1, 2, 3, Kick (Second Chorus)

Questions abound about care feeding modern four-stroke engines article wont answer everything will help bridge gap two-stroke forthe firsttime four-stroke engine owner ELF Randolph 123Kick Second Chorus MOST TYPICAL modelers deeply concerned exact inner workings engines Instead terested good installation necessary maintenance procedures will provide trouble-free operation ideal engine performs like family car start it runs Most us have become accustomed typical two-cycle engine feel very much home install twocycle engine maintain it performs advertised along comes fourstroke-cycle engine alternately known four-stroke four-cycle FS 4S Al though four-stroker appears different breed cat some respects it bit easy handle old familiar two-cycle companies manufacture fourcycle engines same ones have producing two-cycle ones long long time stands reason thus generate sales make profit must produce product too far removed mainstream modeling merchandising standpoint four-stroke engines should similar two-cycle oousins way possible Lets look some similarities slight differences running maintainLeft Just visualize nice big Saito 27 would look favorIte Giant Scale opposed-cylInder plane beautiful piece machinery sweet running extremely smooth also produces scalelike sound pure music Right isa compari son sizes 05 FS-20 its bigger 40 brother Four-cycle engines available sizes run well handle easily Left Most four-cycles come complete set tools Occasional adjustments necessary manufacturers thoughtfully provide equipment instructions handie situation Read manual comes new engine Right Because four-stroke engines require longer mounts two-stroke counterparts several companies now produce full line mounts four-strokes JTec isa good example others can found magazine ads better yet encourage iocai dealer carry 44 Model Aviation ing two types model engines both glow-ignition run al cohol-based fuel percentage oil four-cycles typically 20% less two-cycles 10% 15% nitro needed four-cycles Throttles needle valves work same both types though four-cycles carburetor likely located different place like back engine because intake scheme also less danger fingers spinning prop About same break-in procedure required both four-strokes two-strokes achieve top consistent performance best way accomplish view mount new engine airplane fly setting needle valve little rich first few flights fuel tank location both types samecenter tank line center carburetor Muffler pressure tank can used four-cycle engine desired just can twocycles After flying sessions fourstroke should wiped clean lubricated good quality oil automatic trans mission fluid being best good practice model engine biggest physical difference will affect average modeler type engine mount required four-strokes Engines rear-located carburetors re quire longer mounting rails twocycle shaft-valve counterparts because four-cycles slightly longer stroke crankcase may little wider require different mount spacing Most manufac turers make mounts engines though few hobby shops currently stock Probably will change four-stroke engine popularity further increases Some long mounts rear-intake twocycle racing engines will fit 40-size rear-carb four-stroke engines large see-if-it-fits procedure earliest companies market com plete line four-cycle mounts including sizes smallest engines JTec Co 164 School St Daly City CA 94014 scan ads other companies Wooden beam mounts course another answer particularly retrofitting engine Adjusting needle valve little different youare notusedto soundofa four-cycle engine will never produce two-cycle sound thank goodness may accustomed mellower lower-pitched sound frequency have difficulty telling ear whether needle valve set right Continued page 128 Left basically two types four-stroke engines rotary valves poppet vaives good exampie latter Externai vaives such shouid oiied occasionaiiy cieaned keep popping years Right clear ance between valve rocker arms pushrods poppet valve engines should checked least once year adjusted neces sary Gauges come engines require Procedure simple quick Adjustment required rotary valve engines Left Because four-cycle carbs often separated engines long throat isa slight chance carburetor icing tem perature humidity exactly right Effect less pronounced rear-mounted carbs such Right Remotely-operated chokes welcome addition cowled engines difficult prime four-cycle choking lathe best way get fuel flowing February 1986 45 thing looks like pressure tap bottom thecrankshafthousing real lythe breather nipple H P21 Excess oil will drip breather during opera tion should vented outside engine tightly cowled breather also good place fora squirt lubricant end days flying pics author p1 MULTIPLEXThe Competitors Edge ..-J14 Channel ROYAL mc Especially Competition FlyerI Exclusive Flight tested since 1979 2001 FM Narrowband PCM Fast accurate service repair 7725 E Redfield Rd e 105 tsdale Airpark tsdale Arizona 8526 Beemer RC West Distributors Inc 602 483-9577 MEMORY SOFT MODULE features new Fabtronics Mark 3 CDl pointless system Once treat mill system wont settle anything less coupled 4 cycle have Best Two Worlds works equally well 2 cycles twins two cylindars model size engine unit comes pre-drilled disk sensor clamp mounting sensor engine 90 day warranty complete structions conversion timing procedure Unit operates 48 volt low current drain weight mere 2 oz size 2 x 2 x 75 inches Complete system comes ignition coil spark plug on/off switch ignition cable also available seperately Batteries cluded Please state engine size use ordering Converting ignition has ad vantages such tremendous saving fuel less mess no burned-out plugs bet ter idle name few Nearly engine can easily con verted can switch unit plane car boat helicopter another Installation very easy no special tools needed Complete system$6995 Cash MO Certified Check Plus $300 postage handling Personal checks take time clear Illinois residents please add tax Brochure ndable purchase FABTRONICS 375 Isle Royale RdGalesbury 1161401 Radio Technique/Myers Continued page 125 frequency spacing signif icant indication FM transmitters triplet makes inter ference worse So data tells us certain road better 31M situa tion ban FM entirely dont think idea will sell either George M Myers 70 Froehlich Farm Rd Hicksvile NY 11801 1 2 3 Kick/Randolph Continued page 45 bit lean bit rich Most seem arrive too-lean setting ear isnt good Actually exhaust provides best clue proper setting first few times Set needle valve will small amount visible smoke setting will very close correct get exact consistent peak rpm four-stroke engine set needle valve aid tachometer run four-stroke engines lean less 20% oil fuel subject running four-strokers interesting note manufacturer suggests ffipping prop backwards against cpmpression starting case works fact very first four-stroke engine started flipping prop backwards Following instructions started very first flip Traditional starting hand-flipping no problem four-cycle engines ever same starters used two-cycle engines just effective fourstrokers Although have heard back fires kicking props loose larger engines usually result having needle valve set too lean have never experienced problem An extra quarterturn prop nut seems good insurance Propellers Manufacturers usually suggest range propellers engine ideal propeller use best airplane/engine Maxi mum power four-stroke engine produced lower rpm twostroker other factors trans lates needing bigger prop and/or pitch comparablysized two-stroker amount prop thrust put out low-revving engine may amaze performance figures given engine reviewers some magazinesthose show ing peak power output specific prop specific rpmif developed bench runningdont tell whole story practical usage Bench running doesnt show effects props unloading flight best thing feel try flying different props until best suited airplane found key thing remember thrust propel ler gives speed model fly engine simply turns propeller last item difference fourstroke engines crankcase breather pressure tap Since crankcase part carburetion system must vented relieve internal air pressure piston goes up down bit oil drains breather good idea vent outside airplane engine cowled breather vent good place shot oil after flying session give bearings little protection should part clean-up procedure Four-cycle engines stay No doubt will become commonplace two-cycle engines future dont have get Youll love RC Aerobatics/Van Putte Continued page 47 scores Figure M 1A Rolls seems wind direction never right end up doing maneuver crosswind Its tough enough wind direction down runway nearly impossible well crosswind unless youre right top elevator control except few superior pilots rest us hate little advice potential purchasers 128 Model Aviation