Wings Forum

scubarider2 · Joined: 28 Jan 2008 Posts: 286 Location: Cleveland, GA

I wrote the EAA consultant about this issue. Here is the response:

Dennis,

Thank you for the e-mail. Problems have developed with fiberglass fuel tanks and ethanol blended gasoline stored in them. This problem has become more known with the widespread increase in ethanol blended fuels. The boating industry also has many problems with this.

Some resins used to build epoxy fuel tanks are not resistant to ethanol. Because of this, it is possible that resin could leach out of the tank and be carried into the engine and possibly form deposits in the engine. Over time it could degrade the structural integrity of the tank where the tank may start to leak. The type of resin used to build the tank will dictate if it is resistant to ethanol or not. Polyester resins and some epoxies can have problems, usually vinyl ester resins are resistant to ethanol.

Rotax does not approve ethanol blended fuels in the 912. Many people have used these fuels in experimental aircraft and not had any trouble. The best results are obtained when fresh fuel is used. If left sitting idle for extended periods then problems can occur because the ethanol will attract water and water will be collected in the fuel and not separate out. When enough water is attracted it will phase separate out into a slug of water. Typically, this will happen up at higher altitudes and may not be detected on the ground.

Timm Bogenhagen, EAA #379292
Senior Aviation Specialist
EAA-The Spirit of Aviation

Looking at this response, do we know about the resins used in our tanks??? :?:

Johnny C! · Joined: 07 Sep 2006 Posts: 178 Location: Brevard, NC

The tank manufacturer will be able to
supply very specific info on his materials.
We just have to ask.

I find it reasonable that he may have
started with a perfectly good material
standard, say, several years ago, but
with the advent of Ethanol, he may
not have changed with the times.

Troy or someone, needs to get specific
material info for what was used in our tanks...

Good job Dennis.

John Cochran

stede52 · Joined: 06 Sep 2007 Posts: 261 Location: Carnation, WA

Just an FYI, according to the Just Aircraft tank manufacturer, the vinyl ester resin he is currently using is approved by the manufacturer for all ethanol fuels. He is also changing his manufacturing process to insure that the inside skim coating they apply when they glue the tops and bottoms of the tanks together as hard as the outside.

Steve

scubarider2 · Joined: 28 Jan 2008 Posts: 286 Location: Cleveland, GA

Steve, do you know when the manufacturer starting using the ethanol safe resin? One year, two, ten? Was wondering about all those tanks out there 5+ years old.
Dennis

stede52 · Joined: 06 Sep 2007 Posts: 261 Location: Carnation, WA

Dennis, that I don't know, Troy would need to find out from the tank manufacturer.

Steve

Lynng · Joined: 13 Oct 2007 Posts: 52 Location: Gainesville, FL

As I said before it is only a matter of Troy actually giving the owners specific quality control information that would relieve all this conjecture. :?

stede52 · Joined: 06 Sep 2007 Posts: 261 Location: Carnation, WA

Lynn
I agree 100%, I also think Just should be sending out and offical AD on this issue.

Steve

Dave Krall CFII SEL SES · Joined: 14 Mar 2007 Posts: 357 Location: Seattle WA

stede52 wrote: Lynn
I agree 100%, I also think Just should be sending out and offical AD on this issue.

Steve

Regarding ADs, I received an official AD on the tank safety issue 2 days ago via my email, similar to rinsing instructions thusfar given on this forum.