fuel crossover vent revisited

Dave Clark · Post by **Dave Clark** » Thu Dec 12, 2002 9:00 am

Sorry to bring this up again but I'll have the opportunity to remove the ADF antenna mast in the process of everything else I'm doing soon. I have been flying it three years now with just the mast mount on, not the mast itself. I have very seldom seen evidence of fuel leakage on the cabin top. My old '56 180 didn't have the mast on and it didn't leak fuel either.

Could some of you weigh in with your experiences on this with or without the mast?

flyer170 · Post by **flyer170** » Thu Dec 12, 2002 1:41 pm

Dave.... I made a small mast out of wood that sticks up just high enough to get in the air flow of the vent. I think it is only about 4 in high but I will have to measure it.
I put it on not because of fuel leakage but with the idea that it would deflect objects from entering the vent. I don't think that it made any difference in leaking fuel from the vent. I plugged the small holes on the back of the vent tube and I think that cut back on some of the leakage.
I still get a few stains but I think they are from taxing over rough ground with full fuel tanks and once in awhile from turbulance in the air.
Bob

N1478D · Post by **N1478D** » Thu Dec 12, 2002 2:01 pm

I took mine off when I first bought the plane 4 or 5 years ago. The fuel stain only happens some times, but not all that often. The plane flies as if it didn't even know that it has been removed.

CAS · Post by **CAS** » Thu Dec 12, 2002 2:34 pm

On my C170A I have an ADF sense antenna from an insulator mounted about 12" to starboard of the fuel vent to the fin. There is also a "dummy" post about 6" behind the fuel vent.

I get some fuel staining occasionally from the left tank filler but I don't think that has anything to do with the vent. I have never noticed any staining near the vent itself.

David.

zero.one.victor · Post by **zero.one.victor** » Thu Dec 12, 2002 6:55 pm

I have NEVER had any fuel stains/leaks in the area of the vent. Of course,the ragwing is not equipped with the BS vented caps,as required (by AD) for the other models. I would consider getting rid of the vented cap(s) if that is the cause of the leakage problem.

Eric

JDH · Post by **JDH** » Fri Dec 13, 2002 2:47 pm

Dave and others not getting any apparent leaks. Are you using Mogas or Avgas? Reason for my question is that if you were leaking Avgas, you might not notice, cause it doesn't stain or smell much. But if you are using Mogas, it would stain and smell. Once in a while in turbulence, with my tanks real full, it smells like someone spilled gas while refueling a lawn mower (on top of the cabin). I have a mast on mine, not the original and a bit loose fitting (made out of some sort of black plastic). I plugged the hole in the back of the goose neck and I get less, but still some leakage. JD

zero.one.victor · Post by **zero.one.victor** » Fri Dec 13, 2002 6:01 pm

I proudly burn stinky car gas (hokey-pokey!) in my ragwing,probably about 80-85% by volume. No smells,stains,etc that can't be traced to the pilot!
Also forgot to mention,I don't have any mast,antennae,or anything else in the area of the fuel vent.

Eric

Dave Clark · Post by **Dave Clark** » Sat Dec 14, 2002 1:20 pm

Ok thanks for the input. I use both Mogas and avgas and yes the Mogas leaves a lot more residue. I get a little staining behind the vent tube but not much at all. I have the mast bracket but no mast installen. I've decided to pull off the mast bracket while I'm up there patching up some old leaky antenna hole patches.

wa4jr · Post by **wa4jr** » Sun Dec 15, 2002 12:17 am

I run mogas in my '54 170B with no apparent leakage from the fuel vent stand pipe under any conditions. No holes in the back of the neck, and a small patch of window screen secured over the vent entrance to keep FOD out.

zero.one.victor · Post by **zero.one.victor** » Sun Dec 15, 2002 6:17 am

I have a little piece of window screen secured witha ty-wrap over the open end of the fuel vent to keep out the little buggies,too. I have also seen a hinged cover,similar to my pitot cover,used on a fuel vent. I think it was originally intended as a pitot cover for the later model,heated Cessna pitots.

Eric