While on the subject, I am trying to find out where to drill the holes in the firewall for the motor mounts on an inverted YS F91 4 stroke going in a cap 232. I am not sure because they have always been predrilled. I have the picture of the firewall with the lines drawn but it does not make a whole lot of sense to me. Help anyone. The book says to make it inverted. My ucando 3d flys fine like that.

" should have bought a plane instead of the wedding ring. damn budgeting!!! "

Just remember, "it's easier to beg for forgiveness then ask permission."

Did you put the cross hairs on the firewall extension, or were they marked by the kit or ARF's manufacturer? Normally marks such as these indicate the port/starboard/up/down location of the thrust line, which is what your asking about. If these marks are correctly positioned, this is a centerline you want to continue through to the center of the thrust washer of the engine.

I'd like to help you but I don't have enough information! Is there right or down thrust? Who manufactured this aircraft?

Maybe someone with specific information on this Cap 232 can chime in with the specific information you need.

I am reachable at [email protected] .

I used to think the same thing myself until one forgivness begging session almost resulted in a divorce because I kept doing it. Now I find that I can usually buy more if I consult the family budget before purchases.

Ken

Getting back to RCplanes12 original question on inverting engines: Someone over the years I have the utmost respect for in the engine department is Clarence Lee. Clarence wrote a column in Radio Control Modeler (RCM) entitled "Engine Clinic". The June 2005 issue of RCM may be the last as it appears RCM may no longer be in operation. It is wonderful to note however, that Clarence and Engine Clinic have re-surfaced in the April issue of Model Airplane News! "Low and Behold", one of the letters written to him is a discusion on inverting engines in a P-38! I am in agreement with Clarence on his opinions on inverting. To those of you whom are successful with your inverted engine installations, I say great and I admire your tenacity to stick to your guns!

I would use a higher nitro content in the fuel especially on 2 strokes, solved the problems I had.

The engine that goes inverted needs to be a well broken in and reliable upright engine.

First time you start it inverted, don't.
Start it right side up and run it that way to prove everything is ok. Stop it. Hand choke it, TURN THE PROP TO close the crankshaft opening so all the prime does not drain out whn you set it on the ground.

Plug wire on, flip or spin it, you are running everytime.

Cyclops, Are you speaking about 2 or 4 cycle engines?

I don't agree with that at all. Any inverted engine has the ability to run like crap and cause nothing but problems unless you lower the fuel tank. Most of my fleet is inverted (2's and 4's)and they are all just fine because I pay attention and learn from those who don't. So while I am flying, they mess with the planes and continuously blame everything and everybody but themselves

Cyclic, Whom are you replying too?

sless2,
Those lines on the firewall would be there to give you a reference point for the center of your motor mount. If you have a one-piece motor mount you'd simply align it to those lines so that the intersection of those lines is exactly in the center of the mount. chuckle... Of course, those lines don't exist where that intersection would be, and the exact center of the motor mount is just air too.... But you get the idea.

I'm assembling a Cap232 right now too. Mine however is a KYOSHO .46 size, but it's also got the hole and reference lines. The idea is that you're going to have to position the motor mount to the side and up-or-down in order to have the prop tighten down on the engine thrust washer in the center of the spinner opening in the fiberglass cowling. If the airplane has right thrust (which yours looks to have) then the mount will be positioned somewhat to the "left". And the same idea if the plane has up or down thrust.

One good way to assure that you're about to drill the holes in the right place is to attach your engine to the motor mount and tack glue the mount where you think it should go. Then slide the cowl on and see if the thrust washer is centered in the cowl opening. I'm just about to do that myself. It's important to do this check because ARF makers are often just toy manufacturers. I've had 2 ARFs recently that said they had no thrust offset in the model, yet did. And not only did they have thrust offset after saying they didn't have it, but one of them actually had the reference lines and access hole drilled for UP THRUST when the bloody model had DOWN THRUST. That one would have looked really stupid had I placed the motor where the reference lines showed. The prop would have been "centered" way off center in the cowling.

Don't trust anything the mfg's manual says about an ARF. Those people aren't blessed with perfect translation skills and aren't always very talented at manufacturing flying models either.

Mode one. I use 2 strokes. The ST 90, 35 years old has a Varathane fuel pump on it.

It does not know it should be hard to start, idle, go verticle or dive and have RPM changes.

It just runs.