Ian,
Consult the resin chemist as to which vinylester
to use. There are many types with optimum
properties for different uses. Vinylester is used
for making below ground fuel storage tanks so
there will be one for various types of mogas.
-------------
I used to run Super in the TOP when Super was
available. Then tried straight 100LL Avgas and lost 100 rpm off the top end.
Another bloke with a Ventus CM with Solo engine
lost about 200 -250 rpm doing the same thing.
Going to unleaded with 20% avgas restored the rpm in both cases.
My surmise is that the higher octane Avgas burns
slower effectively retarding the timing. This
could be why when set up to run on 95 Mogas
running ofn Avgas is not so good. It may be that
when running on the higher octane Avgas the two
strokes could benefit from advancing the ignition timing.
Any two stroke experts care to comment?
Mike
At 01:29 PM 5/02/2015, you wrote:
I must admit I used epoxy resin Ciba/GÂ 3600
and not vinyl ester.  I am going to try again using vinyl ester.
I am doing another trial with shell/liberty 98
and BP 98 with smell. In every case the shell
smells like turps is added where as BP smells
normal like you expect fuel to smell like.Â
 People are smelling the difference 100%.Â
 Some are describing the smell as paint
thinners. Shell is a golden bright yellow
colour where BP is more normal fuel colour.
In germany they have zero issues of fuel turning
clear fuel lines a real dark brown so dark you
can not see brought be in 2 months. Sure happens here with liberty /shell
So 98s are not the same.
Ian mcphee
On 04/02/2015 1:31 pm, "DMcD"
<<mailto:[email protected]>[email protected]> wrote:
>>I'll stick to Avgas in the BD-4 even though
the 7:1 compression ratio engine (same as Super
Cub) can handle unleaded from an octane rating basis.
Unless things have changed, with some two strokes used in SLGs like
the Solo engines, the manufacturer recommends using 95, not Avgas. The
claim is that Avgas makes the engine run rougher and vibrate more than
95.
It's difficult to get a real picture but a lot of the US experience,
where they tend to overcompensate and use Avgas instead of 95, seems
to suggest they have more problems overall, not less. Then again, they
can't get the recommended Castrol 2 stroke oil either.
I tend to agree with Mike here regarding resins too. It's really
difficult to point your finger at the fuel without knowing more about
the resins used in the layup.
And the problems and expense of wing fuel bags seem to be not worth
the effort. The recommendations in the manual that I have read say
that they cannot be left with fuel in overnight, that they cannot be
entirely drained either but need to have a small amount of oil in
them. They have a very short life span (8-10 years?) and are sodding
expensive to replace.
Probably cheaper to replace than a fuselage mounted glass tank though!
D
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