#### raghu

##### Senior Member

- Joined
- Mar 19, 2004

- Messages
- 412

- Location
- Pittsburgh,PA

- Aircraft
- J3 cub/ schweizer 2-33/ a few flights on twinstar

- Total Flight Time
- 110

Bramwell does indeed move rather skillfully ( or at times what may seem carelessly) between tpp and nf axis. Obviously no one axis system is perfect and while they simplify one derivative they often complicate the other.

Bramwell's final result are all consistently in the wind axis. To arrive at the wind derivatives though he uses a combination of tpp and nf axis depending on mathematical expedience. Hence if one is trying to compare intermediate results it can get very confusing.

My sense is maybe if we compare the wind axis values ( dz/du, dx/dw... etc. )with your body axis values turned by alphaNF it may be simpler. Just a thought. No reason the current approach would not converge.

Bramwell's final result are all consistently in the wind axis. To arrive at the wind derivatives though he uses a combination of tpp and nf axis depending on mathematical expedience. Hence if one is trying to compare intermediate results it can get very confusing.

My sense is maybe if we compare the wind axis values ( dz/du, dx/dw... etc. )with your body axis values turned by alphaNF it may be simpler. Just a thought. No reason the current approach would not converge.

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