I’ve talked about some performance numbers in the past, but I thought I should write some down after being prompted by a former Cirrus order holder that defected to an A36 … See Dave Humphreys I did make an initial stab.
What are the power settings and what do you use to make descents, approaches, and to comply with ATC instructions. Well folks I have to confess that I sometimes “wing it” (bad), but here are some numbers that I calculated from an actual flight last week.
Conditions: Alt - 3500’ | HG 30.32 | OAT 61F
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RPM/MP KIAS TAS GPH
Level Flight
Full Throttle 2700/26 154 162 13
At the ‘stop’ 2500/23 140 148 9.5
2500/25 145 153 10.0
2000/20 105 111 6.0
Descent KIAS VSI
To the ‘stop’ 2500/- 155 500
2000/20.0 140 800
2000/15.0 100 300
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By the ‘stop’ I mean the throttle is pulled back to the cam or detent point, which is the point at which the prop RPM starts to drop below 2500 RPM. Using the above numbers, if you want to descend from 8000 to 4000 you can pull the throttle back to the stop and fly a constant airspeed of 155 KIAS and descend at approximately 500 FPM.
It is difficult to slow down. It is even more difficult when you have to ‘go down’ at the same time. These numbers should help. I would be interested now that there are few more planes out there what others may be using.