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  #31  
Old 11-14-2014, 11:18 AM
N427EF N427EF is offline
 
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Quote:
One key measure of gasoline volatility is its vapor pressure. Adding 10% ethanol to gasoline will
increase the vapor pressure of the fuel blend by about 1 pound per square inch (psi). However, this is
not of great concern since the maximum volatility of all summer grades is regulated by the EPA and is
at much lower levels than gasoline sold in the late eighties. This has eliminated any hot restart/vapor
lock problems in all but the most sensitive vehicles.
Paige, you are correct!

The same article does however point out the issue involving heat and how properly designed engine compartments have eliminated the vapor lock issue.
The same is true for properly designed fuel systems and cooling systems in airplanes.

It is a very good write up and also shows the higher octane rating of ethanol.
and its ability to resist detonation.

As always I am not trying to sell anyone on the idea of mogas just telling you that it works very well for me in all phases of flight and all seasons as well as it does for my friends who are not as vocal as I am.
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  #32  
Old 12-01-2014, 01:37 PM
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Raymo Raymo is offline
 
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Quote:
Originally Posted by newt View Post
It seems to me that ethanol is a discretionary problem: A builder could choose to construct an ethanol-proof airplane through judicious selection of components and materials, and proceed to operate that airplane significantly cheaper than one which requires "aviation" fuel. Auto makers dealt with this decades ago. Why isn't it the "normal" desired outcome for aircraft builders?

- mark
One other issue that affects airplanes more so than cars is that ethanol blends with water.

The Peterson STC provides a method for testing MOGAS for ethanol, which is to put some water in a small container, mark its level and add MOGAS. Shake well. If the water level appears to rise, you have ethanol in the fuel. Their concerns, documented in the STC, are primarily around increased chances of carb icing but also vapor lock on hot days when the airplane is parked outside and the fuel absorbs heat.

Last edited by Raymo : 12-01-2014 at 01:50 PM.
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  #33  
Old 12-01-2014, 02:39 PM
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Bill Boyd Bill Boyd is offline
 
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Default science 'speriment:

This quality (that allows testing for ethanol) has made me wonder if it is possible to remove the ethanol from gasohol by letting it sit in contact with a water layer. I see a downside, which is water migrating the other way into the gasoline phase, but it might be interesting to try. Might just be a way to take this **** out of our blended fuels (thanks, Congress.)
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  #34  
Old 12-01-2014, 02:47 PM
wilddog wilddog is offline
 
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That could remove the ethanol but what would the octane be without it?
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  #35  
Old 12-01-2014, 03:25 PM
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airguy airguy is offline
 
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Quote:
Originally Posted by wilddog View Post
That could remove the ethanol but what would the octane be without it?
Poor. It's been discussed here several times, do a search and you'll find more than you care to read...

Bottom line is forget about removing the ethanol by water-soaking your fuel, it causes far more problems than it solves.
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  #36  
Old 12-01-2014, 08:42 PM
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L'Avion L'Avion is offline
 
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Location: Memphis
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Default As to ethanol:

http://aerobaticteams.net/vanguard-squadron.html

[The team has over 3,000 flight hours using 100% ethanol. The Vanguards are available for fly-bys for events such as parades and ground breaking ceremonies. The Squadron flies 6-10 airshow events each year. Flying across the country the team promoting ethanol as the fuel for the future. The Vanguard Squadron home is Tea, SD (Lincoln County Airport) which is very close to the largest city in South Dakota, Sioux Falls.]

See also:

Vanguard Squadron, Thunder Over the Valley, Youngstown, OH 2014
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  #37  
Old 12-04-2014, 09:33 AM
Turbofan Turbofan is offline
 
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Modern cars have completely closed fuel systems limiting the possible outside contamination from moisture and therefore don't absorb moisture into the gas through ethanol absorption, airplanes don't have this system.
Low compression engines cannot burn off all the excessive lead and stuck valves becomes the primary concern. Ever cleaned plugs w lots of lead build up with a pick? Stuff is hard as nails, imagine what's happening to your valves and guides. I run a mixture of 50/50 or straight Mogas without ethanol for valve sake only, not economy of fuel. It's also far easier to start a carb engine when it's cold on mogas as it vaporize so much more readily.
Someone said ETHANOL increases octane, not true, ethanol is added last and varies state to state as I understand it.
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  #38  
Old 12-04-2014, 12:57 PM
N427EF N427EF is offline
 
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Quote:
FACT: With a 113 octane rating, ethanol is the highest performance fuel on the market and keeps today's high-compression engines running smoothly.
The reference was made in response to someone wanting to remove ethanol from gasoline.
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