Tip number 3 :
by Nils Norling
Ukey's make great stunt trainers. I finally learned the pattern with one after smashing a Ringmaster & Tutor into the ground many times a few years back. I've always used Fox 35's on mine but I've seen them fly with "stuntified" FP.40's, an O.S. 32 helicopter engine with a home made venturi, a .36 TT & one with a Magnum.40/Macs mini-pipe. They all flew well. Nobody around here has run an FP.25 but from what Brett Buck has told me they're at least equal to a Fox.35 so they should do very well in a Ukey.
Between all of us that fly CL here in Central Oregon we have around a dozen Ukeys. Most of the other guys flying here I taught to fly with a Ukey. All are 35 sized except the #1Ukey 15 kit that Joe Just gave me to build as a prototype. It's the red one in the picture. They all fly well, even after hitting the ground. (Repeatedly, in most cases.)
Here's how I set mine up-
First of all, remove the bellcrank & glue some plywood doublers on the fuse that go well back behind the trailing edge of the wing. The farther back the better. We've used everything from 1/8" lite ply scrap to 1/16" & 1/32" AC ply. Even with doublers we've had them split lengthwise on several occasions after a severe Lawn Dart Maneuver. No big deal, five minute epoxy will fix nearly anything you can do to a Ukey, including breaking the wings & nose completely off. (The black & white one in the picture has had both wings busted off at least three times, the nose broken off at the leading edge of the wing, the fuse split & the tailfeathers split, broken, glued back together & then replaced, it will still fly the pattern as well as it ever did.) I suggest you leave the doubler solid on the inside (left side) of the fuse & cut out for the engine mount only on the outside. If you use a Fox.35 you'll have to make a small hole for clearance of that one lower rear cover bolt boss. Leaving as much material as possible makes the nose quite a bit stronger. I know Joe is putting doublers on some kits now but I don't know if he's putting them on all of them. If yours doesn't have any, put some on it. I use Titebond II.
When (not if) you break off the wings a few times you'll probably have some open cavities in the foam wings. We fill 'em with "rattle-can" foam insulation from the hardware store. Trim off the excess, sand a little & put a piece of clear strapping tape over the foam. It'll be good as new structurally, just a little uglier. More Rustoleum will make it look better if you still care how it looks by then.
Btw, let the Rustoleum dry for at least three days before getting fuel on it & it will stand at least 15% nitro fuel. The Cardinal in the third picture is done in Rustoleum. It's my newest stunter. I flew it in Advanced for it's first contest this past fall & won with a 502. It was my first win in Advanced & the first time I've broken 500, great way to end a season ! :) It's a very nice flying airplane with an ST G-21 .46.
When you re-install the 'crank, remove the stop screw & leave it out. Move the pushrod to the outer hole. Adjust the rear horn all the way to the top. Btw, check the horn (bolt), to make sure the jamb nut is tight, then put some thin CA on the threads around the nut to keep it that way. You may have to put a spacer behind the pushrod guide so it doesn't bow after you move it to the outer hole in the 'crank. Make SURE it can't bind, bow or rub!! No drag anywhere! With the controls set up this way set your handle spacing at three inches. That really doesn't look like much elevator movement, but believe me, it's plenty. Put a quarter inch length of fuel line over the clevises on each end to be sure they can't pop open. Also pull on them HARD while you have the pushrod out to make sure they're soldered solid, I won't hurt to check 'em.
I suggest you re-glue the tailfeathers with epoxy all around where they're glued on from J&J. Check & make sure they're stuck on well, we've had some come loose.
Check the hinges on the elevators too. Make sure they're stuck on well. It's a good idea to sew them on with Dacron thread right through the hinges that are there. I use the Dacron thread from those Mickey Mouse half-A handle sets from Cox, since a buddy gave me a half dozen of them new in the packages. You can get the same stuff from any upholstery shop, ask for Dacron sewing machine bobbin. Figure 8 stitch 'em about every half inch with a large needle, then put a small drop of thin CA in each hole after you're done to seal the wood. The factory ones can come loose after a while. Most are good for a few hundred flights before they start to let go, (depending mostly on how many times the airplane has been in the turf).
If you use a Fox.35/open exhaust, try 3/4 ounce of lead in the tail. It will turn much better. If you use a heavier engine or a muffler, don't be afraid to add more than that if you want a reasonable corner. In any case, balance it on or just forward of the spar, depending on your experience. (Less experience=farther forward) Mine balances right on the spar & will fly a reasonable pattern, although the square corners are pretty round. Plenty good enough for practicing the pattern though. (For a beginner leave the lead out of the tail, nose heavy will make for a very stable flight.)
I use 4 ounce slant-front plastic uniflow tanks. I have an easy to email how-to on setting up plastic uniflows, if you need it just ask me & I'll send it to you, or look in the July-August '00 Stunt News. (You ARE a PAMPA member aren't you?) To make more room for the rear of the tank behind the engine, I dig out the foam from the front of the right wing root before I glue the wing panel on, leaving the wing skin in place. When I glue the wing panel on I smear a little epoxy in the hole to hold the skin back in the hollowed out area & keep out fuel off the foam. It puckers up a little but it's behind the tank & doesn't show much.
When you slide the wing panels on be sure the trailing edge touches the little dowel pin. That will insure the proper wing incidence. Eyeball the panels to be sure they're lined up with each other & parallel to the stab. If you get them twisted you'll have to add a trim tab to get it to fly level. The easiest way we've found to install the wings is to use a long furniture clamp & install both at once on a flat surface with spacers under the wingtips to keep them level, since they are tapered wings. Use epoxy that will give you time to make sure they're straight.
For a finish, I tape off where I want to paint, scuff the wing covering area I want to paint with a Scotchbrite & shoot two or three coats of Rustoleum over everything that needs paint after a very quick sand job. I don't waste a lot of time trying to make a Ukey pretty.
I hold the tank on with four doubled rubber bands going all the way around the front of the fuse & tank or you can use the zip strips provided. I put a 3 inch long half inch square balsa spacer under the tank on the side of the fuse which holds the top of the tank even with the top of the fuse. That will get you pretty close to the same lap times right side up or inverted with a Fox.35.
You'll get better overhead line tension if you drill a third hole in the leadout, right between the stock ones, then move the rear leadout wire to the new middle hole. You can simply run your lines through the leadouts on the wingtip to the bellcrank each time you hook it up, but I found it easier to install regular leadouts.
I drill a hole through the rear of the fuse & make a wire tailskid with a 90 degree bend on the top end to go in the hole & a loop on the other end for a stooge held on with one gear mounting strap.
With a Fox.35/10-5 APC I've found 58' (eye to eye, 60-1/2' OA) lines about right. The airplanes with larger engines will need longer ones. The guy with the mini-piped Magnum.40 flys his on 63' lines, (65-1/2' OA). With an unmuffled Fox .35 I have 3/4 ounce of lead in the tail of mine & it's still easy to fly level, not twitchy at all. I still use it as a trainer & beginners don't usually have any trouble with it. If you want a Ukey to corner don't be afraid to move the CG back until it will glide dead stick without much, if any, any input from you. You might have to narrow the handle spacing to the point where full deflection at the handle will just barely stall the wing. My handle spacing is three inches.