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OpenRocket question - Parachute and Decent Rate

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mjollnir458

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Newbie here so forgive me if I miss what may otherwise be obvious to the experienced.

I am trying to design a rocket for TARC using OpenRocket and no matter what I do as far as parachute, I can't slow down the decent rate. Plus when I use a larger parachute, oddly, the overall flight time decreases and the ground hit velocity increases.

I've tried to stick with parachutes from the list in the database. So, for example:

Estes 82426-30 24in. nylon = 32s flight time and 9.29m/s ground hit velocity
Estes 82426-30 12in. nylon = 34.2s flight time and 8.79m/s ground hit velocity

TARC requirement this year for flight duration is 41-43s. so I need to add about 10seconds, which seems like a lot to me. Maybe something is off with my environment settings in the sim?

I'm confused. :confused:
 

MCriscione

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Post your ork and somebody will help. It sounds like you may have your chute set so it isnt opening right in the sim. Check its parameters for activation, should be set to motor delay.

And welcome! There are lots of great folks and resources here. Youll be glad you joined.
 
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dhbarr

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Post your ork and somebody will help. It sounds like you may have your chute set so it isnt opening right in the sim. Check its parameters for activation, should be set to motor delay.

And welcome! There are lots of great folks and resources here. Youll be glad you joined.
Yup, weight's increasing but drag isn't, chute's not deploying.
 

mjollnir458

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Thanks for the advice.

I had surmised that part of my problem was an increase in weight and that I wasn't noticing the resulting decrease in apogee which was culminating in a shorter flight time.

I was able to reduce the weight in the payload section some and it improved the flight time some, but I still think there is a problem.
 
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dhbarr

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Yep, one or more chutes aren't coming out; I played around with changing one or both of them to 'apogee' as opposed to 'first ejection charge' and got noticable results.

Try keying your payload chute off of lower stage separation, as that stage has no motor.
 
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