Gascolators in Fuel Injection Systems

[frankh]

Thats well overkill..Hmm

But I understand your reluctance to put ONE of them North of the firewall too.

If i did I would probably insulate it.

I understand that the Vans gascolator is rated for the pressure so it can go downstream of the boost pump.

Not sure why it would not work at high pressure..Not that it will ever see any water anyway.

Frank

[lorne green]

Originally Posted by RickWoodall

What i am planning due to regs in Canada and AFP discussions, is one gascolator on each wing root as low as i can, hard plumbed to outside of fues. Then, a flex line from gascolator to fuel line. On a 9 thats not easy but seems to be worth the trouble, i am not sold on mounting it Fwfwd on FI. Would really like to see more pics if other have done it this way, or criticism if this is dumb

Rick, when you get yours done post some pics. I have two Andair gascolators in hand and plan on the same installation.
I remember seeing an 8 somewhere with the wing root install...just can't remember where.

I'm in Italy right now, finishing up two weeks in Tuscany. Really missing my plane....is it OK to call it a plane even though the wings aren't quite on yet?

[airguy]

Silly rabbit - the wing root is where the AFP fuel pumps go!

[lorne green]

Originally Posted by airguy

Silly rabbit - the wing root is where the AFP fuel pumps go!

Pump(S)?

lots o' fuel pressure!

[frankh]

The pressure is the same with one pump running as it is with two..Assuming you follow my design.

Frank

[airguy]

Originally Posted by lorne green

Pump(S)?

lots o' fuel pressure!

Not so much...

Run two pumps (one in each wing) with no engine-driven fuel pump. The pumps run pressurized fuel from their respective wing tank directly to the FI divider, eliminating the risk of vapor lock. Changing tanks is accomplished by shutting off one pump and turning on the other. Both pumps on for takeoff and landing, since they have a return loop and pressure regulator on the output.

I doubt there would be enough room in the ring root for the pump assembly and a gascolator - besides the fact that the gascolator is not necessary on a low-wing aircraft.

[Jeff R]

I have asked this question in the past and I talked to Van's about it and the consensus was to not do it.

The reasons given to me were:

1. Any water that might collect will be blown right through the engine without significant problem.

2. Engine compartment heat will heat up the gascolator and increase the odds of vapor lock.

3. The engine driven pump will have to suck fuel through higher resistance (rather than being forced through it), and this could cause some issues. Don't remember right now what those issues are, though.

4. Another potential source for leaks, and a fuel leak in the engine compartment would not be good.

So, I don't know that having a gascolator is really a bad thing, but it doesn't seem the positives out weight the negative. My main thought for having one was an extra filtration stage, but I guess you really don't need any more than what the main FI filter can provide. At least that was the advice from Van's.

[Ted RV8]

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The question should not be "gascolator for fuel injection systems" but "gascolator for low wing aircraft."

Gascolators are typically used in high wing aircraft because when the aircraft is sitting, if there is water in the tanks, water being heavier than gasoline will flow to the lowest point. In a high wing aircraft the lowest point in the fuel system will be below the tank drains in the fuel lines so just draining the wing tanks will not remove water from the system. A gascolator in high wing aircraft allows the draining of water in the system that is already lower than the wing tank drains.

In a low wing system however, the fuel tanks are at the LOWEST position in the system so any water in the tanks can be removed by the tank drains. A gascolator on the firewall in a low wing aircraft should never have any water in it from the aircraft just sitting. Additional, a gascolator will not stop water that is being force by the pumping action since the flow will not allow it to settle. For this reason a gascolator on a aircraft with the engine higher than the lowest point (fuel plumbing that goes "up-hill") of the tank is useless. As for filtering, you already have the Airflow filter before the electric fuel pump.

For those that have gascolators on RVs--have you ever found any water in them on draining? If so, you have found a new secret to flight, water that can defy gravity.
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William Curtis

William,

You couldn't have said it any better. I had a gascolator on my RV-6 and never saw a drop of water in it. It was carbureted. Tank drains are the lowest point in the system. Gascolator in the system is just another point of potential failure.

Don't understand the Canada regs, but if that's what they are and your in Canada then you would have to use one.

Ted

[andrewbutler]

"Logically, it could work. Also, logically, there are a hundred variables, any one of which could put us in a worse position than we're in now."

I guess that sums up exactly where I am on this one right now! The feedback has been great. Decisions! Decisions! It was much easier when all I had to do for four years was follow the plans!

Andrew.
RV71700
Galway, Ireland.

[rv8ch]

Originally Posted by andrewbutler

I guess that sums up exactly where I am on this one right now! The feedback has been great. Decisions! Decisions! It was much easier when all I had to do for four years was follow the plans!

Almost every time I didn't take Van's advice I have regretted it. If Van's says no need for a Gascolator (and they do sell them, so they could make money selling you one) that's good enough for me.