Ka 4-55 with nozzle no. 19A – discrepancy

Using the factors presented in: Wake Adapted Ducted Propellers, M.W.C. Oosterveld, PhD-thesis Delft University of Technology, Year 1970.
I am getting a good match on the thrust coefficient but a discrepancy on the torque coefficient when comparing calculated values using the polynomials to the chart. Have I mistyped or are some of factors wrong?

Also not sure what the factor 0 7 is meant to be used for?

 

Does anyone know if the polynomial factors are published anywhere else?

 

Hi Petter, seems a bit odd. It's ok up to ~etamax, but kq~zero with kt=zero... no way.

Have you checked other P/D values as well?

 

It's not clear which factor you are referring to.

 

Its more or less the same pattern for all the valid P/D for the Ka 4-55 screws.

When I read in the factors for Ka 4-70 both the torque and the thrust matches perfectly.

I have used the factors from:
Oosterveld, M.W.C. Wake Adapted Ducted Propellers.
NSMB Wageningen Publication No. 345.
June 1970.

and Marine Propellers and Propulsion by John Carlton

Trying to find a second reference to check.

 

The equations are polynomials using factors up to A6,6 B6,6 and C6,6 (see attached image)
The polynomial coefficients table also gives a value for A0,7 etc for some of the screws (see attached image) its not clear to me what this should be used for.