Idea! How to simulate booster recovery in Open Rocket

Ok, this might not work for everybody, but it may work for my downscale of the Velociraptor project.



What if I made the booster into its own rocket. I can't try this here at school right now, but since the booster that I've designed is stable (tail down), perhaps I can simulate how it would recover by inverting the engine and see how it flies... backwards.

Pointy? Side Up!
Jim

Hi,

What's the purpose? The newest versions of OR simulate also the lower stage recovery.

Cheers,
Sampo N.

Sampo said:

Hi,

What's the purpose? The newest versions of OR simulate also the lower stage recovery.

Cheers,
Sampo N.

Click to expand...

He's having trouble because his booster would come in stable: weight at the rear, fins at the front.

Ok,

without any kind of streamer or other recovery device, it looks like my booster would come in at somewhere around 115f/s (78mph) if OR can be trusted...

Uhmmm... Really? After "installing" the streamer, it looks to have slowed down to 461f/s (314mph).



I don't think I trust OR for this kind of "rocket".

K'Tesh said:

Ok,

without any kind of streamer or other recovery device, it looks like my booster would come in at somewhere around 115f/s (78mph) if OR can be trusted...

Uhmmm... Really? After "installing" the streamer, it looks to have slowed down to 461f/s (314mph).



I don't think I trust OR for this kind of "rocket".

Click to expand...

I think that would be wise.

Have you seen these?

Designing Tumble Recovery Booster Stages - Part 1

https://www.apogeerockets.com/education/downloads/Newsletter96.pdf

Designing Tumble Recovery Booster Stages - Part 2

https://www.apogeerockets.com/education/downloads/Newsletter97.pdf

No, I hadn't

Thanks for the links! I'll check it out when I've got some time (Homework and all)

Jim
.

I am designing a very similar rocket and having a very similar problem. I haven't worked on it much since last Spring. I was trying to downscale a Talon and make it into a 2 stage rocket.

Disclaimer - This is still on the build pile, and has not been completed, much less flown. So everything that follows is theoretical in OR simulations

My current design has lengthened the booster by 1" and moved the fins 1" back on the boat tail. This has required the rocket to be gap staged, which is something I have not done yet, and thus the reason it is still sitting in the build pile. I want to build a simple less expensive gap staged rocket, and get some experience before trying it on this project. However, it is currently sim-ing with perfect tumble recovery.

The other thing is, this does change the project from being an exact downscale of the Talon, but I do not have a problem with that. The proportions are still good, and look pleasing to me. I started this because I like dual fins, I like boattails, and I thought wouldn't it be cool if it was a 2 stager. Then realized it would be much easier (and cheaper) as a downscale because I could use BP motors and avoid electronic air starts.

I find some of the speeds that OR comes up with for ballistic recoveries to be a little unbelievable. If my math is correct, 400fps = 273mph. Terminal velocity for a skydiver falling head first is only 175 mph, and that is not reached until falling 1,500 feet. It seems amazing that this little booster can exceed that after falling only 400 feet.

Best of luck to you in solving this problem. I've seen some of your discussions in other threads, streamer recovery, helicopter recovery. I look forward to seeing how you end up resolving this.

My experiment with rotary recovery so far has been a bust, but then again, I was only playing around with one of those hand helicopter toys. So, it's still on the table.
I've played around some more with the streamer (8') and it's working better now that I'm "winding" it in a sinewave fashion, rather than a spiral.

The truth of the matter is that someone forgot to look at how many centering rings he had before placing his last order with Semroc, and making the payment.

One the ideas, that might actually work, would be to imitate some of the old hardware I used to work on... I'm now thinking of a system that is loosely based on the MK82 Snake eye bomb.

[video=youtube;pytjJETpvFc]https://www.youtube.com/watch?v=pytjJETpvFc[/video]