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10% ethanol in 912s

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jpspencer(at)cableone.net
Guest

Posted: Wed Jul 16, 2008 2:52 pm Post subject: 10% ethanol in 912s

Anybody got enough experience with 10% ethanol in  the 912s to know how it tolerates it?

 Thanks Joe

   [quote][b]

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Wed Jul 16, 2008 3:31 pm Post subject: Re: 10% ethanol in 912s

Hi Joe,

This can be a can of worms for a discussion. Kind of like Chevy's and Ford's as far as a personal decision. You might like one, but not usually both.



You will have to make an informed decision and try it.

The 912UL or ULS handles the ethanol just fine. Rotax has in writing up to 5%. The one thing Bing would like to see is alcohol resistant carb floats. There is nothing in the Rotax engine that 10% ethanol will hurt. This was straight out of at least 3 Rotax classes I have taken. I live in a dry climate so humidity and water absorption isn't as big a concern as it is where it is very humid and wet. Just check your fuel for water. You can mix 50/50 with 91 octane and 100LL too if you want to help stabilize some. Some areas around the world use 17%-18% and they don't seem to be falling out of the sky. Just use some common sense as far as high altitude flights and water. It was recommend by Rotax that if above 8K ft. you might consider using 100LL because you might be more prone to have a vapor lock and or if you happen to have a lot of water in your fuel it may want to separate from the fuel in a slug. I worry least about water in the fuel. Many people fly with 10% ethanol. I have seen vapor lock twice now. Both were in my plane. The first time I was doing a dynamic prop balance and running it on the ground with my cowling on and the temps all went pretty high and then I noticed my fuel pressure dropped off and the engine sputtered, but did not quit. I popped the cowling and with in a couple of minutes the temps dropped and the cooler fuel replaced the hotter fuel in the lines and it was running back to normal. The other time was 3 weeks ago. I flew from my field to Nogales, Az. The field is about 1500' higher than mine and the outside air temps was about 95F. I was with another CT aircraft. He was using straight 91 octane. After we ate we were back out in 45 min. Did my run ups and started to roll. Just as I was pulling the nose wheel off the ground at full throttle the fuel pressure warning light popped on and the fuel pressure dropped to 1.5psi.

The engine did not sputter. I aborted the take off and went back to the run up area. I did 3 full throttle run ups and taxis and no problem. By now I had run enough cooler fuel from the wings through the lines to get rid of any vapor or hotter fuel. I took off the second time and all was ok. 

Although vapor lock usually isn't a problem it can be under hot enough conditions and/or combined with a higher elevation. It can be used safely, but just know what to look for or conditions to stay away from.



This is just food for thought and something to use to make an informed decision to which way you want to go.



I have flown a lot with ethanol and this was the first instances I have seen with a vapor lock. Both times it was lack of air flow through the cowling and higher than normal under the cowl temps.



For me personally I would use ethanol before using 100LL. I would also use ethanol free before using ethanol too if I have a choice. I think the 100LL is harder on the engine than ethanol based fuel. 100LL is a more stable fuel. If you have to use 100LL then use some Decalin fuel additive for the lead build up.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

imap8ntr(at)cox.net
Guest

Posted: Wed Jul 16, 2008 5:31 pm Post subject: 10% ethanol in 912s

I have been using the alcohol gas  with no problem in my 912UL.

 ivan

 phoenix az

  

 [quote]   ---

craig(at)craigandjean.com
Guest

Posted: Wed Jul 16, 2008 8:23 pm Post subject: 10% ethanol in 912s

Roger, re: vapor lock - does your plane have a fuel return system?



-- Craig

jpspencer(at)cableone.net
Guest

Posted: Fri Jul 18, 2008 3:45 pm Post subject: 10% ethanol in 912s

Thanks for the comments on ethanol...sounds like it  may be a near non issue so far.

 Thanks again

 Joe

   [quote][b]

lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Sat Jul 19, 2008 6:26 am Post subject: Re: 10% ethanol in 912s

E10 has arrived here in northern NM as well, but due to my altitude, I'm inclined to run either a blend of the E10 and 100LL or 100LL all the time. 



The pure autogas never gave problems with vapor lock, but I don't know how the E10 will fare at 8 to 10,000 feet.... 



LS

_________________
LS
Titan II SS

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Sat Jul 19, 2008 9:35 am Post subject: Re: 10% ethanol in 912s

Hi LS,



The 8k-10k shouldn't be a problem depending on the outside temp and under the cowl temps. If it is not a really hot day and you don't have a lot of heat under the cowling you should be ok. I have flown like many others at those altitudes with ethanol, but I try to keep track of the critical temps that may point to any problem. Engines in general use ethanol in fuel for all types of vehicles at elevations higher than 8k-10k. That said anything could happen under the right circumstances. Many Rotax owners have been forced to run 91 oct. with ethanol. For me personally the ethanol is a lesser evil than 100LL, but this is a personal decision.

If you have to run or just want to run 100LL then I would suggest using Decalin fuel additive for the leading. Decalin is much safer and less harsh than TCP. It can be purchased through Aircraft Spruce.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

rparigor(at)suffolk.lib.n
Guest

Posted: Sat Jul 19, 2008 1:25 pm Post subject: 10% ethanol in 912s

 	  Quote: 	
		   If you have to run or just want to run 100LL then I would suggest using Decalin fuel additive for the leading. Decalin is much safer and less harsh than TCP. It can be purchased through Aircraft Spruce.


	


I am not flying my 914 powered Europa yet, but I did purchase some Decalin

to "get the lead out" from the nice gent who owns the company direct. He

told me the Rotax only needs to use half that of large bore Cont. or Lyc.!

He was supposed to by now be adding a substance to his brew to get out the

yellow deposits of combustion chamber (I forget the exact name of what his

chemical produces when it combines with lead, perhaps lead phosphate??)

but anyway new additive is supposed to help get that out.



Above off topic a bit, what I really wanted to say is he also sells a

tool/kit to measure vapor pressure! It gives you a read out of what

altitude you are safe to! It will take into consideration any mixture of

100LL, Mogas or ethanol and reads on the dial safe, warning, or "look out

below" (Danger).



I don't see it on his website at the moment but worth a call:

http://www.decalinchemicals.com/



I also don't see the decarb get the yellow out anymore but here is the

link, he may just brew this in mix now:

http://www.decalinchemicals.com/DeeCarb.html



In my archives:

Chris Lowery of Decalin sells a fuel volatility tester (as well as other



good fuel handling chemicals), so you can confirm the vapor pressure of



whatever fuel you are using



http://www.decalinchemicals.com/



Some more arcive info to bore you with:

Ron,



        Let me see if I can answer your question more directly.



Decalin RunUp is designed to react with lead and prevent deposits in the 



combustion chamber.  The fact that the lead is now lead phosphate and not 



lead oxide still does not change the fact that the compound exiting the 



combustion chamber contains lead.



Lead oxide is partially conductive and lead phosphate is non conductive,

so 



any deposits that accumulate on the oxygen sensor should be less poisonous

to the sensor.  That is about as far as I can go, I suggest that the

sensor 



is cleaned of any deposits.



Yes, Decalin RunUp does contain the combustion chamber cleanup compound 



(PEA), which I described it in the previous post.  I would still recommend

cleaning the Oxygen sensor on a regular basis.



Hope this answers your question,



Regards,



Chris Lowery



Pres Decalin Chemicals LLC



---

jack.kuehn(at)gmail.com
Guest

Posted: Sun Jul 20, 2008 10:01 am Post subject: 10% ethanol in 912s

I fly all the time with regular auto gas at 8,000 to 10,000 feet, and I never have a problem.  BUT I do have a fuel return to keep things moving, and the fuel lines in in the engine compartment are fire sleeved.  

 

Jack



32S, Stevensville, Montana



On Sat, Jul 19, 2008 at 8:26 AM, lucien <lstavenhagen(at)hotmail.com (lstavenhagen(at)hotmail.com)> wrote:

 	  Quote: 	
		   --> RotaxEngines-List message posted by: "lucien" <lstavenhagen(at)hotmail.com (lstavenhagen(at)hotmail.com)>

 

 E10 has arrived here in northern NM as well, but due to my altitude, I'm inclined to run either a blend of the E10 and 100LL or 100LL all the time.

 

 The pure autogas never gave problems with vapor lock, but I don't know how the E10 will fare at 8 to 10,000 feet....

 

 LS

 

 --------

 LS

 Titan II SS

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=193774#193774

 

 

 

 

 

 

 

 

 

 

 	


 

  [quote][b]

lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Mon Jul 21, 2008 8:42 am Post subject: Re: 10% ethanol in 912s

 	  jack.kuehn(at)gmail.com wrote: 	
		  I fly all the time with regular auto gas at 8,000 to 10,000 feet, and I never have a problem.  BUT I do have a fuel return to keep things moving, and the fuel lines in in the engine compartment are fire sleeved.  

 

Jack



32S, Stevensville, Montana



	




My fuel system is actually pretty simple, just one line coming from the tank, and one after the fuel pump T-ed to each carb. I havn't had vapor lock problems with the pure gas when it's been available, but don't know what the effect of ethanol would be. The plane is a titan tornado so the whole thing is sitting out in the breeze.



The plane sits a lot more this time of year as well (spring/summer is almost always nasty flying weather) so I'm more inclined to keep 100LL in it in these times.



Otherwise, I think I'll just continue to use a blend, hopefully that'll mitigate the bad effects of both ethanol and the lead..... or maybe it'll multiply it, who knows with my luck 



LS

_________________
LS
Titan II SS

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