Today's Message Index:
----------------------
1. 08:46 AM - Re: Mogas versus 100LL (Hinde, Frank George (Corvallis))
2. 09:41 AM - Re: Mogas versus 100LL (J. Mcculley)
3. 12:29 PM - Re: Mogas versus 100LL (Wayne Sweet)
4. 12:50 PM - Re: Mogas versus 100LL (Hinde, Frank George (Corvallis))
Message 1
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| Subject: | Mogas versus 100LL |
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@matronics.com
[mailto:owner-engines-list-server@matronics.com] On Behalf Of Noel
Loveys
Sent: Tuesday, September 26, 2006 7:55 PM
Subject: RE: Engines-List: 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
-----Original Message-----
From: owner-engines-list-server@matronics.com
[mailto:owner-engines-list-server@matronics.com] On Behalf Of Hinde,
Frank George (Corvallis)
Sent: Tuesday, September 26, 2006 12:16 PM
To: engines-list@matronics.com
Subject: RE: Engines-List: Mogas versus 100LL
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@matronics.com
[mailto:owner-engines-list-server@matronics.com] On Behalf Of Noel
Loveys
Sent: Tuesday, September 26, 2006 6:21 AM
To: engines-list@matronics.com
Subject: RE: Engines-List: 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
-----Original Message-----
From: owner-engines-list-server@matronics.com
[mailto:owner-engines-list-server@matronics.com] On Behalf Of Bob Verwey
Sent: Tuesday, September 26, 2006 4:36 AM
To: engines-list@matronics.com
Subject: Re: Engines-List: Mogas versus 100LL
Having digested the technicalities, I still don't know
the effects or dangers of using mogas in an "avgas" engine.....
Bob Verwey
A35 Bonanza
nics.com/Navigator?Engines-List
nics.com/Navigator?Engines-List
nics.com/Navigator?Engines-List
Message 2
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| Subject: | Mogas versus 100LL |
--> Engines-List message posted by: "J. Mcculley" <mcculleyja@starpower.net>
"Hinde, Frank George (Corvallis)" <frank.hinde@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
-----------------------------------------------------------------------------
Message 3
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| Subject: | Re: Mogas versus 100LL |
--> Engines-List message posted by: "Wayne Sweet" <w_sweet@comcast.net>
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
----- Original Message -----
From: "J. Mcculley" <mcculleyja@starpower.net>
Sent: Wednesday, September 27, 2006 9:38 AM
Subject: RE: Engines-List: Mogas versus 100LL
> --> Engines-List message posted by: "J. Mcculley"
> <mcculleyja@starpower.net>
>
> "Hinde, Frank George (Corvallis)" <frank.hinde@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
> -----------------------------------------------------------------------------
>
>
>
Message 4
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| Subject: | Mogas versus 100LL |
--> Engines-List message posted by: "Hinde, Frank George (Corvallis)" <frank.hinde@hp.com>
Yes thanks Wayne,
That was my reading of the situation as well...Clearly some further
baffle/flashing work is in order.
Frank
-----Original Message-----
From: owner-engines-list-server@matronics.com
[mailto:owner-engines-list-server@matronics.com] On Behalf Of Wayne
Sweet
Sent: Wednesday, September 27, 2006 12:27 PM
Subject: Re: Engines-List: Mogas versus 100LL
--> Engines-List message posted by: "Wayne Sweet" <w_sweet@comcast.net>
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
----- Original Message -----
From: "J. Mcculley" <mcculleyja@starpower.net>
Sent: Wednesday, September 27, 2006 9:38 AM
Subject: RE: Engines-List: Mogas versus 100LL
> --> Engines-List message posted by: "J. Mcculley"
> <mcculleyja@starpower.net>
>
> "Hinde, Frank George (Corvallis)" <frank.hinde@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
>
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>
>
>
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