Better Ground It !!

[Steve McGowan]

After a few hick-ups in flight and a shut down on take-off,, this was found to be the problem....

IF you have a Sparrow Hawk II or III I'd suggest that you ground it until you check your gas tanks.. The inner sealant that was installed at GBA is peeling off..



Steve

[barnstorm2]

A couple of friends at my airport had this same problem with factory kit-fox gas tanks.

.

[jw wright]

I had that same problem with my Sparrowhawk II. Took lots of extra time and money to get it to seal. I found mine before I closed it up, and it was so noticable it's hard to believe that someone at the factory didn't notice the problem.

[scottessex]

Was that caused by E10 auto gas?
or is it just bad sealant?

[Chuck Roberg]

That raises a good question about 10% ethanol in auto fuel. Around the Chicago area it's virtually impossible to get 100% mogas because of the epa rules.

Have the Sparrow Hawk tanks been tested with ethanol in the fuel? Has anyone else with a Sparrow Hawk used fuel with ethanol in it successfully?

[Russ Hobbs]

Any idea's as to what sealant might work best, I'd like to coat the inside of the tank to make it bullet proof? I have the original SP-1 kit.

Russ

[striker211]

Yes I've got a SparrowHawk 1 that I used Pro Seal with AND ethanol mobile gas now. I've got 80 hours on it. I replaced both leaky vent drains (actually replaced the o rings for the CAV 160 fittings) and noticed tiny bits of black rubber and dirty fuel during the intitial sampling. I presumed that to be residual rubber from the initial installation. Once I let it drain for a couple of seconds while replacing the valves the fuel is now very clear. So I've had no problems with that. I did find the Pro Seal to be tough to work with and a bit messy. I didn't use enough the first time I sealed the lids trying to be neat, and had fumes. The second time, I used much more with better results.

[GyroRon]

Can you Sparrowhawkers not replace the fiberglass tanks with plastic or aluminum of some sort?

[jw wright]

The problem existed in my tank before any fuel was introduced. Looked liked very poor quality control. Took lots of pro-seal to stop the leaks.

[Greg Lockhart]

Steve, do you know if this type of tank or sealant was used on the early SparrowHawks (prior to II and III)? I have one of the first models and I don't think mine has anything in the tanks that looks like that.
Thanks
Greg Lockhart

[Steve McGowan]

You and I have SH I kits, ( NOT the RAF Mods which were the original conception) the Tanks are independant of each other and then glued into the cabin.. Cabin is held up with L-brackets between the tanks onto the keel as well as a pillar atop the cyclic and keel area between the tanks. Our Tanks,, yours and mine was sealed before they were installed and built with materials not soluble the gasoline "At That Time"

SH II and III tanks are built into the cabin and also bridges the cabin on the keel supporting the weight of the pilot and co-pilot.. The seat /tanks are approx 2 inches wider and deeper in the II and III.

I have had very little problems with my tanks, However I have had a mountain of problems with the II and III to get them sealed.. That I have built.

Pro seal is the only thing that I have found to stop the problem..... That being said.. The pics that I have posted is of the SH II owned by Steve Boyle near Tampa.. I believe the PREP of the tanks were done very poorly and NOT on the internal tops of them.. The bottoms seem to be ok but I doubt will stay that way..

Ron the tanks are molded into the cabin area,, it would be nice to think that a metal/alum tank could be made to go into that area, and it probably can be repaired with Lottsa MONEY and time..

The boating industry is having the same problem,, luxury power boats are having to be re-fitted with metal tanks because the fiberglass will not hold up to the Ethanol being added to the auto gas..

It's a shame that this could have possibly been avoided "IF" it's due to poor preparation or workmanship,, it did cause an engine out on take-off, and could have caused a crash or possibly much worse,, but that also was avoided..

Thankfully we were ahead of it, This time..

Steve

[StanFoster]

Steve- Werent their screens on the ends of the fuel pickup hoses shown inside the tanks? Mine had them.


Stan

[Steve McGowan]

Yes there were screens on them Stan,,
But I have not seem them on the II Or III's

I doubt it would have avoided the engine out on takeoff even with the screens ,,,,,with that much debree in the tanks..

[StanFoster]

Steve- Those tanks were really a mess inside! Amazing!

Stan

[Timchick]

A friend of mine has an ultralight with a fiberglass tank and he's getting a lot of junk clogging up his fuel filter. He thinks it's due to the ethanol. He's flown for years without any problems with that fiberglass tank but has only recently begun to use ethanol.

[utahgyrocop]

This is making me think about my tank arrangement as hopefully soon I will get back on my build.

If I can find a good fabricator, I might have somebody fab me an aluminum tanks and replace the fiberglass ones. Just for the peace of mind. Especially as ethanol becomes more and more prevelant.

Stay safe.

[PW_Plack]

I wonder if a fuel bladder (http://www.atlinc.com/download.php?file=pdfs/NewsReleases/AmeriQuest_NewsRelease.pdf) in the existing tank would be feasible. I have no idea what the cost would be to have one made to size, but if this will be a problem for dozens of ships, perhaps a quantity order could help cover the fixed costs?

[Jim Edwards]

A friend of mine has an ultralight with a fiberglass tank and he's getting a lot of junk clogging up his fuel filter. He thinks it's due to the ethanol. He's flown for years without any problems with that fiberglass tank but has only recently begun to use ethanol.

While doing an annual on my FW Rans S12 Airail we found some cracking of the fiberglass tanks. The factory said they found that the additives the gas companies have been using since the late '90s is what causes the problems. They suggested replacing the tanks with their $600 poly tanks. So, this seems to be pre-ethanol.

[Master Roda]

http://www.flamemaster.com/sealants.html

Maybe?

[pilotescort]

The boating industry is having the same problem,,
It's a shame that this could have possibly been avoided "IF" it's due to poor preparation or workmanship,, it did cause an engine out on take-off, and could have caused a crash or possibly much worse,, but that also was avoided..Thankfully we were ahead of it, This time..

The dirt bikers are also having problems, so check your tank Ron on that new hobby of yours. I just hope someone doesn't have to get killed before there's a SH class action lawsuit

[Steve McGowan]

U stay outta the Phosfate mines... dem gators are too big for ya Brooky

[RotoPlane]

We designed and used fiberglass tanks that held all sorts of ag chemicals and also used some with gasoline....never once had a problem with those tanks. Those tanks were all coated on the inside with a layer of vinyl-ester. Nothing gets through that stuff.....and I'm pretty sure alcohol won't either.

[snowbird1]

I built 5 of these sparrowhawks, and only used ProSeal...
its expensive and really messy but gas proof. Any silicone
will simply fall apart. Properly built fiberglass gas tanks should last
a lifetime as long as the right products are used. Don't go down to
your local autoparts store and buy any silicone, go thru aircraft
spruce. Your really luck those pieces in your tank didn't clog up
around the fuel pickup and cause the engine to starve from fuel.
Oh and its a known problem with the engine stumbling/shutting
down when using the radio with the sparrowhawks. We always properly grounded the antenna/engine computer but rarely had any problems.
We also kept the antenna wire from the radio separate from the
engine/electrical harness.

[automan1223]

I am surprised at this but not really, GBA should have known the only fiberglass / resin mix should have been EPOXY ! not Polyester or vinyl ester, or anything else. The fuel situation has been going on for 10 years now that I know of in the marine industry. It is a combo of things only 1 part of it being alcohol in the fuels. The rest is the you want cheap you got cheap crowd.

Even with prep work those trick sealants always have the chance to pinhole and let fuel walk up the tank wall. Considering the whole structure could be disolved by leaking fuel things could get interesting fast.

Silicone will not hold up against fuel immersion meaning you cannot have it in constant contact with fuel. There are other very serious sealants that I have used to seal poly fuel tanks but I have not used the stuff internally exclusively. I do not want to mention what I use here because I am not 100 % sure it is the right solution for this problem. It appears a better solution is needed .

J