Warbird Information Exchange

When I was at the Dayton air show about 8 years ago I talked to a B-25 operator on the static ramp and he started talking about how the FAA was trying to ban their fuel which would ground the planes. I was a little guy at the time and (obviously) not a pilot but now I realize that he was talking about 100LL and the EPA's continual attempts to outlaw 100LL.

So my question to all you experts is...what effect, if any, will there be on the warbird fleet if 100LL is outlawed and a drop-in replacement is found? I assume Merlins and Wrights can't operate on mogas, ethanol, or <100LL fuel. What about the proposed replacements...do they work in old engines?

I haven't heard anything about this, so at the moment I'm assuming that there are no issues...

Drop-in replacement means it will function exactly as 100LL does now.
So no issue if it is indeed a drop-in.

However from what I hear a proposed "drop-in replacement" has a number of issues so it is debatable.


The future of AvGas is very uncertain.
While a majority of piston aircraft today can run on on MoGas, it is not widely accepted for a few reasons. And yes, you are right, most warbird engines cannot use lower octane then 100.

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Do-17z fact and history site, setting it straight.
There is something deeply wrong with a society more offended by breasts than by entrails.

Remember that 100 octane gas was a relatively recent development when the war started, and most of these engines operated on 80-ish octane fuel originally, at least in the beginning. I think probably most of the engines will be able to continue operating on the new fuel, just not at their normal, wartime power outputs. Where that would likely have the biggest impact is with the twin engine aircraft that when operating with an engine out won't be able to pull the power necessary to give them acceptable single engine performance.

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Defending Stearmans on WIX since Jeff started badmouthing them back in 2005.

The surprise news back in December was that Shell announced that it has perfected a 100LL equivalent unleaded avgas that is 100 octane. We knew of the efforts by Swift fuels and a few other small companies, but the fact that a major oil company was working on it low key for the past 10 years was a surprise. They have submitted it to the FAA for approval. IIRC Swift is also still actively working on it.

Shell unveils lead-free avgas

December 3, 2013 by General Aviation News Staff 9 Comments

Shell revealed today that it has developed a lead-free replacement for 100LL. The lead-free formulation, which comes after 10 years of “exhaustive R&D, as well as successful initial testing” by two OEMs, will now begin a strict regulatory approvals process, according to company officials.

“We are proud of this first for Shell Aviation,” said Xinsheng (Sheng) Zhang, vice president of Shell Aviation. “This advanced product is the latest milestone in our long history of innovation. We believe that with industry support, a stringent approvals process can be completed for this new lead-free product within a short time-frame. We look forward to working alongside our technical partners and authorities to progress the necessary approvals needed to make this product a reality for use in light aircraft engines of all types.”

Avgas currently includes lead in its formulation to meet fuel specifications and boost combustion performance (known as Motor Octane rating). Shell officials say the company has developed an unleaded avgas that meets all key avgas properties and that has a Motor Octane rating of over 100, an industry standard.
“The development of a technically and commercially-viable unleaded avgas that meets these criteria has been seen by the aviation industry as a significant challenge, due to the tight specifications and strict flight safety standards that it has to adhere to,” company officials said in a prepared release.

Shell To get to this stage, Shell Aviation scientists carried out an intensive internal laboratory program, including in-house altitude rig and engine testing. Working alliances were then formed with aviation engine manufacturer Lycoming Engines and the Piper Aircraft. As a result, the formulation was successfully evaluated in industry laboratory engine (bench) tests by Lycoming and in a flight test by Piper.

“Lycoming Engines commends Shell on launching its unleaded avgas initiative,” states Michael Kraft, senior vice president and general manager of Lycoming Engines. “They engaged Lycoming to test their fuel on our highest octane demand engine and we can confirm that it’s remarkably close to avgas 100LL from a performance perspective. This initiative is a major step in the right direction for general aviation.”

“Piper Aircraft is pleased to participate with Shell and Lycoming in this feasibility flight test program,” said Piper Vice President of Engineering Jack Mill. “Recently, we successfully flew an experimental non-production Piper Saratoga with Shell’s new formulation for about an hour. We appreciate the opportunity to work with Shell and Lycoming in this preliminary investigation of the technologies, which could in several years lead to flying unleaded fuel in our production airplanes.”

Shell officials said the company will now work with the aviation industry, regulators and authorities, including the FAA, American Society for Testing and Materials (ASTM) and European Aviation Safety Agency (EASA), to achieve approvals for the unleaded avgas. Shell expects to also work with other OEMs to continue the testing and refinement program as the approvals process progresses.

PW 1830 -92 was rated for 91 octane, 93 octane leaded gas could be used in a pinch,operators in the PI ran their 3's on this fuel on a regular basis.

I had the pleasure of talking to one of the principal engineers involved with the development of this fuel. He was very positive about the prospects that this fuel has shown in testing so far. He was 100 % confident that this fuel is the answer.

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Expert:
Ex: Former.
Spurt: A drip under pressure.

There was an article in the AOPA mag a while back about a replacement fuel which was in testing. Cost to manufacture it was about par with MOGAS, less than AVGAS. The magic question is, how much a gallon? It would be nice (and helpful for GA) if we had a little cheaper alternative.

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REMEMBER THE SERGEANT PILOTS!

Anyone know what the industrial uses of tetraethyl lead are besides gasoline products?

Rather than TEL being made illegal, I suspect that demand might be so low that it isn't profitable to make for much longer.

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When I was tracking an older Porsche--highly modified 1983 911--which had solid and flat, non-roller valve lifters--we used Brad Penn oil, which is an offroad/racing-only oil that is specially formulated to include the important compounds that modern oils (even Mobil 1) no longer have for exactly that rocker/cam interface situation.

Just about anything with an aluminium head is going to have "hardened" seats. There are only just so many alloys that you can use that will match the coefficient of expansion the alu. head,and all of them count as "hard".
All of the "modern"(ie. Lycoming and Continental) engines were designed around either 73 or 87 octane back when they were new. Calling out 100octane allowed the manufacturers a little more leeway with ignition timing, but still well within safety margins. Until you start getting to 11+:1 CR's and 35+ deg. of ignition advance, you are well within the detonation threshold of 100.
What switching to 100 with lots of TEL back in the day did do, was lead to valves sticking and guides wearing out prematurely. Operators guides of the day recommended avoiding 'Ethyl' in the smaller engines. The same build-up claimed to prevent seat wear and erosion stuck to the stems as well and eventually ate the guides. The answer was to switch to exotic hard metal guides.
When 100LL was phased in, with TEL, the lack of lead on the stems caused problems with the guides not getting enough lubrication and wearing out prematurely. Sometimes using the old bronze guides solves the problem.

The real reason no easy substitute for 100LL had yet come forward is the number of regulatory hoops that need to be jumped through, and manufacturers loathe to allow anything new for fear of opening themselves up to liability suits.

When the UK switched away from leaded in 2000 I was heavily involved in British cars. The naysayers and snake-oil salesmen abounded, but combustion doesn't change by Act of Parliament. Any new aviation fuel is likely to have an additive package that addresses all of the real needs of 99% of engines just like unleaded automotive fuels do.

Be more concerned with the lack of phosphorus based additives in base oil stocks. these provided greater lubrication to 'wiping' friction as found on flat tappets and such. They were removed for environmental concerns from ALL engine lubrication oils. This wasn't an issue in most newer cars, but is an issue in non-roller lifter aircraft engines and old cars. Lycoming, amongst others, makes an additive to address this need.

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Lest Hero-worship raise it's head and cloud our vision, remember that World War II was fought and won by the same sort of twenty-something punks we wouldn't let our daughters date.

A solutely nothing. There is only one plant left in the world even making it according to what I have been told.

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Tyler Pinkerton
Active Member of Air Heritage Inc. of Beaver Falls, PA.
Aircraft: C47B, C-123K, Fairchild F-24, Funk Model B, L-21B, T-28B, T-34B
Static: F-4C Phantom II, F-15A, T-3 Provost

A guy who used to work at a local auto parts store that sold various high octane grades of racing gas told me one reason for the higher price of it as opposed to Avgas is that it was street legal, it had road taxes figured into the price.

That may vary from state to state. In Missouri way back when we were required to collect road taxes on 100LL at the airport. We also had a stack of the rebate forms on the counter so you could ask for it back.

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Lest Hero-worship raise it's head and cloud our vision, remember that World War II was fought and won by the same sort of twenty-something punks we wouldn't let our daughters date.

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