Avgas vs mogas etc.

[dick seiders]

To those of you already flying help me out here. Haven't done first flight yet, but it's just days away. Am perplexed by the fuel issue for trips of any distance. I likely won't have the time (25Hrs) flown off in time for Oshkosh, but then again I might. The fuel problem with mogas at 87 octane at 99% of airports that have mogas really complicates it. ( see responses to Marty's inquiry). I am thinking maybe I am too anal about it. So if I plan to fly off the 25, and change the full syn to semi syn and fly up and back (1500mi.) using avgas exclusively then change oil again staying with semi syn but using 93 octane is there really a problem? I don't plan to use TCP or any other lead scavenge material.
Thanks for any input.
Dick Seiders

 

[Geico266]

IMHO you are WAY over thinking this issue.

Use 92 octane (premium) when you can.
Use the 87 octane when available and add 25 -30% 100LL.
Use 100LL if that is all that is available.
Enjoy the trip, and relax!

The engine will be fine if you stick with semi-synthetic oil and change every 25 hours until you get back to 92 octane fuel. One or two tanks fulls of 100LL is not going to cause problems with your engine. It is the constant use of 100LL and not changing the oil as prescribed that can cause problems. I've been doing this for 800+ hours and many cross country trips with the 912 /912S. The only issue I have seen is where the previous owner of I 912S I bought burned 100LL constantly. I had to replace the sprag clutch due to lead build up and improper starting and shut down techniques. After the repairs the engine is still in service today after approx. 1,000 hours.

 

[N162RV]

Just had a thought... What about running 87 octane and adding the over the counter octane boosters? I once had a high compression trans-am that would ping with 93 octane but the 104 octane boost you can buy ant any parts store would take care of the problem....

The only side affect was the plugs would have a reddish haze while using the booster....

 

[N1593Y]

Don't assume that an airport has regular unleaded. As ethanol blending spreads because of the unintended consequences of the RFS mandate in EISA 2007, regular unleaded will usually be the first to go because the gasoline distributors can get more of the blenders credit to offset the costs of the ethanol tank and injector(s) they were forced to buy because of the ethanol mandate. Some airports will switch to premium unleaded if it is still ethanol free. We saw that happen at KPUW in Washington.

If you are interested in insuring that there is ethanol free mogas for aviation see www.flyunleaded.com and write your state legislators and ask them to pass legislation to prohibit the blending of ethanol in premium unleaded gasoline in your state.

 

[Geico266]

There are no issues running a 10% blend with ethanol in the 912S that I am aware of. The engine and fuel system in the RV-12 is designed to handle it.

 

[sandpiper]

Rotax has approved the 10%. I have heard they have tested it with 25%. The Rv-12 appears to be good for it. The only issue would be if your 912 is in another airframe. If so, make sure your airframe manufacturer has approved it.

 

[N1593Y]

Just one caveat about buying ethanol blended gasoline. There is no state or federal law that requires testing to assure the blend ratio. If you buy ethanol blended gasoline from a big brand name distributor and the pump says E10, it is likely E10, but if there was a problem at the terminal with the injector, who knows? Fly by night chains, all bets are off. There have been a number of scams discovered where small chains were selling up to E25 when ethanol was more than a $1/gal. cheaper than gasoline. They were only discovered when vehicles broke down.

We have a mandatory E10 law here in the state of Oregon but the Oregon Department of Weights and Measures has no mobile test equipment that can test the ethanol blending level and they don't do it. They test AKI and vapor pressure. Ethanol blending percentages are only tested if a repair facility notifies them that it appears that a car was damaged by a high ethanol blend. Then the DW&M inspector goes out, takes a sample and sends it to the lab. From what they have told me, no state tests ethanol blending levels unless there is a consumer complaint.

So, the point is, if you are going to use E10 in your homebuilt, and I would never do it because of another problem, phase separation, make sure you use a graduated ethanol test kit like the EAA fuel tester and pay attention to the 10% line. E10 should show up about 6-8 because the water test does NOT precipitate all of the ethanol in a sample, it is only close.

 

[N1593Y]

Rotax has approved the 10%. I have heard they have tested it with 25%. The Rv-12 appears to be good for it. The only issue would be if your 912 is in another airframe. If so, make sure your airframe manufacturer has approved it.

Has Van's approved E10 for the sLSA version airframe?