volks67jl

I was looking at the plans and the tank center line is above the carb. I have the same engine (OS .46fx) and had planned on mounting it upside down. Will this cause problems?

RhyanO

Most times when the tank center line is above the CENTER of the needle of your carburetor, then your engine will be
more prone to flood itself where the tank will want to syphon itself into the engine.
This being known we need to look at the engine you are using, and how it will be mounted... then check the
CENTER of the carburetor with the center of the fuel tank that you will be using. It is important to check this with
the engine and fuel tank you will be using. If your tank is right at center to center location then you are probably okay.
But if your tank is too high say 1/4" or more then you should be concerned. I would try and mount the tank so the
tank centerline is about 1/4" below the center of the needle on your carburetor. Remember to use enough padding around
your tank and make sure that the tank has a nice glove fit you dont want it too tight as this can lead to fuel foaming.

Do you have any pictures of your build so far?

It would be cool to see how you are coming along.

Ryan

volks67jl

Thanks for your quick reply! Here are some pics. I took a pic over the plans so that you can see that the carb in the plans is well under the center line of the tank. Now I may want to mount my engine sideways but I have allready installed the push rod tubes as per the plans. Feel free to check out my build blog at: http://jlewis-ultrasportbuild.blogspot.com/

By the way, I really appreciate the products and support that Great Planes give. I have been pleased with every contact that I have had with them.

RhyanO

Thanks for the pictures.
You might be okay with it setup the way you have it.
GreatPlanes designed the plane the way it is... so I asume that they did what they did for a reason.
I would send them an email and ask them the question about the fuel tank position.

One item that I can recommend for you from looking at your pictures.
I would rout the fuel tubing so it is as straight as possible.
Instead of dropping the fuel tubing down and forward like you have it, I think will lead to pinched fuel tubing causing
all sorts of problems with tuning your engine.
Instead I would rout the fuel tubing up through F-2A then out to the engine.

Ryan

buzzard bait

I'm really surprised that GP would show the tank mounted so far back and so high. I think you are right to be concerned about it.

If you start your engine with the plane upside down in a cradle you won't have any starting troubles, but is that what you want to do? Also, I would expect the engine to go rich when you turn it right side up. Then you lean it out to compensate, and then when you fly inverted the engine goes lean. At least that is what I'd expect.

Please let us know what GP has to say about it.

Yes, a sideways mount would solve the problem, and it's a very nice way to mount an engine -- no flooding.

I agree with above -- you aren't going to kink the tubing like that, right?

Jim

volks67jl

I contacted GP and am awaiting reply. I think that I would rather just mount the engine sideways and not worry about it. Now, how to run the pushrods? (I am using a fixed trike landing gear) I am wondering if I just switch servo positions that would put the throttle on the correct side and then make the rudder servo run in reverse? I have not glued the rear pushrod support in yet so I think I can move the one for the rudder. Everytime I try to figure it out in my head I get confused!! Thanks for the fuel line tip, I will drill a couple of holes and run them through the former.

buzzard bait

Yes, put the throttle servo on the correct side and run the rudder servo appropriately. Jim

carlosponti

My Feedback: (1)

i have a saito in mine and the carb is definitely lower than the tank centerline. occasionally it floods the carb and leaks onto the ground but never floods the engine. this might be because i do not leave the carb open when radio is not on. my saito runs upside down and it runs just fine.

buzzingb

My Feedback: (2)

It looks like you tank is in the wrong plance in comparison to the plans. I have run the tank in the stock location an it did fine but if it is to high you can lower the fuel tank floor.

plasticjoe

My Feedback: (22)

I moved the fuel tank floor down almost to the sheeted area at the very bottom..... I mounted a .46FX also in mine..... I just didn't want it siphoning all my fuel out once I stop it. Mine... it's very close to the carb level and I just padded the heck outa the area with foam to hold it in place. Just finished mine tonight !!

plasticjoe

My Feedback: (22)

this is where I put my tank

volks67jl

I just heard back from GP and they said that the tank placement should be OK. They did suggest that I add a loop or two to stop any flooding problems. I think that I can drill a hole in the former and be sure that the fuel line passed through ABOVE the top of the tank. That plus a loop should stop any problems (I hope).

I am still floundering if I should mount the engine upside down or sideways. Upside down is far cooler looking, although I kinda took away some of its coolness when I decided to make the landing gear fixed trike. This is only my second plane and landing is still not very pretty.

I am also wondering where I should mount my EZ fueler and power switch. If the engine is upside down, I don't want goo blowing on it...but I am used to having the switch on the drivers (left) side......Thoughts?

carlosponti

My Feedback: (1)

i always mount the switch on the side opposite the muffler with no problems. i wouldn't worry too much about which side you mount the ex fueler. mine was on the left near the engine and was above the muffler so nothing got on it. the engine does look cooler upside down and that is how mine is done.

P40 Maniac

My Feedback: (15)

I put my tank at stock location and have my engine inverted which is .46 fx and it runs great and flies great too.

volks67jl

Did you loop the fuel line? I would like to leave a little extra so I can take the tank out again without huge problems if I have to. If you did loop the line, how did you hold it in position?

Thanks!

carlosponti

My Feedback: (1)

i didnt loop the line. i have ran gas engines and on them you do that to keep fuel from siphoning forward. i used velcro straps to loop the line. i would suggest wire ties but i would be afraid of vibration wearing through the line and causing a big mess. in my ultrasport i ran the lines strait through without a loop in the stock location without problems.

Tpilot48

This is off topic but I was wondering if this is a good first kit and what kind of manuvers this plane can do / what it can handle. I put an O.S. 55 AX on my Sky Raider and it ripped the right side of the wing off causing it to crash. Would the same happen with this plane?

Thanks and sorry for being so off topic,
Tpilot48

carlosponti

My Feedback: (1)

this would be a good first kit easy to build and straight forward instructions the 55 ax would be alot of power for this plane but would be alright. you might find that the reason the wing ripped off was either poor construction or weak design. usually 40 sized planes are capable of flying 60 sized engines just the weight usually would be poor for performance. it can do most of the aerobatic maneuvers you would expect. loops rolls spins and snaps. i wouldn't expect it to do harriers elevators or hovers.

jsmeed

I had a .50SX on my US40+ and it was fine so I would think the .55 AX would work. You'll probably want glass the joint between the wings, even though the directions don't call for it.

Unfortunately mine died when I tried my first knife edge at about 30ft. off the ground. Almost caught it but now it's RIP. Purely pilot error, it did a knife edge fine on my friend's shakedown flight.

The plane is/was easy to fly, my first low wing, and seems to be a bit more agile than my US 60 (.60FX), but that could be due to power. I plan on building another.

Anyway, just my $.02.