You can go squeeze yer OWN torpedoes!

a64pilot wrote:I've even been told that a little Marvel Mystery oil will take care of the alcohol.

Rob wrote:FACT .... Mogas stinks, and will stink more if you do not fly often, in which case it will turn to Movarnish, rendering your crab useless...

Sounds to me like running MMO in the gas will remove the Movarnish.

To go on record, I do not think that MM "will take care of the alcohol" I have been told that a couple of times by other people. I guess they use this line of reasoning so they don't worry about their source of fuel.
My point of bringing that up is to show that some people are burning auto fuel containing ethanol, so far with no apparent ill effects. I'm not stupid enough to make any claims one way or the other.
I do think it is interesting that I have heard of no accidents where ethanol was to blame. Of course I don't believe a cell phone will adversly affect a 747's navigation either.
Most of the people that I have met that burn Mogas either don't bother to test their fuel or aren't aware of any prohibition against alcohol.

a64,

A cell phone does not affect an airliner's navigation equipment, and the airlines do not prohibit their use for that reason. They DO prohibit the use of other electronic equipment, such as laptop computers, below 10 K for this reason.

The reason they prohibit the use of cell phones airborne, is because they've been told to by the FAA, at the request of the FCC. It is not and never has been an issue of safety, but rather of how to send the bill.

I seriously doubt that running a little ethanol would adversely affect most aircraft in at least the short run.

I do believe (but this is hearsay from other owners) that BOTH auto gas stc holders (Peterson and EAA) require the user of the STC to TEST each batch of fuel. If I'm not mistaken, that test is specific for the presence of alcohol..

Again, I've burned auto fuel in airplanes. I've also seen some deliterious effects, which at the time, the mechanics attributed to the use of auto fuel. No proof, and no I didn 't crash, so no big deal, right?

Nevertheless, the FAA says NO ETOH. Run what you like, but it won't change the rules at this point, at least. THere are ETOH tests in progress.

Interestingly enough, I've visited with some sprayers who spent some time in south and central america, talking to spray pilots there. Most of them run ETOH fuels in their spray planes, but NEVER over water, or over jungle. Hmmmm. Wonder what that's about? THey dont' even have an FAA.....

MTV

I read every scrap of paper EAA published on the subject before "intalling" the autofuel STC on my aircraft. They've tested EVERY fuel additive allowed in the USA, and all are approved under the STC EXCEPT alcohol of any kind. And even that allows 1% acohol, which works out to 1 pint bottle of Heat per 12.5 gals of fuel.

The primary problem EAA found, was not with the rubber seals and hoses, (though that is a problem) but with water. The alcohol keeps the water in suspension, so you can't detect it, or drain it from your sumps. But then, as you climb to higher altitudes with lower pressures and temperatures, the water can fall out of suspension again. Resulting in engine failure.

Another side effect of the alcohol bonding with water is that it dramatically lowers the octane rating of the fuel. Apparently this can be enough to cause detonation. They site severe cases were float planes refueled at marina's, where alcohol had been added to absorb water in the tanks, only to have all 4 pistons punched out on takeoff. Yikes!

Testing is very easy. I use a 1 liter soda bottle. It's got a mark at the 100ml level. I fill to that mark with water, then fill the rest of the way with the fuel to be tested. Shake the holy heck out of it and watch it settle. If there's no alcohol in it, the water settles out again in a couple seconds, and there the same amount you started with. If there is alcohol, it takes several minutes to settle out again, and there appears to be more water than you started with. I did a test, got a negative, and added 50ml (5%) Heat alcohol and tried it again just to see the difference. Believe me, it's a dramatic difference. Better yet, don't believe me, try it yourself.

Cars don't have these problems because 1. They rarely change altitude by thousands of feet in a few minutes. 2. They have electronic knock sensors that automatically retard the timing. 3. They have circulating fuel injection systems, so a slug of water in the fuel line goes past the injectors causing no more than a momentary miss. This same system also heats the fuel a little helping keep an alcohol/water mix in suspension.

Water is probably why boaters were the first to have problems with alcohol blend fuels, they're the ones most likely to get water in their fuel.

I've read that modern autofuel blends don't have the varnish problems anymore either. And I let an old truck sit for 3 years with the same fuel, no problems, so it seems to be true. But I still won't run fuel, auto or av, that's more than a couple months old in my plane.

Anyway, EAA has pages and pages on this subject and the results of their testing in the members section of their web site. I know, I spent a couple days reading through all of it before using auto fuel in my plane.

Phil

Phil,

Thanks, good information. One slight clarification: The alcohol additive that is allowed for use as an anti icing additive at 1% by volume is ISOPROPYL, not ethanol. I use red can HEET regularly for this purpose, which is 96 % plus pure Isopropyl. To the best of my knowledge, NO Ethanol is approved for any purpose, but I haven't read the EAA materials.

MTV

I've read that modern autofuel blends don't have the varnish problems anymore either. And I let an old truck sit for 3 years with the same fuel, no problems,

Must be regional, in Missouri we have to add sta-bil if the gas is gonna sit for a year or it'll varnish anything it touches. I had to clean up atleast 4 carbs this summer because of it.

Thanks anticub for explaining the reason behind the fear of alcohol.
Chad.

I just started another test that I hope MTV might try in Crookston since he can get the fuel there also. I took a pickle jar with 285 ml of 10% ethanol gasoline mix and added 1 ml of soft water. The water dropped to the bottom and is sitting there in a blob. The fuel was about 30 degrees as it was sitting in my hangar and the water about 60 degrees. It is sitting on the kitchen table for observation. I'll report back later. Getting back to the post about isopropyl at 1%, I'm curious how that works. It picks up all that water that has accumulated and is saturated so I assume it drops out like ethanol supposedly does. It seems to me that would qualify as a slug. When it goes through the combustion chamber what happens?

Marty,

Not sure what your homebrew experiment is designed to prove or disprove??

As to the Isopropyl--It is an ANTI-ICING additive. It is purely for the purpose of keeping any water (alcohol is hygroscopic) from freezing, thereby permitting the pilot to REMOVE said water (and alcohol mixed) from the fuel sumps.

It is NOT intended to permit you to merrily shove water through your engine, though most carbureted engines will swallow some little bits of water at least.

ALL Gasoline has some water entrained, ie: in solution. You can't get that stuff out with no go filters, or sumping, nor will isopropyl help with entrained water.

Don't believe there's water in your gas? Fill your tanks with good clean fuel, then park outside at -40. Sump your tanks and you'll find LOTS of little snowflakes in the fuel. This is the water that was entrained, but with the decrease in temp, the fuel wasn't able to hold as much water in solution, and the stuff precipitated out, and froze into nice little snowflakes. Those little snowflakes can plug your filter or fuel screen.

Isopropyl MAY or may not help with this phenomenon. In jet fuel, they use a product called Prist for the same purpose.

MTV

AntiCub wrote

I did a test, got a negative, and added 50ml (5%) Heat alcohol and tried it again just to see the difference. Believe me, it's a dramatic difference. Better yet, don't believe me, try it yourself. Smile

What does "got a negative mean"? Didn't look like any ethanol present?

mtv wrote

As to the Isopropyl--It is an ANTI-ICING additive. It is purely for the purpose of keeping any water (alcohol is hygroscopic) from freezing, thereby permitting the pilot to REMOVE said water (and alcohol mixed) from the fuel sumps.

The more we discuss this, the more questions I have. Here's an example, we have a car that goes to the gas pump and keeps adding a little water every fill.We add Heet to keep the water from freezing, over time we have a lot of isopropyl and water. Sounds like we have to take the tank and tip upside down to drain eventually since we have no quick drains.. In the real world I've never heard of this. What my point of the test is, is to show that it takes trying to add water to the tanks to get enough to cause problems. I'm careful to keep caps on tanks,jugs, etc. If you can't be careful enough to do this then you probably shouldn't fly.

Here's my observations if it matters. I have had an O-300 powered 172 for nearly 20 years. It had an auto gas STC when I purchased it. I used to use any car gas from the local stations. Never had a problem. Even let the plane sit for extended periods of time and the only problem I had was a sticky primer. Replaced the O-ring and it was fine. Don't know if it was the auto gas or just old.
Only recently have I been concerned about the Ethanol in the gas and now only use premium listed as non-oxygenated. The plane is still purring like a kitten. Besides.....this engine HATES 100LL! I mixed it in occasionally for a benefit on the valves but when I do a cross country and can only get 100LL....I get plug fowling within a mater of a few hours running time. I must lean it from the minute it is started til I shut it down.

Keith

Marty,

Ever look at the tailpipe of an internal combustion engine while its running in cold weather? A lot of that effluent is called water vapor....

As I noted in my earlier posts, most internal combustion engines will pass a certain amount of water through their combustion cycle.

During the era of the piston airliner, they actually injected WATER into the induction to help to prevent detonation, and thus to permit those big radial engines to make more horsepower for takeoff. That was free water actually sprayed into the induction.

Cars send water through the engine all the time, as do aircraft engines. This is the entrained water I mentioned earlier.

Little blobs of free water may also pass through a carburetor, and some injection systems as well.

There is water in all fuel.

All the additives do is keep it from freezing, so that we can drain it, and so that if entrained it won't freeze, but rather fall out of solution and remain in liquid state.

MTV

180Marty wrote:AntiCub wrote

I did a test, got a negative, and added 50ml (5%) Heat alcohol and tried it again just to see the difference. Believe me, it's a dramatic difference. Better yet, don't believe me, try it yourself. Smile

What does "got a negative mean"? Didn't look like any ethanol present?

Correct. The test showed no alcohol pressent, so added alcohol to see what it would look like.

MTV
My recollection is that EAA's STC allowes up to 1% alcohol of any kind, methel, ethel, iso etc. I just used heet as an example since it's familiar and available. I'll pull the paperwork out and confirm that tonight.

Phil

This information came to me in an email today. Passing it along...
ethanol_in oregon.doc
Last summer the legislature passed the renewable fuels bill which specified that all gasoline sold in Oregon contain 10% ethanol starting when ethanol production capacity reaches 40 million gallons in Oregon.

There was no exemption for avgas, nor was there any consideration for aircraft that use mogas, Rotax engines, small engines or marine engines which may require alcohol free gas.

The state has determined that we now can produce 40 million gallons of ethanol. Implementation in the Willamette Valley is scheduled for January 15 & the rest of the state will be required to have ethanol by July 15.

See the attached Word doc. for more complete info. I hope this answers any questions you may have.

Some legislators believe it doesn't apply to avgas, but it is pretty clear it applies to all gasoline. If an agency tries to exempt avgas, some environmental group may sue and force the state to enforce what the legislature wrote, so an agency exemption is not a safe haven.

We need to get rolling with pressure on the legislators now.

We need to get groups with similar concerns involved--boaters come to mind and I have already written to the Association of Oregon Loggers (chain saw concerns). If you know anyone who is active with boating or other organizations that might be affected, please get them involved.

The legislature will reconvene in February. We need to start making them aware now of our concern and put the pressure on them to pass legislation when they reconvene to exempt premium gas and avgas.

Just thought I'd pass along some observations from my little jar test of 285 m/l of 10%. It would equate to 28.5 m/l of ethanol and when I dropped 1 m/l of water in the fuel that would be 3.5% water to ethanol. When the water was added it sank to the bottom in a blob and after an hour or so it appeared to grow to about 3 times the original size---I think combining with some of the ethanol. This is in the house with mid 60's temperature. I then vigorously shook to combine and just a fraction of the original blob dropped out. Then I put the jar in the window sill to warm a bit in the sun( 80's) and shook again. This time nothing dropped out but as the sun faded and the jar cooled the fuel became cloudy. When cooled to the low 60's the water dropped again(about 1 m/l) and the majority of the fuel became crystal clear again. A little while ago I set the jar outside in 20 degree temps and the blob appeared to increase to about 3 m/l again. As you can see, temperature does have a big effect(like EAA says). There is a pretty good visual cue also(cloudy fuel indicated water that is suspended is about to drop). It seems to me a refrigerator or freezer test would detect water saturated fuel and you'd have to be pretty careless to introduce 3.5% water to you fuel.
















9

Gosh with all this testing, trying different fuels etc.

When do you guys fly? Is your time worth nothing?

Looks to me like several of the jug carrying fuel toting gas testers here would save just as much if they used 100LL and just didn't fly the equivalent of the time spent chasing car gas.

Scout,

Amen, Bro.

It seems to be the nature of many to question authority, without the slightest bit of scientific research to dispute what authority suggests.

Frankly, I could care less, cause the engine in my airplane is a 100 LL only engine. As I posted earlier, I've run auto gas in an airplane, mixed with Avgas. Never had a LOT of problems, but I did have some, and I'm convinced that they were in fact caused by the auto gas.

Would I do it again? Maybe, but I never ran auto fuel to save money. I ran it to cut down on lead in the fuel for an 80/87 engine in my plane.

My current engine leads up pretty regularly, and even though I aggressively lean, I have to clean the plugs frequently. A small price to pay for the power.

Run whatever you like, folks. But get out there and fly the dang things.

MTV

mtv wrote:Scout,

Amen, Bro.
Run whatever you like, folks. But get out there and fly the dang things.

MTV

Double Amen to that....

Gump

My January 08 Plane and Pilot magazine just came today. There is a good article about the Vanguard Squadron and how they have been running ethanol in their RV-3's since 1993. They love the stuff.