Sure it wasn’t a Continental O200?
We have no problems getting ethanol free car fuel – many local filling stations get it from a depot supplied by a ship tanker, and the local depot still hasn’t the equipment to add ethanol. Also applies to islands supplied by ship tanker, as opposed to a road tanker on a ferry.
Lycontisauri can be made to work with normal car fuel (that may contain ethanol). I got home from Yorkshire on the weekend in a mogas fuelled Jodel with a Lycoming O-200 in it.
On the other hand, ethanol containing fuel isn’t ideal for the reasons stated, it’s also a little bit less energy dense. Not such an issue for an O-200 or Rotax powered aircraft which doesn’t have a particularly high fuel burn, but I suspect the fuel flow increase would have to be noticeable with E10 and a big engine.
Ethanol does not matter one bit regarding vapor lock. The refineries blend the cocktail so the vapor lock is according to standard due to environmental issues. It will be the same if it is 0% or 20% ethanol, at least in Europe. Modern cars doesn’t care either way, there are no low pressure areas in a modern car fuel system. For this reason the gasoline you purchase in the summer may be very different than the fuel you purchase in the winter. You need to start a cold soaked engine as well, and this may be difficult using summer fuel, it wont evaporate as easily. Using winter mogas fuel in the summer may be a bad solution if vapor lock is a problem, very bad for aircraft for sure with their antiquated fuel systems.
I wonder about those STC for mogas. Mogas is very far from a constant thing. It varies widely. The main problems has nothing to do with ethanol as such, but vapor lock due to different blends with seasons (regardless of ethanol) and in-tank storage over longer periods of time (due to ethanol). How do you “STC” yourself away from these problems?
Using mogas every now and then, cannot possibly hurt anything IMO, considering the octane rating is OK. But the less the aircraft is used, the better it is to use avgas, regardless of STC or not, or Lycoming vs Rotax for that matter. 100LL and UL91/Hjelmco are much better fuels for a typical GA aircraft than mogas is (IMO at least. Just because you have an STC that makes it legal to use mogas, doesn’t mean mogas is just as good as avgas, it only means that mogas doesn’t hurt. Avgas is a more strictly specc’ed fuel)
I got vapor lock on the Aerostar for the first 10-20 minutes at altitude. Had to run with the boosters on, or else it surged and felt like engine was going to quit. And that was with Avgas – can’t imagine how it would behave with ethanol in it!
There are no technical issues that stops Lycomings from using even 100% ethanol. All complications here are entirely “self made” due to certification. Ethanol safe gaskets, rubber, plastic etc have been “invented” centuries ago.
Ethanol free mogas used to be available everywhere. But since Circle K took over from Statoil, the “98 octane” that was guarantied ethanol free seems to be gone, and all their fuels have 0-5% ethanol (could be 0%, but could also be up to 5%, who knows?). Shell still have ethanol free mogas though, and also Exxon. It’s no problem getting it, but if the local gas station have it, is another question.
According to vintage car owners, the biggest (only?) problem with ethanol (5%) is storage. If must not be stored in the tank of the vehicle during long periods, for instance during the winter. Ethanol will absorb water and it will decompose into acetic acid when also oxygen is available. They recommend filling the tanks fully up with 98 octane for longer periods of storage. I guess the same would be valid for aircraft, only using avgas instead of 98 octane mogas. There are also some special additives, bought at car retail stores, that will prevent this decomposition, but I don’t know any specific products.
There you go, learn something everyday! Here in the US, it’s almost impossible to get the stuff. Some guys have their own tanker systems and buys it from refineries direct, but other than that, really spotty. Ethanol is the devil’s work. Should never have been allowed.
AdamFrisch wrote:
It must be downright impossible to do in Europe
Not quite. Especcially in Germany, Austria and Switzerland every small airfield has MOGAS, which complies to this. The Pedersen STC is extremely popular. This was the reason why Pipistrel insists on having a mogas capable engine on their Panthera (all their others are Mogas capable anyhow) and have actually dumped the original IO390 for the IO540 now. MOGAS capability is a huge selling point in Europe, particularly in the aforementioned countries. From what I remember, also in Italy on the various unlicensed airfields there, a lot of this fuel is used.
VW aircraft can use 5% ethanol. I certainly see the microlight guys with Rotaxen using petrol from the local garage.
Yes, but all retrofit Mogas STC’s for Lyco’s or Conti’s are for fuel without ethanol. Petersen doesn’t approve more than 1% of it for their STC. As fars as I know, only Rotax engines can actually use car gas with 10% ethanol (E10). It is virtually impossible to find ethanol free car gas here in the US, where there is less restrictions. It must be downright impossible to do in Europe. Much easier to find Avgas.
