The International Cessna^® 170 Association

Sorry George, but we don't agree with your opinions on avgas vs unleaded base stocks.

Some homework - check the current avgas spec to the spec for the engine as designed. You need to demonstate that they are the same and have not changed. It is very obvious that 100LL does not meet the orginal design specifications. If you still believe it does after reviewing the specs, one needs to question the opinions you've offered up over the years.

One of the local guys buys 100 gal of car gas and mixes water with it (about 10 gal), then drains out the water and alcohol. Does not sound like the right thing to do to me.

Dave your right it doesn't work that way according to some chemists I've talked to because I had the same idea.

Yes you are removing some of the alcohol but your not removing all of it. Yes theoretically at some point most of the alcohol would be removed with repeated mixing of water and then draining off.

But here is the problem. What are you left with?

You see there is no such thing as" gasoline". The term "gasoline" is loosely applied to the mix of chemicals we put in internal combustion engines.

The mix can and does change. That is why there are ASTM standards so that when you buy "gasoline" you are assured the mix of chemicals your buying will perform to a standard in your internal combustion engine.

The "gasoline" or chemical mix meets the standard with ethanol. What's left after the ethanol is removed does not meet the standard. In other words "gasoline" mixed without ethanol is different than what is left after you remove the ethanol from "gasoline" made with ethanol.

The auto fuel STCs require one to use "gasoline" which meets an ASTM standard AND not have other than trace amounts of alcohol. Since your local guy probably can't test the chemicals he has left and prove what is left after he removes the ethanol meets the ASTM he is just as illegal running it in his plane as if he just ran the "gasoline" with the ethanol in it.

gahorn wrote:Mogas... eats up the pewter/aluminum...
Avgas has a much better personality ....

I'm not trying to start the mogas wars again, I'm just pointing out that mogas isn't as economical as many seem to think it is.

I found Lycoming does not want regular unleaded in their engines for two reasons:
1) It contains corrosive chlorine.
2) It has insufficient vapor pressure
Source: http://www.lycoming.com/support/publica ... I1070N.pdf

I looked up a few different sources for exactly what is in Regular Unleaded fuel and none of them listed chlorine. Another interesting thing is to look up 100 LL AvGas. I used a few different MSDS sources and AvGas says it contain Regular Gasoline plus Lead (obviously) and maybe one to four other trace components like Toluene, Xylene, etc.

N1277D wrote:Sorry George, but we don't agree with your opinions on avgas vs unleaded base stocks.

Some homework - check the current avgas spec to the spec for the engine as designed. You need to demonstate that they are the same and have not changed. It is very obvious that 100LL does not meet the orginal design specifications. If you still believe it does after reviewing the specs, one needs to question the opinions you've offered up over the years.

Again...who is "we"?

As for "homework"... the onus is not upon me to do the homework. The engine manfacturers in cooperation with avgas refiners have done all that "homework" already for me. They are steadfastly in agreement that Avgas is the correct fuel for our engines. It matters not what the "original design specifications" were ..... It's more important what the current specifications are now. The fact remains the mfr's are both adamant about what fuel to use... and so that's what I use in mine.

Anyone who uses anything else are the people who must do "homework" to determine if what they are using complies with the law and with good and safe operating practices. I dare say "we" will be a whole lot harder-pressed to show how modern mogas meets either any "original design specifications" or subsequent STC modifications for these engines and airframes.

My personal opinion is that both Lycoming and Continental have a serious department full of lawyers that have a primary duty of seeing that no one in the companyviolates the CYA principal on matters such as the use of mogas.

Are we supposed to disregard all of all of the testing that the STC holders had to do to satisfy the FAA?

blueldr wrote:..Are we supposed to disregard all of all of the testing that the STC holders had to do to satisfy the FAA?

No. We're supposed to pay close attention to it. But just try to find mogas that meets the specs of the STC. (And by the way,... the mogas refiners and their lawyers are also opposed to using mogas in aircraft engines.)

Bring out the gloves I'll referee

As Butch Cassidy said what are the rules for this knife fight N171TD ? With all the talk of lawyers why not give them the knives and have at it. After all that would be better than using rats, more of them and there are some things rats won't do.

I don't know what all you guys are upset about, avgas has never been cheaper than it is right now compared to mogas.

When I first started flying in 1970, avgas was 45¢/gal, twice as expensive as mogas at 22¢/ga. 100% more.

Now avgas is $4.25/gal and Mogas is $3.09/gal, only ±30% more.

I have always said I don't care what it costs, as long as I can get it.

When I lived in Alaska, '47 to '51, mogas was fifty cents a gallon and 80 octane avgas was thirty two cents per gallon.
The difference,of course, was the road tax on mogas.

There were roads in Alaska back then?

The Alcan Highway ended at Big Dela.
The Richardson ran from Valdez to Fairbanks.
The Tok Cut Off ran from Tok to Glenallen.
The Glen ran from Glenallen to Anchorage.
The Steese ran from Fairbanks to Circle.
There was a gravel road from the Steese highway to Livengood.
I was in Fairbanks and have no idea what they had for roads in the Anchorage area. That was, of course, when Alaska was still a territory.

blueldr-
Thanks for the history lesson. I was kinda half joking about the roads being there but never really thought about when they were made. I knew the Alcan was built during the war but had no idea the other main highways were also there that early. I take it the main roads were paved since you mentioned the road to Livengood was gravel. I've driven all the roads you mention plus have flown up the haul road several times at low level. It's still gravel most of the way.

So there hasn't been any new roads built since the 50's, except through the train tunnel to Whittier? I'm assuming the Denali Hwy (still gravel) from Cantwell to Paxson was there.