Hi

Got an ultra sport 40 plus with inverted engine which always gives tuning and starting problems due to hydraulic locks. Sick and Tired and am looking forward to mount it sideways (definitely will).

Please suggest if there would be a change in thrust angle and how to overcome it

Thanks

Hey, shouldn't be any change in thrust angle. It's on the same axis so everything should be the same.

thanks

i also thought the same but needed it from somebody who was sure

Thanks for the help

Siddarth Grewal

I'm running a magnum 70 four stroke in mine. Instead of mounting the engine sideways which would require you to add some weight to the opposite wing. Move the fuel tank. I mounted a Great Planes 10 ounce tank directly behind the firewall all the way down on the bottom of the fuselage. Have never had a deadstick in about 50 flights. Never floods out either. The kit instructions have you installing the tank above the wing. just move it to the very bottom of the fuselage. Looks better that ways anyways.

Dennis

yup sounds like your tank is way to high

Something that is easily overlooked is your fuel. [X(]

As the glow plug is being constantly hit with fuel when inverted, it is very possible to have the "FIRE PUT OUT" by the fuel. [:'(]

Try a higher nitro content and see if it makes a difference (~10-15%)

thanks bbbair but the thing is that i dont use nitro its freakingly expensive this part of the world.

My experience with inverted 4-strokes has been mixed. On my Eindecker, the OS91 will run inverted all day long just fine. On my Bristol M1, the OS 52 ran very poorly inverted and it made no difference what location or height I had the fuel tank at. Both ran the same fuel, 15% nitro. I ended up running the OS52 top side up but had to cut a hole in the cowl.

Hyrdraulic locks come from fuel getting into the motor when it's not running.
The tank is probably too high.. lower it to where the top of the tank is level with the fuel inlet at the carburetor.

Well I'm not sure how this happens, but I have an OS53FS mounted inverted in a Cub, and it ran happily for months....until last week. It has me thinking that there must be another reason. It quit twice in flight.

I also flew a World Models Sports 40 for the first time last week with an inverted OS52FS, and it doesn't seem to run very well at all. It didn't quit, but just didn't put out the power it should have.

I'm willing to look at the fuel tank possibility, but can there be anything else?

I agree about the tank being high. I have a Balsa USA Pheaton !! in which I have an inverted O.S. 46 AX. Never have any trouble unless the engine gets flooded somehow, but not from the normal running/starting of the plane. I have the tank mounted so the top of the tank is about 3/16" above the c/l of the carb fuel inlet.

Jackster

Well, this could be a PART of the problem. There are a number of engines that are designed to run without Nitro - such as the Webras and any engine that is designed as a FAI engine. (long story on that)

Have a look at the instructions for your engine, they will tell you what type of fuel to use.

IF a high nitro content is REQUIRED you could have ongoing problems with getting your engines to run smoothly.

Mounting them inverted will just compound the problem... when in doubt start at the basics, fuel, glow plugs, tuning - then things get simple.