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Remove Hard coded radius value for lateral acceleration in descent under parachute

Open RyanSamF opened this issue 2 months ago • 4 comments

Is your feature request related to a problem? Please describe.

Lateral acceleration for descent under parachute (in the function u_dot_parachute) depends on the air trapped beneath a parachute to determine the mass to divide drag force by. This added mass value depends on the radius R which is hard coded to 1.5 This causes issues with drift distance for smaller rockets and drogue parachutes leading to much higher drift distances than expected

Describe the solution you'd like

Either remove the hard coded value or determine radius based on a hard coded value for the coefficient of drag for a parachute, which is a much more reasonable thing to be hard coded.

Additional context

N/A

RyanSamF avatar Oct 24 '25 15:10 RyanSamF

Could you help us providing references?

Gui-FernandesBR avatar Oct 25 '25 16:10 Gui-FernandesBR

https://github.com/RocketPy-Team/RocketPy/blob/2655a4f955be626d6174547a39998b58c0b8aeda/rocketpy/simulation/flight.py#L1969-L1995

RyanSamF avatar Oct 25 '25 19:10 RyanSamF

@RyanSamF when I say "reference", I was actually meaning "bibliometric references". I'm going to search about it.


I have to investigate it better, but I think @ArthurJWH has already solved this one with his recent modifications to the parachute class

Gui-FernandesBR avatar Nov 27 '25 16:11 Gui-FernandesBR

The main reference for parachute modeling is: https://apps.dtic.mil/sti/tr/pdf/ADA247666.pdf

Gui-FernandesBR avatar Nov 28 '25 00:11 Gui-FernandesBR