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Airport fuel for RV-12 (availability?)
- Thread starter diamond
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Geico266
Well Known Member
The Rotax 912 series can burn 100LL. Cross country trips are not an issue. You can use flight planning services to look for mogas also. AirNav has a feature in it's flight planning section to look for mogas exclusively. If you can find it great, if not, burn 100LL.
About the only issue is oil changes intervals go from 50 hours to 25 hours if you are burning 100LL.
About the only issue is oil changes intervals go from 50 hours to 25 hours if you are burning 100LL.
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Here's a quote from the Rotax website regarding the use of 100LL in their engines
"It is possible but not recommended to use 100LL AVGAS, since the the lead content is like cholesterol to your engine: it will accelerate wear on the valve seats, create deposits in the combustion chamber and sediments in the lubrication system and gearbox. Increased maintenance is necessary to compensate. Unlike "conventional" aircraft engines, lead is absolutely not essential to the proper lubrication and operation of a Rotax 4-stroke aircraft engine. The increased octane rating also has no marked advantage for the operation of your engine."
Are there concerns here? How commonly is 100LL gas used by RV12ers? Are there any engine issues encountered such as mentioned in the Rotax warning I quoted?
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the_other_dougreeves
Well Known Member
The 912s series will run fine with 100LL. Rotax recommends 25 hr oil changes if you use 100% 100LL. Adhere to their schedule.
Having said that, the engine is happier if you use mogas. The difference in the oil and oil filters is amazing - lots of lead accumulating when running on 100LL, nice and clear on mogas. The gearbox will require less frequent rebuilds if you use mogas.
Major downsides to mogas are ethanol and its associated problems, fuel stability and vapor lock. I fly a high wing with the 912S and am not as concerned with vapor lock, although it is a concern.
In reality, I find that I most often have some kind of mogas/100LL mix in the airplane. If I'm flying frequently, I'll use 100% mogas, but if I know the plane is going to sit for a while, I'll fill it with 100LL. By blending, it also keeps the ethanol content below 5% (and let's not get started on the Ethanol debate...)
TODR
Having said that, the engine is happier if you use mogas. The difference in the oil and oil filters is amazing - lots of lead accumulating when running on 100LL, nice and clear on mogas. The gearbox will require less frequent rebuilds if you use mogas.
Major downsides to mogas are ethanol and its associated problems, fuel stability and vapor lock. I fly a high wing with the 912S and am not as concerned with vapor lock, although it is a concern.
In reality, I find that I most often have some kind of mogas/100LL mix in the airplane. If I'm flying frequently, I'll use 100% mogas, but if I know the plane is going to sit for a while, I'll fill it with 100LL. By blending, it also keeps the ethanol content below 5% (and let's not get started on the Ethanol debate...)
TODR
Considering that the first two customer-built RV-12's have only been flying for a couple of weeks, there probably isn't much of a database of information on which to draw....
Considering that the first two customer-built RV-12's have only been flying for a couple of weeks, there probably isn't much of a database of information on which to draw....
I didn't realize that. OK, maybe the better question is how common 100LL is used in the Rotax 912 engine in other planes.
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Check with the guys flying flight Design CTs. It is the most popular SLSA (by a huge margin) and uses the 100hp rotax exclusively.
They have a forum here: http://www.ctflyer.com/
They have a forum here: http://www.ctflyer.com/
steve wyman
Well Known Member
Mark, I just sold my RANS S-7S, after 275, trouble free hours. It used the Rotax 912 ULS engine. I used almost exclusivly 91 octane auto fuel in the engine, except when I went cross country with it. Here in Colorado, ALL auto fuel has 10% ethanol, but I never encountered any problems from the ethanol- in fact, last spring, Rotax officially OKed the use of gasoline with up to 10% ethanol. If you use 100LL, you will have to change your oil more frequently. If you use 100LL, while on a trip, there is no need to drain the tanks of the auto gas or vice versa. I have found that the Mogas that you encounter at some airports is usually a blend, the octane rating of which, is questionable- you would be better off, putting 100LL in the tank. I intend to follow the same regimen, when I get my RV-12 finished. Steve
