any specifics on placement or just stick that bad boy on there?

Hi samp615... Well pretty much just stick the bad boy on there and get to
flying You could move some what forward/back to assist in the CG of
your plane and or connections to the engine, based on all the components
being on the plane and the tank mt. to see the best location.. Depending..
It's good also to give the engine some right thrust, some times down
also.. But your models manual should say if its needed and sometimes it's
built into the firewall.. Hope this helps...

depending on the plane.....it usually goes up front






but not always

Okay, the wise guys are through, I hope. When you mount an engine, depending on the plane you are putting it on, follow the instructions. Many airplanes, especially beginner planes need some down and right thrust. I bought a U-can-do ..60 recently, and whatever Tiwanese or Chinese assembled it, had the right and left sides of the fuselage reversed. yeah, you guessed it, the u-can-do, didn't. It flew horribly. It had right thrust, instead of left thrust and would not do a darned thing, I wanted, until I found and corrected the problem. so before you just stick it on there, like I did, look at the specs and QC setup, thrust line, wing straightness and so on, before you stick it together and go fly it. Oh, by the way, try taping your crystals in with some magic tape also. Mine vibrated loose after many flights and the airplane buried itself just off the run way. Control checked fine before takeoff, but the loose crystal secumbed to the 3D violence during the flight. Happy Landings.

Front is good, mid is super cool & rear is funky, but remember that the pointy end goes first.

If you have a plane with a cowl, make sure you get the engine positioned right for the cowl opening in front... If you can adjust the cowl mounting forward and back, then this is probably not a problem, otherwise you need to be sure you can get a prop on there without rubbing on the cowl...

I like to use the engine to set the CG. I do it last. When the plane is done I put it on a CG machine and slide the engine for the CG I want. I just hate lead. Always check the cowl first. Some will slide a bunch and look good. The last one I did was tapered and would only slide back a 1/2".

David

I'm going to put a magnum 91 4 stroke in a Sig Ryan, I'm building. I will have to set back the firewall, is there any min clearance between carb and firewall, I plan to invert the engine, does anybody have any thoughts on this. I read a thread this has been done.


Chris

A guy at our club has his OS .46 AX mounted inverted, and it seems to run OK. He needs a remote glow plug wire for it to start it... his has not made a very good connection, so one guy has to hold it upside down while another starts it!

I don't think I've seen any 4-strokes at our club mounted upside-down, though...

Inverted 4 strokes run just the same as upright mounted 4 strokes, for that matter so do 2 strokes.

Yup, inverted engines run just fine... I have an inverted 2 stroke and inverted 4 stroke.. No problems... There are however two things to keep in mind... Tank placement is important... If your tank is too high above your carb (as it can sometimes be with the engine flipped over) you will get fuel dripping out of the carb with a full tank of fuel and the engine not running.... Second thing to watch out for is it's MUCH easier to fluid-lock the engine when it's inverted... EVERY time you get ready to start the engine (Assuming your using an electric starter) ALWAYS turn it over a few times by hand to make sure it flips okay... Otherwise if fluid builds up in the head it will lock the piston (fluid doesn't compress like air) and with a strong electric starter on it it's not hard to destroy your connecting rod.