VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #1  
Old 09-21-2017, 07:18 PM
TXFlyGuy TXFlyGuy is offline
 
Join Date: May 2012
Location: Jazz Town, USA, TX
Posts: 332
Default Avgas, or MoGas?

For those flying with V8 engines, what are you burning? 100LL, or 93 Octane MoGas?

What are the benefits? Cost savings? Cleaner oil? Is the alcohol a problem in MoGas?

Are there any airports that sell MoGas?
Reply With Quote
  #2  
Old 09-21-2017, 09:56 PM
simpkinsona simpkinsona is offline
 
Join Date: Dec 2010
Location: Vacaville, CA
Posts: 126
Default Lots of variables

I fly a Subaru 4 cylinder. I use 91 octane auto fuel with ethanol. There's many considerations as to what to use. Lead free in general is better for auto engines. I have had a stuck ring from leaded fuel and that seems to be a common problem with auto engines running 100LL.

You have to determine if your fuel system can handle the more volatile fuel and effects from alcohol. Also if you have higher compression levels or aggressive ignition timing you may need higher octane fuel.

-Andy
__________________
Andy Simpkinson
RV-9a Subaru engine.
Reply With Quote
  #3  
Old 09-21-2017, 09:59 PM
simpkinsona simpkinsona is offline
 
Join Date: Dec 2010
Location: Vacaville, CA
Posts: 126
Default Availability

In general unleaded fuel is rarely available at airports. There's a few airports in the west in Oregon and Idaho. There's some around Oshkosh and scattered around. I usually end up buying leaded fuel when on a trip.

-Andy
__________________
Andy Simpkinson
RV-9a Subaru engine.
Reply With Quote
  #4  
Old 09-21-2017, 10:35 PM
rv7charlie rv7charlie is online now
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 2,555
Default

Try this to find airport mogas.
http://www.flyunleaded.com/mapusairports.html

Leaded gas is pretty bad for aircraft engines, too, in most ways. ;-)

The rotary guys don't have to worry about octane (unless they run a turbo with a lot of boost), and most don't worry about ethanol, either. So most just run whatever pump mogas is within reach.

Charlie
Reply With Quote
  #5  
Old 09-22-2017, 07:10 AM
TXFlyGuy TXFlyGuy is offline
 
Join Date: May 2012
Location: Jazz Town, USA, TX
Posts: 332
Default

Quote:
Originally Posted by rv7charlie View Post
Try this to find airport mogas.
http://www.flyunleaded.com/mapusairports.html

Leaded gas is pretty bad for aircraft engines, too, in most ways. ;-)

The rotary guys don't have to worry about octane (unless they run a turbo with a lot of boost), and most don't worry about ethanol, either. So most just run whatever pump mogas is within reach.

Charlie
Interesting map. In Texas, only 3 available. Guess I'll have to become my own tanker truck, hauling 5 gallon cans to the airport. This is what I did back in the 70's when I owned a C-172. It ran SO much better an auto fuel. But that is way before the EPA ruined the gas with the addition of alcohol.

edit: Just read that gasoline containing the dreaded alcohol MUST be avoided, as it will easily induce vapor lock.

Last edited by TXFlyGuy : 09-22-2017 at 07:43 AM.
Reply With Quote
  #6  
Old 09-22-2017, 08:16 AM
tspear tspear is offline
 
Join Date: Nov 2010
Location: Boston Area
Posts: 135
Default

Quote:
Originally Posted by TXFlyGuy View Post
Interesting map. In Texas, only 3 available. Guess I'll have to become my own tanker truck, hauling 5 gallon cans to the airport. This is what I did back in the 70's when I owned a C-172. It ran SO much better an auto fuel. But that is way before the EPA ruined the gas with the addition of alcohol.

edit: Just read that gasoline containing the dreaded alcohol MUST be avoided, as it will easily induce vapor lock.
You should check the regs, but I am fairly positive you can have up to 99 gallon tank in a truck bed (and you are in TX so you must have a truck) and be legal. Not sure in Texas, but in TN where I lived a few years you could go a select locations which sold fuel for farms and buy gas with no ethanol. Legally, you are supposed to send the FAA trust fund some cash per gallon you use. I think it was 11 cents, but do not quote me on that.

Tim
Reply With Quote
  #7  
Old 09-22-2017, 10:01 AM
SHIPCHIEF SHIPCHIEF is offline
 
Join Date: Mar 2008
Location: Seattle
Posts: 1,327
Default

Vapor lock won't be a problem if your engine has an automotive fuel injection system using electronic controlled injectors and 35 psi fuel lines.
I ran a Mazda Turbo Rotary with 93 octane ethanol free Mogas, not a problem.
Unleaded fuel was required because of the Oxygen sensor in the exhaust pipe.
An automotive fuel injection system pumps all the fuel over the top of each injector. The unused fuel passes thru the fuel pressure regulator and returns to the fuel tank. So the fuel remains relatively cool, and the high pressure at the injector prevents vapor lock.
If you have faith in the reliability of electronic engine control, it is the best system.
When I removed the Rotary engine (I couldn't get comfortable with it) I retained the dual electric fuel pumps and 35 psi 'turn-down' regulator to feed the Bendix style fuel injector servo. I never have heat related re-start problems common with Bendix injection.
I don't use Mogas currently, but I used to carry it in a 55 gallon drum in the back of my pickup truck.
I built a drum cradle, the drum lays on it's side. I placed the big bung at the top, and the 3/4" NPT bung at the bottom. with a ball valve and hose. Fuel easily gravitated to the RV wing tank. You can't fill the drum as full, but it's still enough to fill an RV. The drum laying down in a cradle is lower in the pickup bed and easier to fill at the gas station. You can strap it down tight and clamp a ground wire to the drum, truck and a ground wire to the plane.
__________________
Scott Emery
http://gallery.eaa326.org/v/members/semery/
EAA 668340, chapter 326 & IAC chapter 67
RV-8 N89SE first flight 12/26/2013
Yak55M, and the wife has an RV-4
There is nothing-absolute nothing-half so much worth doing as simply messing around with Aeroplanes
(with apologies to Ratty)

Last edited by SHIPCHIEF : 09-22-2017 at 10:25 AM.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 09:47 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.