Avgas shortage

[Learjockey]

I keep hearing rumors about a potential avgas shortage in the next 5 years. Can the the cozy airframe handle mogas and then the next question would involve what type of engine to use. I want to do the standard Lycoming 360 but, what if I can't get gas for it?

[Crazycanuck]

Don't worry, Adam Smith will continue to provide AVGAS so long as there is a need.

 

I would love to be able to put mogas in my plane, but from what I have read the extra savings isn't worth the risk.

[Waiter]

This discussion makes the rounds about every six months. I'd recommend doing a "Search" on Autofuel".

 

With 100LL approaching $5 per Gallon, I can save $1.50 to $2.00 per gallon by using AutoFuel. That equats to about $20 per hour.

 

I've burned Autofuel in all my aircraft, The only thing I've noticed is, I can now fly about 1/3 more often that I could if I was burning 100LL.

 

My LongEZ has over 2600 hours on it, most of these hours were with Auto fuel.

 

Generally, if your running compression ratio of 9:1 or less, you shouldn't have any problems.

 

Waiter

[longezdave]

I too flew my Long with primarily auto fuel for the first 470 hours. I never had problems at all even after shutting down on a hot summer ramp and restarting later (no vapor lock).

 

I then found a cracked cylinder and overhauled using 9.7:1 pistons. Naturally it has been 100LL ever since.

 

Worst case for me is to go back down on compression and back to auto fuel if the need arrises.

[brainfart]

I don't know about US autofuel, but here in Europe there are plans to add increasing amounts of alcohols to the gasoline in the next few years. Alcohols will affect many epoxies.

[Crazycanuck]

I read an article in one of my flying magazines recently about a group of demonstration pilots that run their Lycoming engines on 100% ethanol at various airshows. They have a total of 3000 hours on ethanol with only minor alterations to the engine and say that they have done so without a problem. Most notably they say there is a significant increase in HP with ethanol. I also know that ethanol has a higher natural octane rating than petroleum gasoline.

 

Why couldn’t the fuel tanks be lined with a coating that can withstand ethanol based fuels?

[Cozy1200]

I'd liked to read that article if you can remember which mag it was in.

[rickh]

I read an article in one of my flying magazines recently about a group of demonstration pilots that run their Lycoming engines on 100% ethanol at various airshows.

I'd be interested in the link also. BTW, there was (is?) a site dedicated to E-85 ethanol, think it was U of Iowa or sumpin.

Why couldn’t the fuel tanks be lined with a coating that can withstand ethanol based fuels?

No reason they can't. I'm looking at Vinyl-Ester resins. I understand (read: I read it on the internet so it must be true) vinyl-esters are used in many underground fiberglass fuel tanks. Flue liners, corrosion resistant tank liners, ... It's got a pretty high Tg also.

 

Used as a final skim coat when I do the strakes, or used as the resin in a thin glass veil as a 'bonus' layer over plans BID/UNI/Epoxy. Or not.

 

Though I'd probably need to limit myself to a low compression Lycoming, it would give me an additional option for fuel. If avgas got to $12.00/L

 

Rick

[michaelj]

I ran autogas in my C150 for about 600 hours without any problems. Before running the auto gas I replaced the plastic carburetor float with a brass float. My Cozy drank a lot of auto gas with no problems. Just to satisfy myself I would only put Avgas in the left tank and would mix avgas and auto fuel in the right tank. I would always run on the left tank for takeoff and landings. When I got up to my cruising altitude I switched to the right tank. I always bought my gas at the same station every time. It should be safe to say that avgas is much cleaner than road gas. My current project is a low compression 0320E2D and will probably drink some autogas since avgas is already $5/gal here. I just put a brass float in the carburetor this last week. My break in will be with avgas only.

[raiki]

I read an article in one of my flying magazines recently about a group of demonstration pilots that run their Lycoming engines on 100% ethanol at various airshows.

One thing to remember here is that the Stoichio-metric air-fuel ratio of gas is around 14.7 whereas ethanol is 9 (and methanol even worse). This means for the same air charge mass, more ethanol will be needed that gas. Ethanol also has less heat energy per lb (13,000 btu/lb for ethanol, 17,000 btu/lb for gasoline), but because more is going in per stroke the same (or more) heat energy will be produced in total (close enough).

 

So when you consider higher consumption this means ethanol is not as great as it first seems. Given the figures above an ethanol engine with the same HP as a gas engine would require a 60% increase in fuel flow. Imagine your 10gal/hr Cozy now burning 16gal/hr. Not a nice thought.

 

Now I am not saying it can't be done, in fact you could raise the compression really high to gain some HP but that means no gas anymore. The number in real life might not turn out this bad but I am sure they wont be a whole lot better.

 

Also I am not a chemist or engineer or anything like that. This is just what I have learnt from playing with fuel injection (Fords EEC and the Megasquirt) anf flying alcohol fueled model planes/helicopters.

 

Anyhow thats my thoughts on it, by all means do your own research. I could be wrong.

[Crazycanuck]

I'd liked to read that article if you can remember which mag it was in.

It was in the January 2008 issue of Plane and Pilot.

 

I also found the link to their website.

 

http://www.ethanolairshows.com/

[emteeoh]

Do cozy builders typically coat their tanks with jeffco?

[CBarber]

Don't know about the typical Cozy builder, but I used Jeffco in my Velocity SE.

[emteeoh]

yeah, that's the thing. Every time I read about jeffco, its in the context of a velocity, not a cozy. It comes to mind because the velocity builders seem to be using it because its more resistant to other fuels than the epoxies being used, or at least, that's what I understand to be the reason.

[CBarber]

That is my understanding as well.

[wolf.]

5$/gallon AVGAS that would be my joy overhere, I refulled last sunday here in Italy and I payed 2.4€/L that would be like 14$/gallon. I need the MOGAS..

 

 

wolf.

[RGlos]

My LongEZ has over 2600 hours on it, most of these hours were with Auto fuel.

Waiter

I take you used 93 octane autofuel?

[Waiter]

I take you used 93 octane autofuel?

Nope!, Standard ole 87 octane.

 

My O-320 has 8.5 pistons in it.

 

If you are using a higher octane, make sure the fuel isn't using Alcohol for the octane booster.

 

Waiter

[RGlos]

If you are using a higher octane, make sure the fuel isn't using Alcohol for the octane booster.Waiter

I'm not exacly shure how to do this. Is it marked on the pump?

What brand of gas were/are you using?

 

Rick

[jwright]

Here's a link to an SAIB that outlines the test procedure to check for ethanol. Very simple to do; no need to buy a "testing kit"... http://www.eaa.org/autofuel/saibs/10_27_06%20-%20CE-07-06.pdf

[Neverquit]

I've been told all this time not to worry about methanol if I lined the tanks with Jeffco. We've been told that for 10 years now. What's the big deal?

[Richard Schubert]

Known Problems:

 

 

 

Alcohol attacks some seal materials and varnishes on cork floats of fuel level indicators. This could cause leakage of seals and release particles of varnish from floats, causing blocked screens in fuel lines or blocked carburetor jets. Excessive entrained water carried by alcohol could lead to fuel lines blockage or blockage at screens or valves when operating at low ambient temperatures at ground level or at high altitude. Fuel volatility is also increased with the addition of alcohol in a manner that is not detected by the Reid Vapor Pressure test which is used to determine if a fuel meets the automotive specification. For example, a gasoline with alcohol will meet the Reid Vapor Pressure limit of 13.5 psi but it will behave as though it has a volatility of roughly 20 psi. Gasoline's with alcohol will also phase separate. Phase separation occurs as the gasoline/alcohol blend cools, such as when a plane climbs to a higher altitude. When water that is absorbed in the fuel by the alcohol comes out of solution, it takes most of the alcohol with it. The quantity that comes out of solution cannot be handled by the sediment bowl and tank sumps. Furthermore, if the alcohol is used to raise the octane of the base gasoline, the gasoline that remains will not have sufficient octane to prevent detonation.

[yak55x]

The only problem I've encountered with mogas is that aircraft Mil spec fuel tubing was eaten away and swollen on the inside. I never noticed untill a pinhole leak started whizzing on my neck - on the ground after a fill up fortunately. It was a Kitfox which has fuel lines in the cockpit. Mmmmmm not a great idea....? Just posting an experience. I just changed the lines to auto fuel tube and all is well for 3 years. Avgas I'm guessing has some nice stabilizers in it too. It doesn't autooxidize and go "bad" so much as autofuel.