I use 65 for a "reference speed" in my ragwing. For short field I usually try for 60 on final. I still get a lot of float,but if I use less than 60 the controls feel real mushy. When I first got the airplane,I did some landing-configuration stalls to come up with said reference speed. 2 people on board,most of the way full of gas,power off full flaps (woo-hoo!) it stalls at 47 IAS--rounded up to 50,times 1.3 equals 65,times 1.2 equals 60.
A friend of mine just bought an A model,her instructor (who owned that plane at one time) taught her to use 50 on final for short field. It stalls a little slower than mine (44),but doesn't feel as mushy under 60.
Eric
vortex generators
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
IAS and Approach Speeds
My 170A was missing a calibration card for the airspeed indicator. So we went up and flew it around at various indicated airspeeds on different headings to calibrate it using the GPS and correcting for altitude, barometric pressure, and temperature.
The calibration in mph was:
IAS 40 50 60 70 80
TAS 56 59 65 74 82
If you stall at 50 IAS then an approach speed given by 1.3*59 = 77 or about 72 indicated. For a short field 1.2*59 = 71 or about 65 IAS. 200 lbs under gross you could reduce these numbers by about 5%. (Vs/Vso ~ Sqrt (weight/gross weight) )
The calibration in mph was:
IAS 40 50 60 70 80
TAS 56 59 65 74 82
If you stall at 50 IAS then an approach speed given by 1.3*59 = 77 or about 72 indicated. For a short field 1.2*59 = 71 or about 65 IAS. 200 lbs under gross you could reduce these numbers by about 5%. (Vs/Vso ~ Sqrt (weight/gross weight) )