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100LL question


Roger Lee

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Hi All,

 

The answer is that the lead begins to foul the rings which causes them to start to stick and not move freely. Because they loose some of that close tolerance free movement it allows some oil to pass which burns some oil.

 

Bottom line the longer you use 100LL the sooner your engine and gearbox may have an issue. Try to use 91 Oct. auto fuel and the ethanol is okay.

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  • 3 months later...

At my recent annual we revisited the issue again, and there might be a different angle for the CT. Apparrantly, ethanol tears up the sealant inside our fuel tanks over time. My mechanic had an extreme example, documented on the other forum, where the plane was down for something like 6 months while the factory reps came over and puzzled it out, and the owner sold the plane at a big loss in frustration. He has seen several older CTs with leaking tanks that might be caused by ethanol. His opinion was that we might all be going there at different rates on the left coast, depending how often we fly, as our planes here using auto gas drink more corn juice than you have to back east. I am changing to a 50:50 blend of auto and avgas, even though that will raise my fuel costs. WF

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I have been using the ethanol for 4 years. I did have a tiny pin hole leak in one tank on the bottom of one wing at 1.5 years. It will show up as a small gas stain about a nickel in size and then spread out in fingers. The coating Kreem Weiss is impervious to the ethanol. The only thing that may cause a pin hole leak would be a missed spot during the coating and over time this will seep through the carbon fiber. I pulled my wing and re-coated with the Kreem Weiss. If any of you get a leak it isn't from the ethanol with a Kreem coating, but a poor job during the coating. Pull the wing and re-coat. It isn't that hard, but takes time for the Kreem to dry fully. About a week start to finish this time of year.

 

I would question his interpretation on what has caused any leaks. I remember that case and saw pictures. If I remember right he had all sorts of brown colored build up in the wing. It was something no one including the factory had ever seen before. I would question his "CT's having leaks because of ethanol theory" because if it was an issue we would have heard of other people across the nation with these problems. There has been a couple of leaks, but they have been poor coating issues and not ethanol eating Kreem Weiss. With 325 CT's flying around the country and the majority using 91 Oct with ethanol this would be a big issue if it were a real issue. How would he explain the couple of leaks from the CT's using 100LL? That leaves approx. 1200 + CT's around the world and quite a few with ethanol fuel, the Europeans use some ethanol up to 17%-18% and in Brazil up to 24% and they aren't having any issues.

 

I think your friend or mechanic has misinterpreted leaks caused by chemicals verses mechanical and human failure.

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Hi. I'm quite a newbie to the whole aviation scene, but the above story raises a big question. The senario sounds like a serious manufacturing error. Shouldn't the Flight Design, not you have to deal with it and get it fixed properly? Shouldn't they have to do recalls, the same way we have with cars? THX. (PS Great site, nice way to learn.)

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Howdy CRS123,

 

Just like any MFG for any product you can have a flaw or a bad part. So long as the MFG stands behind their product that should work. There has literally been only a couple of wing leaks and they got fixed. I have never had a problem with FD standing behind their product. They have done a good job with their support and standing behind any manufacturing defect. There is nothing here to recall. When I had my little leak they sent me the extra Kreem Weiss and I re-sloshed the tank. The tanks in a CT are pretty much impervious to any fuels and FD has done a good job to use the proper parts and chemical sealer to make sure we don't have issues. Many people with UltraLights and LSA can't make that claim and chemicals like ethanol will eat their parts. Rotax is another one that has a good system to ensure we can use local fuels.

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Howdy Roger,

 

Thanks. It's good to know they stand by what they make. I didn't know how involved the repair was. A little 'sloshing around the tank' seems nice and simple. I read a story a while back about the pilots who had a plane with diesel twin engines who ended up quite stuck when their company went bankrupt. Very glad to know it's not the case here.

 

Cheers!

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