Nelvick

My Feedback: (2)

First sorry for my english that is so bad.

I have a new U-Can-Do 3D 46 with a brand new Saito 72. I do the instalation of the tank by the manual. The engine is inverted acording the manual. The problem is that the tank is more high level than the carburator. What happen is when i fueling the tank the fuel is leak from the carburator with the engine off. When i star the engine the fuel is consumed in 3 minutes in idle. I cant find the way to restrict the fast leak of fuel for the gravity. I dont know if exist something to solve that. I change the fuel filter and nothing. I cant move the tank more down. How can i solve the problem?

Bad_Daddy

You need to install the tank and engine so they are level to each other, or you will constantly have the problem you do. I'm not sure if something like a Perry pump would even give you any help (if they are made any more).

Nelvick

My Feedback: (2)

Well. i dont have more space for move that. if you see the picture of the manual the carburator is more down than the hole of the tank that is in the midle of the engine mount.

The picture show a OS 70. i have a Saito 72 that is just a little bit more down.

expo

My Feedback: (20)

Tu ingles es bueno. Mi espanol es peor!!

I fly a Ucando 60 with a Saito 100. I know what you mean about the high mounted tank--you would have to butcher the plane's bulkheads to lower it. I tried running a 2 stroke on it and it would flood out at idle every time. I don't have any problems with my Saito leaking or idling but when I originally set it up I looped the fuel line through the firewall, up over the engine mount as close to the top of the cowl as I could, then down to the carb. This may have compensated for the high tank. Let me know if it works.

Bueno suerte

FlyingPilgrim

My Feedback: (26)

To stop the fuel from siphoning through your carb while it is not running, make sure the throttle is all the way closed - not just at idle position. If it is still leaking, you can get a pair of medical hemostats to clamp the fuel line shut until ready to fly. The problem you will still have to overcome is tuning the carb with the tank so high. It is going to run rich when upright/level, but lean when inverted or on uplines. I would try to adjust the carb with the plane inverted to avoid it leaning too much when in "normal" attitudes. The best option would be to get a YS, which doesn't care where the tank is.

Nelvick

My Feedback: (2)

What is a YS ??

Flying freak

Engines that use high pressure fuel tanks, VERY STRONG likes lots of nitro (30%) and very $$$$$

http://centralhobbies.com/Engines/ys/ysengines.htm

FlyingPilgrim

My Feedback: (26)

Nelvic, sorry, YS is the brand of engine as Flying Freak explained. They pressurize the intake charge (supercharge), pump the fuel (injection), and regulate the fuel pressure in a very efficient way resulting in much better power with little weight gain, and reasonable expense. In your case, the benefit would be that you can place the fuel tank at any height. Another benefit for precision flyers is they can move the tank back over the Center of Gravity (CG) so the plane has the same balance at take-off with a full tank as it does landing after burning up most of the fuel. If you do a search here on YS, you can learn a ton about them. Since you already have a Saito, I would just see if you can make do with your tank situation with some tuning comprimise. There should be some others here with the same plane/engine combo that can chime in to give you some advise.

Villa

Sometimes my tank is a little higher than recommended and fuel will flood the engine when it is not running and the tank is full. I pinch off the fuel line to the carburator with a small spring clip like sold at STAPLES when the engine is not running. Tabaja bien.

Nelvick

My Feedback: (2)

But. What i can do in the case that the engine is running very very rich? let me explain me. I can adjust the carburator without problem to hold the gas but, my question is. When the plane is flying inverted i can have the risk that run very lean or the engine can cut? or the exoust presure is enough to run well?

jetmech43

My Feedback: (9)

try a perry oscilating pump designed for 4 strokes

jetmech43

My Feedback: (9)

http://www3.towerhobbies.com/cgi-bin...?&I=LXDG61&P=0

Campy

My Feedback: (1)

Unfortunately, MOST plames with an inverted engine require "hogging out" some of the formers (cutting them out ) to lower the tank, then re-enforcing the areas you cut out to keep the strength. You should also check out a different shaped tank - perhaps one that is longer and wider, but not as high may help although, again, some hogging will most likely be required.

If that is not for you, a Cline regulator will solve the problem. I have used the Cline with excellent results, however, I have not tried a Perry pump. The Perry pump is also supposed to work well.

Nelvick

My Feedback: (2)

Guys thanks for the information. I already order the Perry Oscillating Pump. I will wait for the shiping and when i install that i will let you know how works.

Rodney

Another solution (but it requires a fair amount of rework on the cowl etc.) is to remount the engine by turning it 90 degrees on the firewall. This gets the carb up to about the midpoint of the tank.

Nelvick

My Feedback: (2)

Well but my question is. Everybody that have a U-Can-Do have the same problem??

Irtsysop

So pissed, as I was building this I could see the tank was so much higher. The OS 91 just pisses until the tank siphons itself dry. I looped the fuel line but it is still just a siphon.
Thanks for letting me vent!

jaka

Hi!
It's an easy fix!
Set the Engine 90 degrees to the left and use a Uni-flow tank system or betetr yet a Tettra "Bubble less" tank.
third and fourth picture shows how a Uni-flow tank is set up.
Or... just lower the tank (butcher out some of the unnecessary bulkhead material).

Irtsysop

Thanks Jaka,
looks like a left turn it will be. Too bad i already cut up the cowl for the inverted mount. Thanks for the pictures. Ill,try to post as well.
happy flying.

Rudolph Hart

A cline or ironbay regulator will fix all.

jester_s1

Yes, the Cline regulator will be the easiest and most reliable solution to the problem. The Cline regulator is a demand regulator, which means it won't let fuel be pushed through it, but it will let fuel be pulled through it. So no matter how much tank pressure there is, only the intake vacuum on the engine can actually make fuel flow. It will stop the siphon problem, and it will give you a consistent fuel pressure so the engine doesn't go lean in an up line.