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  #31  
Old 02-11-2012, 09:16 PM
frankh's Avatar
frankh frankh is offline
 
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Location: Corvallis Oregon
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Quote:
Originally Posted by sheepdog View Post
I had been over the years watching the vangards flying on ethanal, the pilot I talked with said he burns 30 percent more ethanal for the same power settings than avgas.
That said if you decide to burn any gas with alcohol in it remember, your gascolator
is useless and any water that would have collected in the bottom will mix and go right through the mesh that water on its own would not. I had the misfortune of
running 10 percent through my 450 International tractor once. The glass turned yellow as the gasohol and water ran out of the carb mixed with a little gas. Engine started then quit a few minutes later with no possibility of a restart until fuel line was cleaned. No I did not clean the cup before I placed fuel in it as I could usually run most of the year with standard Unleaded and pick up a quater of the glass with water.
Thought about using Premium unleaded in my RV but only if I recieved the gas from
my local fuel supplier. He said he would test it for no alcohol and drop it off at the house in 55 gallon drums.
Once again this comes down to annecdotal evidence and each of us must make the best informed choice we can. For me E10 works just fine. With my on board fuel flow monitor (proven to be amazingly accurate) I burn 7% more fuel running LOP to make the same cruise performance in the RV. This is running LOP.

I would suggest that any water in the fuel is perhaps more of a risk in a carburetted engine due to the increased surface tension of water potentially making it difficult to suck it out of the jet.

fuel injected motor does not suffer from this draw back.

I believe you must have gotten a LOT of water in your tractor's tank, you simply don't see cars pulled over by the side of the road due to water in the fuel. Maybe you were suffering from the extra surface tension issue I described above?

Of course all modern auto's are FI'd so maybe there is some evidence that carbs and E10 have a greater risk.
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  #32  
Old 02-11-2012, 09:23 PM
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frankh frankh is offline
 
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Quote:
Originally Posted by N1593Y View Post
Answer: No. EAA, the FAA, Cessna, and others conducted studies ? they have all determined that a 10% ethanol and gasoline mix is not compatible with aircraft use. Further testing will not change the basic fact that to use ethanol-blended autofuel in your aircraft will require a total fuel system re-design costing well over $10,000 per aircraft.

11. What are the modifications I must make to my aircraft to be able to use ethanol-blended auto fuel?

In July 2002 Cessna engineers researched and produced a document called ?Evaluation of Ethanol-Based Aviation Spark-Ignition Engine Fuel.?

In this study Cessna noted that ethanol has the potential to produce up to 15% higher power outputs along with cooler exhaust gas and cylinder
head temperatures than 100LL. However, they also noted that to obtain those results required them to have a fuel flow 47% higher than 100LL.

Cessna indicated that ethanol-blended fuels are not compatible with airframe parts (aluminum, etc.), and fuel bladders and rubber parts (hoses, O-rings, etc.) ? the ?soft? parts of an aircraft fuel system. The report also indicated problems with calibrating capacitance-type fuel indicating systems, and long-term fuel storage issues (refer to question 6. above).

The Cessna team attempted to develop a solution to these issues, and stated the easiest solution was to raise cylinder compression ratios by installing taller pistons in each cylinder. This solution was not promoted due to the very high cost of the conversion and the years it would take for the FAA to recertify the engine with the new components.

Bottom line, EAA does not believe solutions available in today?s marketplace would be economically feasible for the average general/recreational aircraft owner.
Any system re design on a certified aircaft will cost $10,000..We on the other hand are not limited to rediculously high costs and may build perfectly reliable fueling systems at low cost. Of course this means you either junk the mechanical fuel pump like I did or rebuild it with alcohol reistant components.

As to burning 47% more gas to make 15% more power..well OK..but why do you want 15% more power in any case..Like I said in an RV at cruise LOP its 7%..actual data in an actual RV.

Not aluminium etc...not seen any corrosion so far.

Hoses etc?..Use teflon lined and there is no problem...

The surface ension of water getting into a carb might be an interesting issue.
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  #33  
Old 02-11-2012, 09:30 PM
vgb vgb is offline
 
Join Date: Aug 2007
Location: northern Cal
Posts: 111
Default E10

Just tore apart my portable compressor carb and it was corroded so bad that i had to buy a new carb. I even put stablizer in it.So your fuel better be mighty fresh and burn it off but I don't want that stuff in my plane carb.
I can buy clear gas in Oregon just over the border.Should have used it in the compressor!!!!
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  #34  
Old 02-11-2012, 10:06 PM
Ted Johns Ted Johns is offline
 
Join Date: Feb 2006
Location: Sherwood, Oregon
Posts: 236
Default Aluminium alcoholates

Quote:
I burn 7% more fuel running LOP...
Even that increase is a bit surprising. A 10% etoh - gasoline blend has about 3.3% fewer BTUs. BTUs are what make the fan go round...

Regarding corrosion, I did a little research on "aluminium alcoholates". There are quite a few primary research papers on this subject. Seems that the big concern is with liquid etoh and hot aluminum of the wrong alloy composition. Vapor blend with 10% etoh blowing through the cylinder head ports is not too likely to cause any problem, even if the heads aren't the "correct" alloy choice.

The alloys with problems are ones that contain copper. Analogous to the wrought alloy type 2024 that is common to RV structural parts, casting alloys of type 2xx.x contain copper.

Casting alloys of 4xx.x (silicon alloy) or 7xx.x (zinc alloy) are much preferred for corrosion resistance.

So, one would expect that the automotive environment would be a good place to discover this type of corrosion problem. Sure enough, Holley carburetors went through a "recall" in recent history. It seems that they used the "wrong" alloy for float bowls, and paid the price for the mistake. So it doesn't surprise me that in the real world, some carbs have
problems and some don't. Your low cost vendor for cast aluminum trinkets is likely the third world, and not too fussy about alloy choice.
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  #35  
Old 02-11-2012, 10:45 PM
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rocketbob rocketbob is offline
 
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Location: 8I3
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I have run 87 mogas for nearly a thousand hours without issue in my RV-6. Most of it E10. Last April my -6 was one of the aircraft destroyed at SNF, and I bought the salvage back and will be rebuilding it after my Rocket is finished.

Tonight as I was out shopping with my wife and kids I thought I should check the tanks this evening for any corrosion. The last fill up was mogas, before the tanks were drained by the SNF recovery mafia.

So my wings have been sitting for almost 10 months. I opened one of the tank access panels in the root and was almost overcome with the stink of stale mogas. Holy moly it smelled bad. But as I looked inside I noticed everything I could see was perfect. No corrosion. Nada. Nothing. Zip.

I also checked the fuel lines in the fuselage for any corrosion. Nothing wrong that I could see.

A few months ago I sold the carb and before I sold it I opened it up and inspected it. Again, Nada. Nothing. Zip.
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Last edited by rocketbob : 02-11-2012 at 10:48 PM.
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  #36  
Old 02-12-2012, 06:59 AM
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Jerry Fischer Jerry Fischer is offline
 
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Location: Winder Ga
Posts: 914
Default Rocket Bob's Carb

I have about 15 hours on Bob's old MA4-5 in Miss Sandy, and no issues so far. I do run 100LL at $ 4.87/gal when it's available otherwise I pay the going rate. I did flush my tanks just prior to wing attach back in November with 91 octane marine (no ethanol) gas purchased at a nearby marina up on Lake Lanier her in NE Georgia. 52A is expecting to install Mogas tank this spring to sell 91 octane ethanol free fuel at about $1 /gallon under the 100LL price. I think he will do a land office business as most 100LL in the Atlanta Metro area is well over $6/gallon. Just my .02
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Last edited by Jerry Fischer : 02-12-2012 at 07:00 AM. Reason: spelling
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  #37  
Old 02-12-2012, 07:14 AM
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kevinsrv7.com kevinsrv7.com is offline
 
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Quote:
Originally Posted by frankh View Post
I think this all points to lack of evidence..I.e there just arn't that many airplanes running on E10.

So we are really left with a mixture of reports and personal experience.

As for my personal experience I have about 400 hours an almost exclusively E-10. My airplane resides in a hanger and the premium gas sometime sits in the tanks for a month or two when I'm busy and don't get to fly much..Note I always do at least a half hour round the patch once a week.

Every year I dismantle the steel fuel hose fiting at the FI servo and drain the tanks.

My system is designed to pump Ethanol (i.e no mechanical fuel pump, AFP FI system and o rings changed for flourosilicone in the tank drains).

My personal experience is:

1) No corrosion anywhere, in the tanks or steel fuel fittings. No products of corrosion noticable in filter screens.
2) No seals failed and certainly no vapour lock (it was designed this way after all)
3) No noticable water absorbtion..Not sure how I would know anyway..With FI the surface tension changes you might see with E10 in a carb (if any) are irrelavent.
4) No bad gas as far as is noticable.
5) recent boroscope check revealed a clean top end with no signs of damage (I would hope not!)
6) Running LOP at 24*24 the gas consumption rises to about 7.6GPH vs 7.0 for stright gas or 100LL.


Bottom line..from my experience so far I have no intention of ever running 100LL if I can avoid it. I would avoid E10 but only for the reason its a rip off!

Frank
Thanks Frank for the first hand experience. Based on your input, shall I assume you had no compatibility issues with fuel tank sealant and E10?
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  #38  
Old 02-12-2012, 06:16 PM
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frankh frankh is offline
 
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Location: Corvallis Oregon
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So far no..I checked with the manufacturer and they told me it was compatible.

I have a few paint bubbles like other quick built tank owners but nothing that looks any different.

I will need to look at prices of ethanol free mogas, today I filled up my cans at 3.67.. ad 7% for extra burn equals 3.93 effective cost.

Depending on what they sell straigh gas for in Corvallis may make it not worth bothering with 10 ETOH.

Of course Rocket Bob uses 87octane (car) regular and I use premium..I just haven't had the courage to drop to 87 Oct yet..
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  #39  
Old 02-12-2012, 06:54 PM
molson309 molson309 is offline
 
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Location: Longmont, CO
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I put E10 in a Honda portable generator. After sitting all winter the generator would not start, and when I disassembled the carburetor I found extensive corrosion in the float bowl, which had clogged up the jets. I cleaned the carb and have since used non-ethanol gasoline, which has not caused a repeat of this problem.

Also had a dirtbike that required a carb cleaning after leaving ethanol gas in it over the winter.

No more ethanol gas for me in anything that doesn't get used regularly. Too much potential for corrosion.
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  #40  
Old 02-14-2012, 08:28 AM
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gvouga gvouga is offline
 
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Location: Raleigh, NC
Posts: 113
Default Vapor Lock Data Point

I decided to test out my new oxygen tank and take my plane up to 17,500' the other day. At about 13,000' I started to get fuel pressure fluctuations. Turned on the electric fuel pump and everything settled down. Kept turning boost pump on/off as I climbed to see what happened. At ~16,000' the engine would lose power and stop working on just the mechanical pump. The electric pump would bring everything back to normal on up to 17,500' where I stopped.

Fuel - 100% E0 93 octane
OAT - ~-10F @ 15,000' (It was a cold clear day and ground temps were ~35F)
Powerplant - IO360, FI, Lightspeed EI, 1 mag

I suspect I was getting bubbles in the fuel lines which is what caused the fuel pressure to drop off. Turning on the boost pump would provide the extra pressure to condense the fuel back to liquid. At least that's my best guess at this point.

Anyway, I'll probably test again with AVGAS to see if I see any similar conditions. Just wanted to pass on the data point.

Greg
RV-7
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