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Re: Speeds at Altitude
My cabin pressure runs about 9K at FL250 about 5 pounds differential. I
run LOP this is required to keep the TIT temperatures in reasonable range. It is
possible to be very rich of peak at slightly more power but I don't like the
range at 20+ GPH (don't fly there and don't have exact numbers). My experience
with pressurization was that I had leaks around the door seal. I added some foam
for the seal to seat against and the door seals better and I am now able to get
5 pounds. If you can not get 5 pounds I suspect there is a
leak.
I
climb at 30 to 31 inches 2500 rpm to get to FL 250. I manage my airspeed to
maintain CHTs at 400 degrees (or less) I can only climb 800 to 1000 fpm
continuously at about 160 to 180 kts depending on temperature. I can climb
faster for short periods. The power is there, with better engine cooling faster
climb at lower airspeeds would be possible.
What is your pressurization status at this sub-28" MAP and FL250....cabin
altitude and PSI differential?
I've noticed that my IAS is about the same 188-192 regardless of MAP power
setting (30" to 36", 2500 RPM). Obviously, fuel flow is different.
And you are LOP with 15.3 gph, which makes the power output here even lower
than ROP operations, here at something ~50%.
And what are your cruise CLIMB power settings to get to FL250?
Thanks.
Jeff L
I saw 343 Kts
groundspeed today.
FL
250
2450
rpm
27.5
inches
15.3
gph
270
TAS
wing tape
installed
Lancair IV-P
N776CM
Michael Newman
Dragonnorth Group
319 Dean Rd.
Brookline, MA
02445
Cell: 617 821-4608
Home: 617
566-7975
Fax: 617 566-7975
www.dragonnorth.com
mnewman@dragonnorth.com
--
New email address: liegner@embarqmail.com
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