You folks have most likely answered this before, but since I don't know I'll ask anyway.
Can you mount a 4stroke upside down, so you can enclose it in a cowl? (Like in a Scale Warbird?)
If you can what about the crankcase vent and the valve covers, or is that a non issue?

Yes Sir, lots of them are flying that way, just be a little more careful about setting the low end needle, as in slightly leaner than upright, many guys invert the plane for easier starting.

Just start it inverted and all will be well...

You can Run a short fuel line from the crankcase but it is not necessary.

What are you runnin'/flyin'?

Keep us posted,
james

I am starting a Contender kit and I wanted to put a 4stroke in it and thought it might look better if I could hide the head in the cowl. I just finished putting floats on my trainer for snow and water flying and needed something else to do.

Pattern and scale guys have been running 4-strokes inverted for years. Few people even bother with on board glow igniter's. I even ran my OS .48 Surpass inverted in a small Zlin. They run great just as they would in a model with the engine upright and you were to fly inverted the whole flight. Just be careful you can pull the prop through compression before trying to start it to be sure you haven't hydro-locked the engine with too much fuel.

John

I've read your comments, but am still a little unsure about something. The engine has a vent in the bottom of the crank case to drain excess oil. You are supposed to connect a fuel line to it and drain it through the bottom of your cowl. With the engine inverted, all that oil will be sitting in there sloshing around, and after a while wouldn't that hurt the performance. Does routing the fuel line below the crankcase help somehow? Thanks

Alex

I spoke to the Guru at my LHS and he said 4 strokes do just fine inverted. Apparently, the pressure inside the crank blows the oil out no matter what postition it is in.
By the way the same Guru gave me the idea of gettinga Saito Gloden Knight .72 and mounting it in the correct oreintation with the Gold valve covers exposed. That would look pretty cool.
I know you are thinking this Guru is looking to make money, yep, your right, but he has plenty of information for free and his prices are very competitive. Besides, he is one heck of a nice guy.

Snow, I run a Saito .30 inverted in a small Cub, the vent is on the front top of the engine inverted and it vents fine, also it idles and transitions fine on a Hangar 9 Super plug with no on board glow power.

I run a Saito 91 inverted on my UCD and never seem to have a problem getting it started or keeping it running. I don't use an onboard glow but I did buy a remote glow igniter so I could attach the glow igniter a little easier.

alright thanks for all the good info, with it inverted do you run a fuel tube down to the bottom of the fuselage anyways or is there another way. Thanks for the help so far.

alex