clguru

My Feedback: (5)

Is it OK to have your UAT tilted toward the rear of the aircraft, if your engine is in the rear?
I noticed the BVM shows it leaning toward the front.
The fuel pump in my plane is going to be behind the UAT, so I was thinking of tilting it rearward to minimize the amount of fuel line that it would take to loop it around. Is there any reason that I should not do this?

Dan

seanreit

My Feedback: (60)

I can think of a lot of reasons not to do this, but the one that comes to the top of the list is the fact that about 3 minutes into your flight you will likely flameout your engine due to loss of fuel in the UAT.

Not to be a smart ass, but the location of your engine and fuel pump have nothing to do with how and what the UAT does. You can tilt it forward almost to 90 degrees flat, but best is simply straight up and down. A few more inches of tubing will mean nothing to your system.

Good Luck,

Sean

mr_matt

My Feedback: (10)

Why does having a UAT tilted to the rear make the turbine flame out?

TREADSTONE.

..Indeed...and some of the other reasons..

seanreit

My Feedback: (60)

In my experiance tilting a header tank backwards creates a draw of air in the uat/header tank by sucking air out of the clunk in the main tank. Unless I'm missing something here, he will suck all the fuel out of the header.

Just came across this a few weeks ago losing engine by the header installed with tubing to the rear.

This is from all the down attitude in a typical flight. I guess if you keep the nose up the whole time you won't flame out.

In other words, if you drew air into the UAT from down attitude and then went to the upline with the header aiming backwards, how many times could you do that before the UAT was empty?

With a 2 ounce Header on a Top Gun Mig a few weeks ago, we found that it was just a few minutes into the flight. I mean if the UAT was installed upside down, it would work for some amount of time.

seanreit

My Feedback: (60)

Now there's two of you? what am I missing here? Sounds like I have something to learn, but my experiances suggest the header will empty.

matten

I installed a UAT on a Bandit (no other way to do it because of space limit) facing backward to the tail of the airplane and tilted 45 deg up, never have a problem.

Regards,
RM

clguru

My Feedback: (5)

I didn't think there would be a problem. If you get air in the UAT, it means that your getting it from the main tanks. If that happens, it will happen no matter what the attitude of the collector tank is. UAT's are supposed to stay full anyway if the rest of your system functions properly, or so I thought.

Dan

TREADSTONE.

.. Dan thats the way i had it figured.... and the reason for having the UAT at 45 degrees or so was to allow the air to collect in the top corner of the tank near the two fill/vent lines so you could easily bleed any trapped air off as and when necessary.

john agnew

Guys

I have used a UAT in both a vertical and 45o position without any problems. For those of us who don't like to throw money away at £50 per model for UAT's I now use a Graupner 6oz hopper tank with an Orbit clunk centralised in the tank on a piece of stiff tubing. The tank comes wirh good quality fittings which fit tygone perfectly. 15 minutes work and you have a reliable hopper , I am currently using three of them, cost about £16 each.I always check the fuel in the hopper on landing and it has always been full with only a small amount of air at the top of the tank. I have run the main tank empty and the hopper down to half full on one occassion when the gear would not come down and I had to fly some hard extra turns to release it.

I mount the tanks both horizontally and at 45o and it doesn't seem to make any difference. The original idea came from David Gladwin who does seem to know a bit about fuel systems and he is not a man to skimp on anything.

John

Bill_Jehle

My Feedback: (1)

Four jets, all with the UAT tilted toward the rear, and never had a flameout because of it.