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10-06-2015, 08:27 AM
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Join Date: Jan 2005
Location: SC
Posts: 12,887
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Quote:
Originally Posted by airguy
Since Lycoming will not tell anyone what the internal components are made from, no, nobody can be certain. The only evidence that can be gathered is direct experience - which seems to indicate that (at least the more recently manufactured) materials are tolerant.
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A few hundred hours means nothing. You need to know and understand the chemical composition of the materials involved and their potential interactions. Also, Lycoming can't and won't change the materials used within their engines without going through some type of expensive certification process. Thus, it is possible that the materials used in your engine may be the same as those used over the past decades.
It is irresponsible to say it is OK to use something in your engine when it is unknown what the impact, if any, will be. I'll give you an example, some years back one of our South American members posted his experience running auto fuel with ethanol, as they were required to do. One of the issues they have is that their engine driven fuel pumps tend to have a limited life span. (I don't recall the length.) The solution was to keep an extra fuel pump in their hangars. That is not a solution and the thought of the pump going out while on a trip is not appealing.
__________________
Bill R.
RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html
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10-06-2015, 08:28 AM
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Join Date: Feb 2005
Location: Chesterfield, Missouri
Posts: 4,514
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Quote:
Originally Posted by airguy
Since Lycoming will not tell anyone what the internal components are made from, no, nobody can be certain. The only evidence that can be gathered is direct experience - which seems to indicate that (at least the more recently manufactured) materials are tolerant.
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And neither will Tempest confirm it, I tried to get them to do that a while back. All they would say is we have no reports of pump failure due to ethanol. They were conducting material certification tests at the time but the program was cancelled, so I was told by a Tempest person later.
The situation regarding the mechanical pump needs to be known before accepting E10 as a successful alternative fuel, the pump materials may not like it. There is no way to be sure.
Why pump manufacturers will not say what the materials are is corporate legal arrogant stupidity. They do not have to endorse the materials for any fuel, just let the customer know what they are so he can make that decision.
__________________
RV-12 Build Helper
RV-7A...Sold #70374
The RV-8...Sold #83261
I'm in, dues paid 2019 This place is worth it!
Last edited by David-aviator : 10-06-2015 at 08:30 AM.
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10-06-2015, 11:32 AM
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Join Date: Jan 2005
Location: Twin Cities, MN
Posts: 1,565
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Quote:
Originally Posted by N427EF
No, I am not!
I am looking at the vanguard squadron and their 15 plus years of operating
with a standard mechanical fuel pump and my concerns are none.
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That would assume there is just one fuel pump, or that you have the same part # as the Vanguard squadron does.
Have you verified either/both?
__________________
Brad Benson, Maplewood MN.
RV-6A N164BL, Flying since Nov 2012!
If you're not making mistakes, you're probably not making anything
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10-06-2015, 11:38 AM
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Join Date: Sep 2007
Location: Central IL
Posts: 5,516
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Quote:
Originally Posted by David-aviator
And neither will Tempest confirm it, I tried to get them to do that a while back. All they would say is we have no reports of pump failure due to ethanol. They were conducting material certification tests at the time but the program was cancelled, so I was told by a Tempest person later.
The situation regarding the mechanical pump needs to be known before accepting E10 as a successful alternative fuel, the pump materials may not like it. There is no way to be sure.
Why pump manufacturers will not say what the materials are is corporate legal arrogant stupidity. They do not have to endorse the materials for any fuel, just let the customer know what they are so he can make that decision.
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If your livelihood depended on revenue from these pumps, you would not tell the world what was in there either. Too many copiers ready to exploit, and they might retain liability for the "will fit" parts anyway.
In the certification process, the materials, and processes are required to be provided to the FAA. I remember a Conti lawsuit was lost (or settled) when a "will fit" connecting rod failed. FAA said that the rod was manufactured to the specifications, processes, materials, and heat treat of the originals, thus it was a design defect and Conti was still responsible. Now THAT is ridiculous!
One might get a FOIA request to obtain such information, but it sure seems like a lot of trouble, as there are other failure modes in other components that also need to be addressed.
__________________
Bill
RV-7
Lord Kelvin:
“I often say that when you can measure what you are speaking about,
and express it in numbers, you know something about it; but when you
cannot measure it, when you cannot express it in numbers, your knowledge
is of a meager and unsatisfactory kind.”
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10-06-2015, 01:02 PM
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Join Date: Oct 2006
Location: Garden City, Tx
Posts: 5,145
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Quote:
Originally Posted by N941WR
A few hundred hours means nothing. You need to know and understand the chemical composition of the materials involved and their potential interactions. Also, Lycoming can't and won't change the materials used within their engines without going through some type of expensive certification process. Thus, it is possible that the materials used in your engine may be the same as those used over the past decades.
It is irresponsible to say it is OK to use something in your engine when it is unknown what the impact, if any, will be. I'll give you an example, some years back one of our South American members posted his experience running auto fuel with ethanol, as they were required to do. One of the issues they have is that their engine driven fuel pumps tend to have a limited life span. (I don't recall the length.) The solution was to keep an extra fuel pump in their hangars. That is not a solution and the thought of the pump going out while on a trip is not appealing.
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The Vanguard squadron has quite a few more hours than "a few hundred". I'm not advocating one side or the other, so I'll thank you not to take me to task for it. I removed my engine driven fuel pump entirely, so I'm much more of an experimental heretic than those merely wanting to run E10. 
__________________
Greg Niehues - SEL, IFR, Repairman Cert.
Garden City, TX VAF 2020 dues paid 
N16GN flying 700 hrs and counting; IO360, SDS, WWRV200, Dynon HDX, 430W
Built an off-plan RV9A with too much fuel and too much HP. Should drop dead any minute now.
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10-06-2015, 02:01 PM
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Join Date: Jan 2005
Location: SC
Posts: 12,887
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Quote:
Originally Posted by airguy
The Vanguard squadron has quite a few more hours than "a few hundred". I'm not advocating one side or the other, so I'll thank you not to take me to task for it. I removed my engine driven fuel pump entirely, so I'm much more of an experimental heretic than those merely wanting to run E10. 
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Sorry, the tone of my reply was a bit negative, that was not my intention
Your setup is different than what is normal and the tone of the thread is, "All is good with ethanol, come on in, the water is fine".
You have obviously gone off the reservation with regard to your fuel system but most have not and to advocate thay ethanol will not harm a "stock" airplane is irresponsible.
A lot of people read these threads now and in the future and often the long term results are not posted back to them and highlighted. This applies to building advice as well. I'm sure we have all seen building tips that make us cringe and hope no one follows the example.
In the case of ethanol, there are too many unknowns to put out a blanket statement that all is good. Even more so to use the marketing team known as the Vanguard Squadron. I'm yet to see a list of all the mods they have done. Also, I highly doubt they are running carburetors, as many of us are.
Again, my apologies for coming across so harshly above.
__________________
Bill R.
RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html
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10-06-2015, 02:52 PM
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Join Date: May 2006
Location: Pocahontas MS
Posts: 3,884
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FWIW, I had phone conversations several years ago with an engineer at Tempest, and while he didn't specify materials, he did tell me that all their current production fuel pumps are immune to alcohol degradation. The gist of the conversation was that current production basically uses what's in the automotive engine driven fuel pumps (yes, you can still buy them), and the automotive pumps have to stand up to E-whatever. They obviously won't put that on paper, because they haven't jumped through all the FAA-required hoops to change the fuel ratings on the pump. No real reason to, since FAA won't allow E-gas in type-cert a/c.
The same guy said also that there are no issues with E-gas in Marvel-Schebler carbs; even the antique that's on my O-320B2A (same parent company).
Again, FWIW. Anyone who's interested shouldn't take my word; they should ask for themselves. It's worthwhile to remember that hearsay is hearsay, no matter which position is being advocated.
I don't run E-gas yet for two reasons. First, my tanks were built in the early 1990's & I don't know what was used for sealant, and second, at the rate I fly, it would take years to pay back a fuel pump change (antique, non-E-proof pump).
But I have run E-free premium mogas for at least a decade with only one incident of rough running, due to my own stupidity: Old, winter blend mogas; plane sat on a blazing hot ramp (100F+ ambient temps) for hours followed by a takeoff during the hottest part of the day. I've had rough running issues with avgas in similar situations, so it's pretty hard for me to blame the mogas.
Charlie
Last edited by rv7charlie : 10-07-2015 at 03:49 PM.
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10-06-2015, 02:55 PM
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Join Date: May 2005
Location: Tuttle, Oklahoma
Posts: 2,563
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Quote:
Originally Posted by N941WR
. . . Again, my apologies for coming across so harshly above.
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Perhaps openly chastising posters and name calling are the culprit. Just a thought, but lecturing others tends to indeed come across as a bit negative.
Don't you think this post has a ring of negativity to it?  Just sayin'.
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10-06-2015, 03:35 PM
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Join Date: Oct 2005
Posts: 1,516
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Re posted many times.
Here it is again
Quote:
Default The Vanguard Squadron, 16 plus years of ethanol use
Gary Kuhns, lead pilot of the air show squadron, ?The Vanguards? has info on ethanol use. This is no surprise, they have been practicing and performing in RV-3s all the while running the IO-320 engines on ethanol and all mixtures of ethanol and avgas when flying x-country to and from the show sites. I figure with their 16+ years of ethanol experience, they can provide some insight for my own flex fuel project. In addition, by putting the team?s experiences out here on the board, hopefully it will answer a question that has come up occasionally on the vansairforce boards. What about the Vanguard Squadron? What have they done to the airplanes so they are ethanol compatible?
This posting is based on 3 or 4 conversations I had with Gary during 2010. The last conversation we had, Gary added some clarifications and corrections to the draft I had sent him.
Basics on the Vanguard airplanes
Four similar Rv-3 airplanes, N6GT, N16MR, N19EH, N25RV
IO-320 and wood Sensenich propellors
Fuel system
Like many other early Rv-3s, all four Vanguard airplanes have 24 gallon fuselage tanks. However, two of the four also sport wing tanks giving them impressive fuel capacity. None of the fuel tanks were built using special procedures or unusual materials as the planes were built with avgas in mind. Aerobatics are flown with wing tanks (if present) empty and fuel feeding from a flop tube inside the fuselage tanks. All have a factory type mechanical fuel pump and backup electric pump on the firewall. In order to accommodate the higher fuel flow needed with ethanol, Airflow Performance, Inc has re-calibrated the Bendix fuel injection systems. None of the airplanes have fuel drain sumps or gascolaters, Gary reports they were removed when they realized they weren?t performing any function. There is no separation of water and any particulates are trapped at the screened inlet to the Bendix fuel servo. All four have avgas priming systems for cold starts. They use a small fuel tank, (weed-wacker size) mounted behind the seat to feed the priming system.
I specifically asked Gary if they have had any fuel pump failures or tank sealing problems. He couldn?t recall any, and he asked the rest of the team if they experienced any issues. None. Gary did report Van?s Aircraft advised flop tubes needed inspected for softening/swelling. All four airplanes got the inspection and flop tubes were in good condition.
Engine setup.
All four airplanes now run high compression ratios. Three of the engines had engine work and the 10 to 1 setup by FWF/Demars approximately 20 years ago. Two of those engines are still in use. The third, N16MR got a new engine set up as 10.8 to 1 compression by Central Cylinder, Omaha NE. Gary?s N6GT was for many years just a stock 160 hp 320. The recent rebuild at Central Cylinder utilized the old crankshaft and case, though he reports the case got beefed up. Central Cylinder set his engine up with the custom pistons as well and he is running 10.8 to 1.
All four engines are have inverted oil systems.
Performance.
The team is very happy with the airplanes performance. Gary as formation lead, runs partial throttle throughout the routine, allowing the others to apply power as necessary for positioning. The team appreciates the consistency, smoothness, and reserve power that is available with these airplanes. Gary did not report any detailed performance testing, as they are very happy with how the planes performed, so they haven?t been in a troubleshooting or documentation mode. On Gary?s lead airplane, N6GT, he reported the rebuild shop saw 175 HP on their dyno running avgas. Gary?s estimate of HP while running on ethanol based on climb rates and speed is an additional 10 HP. (probably due to charge cooling, compare the latent heat of ethanol to gasoline, the ethanol is cooling the inlet stream- Stan).
Cold starting on ethanol is a problem. The engines like pre-heaters. The avgas priming system is used when below 50 degrees F. Once the engine is running, the avgas isn?t needed. Gary reported they had trouble finding fuel ethanol near one air show, so they used a local E-85 pump and had no trouble on starting. The 85% ethanol with the 15% gasoline likely provides enough easily vaporizing components for cold starting.
Gary reports no vapor lock issues, though he does caution they don?t have any significant experience at higher altitudes (over 10,000 feet). They don?t spend time up high.
Gary did report that back in 1993, he remembers a short clean out period when the engines were switched from avgas to ethanol. They observed some smoke in the exhaust as the ethanol loosened carbon up and the engine cleaned out.
Fuel composition
Ethanol, but when traveling back and forth to air shows, they will use 100LL as necessary, since that is what is available at fuel stops. Gary suspects they have run on about every possible combination of ethanol and avgas.
**The non-technical, keep it simple folks say, 100% ethanol, but pure ethanol doesn?t exist legally in the US motor fuel market, since gasoline presence is required by law so the liquor taxes continue to flow. The highest ethanol concentration you?ll legally see outside the production plant fence will still have 2 to 5 percent gasoline, and this is what the Vanguard squadron normally consumes, as do folks seeking ethanol out for racing. They find a plant or distributer who will sell the denatured ethanol (Stan?s comment).
Fuel flows
Gary reports approximately 15-20% more fuel flow on ethanol than avgas. The fuel injection system was set up for the higher fuel flow, so when running avgas, operations can easily be over-rich. The pilot compensates with the mixture control but it?s fairly close to the lean edge of the adjustment window. Tractability on avgas is OK if the pilot stays on top of it.
Some comparative fuel burns. Numbers come from the digital flow meter on Gary?s N6GT. Slightly rich of peak at 7500 to 8000 feet 140 to 145 knots, Gary sees about 9.3 gph on ethanol and 8.4-5 on av-gas. Gary?s leaning protocol (fixed pitch), lean until RPM loss, then go rich to gain back RPM, then a touch more rich. Gary observes 350 to 375 F CHT?s in cruise. He is in the cruise ROP camp, so if he observes CHTs approaching 400 F, he adds fuel.
Warning on carbs. Gary reported a carburated engine operator running on ethanol had a fuel stoppage. The operator told him of occasional fuel interruptions as the airplane warmed up (about 20 minutes into operations). The problem was traced to inlet valve seat. Apparently, the fiber seat would swell and cut off fuel flow. The operator reported the seat was replaced with brass and the problem was fixed.
Lastly, I will mention that Poet (previously known as Broin) sponsors the squadron, and if you?ve seen the airplanes or been to their website ethanolairshows.com you?ll already know this. So, the airplanes fly largely because a well known and successful ethanol company has chosen to support their efforts. What that means I don?t know for sure, but given the anti-ethanol aviation landscape, the corporate support is likely the one thing that allowed the ?test? to occur. Who else would have done such a thing? In talking with Gary, it seems pretty simple. I get the sense that they'd been doing this for so long and it has worked so well, that running on ethanol is a non-issue. Interesting, considering all the predictions that have been made on what will happen to gaskets, fuel lines, fuel pumps, and etc.
__________________
Stan
1990 RV-3 (now apart, upgrades in the works)
1959 C172 O-360
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__________________
Ernst Freitag
RV-8 finished (sold)
RV-10 Flyer 600 plus hours
Running on E10 mogas
Don't believe everything you know.
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10-06-2015, 06:13 PM
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Join Date: Jun 2015
Location: Alberta
Posts: 84
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If you look at the Petersen Auto Gas STC site, there is good info there about using car gas in planes, and with tens of thousands of STC's for certified planes. I would think they know a little about car gas.
The main problem with ethanol in fuel it its ability to attract water from the air, and when conditions are right, the water separates from the fuel and then you get to run a quantity of water thru your carb, or injectors. Unless you have a real special engine that runs on water, this can be an exciting time I would think.
I have flown probably 500 hours with car gas in a Cherokee, and RV6A, and have heeded the good advice to use gas that is all gas and not gas with corn squeezins mixed in, and it has always worked super for me.
You used to be able to get 87 octane that was pure gas, but its hard if not impossible to find now. Super unleaded is often pure gas, and if you ask the dealer they should even have a data sheet on their gas which gives the specs.
__________________
RV-6A slow build,
serial # 21681. First flight March 1993
Dec 2019 donation paid
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