Matronics Email Lists Forum Index Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
 
 Get Email Distribution Too!Get Email Distribution Too!    FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Mogas versus 100LL

 
Post new topic   Reply to topic    Matronics Email Lists Forum Index -> Engines-List
View previous topic :: View next topic  
Author Message
bonanza(at)vodamail.co.za
Guest





PostPosted: Mon Sep 25, 2006 11:08 pm    Post subject: Mogas versus 100LL Reply with quote

Having digested the technicalities, I still don't know the effects or dangers of using mogas in an "avgas" engine.....

Bob Verwey
A35 Bonanza
[quote][b]


- The Matronics Engines-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Engines-List
Back to top
Float Flyr



Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

PostPosted: Tue Sep 26, 2006 5:22 am    Post subject: Mogas versus 100LL Reply with quote

Lets see...
The certified engine should have a certain amount of lead in the fuel. Yes it fouls plugs but that is why the plugs should be inspected and cleaned/replaced on a regular basis.

The certified engine is pretty high compression so to prevent pinging, detonation and backfiring it should have a pretty good diet of high octane gas.

The certified engine may fly at higher altitudes. Avgas isn't as volatile as MOGAS so more of it will actually get to go through your engine and not out the vent.

Rubber fittings in the aircraft carbs and fuel system may not be alcohol safe. Some fuel system component$ may turn to very expensive mu$h if exposed to alcohol in some MOGAS for extended periods of time. Be aware that Alcohol, if it's in your MOGAS, has an affinity for water (moisture) so it's use may require the use of carb heat

My best guess, and that's all it is, is most MOGAS supreme (booze free) should be ok for use in certified engines that aren't doing continuous full power applications or flying over 6000 feet on a regular basis. check to make sure that your insurance doesn't have any problems with the use of MOGAS and the federalis are happy with an STC.

Be sure to get the opinion of your A&P or AI. He will be aware of what's available in your area and be able to advise you what is best for your area.



Noel [quote]
--


- The Matronics Engines-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Engines-List

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats
Back to top
View user's profile Send private message Send e-mail
ogoodwin(at)comcast.net
Guest





PostPosted: Tue Sep 26, 2006 6:08 am    Post subject: Mogas versus 100LL Reply with quote

I'm not addressing the other factors, but I will say 6000 feet is no obstacle for mogas. My vehicles spend more time between 6000 and 10000 than below it and it's no problem.
[quote] ---


- The Matronics Engines-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Engines-List
Back to top
Jim Baker



Joined: 30 Mar 2006
Posts: 181
Location: Sayre, PA

PostPosted: Tue Sep 26, 2006 6:47 am    Post subject: Mogas versus 100LL Reply with quote

Quote:
The certified engine is pretty high compression so to prevent
pinging, detonation and backfiring it should have a pretty good
diet of high octane gas.

I'd probably take issue with this statement on this point. Most
aviation engines aren't high compression. Most are in the 8 to
9.5 range with some down to 7 and some up to 10.5. True, there
are high compression piston sets but the majority of aircraft don't
run them. The primary issue is cylinder volume as it relates to
octane ratings. In order to not have all the nastiness of the
above mentioned maladies dual ignition is used to control the
flame front propagation.

But then, you all probably already knew all of that anyway.....

Jim Baker
580.788.2779
Elmore City, OK


- The Matronics Engines-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Engines-List
Back to top
View user's profile Send private message
frank.hinde(at)hp.com
Guest





PostPosted: Tue Sep 26, 2006 6:48 am    Post subject: Mogas versus 100LL Reply with quote

So cars in Colorado boil all of their fuel off or what about cars that drive up Pikes Peak?

I flew at 10K or above in mY old Zodiac and NEVER had fuel boiling off.

OK so lets get to some real numbers....I have tested numerous batches of autofuel and the very worse was a winter blend of REGULAR gas...That showed some boiling at 11k.

The premiums were all good to about 15K.

It is very simple to do a vapour pressure check and I agree it should be done. Also your fuel system needs to have good vents and a system design that does not excessively suck on the fuel.

As to "pretty high compression".....well Superior warrants their engines for 92 OCT mogas up to and including 8.5:1 CR.

The real issue for me in using Mogas is not can it be run safely...It can, there are many engines that see nothing else....The issue is at what CHT and what mixture regimes.

Mogas has a detonation danger zone around the 50F ROP....Max cruise CHT is 400F for a 360 Lycoming...A higher CHT will be more likely to detonate and so will a lower octane fuel...So the question is what is the max CHT and where should one put the mixture control for cruise flight. There is no point in running cheaper gas if you have to burn so much more keeping the CHT's down.

Having said that there are so many OWT's out there and they really do nothing but prevent real progress on the issue.

We need real data or engines run for the long term and information on HOW they were run and what happened.

Frank

From: owner-engines-list-server(at)matronics.com [mailto:owner-engines-list-server(at)matronics.com] On Behalf Of Noel Loveys
Sent: Tuesday, September 26, 2006 6:21 AM
To: engines-list(at)matronics.com
Subject: RE: Mogas versus 100LL

Lets see...
The certified engine should have a certain amount of lead in the fuel. Yes it fouls plugs but that is why the plugs should be inspected and cleaned/replaced on a regular basis.

The certified engine is pretty high compression so to prevent pinging, detonation and backfiring it should have a pretty good diet of high octane gas.

The certified engine may fly at higher altitudes. Avgas isn't as volatile as MOGAS so more of it will actually get to go through your engine and not out the vent.

Rubber fittings in the aircraft carbs and fuel system may not be alcohol safe. Some fuel system component$ may turn to very expensive mu$h if exposed to alcohol in some MOGAS for extended periods of time. Be aware that Alcohol, if it's in your MOGAS, has an affinity for water (moisture) so it's use may require the use of carb heat

My best guess, and that's all it is, is most MOGAS supreme (booze free) should be ok for use in certified engines that aren't doing continuous full power applications or flying over 6000 feet on a regular basis. check to make sure that your insurance doesn't have any problems with the use of MOGAS and the federalis are happy with an STC.

Be sure to get the opinion of your A&P or AI. He will be aware of what's available in your area and be able to advise you what is best for your area.



Noel [quote]
--


- The Matronics Engines-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Engines-List
Back to top
Float Flyr



Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

PostPosted: Tue Sep 26, 2006 6:24 pm    Post subject: Mogas versus 100LL Reply with quote

I'm glad you brought up that fact. MOGAS is formulated a number of different ways. The formula used for winter and summer are different as are the formulas used in the mountains as opposed to those formulas sold in low altitude areas. 100LL has one formula regardless of whether you buy it in your home town, Timbuktu or Alert. I do know of cases where gasoline was being transported in accidentally open containers at lower than O2 altitudes and arrived only half full. The reason given was because of the volatility of the fuel it simply evaporated at the altitude.



Noel [quote]
--


- The Matronics Engines-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Engines-List

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats
Back to top
View user's profile Send private message Send e-mail
Float Flyr



Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

PostPosted: Tue Sep 26, 2006 6:57 pm    Post subject: Mogas versus 100LL Reply with quote

I especially agree with your last statement Frank. The problem in getting the real figures is the number of different blends of MOGAS available. I think your Zodiac may have forward facing vents in the fuel caps which help to pressurize the fuel system and prevent evaporation at altitude.

I run MOGAS in my little Kitfox two stroke. I know that's a good stretch from the engine in the Beech, Two stroke vs. four stroke, two cylinders vs. four cylinders and of course air-cooled boxer vs. inline liquid cooled. Not to mention the roller bearings in the little R. All my flying is low altitude and so far all summer flying. That may change this winter.

I have serviced several certified aircraft, some use MOGAS, others 100LL. Again none of them fly above 10K.ft. Some have trouble getting above 1500' that happens when most of your flying is to the closest fishing hole to fill the frying pan for breakfast.

The only difference I've seen is on the plugs and in the oil. The MOGAS is much cleaner on the plugs and at better than $50/plug it's a plus not to have to do as much cleaning, a practice that's not recommended by plug manufacturers but apparently very common.

It is interesting that the insurance Co.s don't seem to like the MOGAS because they won't write policies for commercial planes using MOGAS to carry passengers but they may allow it for use in aircraft used for training.



Noel [quote]
--


- The Matronics Engines-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Engines-List

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats
Back to top
View user's profile Send private message Send e-mail
frank.hinde(at)hp.com
Guest





PostPosted: Wed Sep 27, 2006 7:46 am    Post subject: Mogas versus 100LL Reply with quote

Indeed thats why I would always test a sample with a vapour pressure tester...You can make your own too. It very quick.

I spoke to Todd Peterson yesterday and he told me they did detonation margin testing with 89.5 octane motor fuel (i.e a degraded 91 oct mogas). They found the detonation margins to be no different to 100LL...In other words lean as you would with 100LL.

With a properly designed fuel system we're good to go...I might continue to run LL for antoher 5 hours or so complete the break in (I got 22 on the tach now) and maybe get the CHT's downn a little more before switching.

Frank

From: owner-engines-list-server(at)matronics.com [mailto:owner-engines-list-server(at)matronics.com] On Behalf Of Noel Loveys
Sent: Tuesday, September 26, 2006 7:55 PM
To: engines-list(at)matronics.com
Subject: RE: Mogas versus 100LL

I especially agree with your last statement Frank. The problem in getting the real figures is the number of different blends of MOGAS available. I think your Zodiac may have forward facing vents in the fuel caps which help to pressurize the fuel system and prevent evaporation at altitude.

I run MOGAS in my little Kitfox two stroke. I know that's a good stretch from the engine in the Beech, Two stroke vs. four stroke, two cylinders vs. four cylinders and of course air-cooled boxer vs. inline liquid cooled. Not to mention the roller bearings in the little R. All my flying is low altitude and so far all summer flying. That may change this winter.

I have serviced several certified aircraft, some use MOGAS, others 100LL. Again none of them fly above 10K.ft. Some have trouble getting above 1500' that happens when most of your flying is to the closest fishing hole to fill the frying pan for breakfast.

The only difference I've seen is on the plugs and in the oil. The MOGAS is much cleaner on the plugs and at better than $50/plug it's a plus not to have to do as much cleaning, a practice that's not recommended by plug manufacturers but apparently very common.

It is interesting that the insurance Co.s don't seem to like the MOGAS because they won't write policies for commercial planes using MOGAS to carry passengers but they may allow it for use in aircraft used for training.



Noel [quote]
--


- The Matronics Engines-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Engines-List
Back to top
mcculleyja(at)starpower.n
Guest





PostPosted: Wed Sep 27, 2006 8:41 am    Post subject: Mogas versus 100LL Reply with quote

"Hinde, Frank George (Corvallis)" <frank.hinde(at)hp.com> writes:

(SNIP)Mogas has a detonation danger zone around the 50F ROP....Max
cruise CHT is 400F for a 360 Lycoming...A higher CHT will be more likely
to detonate and so will a lower octane fuel...So the question is what is
the max CHT and where should one put the mixture control for cruise
flight. There is no point in running cheaper gas if you have to burn so
much more keeping the CHT's down.(SNIP)

I've seen data from Lycoming stating the O-360 at CR of 8.5 to 1 has an
allowable CHT of 225C (437F) when operated at less than 75% power and
245C(473F) when greater than 75% power.

Not that I would advocate routine operation at these levels but I'm
curious where you found the 400F cruise limit for the 360 Lycoming?

Jim
-----------------------------------------------------------------------------


- The Matronics Engines-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Engines-List
Back to top
w_sweet(at)comcast.net
Guest





PostPosted: Wed Sep 27, 2006 11:29 am    Post subject: Mogas versus 100LL Reply with quote

To chime in here, I talked to Lycoming on the phone several years ago when
my O-360A1A was running at CHT's a bit over 400F. It was stated by the
representative that longevity of the engine would be affected at those CHT's
and to try to get them down below 400F.
Wayne

---


- The Matronics Engines-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Engines-List
Back to top
frank.hinde(at)hp.com
Guest





PostPosted: Wed Sep 27, 2006 11:50 am    Post subject: Mogas versus 100LL Reply with quote

Yes thanks Wayne,

That was my reading of the situation as well...Clearly some further
baffle/flashing work is in order.

Frank

--


- The Matronics Engines-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Engines-List
Back to top
Bob H



Joined: 01 Dec 2006
Posts: 43

PostPosted: Mon Dec 04, 2006 8:40 am    Post subject: Re: Mogas versus 100LL Reply with quote

A Bonanza driver in Big Bear, CA has used 89 oct mogas for 18 yrs and 2500 hrs with no ill effects. And in last 5 yrs, Cailf mogas contains 10% alcohol. He does monitor any rubber components for deterioration and so far, all is ok. Elevation here is 7000' and we routinely fly at 9500' on long trips and into desert heat in summer. Pulled cyl heads recently and found minimum buildup on valve backs and good seat contacts;relapped valves anyway.
Bob H


- The Matronics Engines-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Engines-List
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Matronics Email Lists Forum Index -> Engines-List All times are GMT - 8 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Powered by phpBB © 2001, 2005 phpBB Group