[AlaskaRC] Anyone good tuning an engine

Fri Sep 11 19:45:53 AKDT 2009

I think it is a combination of the low end adjustment and not enough
pressure. Even on full throttle I have to have it rich to keep it going, not
just a little rich, but almost 4 full turns open. Any less and it will die
strait away when nose up.  Also, it is loading up, but I am not sure if that
is because it is so rich or if the low end needs adjusting. I am going to
plug one hole temporarily to see what happens. I have been reading a lot
about problems with the pitts muffler and the OS .55 AX, a lot of people
seem to be having this same problem and pinching off a down tube fixes it. I
think trial and error is the only thing going to fix this engine. 

-------Original Message-------

From: akflyer
Date: 9/11/2009 11:31:51 AM
To: ARCS mailing list
Subject: Re: [AlaskaRC] Anyone good tuning an engine

I run lots of engines inverted with pitts muffs.  Check your glow plug, and
the idle adjustments.  Sounds like it is loading up on the low end or your
plug is too cold.  At idle, pinch the fuel line.  How long does it take for
it to die?  If more than a few seconds, your probably rich on the low end. 
Most transition issues are due to the low end adjustment.

Leni

--- On Fri, 9/11/09, bob at jetmodeler.com <bob at jetmodeler.com> wrote:

From: bob at jetmodeler.com <bob at jetmodeler.com>
Subject: Re: [AlaskaRC] Anyone good tuning an engine
To: "ARCS mailing list" <alaskarc at lists.alaskarc.org>
Date: Friday, September 11, 2009, 10:11 AM

Hello, Nathan,

Before you plug one of the down-tubes, you might try one more thing.

Try fueling the tank with only 1/4 tank of fuel...then, after going to full
throttle, point the nose straight up. After a few second, if the engine dies
 the problem may be with the pick-up tube in the tank.

Good luck,
Bob

-----Original Message-----
From: Nathan Stanfield [mailto:NathanStanfield at hotmail.com]
Sent: Thursday, September 10, 2009 08:08 PM
To: 'ARCS mailing list'
Subject: Re: [AlaskaRC] Anyone good tuning an engine

Ray,
Thanks for the help! I am going to try plugging the pipe tonight and I will
test it out Sunday. I was so happy today when it flew, but then terrified
when the engine died, but the dead stick landing was one of the best
landings I have ever made. Too bad I had to power to go around and land
again. I will be out at Elmendorf Sunday if anyone wants to come out and fly
with me. 

-------Original Message-------

From: ray hoffman
Date: 9/10/2009 5:50:45 PM
To: ARCS mailing list
Subject: Re: [AlaskaRC] Anyone good tuning an engine

Hi Nathan, I had the same problem, when I put Pitts mufflers on my B-17. I
had problems with all the engines running right. So I did just what you're
thinking. I cut off one pipe, leaving maybe a 1/2 inch. I plugged it with a
wood dowel.Just be sure to drill a very small hole in the center of dowel,
so oil can drain. If you have trouble with afterwords, let me know, and I'll
help you tune it personally. Hope I helped.

Ray

--- On Thu, 9/10/09, Nathan Stanfield <NathanStanfield at hotmail.com> wrote:

From: Nathan Stanfield <NathanStanfield at hotmail.com>
Subject: [AlaskaRC] Anyone good tuning an engine
To: alaskarc at lists.alaskarc.org
Date: Thursday, September 10, 2009, 3:41 PM

Hello all, I am a new member of the club and just got to Alaska a month ago.
I have an OS .55 with at Pitts muffler that is giving me problems. It runs
well on the stand but dies as soon as I try to throttle up to take off.  I
have tuned it the best I can, its just rich enough so that it does not lose
power when pointing strait up, but I think with the pitts its not getting
enough back pressure and is running rich to keep it going when pointed up. I
think if I pinch off one of the two exhaust outlets it might help??? Anyone
willing to come out to Elmendorf field on Sunday to help me with it? Or does
anyone have any ideas about what I could do to fix this?
Thanks,
Nathan 

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