophy buying engine cost engine may dictated its intended use set up finished Purchasing high-performance competition engine trainer sport model probably wise decision Im certain Id want Indy-car engine Dodge van Again its wise nose around looking asking questions doesnt take Einstein figure out what combinations fly well field odel Aviation ly $495Z
Edition: Model Aviation - 1996/05
Page Numbers: 27, 28
Edition: Model Aviation - 1996/05
Page Numbers: 27, 28
U Bob Underwood 5P74 Y@KU MODELING IS LIKE other activity involves technically oriented products breed undergoes continuous evolution refinement find new approaches older established methods tweaked make better Sometimes better just tad ten tads over few years adds up great glob course technical terms An excellent example propulsion unitsengines motorswhatever used make powered models fly providing thrust recent addition power mode true jet engine several thousand dollars pop its level sophistication its NewComer issue illustrates point regarding development Within standard engine forms old two-strokes dating early 1900s underwent constant subtle changes Power levels rpm increased steadily through improvements materials experimentation timing porting etc Four-strokes converted chain-saw gasoline engines made appearance modeler suddenly armed multitude weapons wage power battle task became complicated advent propeller research Prompted desire reduce sound noise revolution pun intended props has very helpful use highly refined high-pitch props RC Pattern airplanes has produced power sound ratio fantastic ramifications progress through competition has rippled through model community Unfortunately NewComer task getting started has become complicated choices greater So what use guideline Manufacturers dealers generally attempt provide some help tendency equate model size weight wingspan etc engine size size range two schools thought regarding size range club expert will tell hug low end displacement range keep out trouble having too much power other club expert will tell bang top end range sometimes go larger can always throttle back youll have extra power need can pitfalls approach started flying RC 1967 chose Falcon 56 56-inch wingspan 19 two-stroke engine standard combination time model flew nicely Now model 50-60-inch span considered 40-sized model Thats spite fact modern sport 40 usually whale lot powerful 23 years ago own observations relative getting started Stay within power/size range recommended manufacturer tendency lean toward top end larger size suggested several reasons use smaller-size engine may have wring out rpm make model fly well always run risk leaning out engine too far too little fuel fueL/air mixture frying short order always possible underprop use lower-pitch prop manage excess power can also run engine richer fuel/air mixture Since early models built tend tailheavy little extra engine ballast may bad other considerations selecting size range starting model general rule suggests smaller models difficult fly sensitive overweight conditions generally control-sensitive other hand larger can equate expensive true initial expense model finishing material engine also overall upkeep Check cost fuel instance As result factors will notice trainers 4060 size range RC 40-and-slightlybelow Control Line produces reasonably sized model flies well easy transport doesnt bend pocketbook other factor may affect selection have thought ahead stage two aeromodeling growth may engine size etc dictated future model choices would shame have perfectly good engine isnt usable future project RC same true radio systems previous column suggested minimum five channels though trainer may utilize three throttle rudder elevator Yes know basic functions take four channels really U May1996 27 retracts other stuff Another difficult decision whether use two-stroke four-stroke engine Some considerations Cost Four-strokes generally expensive However use less fuel theyve got parts wear Fun huh Sound unmuffled four-strokes tend quieter least engine note harshness less objectionable Does club have restriction Weight rpm As general rule fourstrokes heavier operate lower rpm two-strokes However will often swing bigger prop creating much thrust During last few years significant strides have made closing gap between two- four-strokes long time least efficient parts power system prop true regarding power sound reduction As modelers tended complicate issue having relatively closed minds about engine/prop size correlation onetime charts said 40 lOx 6 6011 x 7 Well props have gotten much better modelers much wiser selecting proper diameter pitch specific application engine has power curve dictated various factors model due its configuration potential use has specific prop/engine needs job link up Fortunately trainer applications adaptability covers wide range stick somewhere middle engine manufacturers diameter/pitch range should have no problem doesnt hurt experiment little just dont lug engine down too far field competition communities have very helpful spurring development Youve probably noticed cost engines given size covers wide range subscribe theory espoused mother-in-law youll select expensive engine based concept premise should buy best served well indeed furniture owned would wear forever style didnt beware following philosophy buying engine cost engine may dictated its intended use set up finished Purchasing high-performance competition engine trainer sport model probably wise decision Im certain Id want Indy-car engine Dodge van Again its wise nose around looking asking questions doesnt take Einstein figure out what combinations fly well field odel Aviation ly $495Z
