macrafic

macrafic

Well Known Member
My tanks are complete, but the wings are not yet mounted. I have to do the service bulletin on them yet, but wanted to address vapor return lines at the same time, should that be necessary. I am planning on a fuel-injected engine.

Do ALL fuel-injected engines require a vapor return line? How about, specifically, Aero Sport and Superior? Do they require vapor return lines to both tanks? How does one control the tank to which the vapor/fuel is returned? Finally, what are your suggestions for plumbing the line(s) (route, location in the tank, materials, etc.)?
 
If you go with Airflow Performance FI, then you will need to provision a purge return. It can be as simple as teeing into one of the supply lines. It can be as complicated as using a fancy dual selector valve (i.e. Andair).

With a Lycoming/clone, if you don't use AFP injection, you won't need a purge return.

Then there's the new ECI injection system which I believe does need a full-time return...don't know the details on that.

Bottom line -- it depends on the injection system, not the engine builder or engine mfr.
 
Not sure

I'm probably not providing much help here. I'm at least a year from even ordering an engine, and as such have not done much beyond determining that I would like an IO-360, 180HP, CS prop.

I just finished one tank and will be starting the other soon. As such, I wanted to be sure the plane would handle whatever I could put in there now, or a few years down the road. So, I plumbed the tank for a full return using 1/4" Aluminum tubing run to the second bay. If I need it, great. It's there. If I don't, that's fine too, I can just cap it. The 1/4" Al tubing was left-over vent line tubing, and I got a couple of extra fittings. Weight penalty is minor. Labor wise it's far easier to do now than it would be later.
 
I don't want to hijack the thread, but I have the same/similar question. My tanks are both sealed without a return. I'm planning on Airflow Performance fuel injection. I know it's possible to T the purge line into one of the lines between the fuel valve and the tank, but is it possible to use a double stack andair fuel valve with the lines set up so that the purge valve automatically returns fuel to the opposite tank the fuel selector is set too? This would save having to always select one particular tank to purge.
 
Guy, I don't know the answer to your question, but I believe I see a problem with what you want to do. There would be a tendency for the "return" tank to vent. If you have two full tanks, feed from the right and return to the left, you could see precious fuel vent out the already full left tank.
 
VAPOR LINE SIZE

I will be using ECI F.I. anyone know what size tubing is needed for return line.
 
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