#### Jean Claude

##### Junior Member

- Joined
- Jan 2, 2009

- Messages
- 2,185

- Location
- Centre FRANCE

- Aircraft
- I piloted gliders C800, Bijave, C 310, airplanes Piper J3 , PA 28, Jodel D117, DR 220, Cessna 150, C

- Total Flight Time
- About 500 h (FW + ultra light)

Juergen,

For your calculations, I think you should only use these NACA data:

- Specific weight (Column D)

- Dynamic pressure (Column H)

- Rotor lift (Column P)

Then, calculate and compare the corresponding results:

- Shaft attack angle (and comparate to column G)

- Rotor speed (and comparate to column I)

- a0 (and comparate to column R)

- a1 (and comparate to column S)

- b1 (and comparate to column T)

It seems to me that your calculations is very consistent (except b1)

I assume that in reality the radial velocity can then unload profiles, thus reducing the necessary theoretical attack angle.

It seems to me that this assumption is confirmed by the value of b1 measured higher than theory predicts

Le régime calculé du rotor dans ces conditions de charge, de pression dynamique et de masse volumique est 143 t/mn, tandis que la mesure a donné 133.1 t/mn

L’angle d’attaque calculé du disque est 7.2°, tandis que la mesure a donné 1.1° (arbre) + 5° (a1)= 6,1°

L’angle de battement longitudinal a1 calculé est 5.3°, tandis que la mesure a donné 5°

L’angle de battement transversal b1 calculé est 2.8° tandis que la mesure a donné 3.9°

For your calculations, I think you should only use these NACA data:

- Specific weight (Column D)

- Dynamic pressure (Column H)

- Rotor lift (Column P)

Then, calculate and compare the corresponding results:

- Shaft attack angle (and comparate to column G)

- Rotor speed (and comparate to column I)

- a0 (and comparate to column R)

- a1 (and comparate to column S)

- b1 (and comparate to column T)

It seems to me that your calculations is very consistent (except b1)

Yes. Case 2 is to high forward speed, where the induced velocity (and the non-uniformity) is négligeable. Just as your theory!Interestingly the lateral disk tilt calculated by my program for case 2 agrees fairly well with the measured value. Perhaps the rotor in case 10 is in a flight state which is not very well captured by the theory.

My spreadsheet tells me that the autorotation of this gyroplane is not possible beyond mu > 0.5Could you please also calculate case 2?

I assume that in reality the radial velocity can then unload profiles, thus reducing the necessary theoretical attack angle.

It seems to me that this assumption is confirmed by the value of b1 measured higher than theory predicts

**Résultat pour les données correspondantes au vol plané n° 1**Le régime calculé du rotor dans ces conditions de charge, de pression dynamique et de masse volumique est 143 t/mn, tandis que la mesure a donné 133.1 t/mn

L’angle d’attaque calculé du disque est 7.2°, tandis que la mesure a donné 1.1° (arbre) + 5° (a1)= 6,1°

L’angle de battement longitudinal a1 calculé est 5.3°, tandis que la mesure a donné 5°

L’angle de battement transversal b1 calculé est 2.8° tandis que la mesure a donné 3.9°

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