About Cruciform Missile : Difference between + and x flying orientation

MISSILES, historically, and even in current design and development are of cruciform type with low aspect ratio wing/control fins. This was mainly due to carriage point of view and more often than not, it needs to be stored in launch tube/canister unlike aircraft with high aspect ratio surfaces. In most instances, missiles fly in “plus +” or “cross x” orientation.

Considering pitch control of a cruciform missile, in “plus” configuration, if both the horizontal fins are deflected downward, by an amount δ, this results in an upward force F in the pitch axis. Now , the same missile with 45° roll orientation and all the four control fin deflected downward by an amount δ, a force equivalent to √2 times of the force F is produced in the vertical plane in the “cross” configuration.

Body axis coordinate system

 

Definition of Wind and Body axes flight parameters

 

 

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