Calidus fiberglass fuel tank

R

Rainman

Junior Member
Joined
Apr 25, 2017
Messages
137
Location
Boerne, TX
Aircraft
Mooney M20K, AutoGyro Calidus
I’ve had my 2013 912 ULS Calidus for a couple of years. It had 100 hours when I bought it, and I’ve put on over 220 more in the two plus years I’ve had it. During my time I’ve mainly used 93 octane gas with 10% ethanol and fuel stabilization. This week I discovered the fuel tank is leaking and delaminating. I’ll get it repaired in the short term, but have ordered new tanks. The two tanks are about $1300 US each. Consider using 100LL if ethanol free high octane fuel is not available to you. Changing your oil twice as often is still easier and cheaper than replacing your tanks. Ray
 
Rainman said:
I’ve had my 2013 912 ULS Calidus for a couple of years. It had 100 hours when I bought it, and I’ve put on over 220 more in the two plus years I’ve had it. During my time I’ve mainly used 93 octane gas with 10% ethanol and fuel stabilization. This week I discovered the fuel tank is leaking and delaminating. I’ll get it repaired in the short term, but have ordered new tanks. The two tanks are about $1300 US each. Consider using 100LL if ethanol free high octane fuel is not available to you. Changing your oil twice as often is still easier and cheaper than replacing your tanks. Ray
Click to expand...


This should have been expected. I became painfully aware of this when we replaced 27 fuel tanks in trikes in 2007. There is no composite resin that I know of that will handle ethanol for long periods of time. Period. I also know if the fuel tank has dissolved resin what it does to a 912 intake manifold and how to clean it out. Its not that hard but definitely needs to be done.

That is the reason we had switched to metal fuel tanks even though composite ones are easier and cheaper. Of course the cheapest ones are cross-linked Polyethylene like in the MTO Sport and they do handle E10 well. They usually last about 10 - 12 years and then become hard and discolor. At that point they should be changed but 10 to 12 years is a long time. So anyone out there with composite tanks, try and stay clear of any Ethanol in the fuel
 
My repair guy fixed the fiberglass tank and applied sealer in the short term. I’ll replace the three year old battery while the tank is out and I have access. When the new tanks arrive from Germany I’ll install them. Lesson learned.
 
AutoGyro USA discovered that they had Calidus tanks on hand and have sent them. Replacing the right tank involves removing the oil tank and plugging the oil lines to prevent the need to “purge” the oil pump of air. I’ll close out this thread once I have it flying again. Ray
 
I wonder what effect the "fuel stabilization" has had on your tank. Why did you feel you needed to add that?
 
You should be be careful using car gas in aircraft. There really is no guarantee of its quality and stability. If you find a good source, stick consistently with that source and on cross country flights just use 100LL
 
I have used (fresh) premium auto fuel in my PPG, trikes, airplanes and gyros, all over the country and never had a problem. The only aircraft I run exclusively on 100LL is my Rans S-10 because it has fiberglass fuel tanks. I also run 100LL without issues in my motorcycle, lawnmower and houseboat since those rarely get used. Ethanol free fuel is still not readily available in central TX.

Eric
 
I think I've asked this in another thread somewhere but don't recall if it was addressed. Is there a liquid product that one could pour into a dry composite tank, roll it around to coat the inside, and it dries to form an inert, rubbery membrane to both protect the tank and to form a puncture-resistant crash bladder if applied thick enough? Does such a product exist or has been tried? Or is this a bad idea?
 
Brian Jackson said:
I think I've asked this in another thread somewhere but don't recall if it was addressed. Is there a liquid product that one could pour into a dry composite tank, roll it around to coat the inside, and it dries to form an inert, rubbery membrane to both protect the tank and to form a puncture-resistant crash bladder if applied thick enough? Does such a product exist or has been tried? Or is this a bad idea?
Click to expand...

It does apparently exist... I just found this in the internet...

Clear Ethanol Proof Fuel Tank Sealer Kit for tanks up to 15 Litres: Amazon.co.uk: Car & Motorbike

Buy Clear Ethanol Proof Fuel Tank Sealer Kit for tanks up to 15 Litres at Amazon UK. Free delivery on eligible orders.
www.amazon.co.uk
 
Eric S said:
I have used (fresh) premium auto fuel in my PPG, trikes, airplanes and gyros, all over the country and never had a problem. The only aircraft I run exclusively on 100LL is my Rans S-10 because it has fiberglass fuel tanks. I also run 100LL without issues in my motorcycle, lawnmower and houseboat since those rarely get used. Ethanol free fuel is still not readily available in central TX.

Eric
Click to expand...

True. I have also. I check it carefully and have not had problems but recently one of our customers had an engine out and went down causing extensive damage to his gyro. The gyro had to be heli lifted out. When the engine was checked it had carb bowls full of water. Gas was cloudy in the tank. It seemed to have phase separated. The fuel system was cleaned and fresh gas put in and the engine ran fine. Customer says he sampled the fuel in pre-flight as well. Ethanol fuel does increase the chances of vapor lock for sure
 
Last edited:
XXavier said:
It does apparently exist... I just found this in the internet...

Clear Ethanol Proof Fuel Tank Sealer Kit for tanks up to 15 Litres: Amazon.co.uk: Car & Motorbike

Buy Clear Ethanol Proof Fuel Tank Sealer Kit for tanks up to 15 Litres at Amazon UK. Free delivery on eligible orders.
www.amazon.co.uk
Click to expand...

Just be careful. I did not use this particular one (it seems to be not available in the US) but I tried various other brands and none of them really worked and many started peeling off with Ethanol fuel causing blockage. You can't pull over in an aircraft. Best practice is still to just use non-ethanol fuel with composite tanks or just use Avgas 100LL and do oil changes every 30 hours and use TCP in the gas
 
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The tanks have been replaced with new ones from AutoGyro and the oil system tested to be sure air was not allowed in the lines/pump. I added some 100LL and it started up after adding some throttle on the third attempt. Thanks for the advice, I always learn more about gyros when I consult you guys with so much more experience. Ray
 
Great. I would advise that you find a gas station with non-ethanol fuel and mostly use that. Sometimes it’s hard to find 91 or 93 octane gas in non ethanol. To compensate you could put in 10% 100LL. With this if you do oil changes every 50 hours and spark plug changes every 100 hours, it should serve you well
 
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