In a message dated 12/29/2005 9:12:10 A.M. Central Standard Time,
marv@lancaironline.net writes:
George,
Could
you gather a little data for me?
Sure.
I know that the big bore TCM
engines - - if set up properly LOP at high
power at altitude,
will always operate nicely with no mixture
adjustment after a long
descent.
Hmmm... At 2500 RPM and pulling back to 17-19 inches (maintained thru
the descent), I always twist the Mixture vernier for a bit more fuel every
few thousand feet as the EGTs change (rise) in a 400+ fpm descent
that forces me to operate at 190-210 KIAS with ram air pressure greater
than it was at cruise. Usually, when I level off, the mixture will be just
about right to either finally slow down or reapply power back to 25" MAP.
But I don't have any recent experience
(I owned a Mooney for 1500 hours
- - years ago <g>) with
the fuel system on the Lycoming engines. What
happens to
your engine if you have it well LOP at altitude and then
descend
without adjusting the mixture and power up after a 10 or 15K
foot
descent ???
Hmmm.... OK, at the next opportunity, I will perform a constant
speed (135-140 KIAS) climb to 12000 feet (away from ORD), set up cruise at 30-40
LOP, and descend (say 500 fpm or so, I don't have TRU-TRAK) as you requested
unless something exotic occurs - I will be writing furiously during this
exercise unless the traffic alerter starts to nag at me. For those
interested, I will be reporting LSE timing also.
Scott Krueger
AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL (KARR)
Happy
New Year to all!