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100LL Future and Engine Purchase Concerns
I'm probably a year or so away from looking for some type of propulsion system for my -14 project:). As decision time gets closer I become more concerned about what I?m hearing about the uncertain future of 100LL. When I discuss these concerns with others, the typical statement I hear is ?they?ll come up with something?. Well, this issue has been around for many years now, and so far a suitable replacement is yet to be produced. Apparently, it?s a little more challenging than expected. I wonder will the whole 100LL phase out plan just go away, or will some type of ?band-aid? fuel be introduced until engines can catch up with the times. I realize this can be a controversial subject, and I may be overreacting. I imagine the folks that already own the 100LL burning engines are likely hoping for some type of 100LL replacement, or that the FAA/EPA will give up on the AVGAS phase out plan all together. On the other hand, the group that have yet to buy engines are hoping for some type of miracle, and a new engine will be developed that doesn't require 100LL,..and will be similar in weight, shape and fuel burn of the Lycomings. Big wish list I know.
Again, I may be overreacting to this, but this 100LL thing has kind of taken the wind out of my sail for my build motivation. I enjoy my project, and have no intention of throwing in the towel. However, I just can't bring myself to buying an engine that requires a fuel with an uncertain future. I would love to put a small turbine, or diesel up front. However, I just don't believe the current options are a good fit for the RV-14. I'm keeping my fingers crossed though! It appears the most likely scenario may be sticking with the lycoming and modding the engine to burn something other than 100LL. I've heard the engine for the 14 (Lycoming IO-390) with a compression of 8:7:1 is just over the limit for running a lower octane unleaded fuel. The 390 would need to be derated, and have hardened valve seats. I have not researched what the derated HP would be, or if it would it be sufficient for the RV-14. My knowledge of piston airplane engines is pretty basic, but I'm learning. So...anybody else out there have issues with buying an Avgas burning engine given the 100LL issue, or is it just me?? Here's some links that help "fuel" my concerns: FAA PAFI program updatehttps://www.faa.gov/about/initiatives/avgas/ AVGAS facts and Future https://www.shell.com/business-custo...-30071515.html 100LL Replacement or not? https://www.avweb.com/blogs/insider/...-230953-1.html The need for leaded Avgas (This site has interesting info of all kinds) http://www.epi-eng.com/aircraft_engi...e_of_avgas.htm and on the R&D front: What happened to this NASA project? https://www.grc.nasa.gov/WWW/PAO/PAIS/fs01grc.htm Give Continental credit..at least they're trying! http://www.continentalmotors.aero/di...l-engines.aspx Turbine Aeronautics (wishing these guys luck!) https://www.turb.aero/ PBS (there was one of these in a 10) very pricey and fuel burn issues. would love one though! http://www.pbsaerospace.com/our-prod...rboprop-engine |
GAP Piston Engine
This is all my my ancient memory banks. The specs were quite aggressive and any qualifying product would be drool worthy. A very long time ago, a Continental Engineer working on the GAP piston engine told me (right or wrong) that the engine had met all of the design criteria. If just one of the OEMs would pick it up, it would go into production. Assuming that was true, they missed the market; not their fault. The spec called out a 200HP engine. At that time, the exp and commercial market were going to bigger powerplants. Continental was subsequently sold to the Chinese so it's doubtful we'll ever see anything for our market from these tax dollars.
Maybe someone else has better info/memory. Hopefully they will reply. |
Not at all.
I don't think you will get many answers on this one as no one knows what the final look of the fuel change over will be at this time. I can say that many of us have planed for this many years ago using our dealings with engines, engine parts and systems. You have a good starting point by looking at the compression ratio as a guide. The new fuels are targeting the standard of 8.5:1 as that is the set that most of the old aircraft engines have used down throw the years. We know that we can burn 92-93 Oct. UL fuels in these engines now. And if you look the engine companies are starting to go back and approve the use of Mow. gas of this grade in these new and older engines with that set-up or configuration. The newer FAA approved fuels will have to target at least that market if not higher Octane ratings. So I have no personal problem with an engine that burns fuel of that grade or standard. I personally think that the fuel or fuels that will be given the green light will be closer to the 100 Octane level in the end. WE built our fuel system to be able to be used with any "E" fuels for just these reason and compromised by putting 9:1 compression pistons in, instead of 8.5:1.
The big catch in all of this is "WARRENTY", or who will pay if the new fuels do damage to my nice costly engine. If you don't have big sponsors and have to swallow that pill for yourself, I can more than see the stress this would generate. I think they have good replacements already, it is I think the liability and the jockeying for a place at the profit table that is the thing that is dragging out the time table. In the engine world, fuels are often hand blended to meet the need of that use. Some of us still do it a little. This may not help you but it is another two pennies to throw in the pot. Yours, R.E.A. III # 80888 |
My $.02 if you are early enough, use high pressure auto fuel injection hoses in any thing fuel related and make provision for a possible fuel return.This type of
thinking allows for any fuel/system in future. I know it?s not politically correct, but an acquaintance used high test auto fuel in his Bonanza for 30 years ! |
I'm rolling up on 275 hours now on my IO360 running Walmart-grade 91 premium autogas with ethanol on 8.7:1 compression with no issues. I did build the entire fuel system on the airplane with ethanol exposure in mind and eliminated all but one natural rubber O-ring which I found a couple weeks ago, it finally started leaking at about 250 hours.
The engine is quite happy burning 91E10, in-flight performance is within a percent or two of the 100LL standard, I can't tell the difference without digging into the Dynon performance data on a long cross-country. Handling the fuel here is going to be the trick for you and most others though. I am based on a private strip just over 30 miles from the nearest "real" airport with fuel - so I have my own tank on my strip. I took a used milk container, 125 gallons stainless, and steam cleaned it, set it on a 275-gallon chemical tote frame so I can pick it up with forks on a tractor, and put a pump and battery on the frame. I can fork it onto the back of my pickup and take it to town for a fill when needed, easy-peasy. |
Be careful here
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Fly safe. |
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Not a definitive answer, but FWIW
The EPA and FAA have been battling and saber rattling this since lead was removed from cars. I worried about that too, but proceeded ahead with my M1B. The serious issues to be resolved for a replacement fuel are for turbocharged engines. Many are out there and cost a lot more than our normally aspirated units. Owned by people with lawyers.
My invested opinion was to build on, fly and enjoy. If it becomes an issue there is a lot of pressure to apply to the situation, politically, (AOPA, EAA, etc) and technically. On an optimistic note, I am sure that Ross will have a fully developed EFI system ready with knock sensors, O2 sensors and full timing control with diagnostics (OBD-X) ready for the task. :D |
What Lycoming has to say
I like to go back to the manufacturer of the engine to see what they have to say.
Lycoming on Unleaded fuel part 1. Lycoming on Unleaded fuel part 2. Lycoming on Unleaded fuel part 3. Lycoming Service Instruction 1070Z. If that is too much to read, most of the parallel Lycoming engines (150, 160, 180 HP) used in our RVs will operate just find on alcohol free premium auto fuel. As a side note, the Superior Vantage 180 HP engine was certificated on 100LL and auto fuel. Check the type certificate data sheet. That engine is same bore and stroke as the Lycoming and the parts used to fabricate it are for the most part FAA / PMA approved for Lycoming engines. |
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