Drag coefficient editing

[josepoyan]

Hi,

I am new to OpenRocket and to aerospace in general.

Does anyone know how to manually edit the Drag coefficient of the rocket please? Is there any option to do this?
I've been give the task to learn the software and also find where is this option in order to help someone in my team.

Thanks in advance!
jose

 

[Kelly]

I don't think that's possible, though others here are more familiar with the software than I.
What is the use case for this? In what situation would you find it necessary to do this?

 

[neil_w]

This thread may be of interest: https://www.rocketryforum.com/threads/changing-cd-in-openrocket.139708/

 

[Banzai88]

I don't think that's possible, though others here are more familiar with the software than I.
What is the use case for this? In what situation would you find it necessary to do this?

Tweaking the CD allows you to tune the sim to match real world performance. This includes the user putting in the correct launch altitude and temp, too.

OR only has a few options for CD based on finish, and given that limitation, I've always been able to use one of the pre-programed options to tweak the sim to within 1% of real world....which is more than close enough for planning purposes.

 

[Scott_650]

Thrustcurve has a built in range for CD - High=1, Average =.6, Good=.45 and Perfect=.3 - not sure how OR’s “Finish” options correspond. Oddly enough even though I routinely use TC in the field to double check motor selections I’ve never checked it against any onboard altimeter readings…need to put that on my post launch checklist I suppose…

 

[neil_w]

Thrustcurve has a built in range for CD - High=1, Average =.6, Good=.45 and Perfect=.3 - not sure how OR’s “Finish” options correspond.

They don't, really... OR-calculated Cd is a combination of the rocket design *and* the finish. So you could have a complex polished rocket with a Cd of 1. Although a Cd of .3 with a rough finish would probably be pretty difficult (or maybe impossible).

 

[josepoyan]

This thread may be of interest: https://www.rocketryforum.com/threads/changing-cd-in-openrocket.139708/

Yes, this is very useful. Thank you!

 

[josepoyan]

I don't think that's possible, though others here are more familiar with the software than I.
What is the use case for this? In what situation would you find it necessary to do this?

Thanks for the reply. It is a good question. It was a task assigned to me so to pass the finding to another member of my team. With time I will gain experience with the software myself.