Kent Misegades blog on aviation fuel report

[jrenwick]

Our own Kent Misegades has something important to say about the FAA's recent report about fuel use by piston-engine aircraft: http://www.generalaviationnews.com/2011 ... ly-flawed/

[minton]

I think a club responce to the FAA is in order!!

[blueldr]

I've burned mogas in my airplanes since I was up in Alaska back in 1947, and I've never has even one sneeze from using it. Back in those days, shortly after the end of WWII, there were a lot of ex military pilots running "Non Skid" (Non Schedueled) air services flying C-47s and C-46s and even some C-54s. A whole s--t pot full of them carried one tank of av gas for take off and landing and the rest filled with mogas for cruise. Often the fuel trucks serviced the airplanes after dark to keep from being too conspicuous. There later was an STC for mogas in some of those engines.
I have always asked the nay sayers how much actual PERSONAL bad experience they had with mogas and it always boils down to none, but they heard about it.
Actually, when I was in Alaska and it was still a territory, 80 oct. av gas was $.32/gal. and civilian mogas was $.50/gal. due to the road tax. However, I was working for my uncle and his company had all kinds of mogas laying around and what I managed to run through my old Lycoming O-435 on my Stinson L-5G was probably less than the daily spillage in the motor pool. One Herman Nelson heater burned a lot more gas than my airplane did.

Damn, but those were the good old days! I was a Master Sergeant and still only in my twenties.

[GAHorn]

I've burned mogas in my airplanes since I was up in Alaska back in 1947, and I've never has even one sneeze from using it. Back in those days, shortly after the end of WWII, ...There later was an STC for mogas in some of those engines.
I have always asked the nay sayers how much actual PERSONAL bad experience they had with mogas and it always boils down to none, but they heard about it.....

Dick, you know that I love you. But you've GOT to quit telling people this story unless you emphasize that the mogas you had was 20th-Century mogas (which contained tetraethyl lead, by the way)....not 21st-Century ethanol-laced concoctions.

Let me break your mantra about those who say they've only HEARD about it: I used mogas almost exclusively in my Aeronca Chief and never had a single engine problem from that practice. I probably saved a lot of money over the price of avgas. That was in the mid-1980's and the mogas I used did NOT CONTAIN ETHANOL and and it met ALL the specifications in the EAA STC for that airplane....even though I (horrors) did not actually own that STC. Things worked out just fine until one day the fuel line and brass Imperial fuel valve (almost identical to those in ragwing and A-model 170's) was damaged by that fuel ...and 16 gallons of it ran into the belly and aft along the inside of the fabric until it found seaplane grommets and dripped out onto the ground, soaking it and the ground beneath two airplanes tied down next to mine, this being discovered by the owners while they preflighted their airplanes. The College Station fire department was very kind and told me they'd not invoice me for their callout for the cleanup....THIS time, and how fortunate I was that no one created a spark before they arrived on-scene.
(In those days I was blithely ignorant of and lax in my responsibilities to others and stupidly did not carry liability insurance. I was fortunate that my activities did not cause those other two airplanes to burn up.)
The SAME type of rubber was used on the Aeroquip hoses back then as up until recently, and most Cessna 170s still have those old unreformulated rubber hoses and gaskets and seals and DEFINITELY still have the same fuel valve and fuel line materials. They do NOT handle ethanol and modern fuels as well as they handle avgas.
On TOP of all that, if mogas is used...it should be carefully selected and determined to be CLEAN, and FRESH! With NO ETHANOL!

So...if you or anyone else can still find some 1940s-1980s 20th-Century mogas that's STILL CLEAN AND FRESH.... you're probably OK to use it in Cessna 170 aircraft....as long as people still enjoy rebuilding fuel valves.

Otherwise, when recommending people to use mogas in certificated airplanes please also mention all the requirements of STCs, fuel specifications, cleanliness and freshness and warn them about the short storage life and increased maintenance expenses which are virtually assured.

I sincerely hope that aviation grade unleaded fuels are available soon...but until then.... beware auto gas.

[blueldr]

George,
Your problem with the mogas and the (metal ?) fuel lines and metal fuel valve are puzzling. What took place? surely the metal was nor damaged by the petroleum fuel, was it? I have no idea at all what kind of special metal has been used in the fuel lines and valves of the airplanes that i've been involved with.
As matter of fact, I've used mogas containing lead, MTBE, and ethanol up to 5%, in three C-170Bs that I've owned, including the one using the Cont. IO-360 fuel injected engine, and I've still never had a problem.

[GAHorn]

Dick, as far as I know Aeroquip never made metal fuel lines. I was speaking of the rubber fuel lines such as those which connect gascolators to carburetors.

However... I will explain to you why modern concoctions of mogas is not nice to metal fuel system components.

The metal fuel lines and components in Cessna 170s are made of aluminum and steel, and carbs are made of steel and iron. Late style fuel valves are made of aluminum, steel, and are lubricated with special grease which is resistant to petroleum...but is not resistant to alcohol. Ethanol and ethanol-laced mogas is corrosive to aluminum and steel. It also damages rubber O-rings, seals, gaskets and other parts of carburetors and fuel valves. (Fuel valves have seals, gaskets, and packings made of materials which are attacked by ethanol and most other alcohols.) Ethanol washes lubricants off of fuel valves which can then gall and seize. The early (ragwing and A-model) valves are made of unobtainium, which looks like brass and the cost of replacing that type of valve with a later valve is roughly the same as raising a toddler thru post-graduate school.

Check the prices of carburetors and carburetor overhauls if the price of engine stoppage in-flight does not concern you, and see if you still want to run ethanol-laced mogas in your airplane.

If you still want to do that...then disregard everything I've said. And do the rest of us a favor: keep your insurance policy paid up and log the fuel used in your machine so we can determine which airplanes we're interested in buying and which we're not.

Now I know you and I know how your experience and knowlege can benefit those who would listen to most of what you have to offer. But this mogas thing is not one of your strongpoints because your experiences with it are outdated and obsolete. And there's no way that can be circumvented without the risks mentioned. Even FAA Administrator Randy Babbit knows the effects of alcohol and he does not condone it for airplane use.

[blueldr]

Kind of makes me wonder what in hell they put in automobiles and race cars to preclude their getting eaten up by the alcohol. And in my Italian motor scooter too.

[GAHorn]

Kind of makes me wonder what in hell they put in automobiles and race cars to preclude their getting eaten up by the alcohol. And in my Italian motor scooter too.

Your Vespa (and auto) doesn't change altitudes and temperatures like airplanes do, nor does it allow as much moist air to enter it's small tank and then become chilled, and they use different stuff to construct auto and scooter fuel systems than they did 60 years ago, stuff like stainless fuel lines and alcohol resistant rubber hoses and gaskets. Nor does your typical auto sit around for weeks between operations. An aviation-level of reliability isn't required of your Vespa, and it's fuel system components are neither as expensive nore as difficult to resource as airplanes are either.

But you knew that and are just being grumpy about what you know to be true.