Calculate Main Rotor Downwash

Подпись: AiM NEW — AiM OLD- Подпись: (A.9)

With the advance ratio components evaluated, the main rotor downwash can now be calculated using the iterative technique described in an earlier chapter:

A good starting value, for the iteration, is that for hover, namely:

Подпись: (A. 10)Ai OLD — 2^/~Ct

This now determines the downwash AiM.

A.3.1.3 Assemble Main Rotor Powers

The main rotor power components can now be calculated. Induced (note that the induced power factor kiM is included):

Подпись:PiM = kiM • Tm • VTM • ^iM

Подпись: PPM Подпись: (A. 12)

Profile:

Parasite:

Подпись:Подпись: (A. 14)PpARAM = D • V

Summing for the total:

Ptot M = PiM + Ppm + Pparam

A.3.2 Tail Rotor

The main rotor torque is now obtained from the total main rotor power, from which the tail rotor thrust value necessary for torque balance is calculated.

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