Calculated Stall speed at flying weight

[Jaybird180]

Most POHs give VS speeds based on full gross. There are circumstance where it would be helpful to be able to better calculate stall speed at less than gross.

Is there math for doing this? Can it be interpolated from performance charts or do you just need to do the flying and testing?

 

[MauleSkinner]

Convert the MGW stall speed to calibrated if it’s not already, and then take the square root of W/MGW to get the ratio of (adjusted Vs)/(Vs for MGW).

One place this is frequently used is to determine an appropriate approach speed for your weight.

 

[Joe_B1]

Just take it up and stall it.

 

[dmspilot]

VSnew = VSold √(Wnew / Wold)

 

[Daleandee]

There are a couple of "rules of thumb" that are sometimes used. (Caveat: my plane is experimental so not sure how this works for you):

Vs new = Vs old weight x √(new weight / old weight).

Another one goes like this:

“If weight is reduced by 10% from MTOW then Vs will be reduced by 5%, and conversely, if weight is 10% over MTOW then Vs will be 5% higher —“

At the end of the day I agree with Joe_B1 ... take it up high and do some testing.

 

[dmspilot]

There are a couple of "rules of thumb" that are sometimes used. (Caveat: my plane is experimental so not sure how this works for you):

Vs new = Vs old weight x √(new weight / old weight).

Another one goes like this:

“If weight is reduced by 10% from MTOW then Vs will be reduced by 5%, and conversely, if weight is 10% over MTOW then Vs will be 5% higher —“

At the end of the day I agree with Joe_B1 ... take it up high and do some testing.

The first one is the actual formula derived directly from the lift equation. The second is the rule of thumb estimate for the first.

 

[WannFly]

get an AOA