"Stormlord" <Stormlord.3bncon@[EMAIL PROTECTED]
> wrote in message
news:Stormlord.3bncon@[EMAIL PROTECTED]
>
> I have a fairly new (less than a year old) OS .61FX mounted upright in a
> Twist 3D 60 with a 13x6 prop. The engine has been properly broke in and
> has about 20 flights on it.
> I'm having a problem that I'm not sure how to solve.
> When flying the plane at around 1/4 throttle, if I fly inverted, it
> will die and I have to dead-stick the plane to the ground.
> It doesn't seem to happen when I do this at 3/4 or higher throttle, but
> it does stutter from time to time, it just doesn't quit.
> I never have a problem whatsoever if I don't fly inverted ... runs
> through a tank of fuel just fine and I can do anything I want with the
> plane.
>
> At first, I thought the clunk was getting stuck and sucking air, but
> this is not the case.
> The clunk is free and not getting hung up anywhere ... also, when the
> plane lands dead-stick, upon inspection, there is fuel in the fuel line
> all the way to the carb with no air bubbles in it.
>
> Is there a way to correct this problem? Anyone ever had this happen
> before? I'm not sure where to start, I've never had this issue
> previously.
>
> I've tried leaning and richening the engine with the main needle valve
> (no difference - the problem is repeatable), and I've changed to a
> hotter glow plug (from an OS 8 to a 3) so far.
>
> I'm just not sure what's causing the condition, so I'm not sure what to
> try to fix it.
>
> Could the engine be flooding itself upside down somehow, causing the
> glow plug to foul out? What would cause that and how can it be
> corrected?
>
> I pulled the glow plug after one of the dead-stick landings and it was
> not wet, but with a hot engine, I thought maybe it had eva****ated after
> normal level flight had resumed (even though the engine was not
> running).
>
> Just not sure where to go with this and I'm searching for some ideas to
> try ....
Like the other reply, I think that the fuel tank is probably set too low
causing a tank high position when inverted. This can easily drown your
engine with an overly rich mixture. I would set the tank up dead centre
with
the needle valve (had to for pattern flying where there is a lot of
inverted
and outside manoeuvres). Then very carefully adjust the low end mixture so
that it isn't too rich. You have to make adjustments to both the low and
high end mixtures as you are tuning. You know that you have the low end
mixture pretty close if you have the engine at idle for several seconds
and
then pinch off the fuel line and the engine dies without a great increase
in
rpm. There should be a slight rpm increase before dying. Properly tuned
there should be little to no hesitation when going from idle to full
throttle.
Good luck
--
Ron P
If we are what we eat then: I'm fast,
cheap and easy and past my best before date
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