[avee8tor]

Guys,

Any thoughts on what will replace 100LL. I heard about AGE85 having good results but do not know if this is available yet.

Avee8tor RV-10

 

[danielhv]

while this is not an issue for me yet, i will one day have to put an engine in this plane... id like to see something that is compatable with 100LL and something else thats redily available...

 

[airguy]

I doubt we'll see the demise of 100LL soon, but I've been wondering lately how to go about making a fuel system safe for "oxygenated" fuel (read: contains ethanol).

I'm mainly concerned about the affects of alcohol on the various seals in the fuel injection and lines. Does anyone have specifics on this?

Don

It's highly unlikely you'll find accurate information on the web about this, due to the high liability factor involved.

It is possible, but it's going to be very difficult to find out how. I would simply point out that automobiles drive millions of miles every day with ethanol fuel without issues. One would do well to look at the methods and materials they use for their fuel systems.

 

[Bob Brown]

Only thing I've noticed since we "got switched" to 10% ethanol fuel in Oregon is an 8-10% loss of mileage in all our vehicles. That might be something to check on in our aircraft...a 10% loss of range is fairly significant when you can't just run down the street for fuel.

 

[RScott]

I have had the same experience as Bob--loss of mileage. Went to Colorado to pick up my engine and none of the other states besides Oregon had ethanol. Got 14% lower mileage on Oregon gas with 10% ethanol and that despite the fact that the freeway speed limit in Oregon is 65, while in other states it was 70 or 75. Checking my records for previous years when we had a seasonal mandate for ethanol, it looks like I usually lost more like 10%. Unfortunately, we don't know what the mileage impact on the national fleet is--it hasn't been studied.

It would be pretty stupid to add 10% ethanol and lose 10% mileage.

In the news, it is evident there is growing dissatisfaction with ethanol as people starve while we grow food for fuel. Using food for fuel was recently called a "crime against humanity" by a World Food Bank official. There are environmental issues, the energy balance is still questionable, our ability to get significant relief from imported oil is limited (replacing 10% of our fuel with ethanol would require diverting 1/3 of our cropland to fuel production) and other reasons may get us off the alcohol kick in a few years.

 

[fliier]

One website discussing the merits of AGE-85 indicates the energy from AVGAS is 112,200 BTU/gal vs 88.2 BTU/gal for AGE-85, or a 21% decrease. AGE-85 is 80-90% alchohol

See http://www.age85.org/Research.htm

The website is interesting in that it discusses the pro's and con's of alchohol, though it definitely has a pro-alchohol bias.

I would suspect the decrease in range per gallon is proportional, though I don't know if that relationship is linear. . . I don't know if energy density translates directly to range.

When I reviewed the manufacturers website for the Flamemaster product that Van's sells in place of Pro-seal, it indicated a high resistance to alchohol.

One thing you could do during the building phase is to add the Safe-Air extended tanks, or at least make provision to add them later on. These would give you an additional 20% or so fuel capacity.

John Allen

 

[Bob Brown]

I burn 100LL for now, so its not an issue, but since I'm a big guy, adding extended tanks would not by a solution for decreased range...its a weight problem, not a volume problem. 10% of 42 gallons of fuel would equal 25 lbs of lost useful load...

 

[Garage Guy]

Any thoughts on what will replace 100LL. I heard about AGE85 having good results but do not know if this is available yet.

Consortium out of South Dakota State did a lot of AGE-85 development in the late 90's but they don't seem to have done anything in the last couple of years. See http://www.age85.org

One thing that came out of their early work was Texas Skyway's STC SA09530SC to convert a O-470-U to run AGE-85. Interestingly, this required very few changes: mainly making sure the fuel bladders are nitrile rubber, and installing 20% larger jets in the carburetor. They put 1000 hours on their test engine in a C-180 with no problems.

So what is the problem? Apparently FAA doesn't want to certify engines to run AGE-85 anymore. And without widespread FAA certification, producers aren't going to make AGE-85. So here we are.

Note that a number of things make AGE-85 issues distinct from issues around ethanol-blended automotive gasoline, even E-85, though they both have ethanol in them.

 

[leeschaumberg]

The fuel of future

As time passes LL100 Aircraft fuel will become a sad way to go. It will go up in price and then ALL lead will become illegal. So this only leaves one fuel for piston aircraft. Guess which one?

 

[avee8tor]

Ethanol

Guys,

Any thoughts on what will replace 100LL. I heard about AGE85 having good results but do not know if this is available yet.

Avee8tor RV-10

I have noticed with my old Nissan P/U - 4 cyl 5 speed, by not allowing the engine to go no higher that 2000 rpm and accelerating lightly, I am getting between 26 and 27 mpg around town and I am using 10% Ethanol auto gas. I do not go over 55 mph when on the highway. Guess driving style can play a small part too.

Hopefully the engineers will come up with something.

Cheers all.

 

[hevansrv7a]

What's going on when burning 10% Ethanol?

If you get X mpg on [1.0 petrol + 0 ethanol], then change to [0.9 petrol + 0.1 ethanol] the contribution of the ethanol would have to be zero to reduce the combined mpg to 0.9 X. Since conventional information holds that 1.0 ethanol is worth about 0.9 petrol, the net effect of 0.1 ethanol should be minus 0.01 X mpg more or less.

But, real-world observations are much different. There are other variables at work here including the variable energy content of a volume (not weight) of liquid fuel. Warmer fuel contains less energy because it expands. Perhaps a bigger issue is something about how the engine "feels" about burning 10% ethanol. Maybe the electronics are not coping correctly? Do oxy sensors trip on the alcohol blends? I always wondered why you'd add oxygen to a fuel that you burn in a system that senses the oxygen in the exhaust and changes the ignition timing, etc. to manage it.

I note in passing that my '97 Prelude with 230k miles just aced the Ontario Drive Clean test running mostly regular (premium is called for), probably with at least 5% and as much as 10% ethanol fuel purchased in Michigan. The readings were very, very good - most were an order of magnitude under the limit. So whatever is going on, my ten year old electronics are burning cleanly. I think the mileage may be down 1 or 2 mpg, but with a car that old how could I know?

Does anyone have any good information on this?

 

[RScott]

In trying to develop data to use in lobbying Oregon legislators, I searched high & low and found no studies that compared the mileage with and without ethanol. All I found were anecdotal reports. There are lots of those, and I found none that claimed a higher mileage and all reported a loss of 5% or more, usually 10-20%.

Ethanol has about 67% as many BTU's per gallon as gasoline. Theory would suggest that if you have gas diluted 10% with ethanol, you should have only a 3% loss of mileage. Real world experience seems to be different, suggesting the ethanol somehow changes how the mixture burns in the cylinder or something else is happening. Maybe the O2 sensor sees a leaner mixture since ethanol is an oxygenate, and the engine runs a richer mixture.

 

[Gary Bricker]

Gary Bricker

If you have a car that is not designed for E 85 it can destory the fuel system. The type of rubber products (hoses, O'Rings, etc) are different for E85. In the DFW area we have some E85 stations. I have tech notices from our company that tells all about it. If someone wants it send me a pm as I don't know how to post it here.

 

[osxuser]

Actually the Swede's already came up with a way. Because of the higher octane rating in ethanol, they simply detect when ethanol is present in the fuel and turn up the boost on the turbo a little. Fixes the mileage problem right up . Saab uses this in some of their European models from what I understand, and it seems like I'll be doing the same to my VW 1.8t when I chip it, since CA is on the 10% ethanol craze as well. Hope to get 32ish MPG instead of the current 25-27.