I was just wondering about how the Evolution .46 I just put in a VQ P-51 will run inverted? It is slightly (2-3mm) lower then the tank, should I be concerned with this as well. I have run the motor alot before this. (100 flights) What can I expect, any major draw backs?


Thanks Shane

I'm pretty sure you did'nt mean lower than the tank itself. You probably meant that it's lower than the fuel draw. If that is correct, 2-3mm will be no problem at all.

I don't know that airplane, but if it's possible, run a long fuel line above the level of the top of the tank to avoid any siphon. It should not be a problem as 2-3mm is not enough fall to create a very powerful draw. BUT, a break in the siphon would help if you are going to leave it fueled for a while before you start it.

Most glow engines run VERY well inverted. In fact, all of my glow engines, except one, (and one of my gas engines), are inverted and I have had no issues at all. The only thing I hate about it is connecting the igniter...and I LOATH remote glow because they break too easily and generally suck.

It will run FINE. Mount it and go fly....

HAVE FUN!!!

I took my Evolution .46 off my trainer and put it on my Tower Hobbies Voyager which is set up for a inverted engine and it seem to do alright, no loading up etc but I never did fly it just taxi around the yard to see what it would do. Carb inlet was around 1" lower than that of the tank this was using a quick fueler hook in. Some engine will run inverted and some have problems only way to know is to try it and see.

The motor does not know it's inverted.

I will try that with the extra fuel line above the tank level. This model has considerable room up front, the engine is completely enclosed with room to spare. Am actually going to be putting the YS.63FZ S in it but wanted to test the structure before hand.

On further inspection I realized that I am indeed lower than the draw line. Almost 1" lower, hopefully this will work so I can get it maidened this weekend.

Thanks guys, Shane

If the fuel tank is above the level of the needle valve then most 2 strokes will load up while flying and die when the glow plug gets doused out. 4 strokes are a different design and aren't really position sensitive. Side ways mounting even at a downward angle would probably be ok as is the case in the Great Planes Stuka but lower than that will give you problems. imo. [8D]

I had problems with a Evolution 1.00NX inverted but no problems with the .46 inverted.

In the former case I found the problem to be more with the limiters, that do not usually permit you to adjust the engine properly.

Once you have the engine dialed in correctly, the engine runs just fine inverted, in both cases.

Right on.. [sm=thumbs_up.gif] I thought it would be ok just wanted to be sure.

In the case of my tank/carb position, would a pump or check valve fix this? I can move the motor, i just don't want another set of holes in the firewall,, lol We'll see if the weather holds out...

Thanks, Shane

Your putting in a YS, however you are going to "test" the plane with another motor? Why would you do that and change 100% of everything about the plane after it is flying?

On one of my ARF planes (I forget which one...)... the carb would be a bit under the tank ports in a normal mounting arrangement.

So the instructions tell you to effectively mount the tank inverted. That is with the stopper on the lower part of the tank instead of towards the top.

That is how this manufacturer suggested getting the levels correct.

I've tried a check valve, and have had bad luck with them thus far as they sometimes mask getting the engine tuned up properly.

Unless you have a real siphoning problem, once you get the .46 tuned up, you'll not need the pump at all.


I wonder how much the tank/carb relationship is overstated though?

I've run my engines on test stands and have moved the tank into all sorts of high and low positions and have not encountered any big problems as long as the line lengths are reasonable. This with the engine/stand turned to many different positions as well.

Of course that was on a stand...

These planes have had 1 or 2 instances where there was wing failure, the .46 will be more than enough to stress the wings for my type of flying. I am familiar with 40 size P-51's and will know what to expect without overdoing it. My motor is set where the YS will sit, thus the reason for it being low. Doesn't matter where the YS motor is mounted in relation to the tank. Also, I would rather loose the .46 if there was a problem.

Tank only goes one way as the wing dowl sets on top as a kind of brace. Thats a whole other set of mods.

Now if I could only find a retract servo I will be set, "everybody is out"..

Later Shane