REFLECTOR: Fuel pump cooling
Scott Derrick
scott at tnstaafl.net
Tue Aug 28 20:20:34 CDT 2012
I've had this happen a few times this summer on flights longer than 2.5
-3 hours. Ran all winter with no problem so I think its heat related.
I typically run LOP, better mileage, lower temps,less pollution.
I can easily setup LOP when reaching my cruise altitude. I rarely have
to re-adjust it after getting in the desired setting.
When its really hot, say 15C+ at 11500, after a couple hours the mixture
seems to wander just a little bit and I have to periodically re-adjust
to get it back. We are talking less than 0.1 GPH change.
Once I get the engine really heat soaked after a few hours of
flight(when the LOP starts to be work to maintain) and then stop for
gas, take off climb to altitude, now its really hard to get it to run
LOP? It over leans, then under leans. If I then run it for awhile ROP
and let things cool down from the climb, I can get it to run LOP but I
still have that intermittent wandering mixture. Let the engine cool down
over night, next morning LOP is easy again with a engine starting from
cold. I've had a few departures after it sat for a couple hours after
landing and it leans easy then too. Only those hot fast turn arounds
exacerbate the issue.
I noticed the T210 that uses this same engine has a cooling duct running
to the fuel pup which is shrouded. I don't have this. I'm thinking
maybe it takes summer temps and a couple+ hours to get the fuel pump
really hot enough to, I don't know, loose it mind?
The turbo setup on this version TIO520 is very sophisticated. Once you
set the throttle you can climb, descend and change prop rpm and the MAP
doesn't move at all. Very easy to fly. My fuel pump is from that
original turbo setup.
Lycomings use an entirely different fuel pump so I don't think their
setup would apply.
Any body else see this problem thats running LOP? Is your fuel pump
cooled? This is a 1986 vintage 520, with I think a similar fuel
pump(carbon vane) is used on later models.
Scott
--
What the superior man seeks is in himself; what the small man seeks is
in others.
Confucius
More information about the Reflector
mailing list