Don't have access to the flight test data. The Piper POH I was quoting refers to IAS for stall speed calculation, max weight only. The calibration chart lists negligible change for flaps, possibly 1 kt less calibrated than indicated, and a slight decrease for flap zero at low speed changing to slightly higher at high speed. Although at low speed close to the stall this is probably a little more out than the chart indicates.
If you take the calibrated flap zero stall speed and adjust 1.2 you pretty much get the flap zero lift off speed in this aircraft. 1.2 x 59 = 71
For flap 25 1.2 x the 55 kts listed speed arrives at 66. There would have to be a big difference between CAS and IAS for this to achieve 1.2Vs, lift off being stated at 59 kts.
It makes sense why piper advises 70kias as a more appropriate speed to aim for as it is close to the Vs clean x 1.2.
One thing that's got me thinking of is how much difference is there in accuracy at various flight attitudes and configs of the Piper pitot static head vs Cessna static port and pitot tube.
Last edited by 43Inches; 4th Apr 2014 at 03:25.