IAS -> CAS calculation when not in POH

[Pilotdaddy]

Part of the CPL flight test is to be able to calculate the Vref for the aircraft. This is done with the formula below...

Vref = 1.3 * Vso (KCAS) * Sqrt (landing weight / gross weight)

I have a 1969 140B which doesn't have an IAS to CAS chart. How do I go about calculating this? I know that the utility of such a precise calculation is probably close to nil, but I just want to be able to do it if asked on the flight test.

Can I safely assume IAS=CAS for this excercise?

So, given Vso = 55mph, landing weight = 1,888 lbs, gross weight = 2,150 lbs...

Vref = 67mph?

 

[N4655R]

 

[Pilotdaddy]

 

[cthouston]

 

[cthouston]

 

[skywag]

 

[Pilotdaddy]

 

[reb]

 

[jruhnke]

 

[kshaw]