Discussion Overview
The discussion centers on the behavior of barometric altimeters in response to horizontal pressure gradients during high acceleration scenarios, particularly in subsonic flight regimes. Participants explore the implications of airflow dynamics on altimeter readings while a missile accelerates horizontally.
Discussion Character
- Technical explanation, Debate/contested
Main Points Raised
- One participant questions how a barometric altimeter will react to horizontal pressure gradients during horizontal acceleration, specifically whether it will change readings at a constant altitude.
- Another participant notes that the air pressure measured by the altimeter is influenced by its position on the missile, indicating that head air pressure is higher than tail air pressure, and that higher altitude correlates with lower air pressure.
- A similar point is reiterated regarding the dependence of altimeter readings on the position of the missile surface, emphasizing the need for static ports to be placed where airflow velocity matches the freestream conditions.
- A later reply discusses the imperfections of static ports, mentioning that disturbances from airflow around the airframe must be considered. It highlights the role of Computational Fluid Dynamics (CFD) modeling in addressing these issues and describes calibration processes used in flight testing.
Areas of Agreement / Disagreement
Participants express differing views on the impact of airflow dynamics on altimeter readings, with no clear consensus reached on the specific effects of horizontal acceleration on barometric measurements.
Contextual Notes
Limitations include potential assumptions about airflow uniformity and the specific conditions under which the altimeter operates, as well as unresolved details regarding the calibration of static ports.