Playmate Jr.

From the publishers ofIN THIS ISSUE1 Cloud 9ElectronicallyControlled CO 2 ?by John WorthPLAN OFTHE MONTHDream Stikby Beau Christian2 On the Flyby Tom AtwoodHOW TO4 Convert a Coxfree-flight to RCby Mike BlottPRODUCTREVIEW5 CastleCreationsPixie-7PA programmableelectronic speedcontrolby Bob AberleHOW TO6 Cub Canardby Ed CouchFLIGHTREPORT8 NortheastSailplaneProductsPique 3by Thayer SymePRODUCTREVIEW13 JETI JES 06-3PProportionalcontrol forthe AstroFlightBrushless 010by Bernard Cawley Jr.14 Micro Scoop2001 ToledoRC Expoby Bob Aberle16 Source GuideON THE WEBSITEwww.rcmicroflight/may01Ilike package deals. Whenassembled by a reputable company,they give you thebenefits of careful engineering(so the components match)and volume purchasing (so theycost less). The Merlin electric RCpark flyer is a good example;Megatech bundles everything youneed to fly this entertaining planeinto one well-packaged box andsells it for a great price. Inside, youwill find a fuselage made of carbonfiberrods and a set of thin but verystrong foam-sheet wings and tailfeathers with leading and trailingedges reinforced by carbon-fiberrod (not dowels). The receiver,speed control and servos havealready been installed, and you willneed just a few minutes to attachthe rudder and stabilizer and tohook in the wire pushrods. Themotor, prop, drive battery, chargerPlaymate Jr.Suprising speed!by Dave Robelen • aplusfarm@hovac.comJUNE 2001MODEL REVIEWMEGATECHMerlinand transmitter are also included.The only thing you must supply isa pack of 8 “AA” alkaline batteriesfor the transmitter. The motor batteryalso powers the electronics andcuts off the motor at low voltage toleave power for the receiver and servosto get you home.The ball-bearing-equipped,geared motor slides right onto themotor stick; simply plug it into thecircuit as you would plug in a lampContinued on page 4About 16 years ago, I designed and published a plan for a lowwing,3-channel model I called the “Playmate.” Many modelersenjoyed this design and built it from both plans and kits. As Ibecame more involved with the RC electric micro-flight movement, I began to lookfor a model that I could scale down. The more I examined the possibilities,the more the Playmate looked like the top candidate. Of course, this conceptof “a model of a model” is old news to the free-flight fellows whoalready enjoy flying “older” models in smaller sizes.Pby Don RossMICRO FLYERP L A N O F TH E M O N T HContinued on page 2WWW.RCMICROFLIGHT.COMJune 2001 1

PLAYMATE JR.found the engine easy to make: I used a drill to spinthe round parts while I shaped them with a Dremeltool fitted with a cutoff wheel.■ I carved a prop for the prototype, but a PeckPolymers 6-inch plastic prop trimmed to 5.75inches works just fine.■ The most suitable motor for this model is theDC5-2.4 geared with 4.2:1. I installed mine (andthe dummy engine) with double-sided carpet tape,and I used a balsa scrap—sanded to the side-thrustangle—to keep it aligned.■ I installed a tiny switch and unisex connectors(available from Cloud 9 RC). To balance my model,I put two cells in the rear of the cabin. The elctronicsfit rather snugly; trial-fit and plan their positions.■ Music wire makes very nice pushrods; 0.020-inch-diameter is stiff enough.■ My hinges are plastic tape applied to one side ofthe surface, and I allowed a 1 ⁄32-inchhinge gap.■ Set the Playmate Jr. up with thecontrol throws shown on the plan,and double-check the balance point.■ If you have a tachometer, check proprpm; I recorded 3,900 to 4,000rpm ona fresh charge.AIR TIME!Hand-launch the Playmate Jr. or takeoff from smooth pavement, and practicesome “soft stuff.” My Playmate Jr. climbs at anysetting over ? throttle. Be gentle with the controls atfirst while you get a feel for this little thoroughbred;things can happen pretty quickly. My Playmate Jr.does more manuevers than any of my previousmodels: loops, stall turns, smooth rolls, snap rolls,true spins and touch and go’s. On 5 cells, maximumduration is about 6 minutes. Spend some time gettingused to your new little bird, and be thoroughwhen you trim it to ensure smooth flight, especiallyin manuevers. Enjoy, and let me know how youmake out.See the Source Guide on page 16 for manufacturers’addresses. MEGATECH MERLINContinued from page 1at home. It takes about an hour tocompletely assemble the Merlin, andthat includes applying the neatdecals. These decals use a mountingmethod that is new to me—eachdecal is furnished on a heavy browntop paper with a removable transparentplastic cover. Remove theplastic face cover, place the decalface down on the surface, slide iteasily into position, and then wetthe top paper with a sponge. Wait 10seconds, and slide the top paper off;this leaves a decal that consists ofjust a layer of paint.The pushrods slide inside plasticguides, and the carbon-fiber undercarriageand wheels snap togetherlike Lego-brand plastic buildingbricks. The back of the 12-inch propis recessed to lock in the rear nut,and there’s even an extra prop for usduffers.A peak charger that runs off yourcar battery and plugs into the cigarettelighter is furnished with the kit.The 6-cell, 600mAh, NiMH batterycharges quickly and produces 7 minutesof flight at full power and about 15minutes at cruise. The RC frequency is in the72MHz band so there are no interferenceproblems with 27MHz stuff nearby.With 511 square inches of area on theThe Speed 280-size motor and 5.6:1 gearboxare enclosed in a clear plastic housing andslip easily onto the motor stick. The stickitself is carbon fiber, as are the rest of thestructural elements.The two servos come installed in the fuselage,along with the receiver and speedcontrol. The pushrods are prebent and hookin easily after the tail has been attached.49 1 ⁄2-inch-span wing carryinga flying weight of just 17ounces, you have a potentialfloater. The wing loading is4.8 ounces per square foot(0.93 grams per squareinch)—low enough for adecent thermal flight.The Merlin’s handling isvery predictable, and thefirst flights are uneventful.The model’s big wheels permit smoothground handling and easy ROG at 3/4 throttle.The Merlin climbs briskly, and powercontrol is smooth throughout the range. Themodel is quite rugged; it survived a few walllandings in a tight indoor site. Beginners flyingin tight spaces will need to avoid havingthe large rudder area cause the plane to banktoo steeply. New kitswill sport a 7-cell batterythat shouldpermit loops fromlevel flight and thezooming takeoffs sobeloved by glowpowerfliers.Altogether, theMerlin system is avery good buy foranyone who wants toget into micro RC. Itperforms as well asany park flyer I haveseen and can handle indoor flying in all butthe smallest sites. The complete system costs$199.95. For those who already have an RCsystem, the kit alone with ball-bearing gearboxand prop is just $79.95.SPECIFICATIONSWingspan: 49.5 in.Wing area: 511 sq. in.Length: 30 in.Weight: 17 oz.Motor: Speed 280, geared 5.6:1Prop: 12x8Radio: 3-channel (included)Price: $199.95 (package), $79.95 (kit only)The tail surfaces andwings are made of thinbut very strong sheetfoam, and all the controlhorns come installed.See the Source Guide on page 16 for manufacturers’addresses. 4 RC MICROFLIGHT