My dad just picked up a plane with a barely used OS46fxi, Is that the same as the 46fx? I have a 46fx and an ax and they are great little engines.

I asked a while back because my used decat came with the fxi. It has an upgraded HSN mount or something like that, but everything else is the same. It performs very well in my decat, and I think its what came in all the nexstars until the ax came out.

Ok. second question is, The engine came on a nexstar, his last trainer turned into tooth picks. the covering on this thing is terrible!! I'm not sure what covering it is, but there is a couple of spots that need ironed back down and a couple of holes that need patch work. I have some monocote and some towercote. will either of these work.

I wouldn't see why they wouldn't work. Towerkote is not the easiest to work with, but it will work. Haven't used monokote, but it should be fine as well. If you want to use them together, I would suggest putting the monokote down first, then laying the towerkote over it. The towerkote doesn't use as much heat as the monokote.

use the monokote, try to clean the location with alcohol first so the new monokote will stick to the old one.

Alex

What Alex said. The Nexstar is covered in Monokote, so you can repair it with Monokote with no problems.

As far as the engine. The FXi is sold ONLY on the Nexstar. In fact, you can't even buy one on the market. You can only get it with the Nestar plane. While it's got a few cosmetic differences it's pretty much the same as the AX. I say that it's closer to the AX than the FX because of the remote needle valve mount. On the true FX engines the remote needle valve mount is molded in to the engine backplate. If you crash the plane you can pretty much count on that bracket snapping off, and you have to buy a new backplate (~$15) to fix it. On the FXi and the AX the needle valve mounts on a metal bracket that is bolted on to the back of the engine. In a crash this will simply bend and can be straightened very easily. The FXi is a great running engine and will do fine on any 40 sized plane.

Ken

I know all to well about the back plate of the fx. I had to replace it no to long ago.

The FXi is essentially a OS 46FX with a low compression head.

If you Place a FXi next to a 46FX, a 46AX, and a LA46, you will see that it is not like the AX at all because it has a 6 bolt head and not a 4 bolt head. The FXi doesn't look like a FX on the top side, the head is different. The head on a FXi looks like a LA 46 head. Yet the needle valve assembly on the FXi is like that on the newer LA and AX engines.

The morel to this story is that the FXi is a 46FX with a low compression cyl head. It starts and runs easily but does not have the power of the FX or AX engine. Yet is has more power than the LA 46.

About those pesty backplate remote needle mounts, you can save yourself some cash (if you think you might crash) by either scoring the mount or just cutting it all the way off before hand. Cut it off close to the backplate, drill a hole in the tab left on the needle, and screw it down to the firewall or something, and you're good to go, problem solved. Or, for that matter, just let the needle float free, held in place by the fuel tubing.

It's pretty much normal to see the OS .25FX's in combat planes done this way, since the first thing that happens to them is the needle mount getting broken off in a mid-air or crash.

On some .46AX's I have in a twin, I took the needle mount off the engine backplate and screwed it to the firewall, made for an easier mounting with the needle at an easier to access angle and location than if it was attached to the engine.