Bluefin Tuba

Did you get an altitude on the J flight? It looks like you lengthened Tube, did you have an altimeter in it?

iter said:

Sure, here it is. OpenRocket can't do tube fins. I simulate them with long, thick straight fins so that total cross-section is roughly equivalent. This is only a coarse approximation of course, and completely unreliable as you approach compressibility.

Ari.

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Thanks very much!

Yup, I totally get that. One if the reasons I wanted the file was to see how you modeled the tube fins

How good have the predictions been?


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I put a little payload section on BFT (lavender--Leah helped me paint it) for an experimental telemetry setup. I had one good flight with it (post from April 12) on I280 where baro altimeter recorded just over 5,000'. I upgraded it with GPS for Black Rock, but transmission cut out at 1,400' on the H45 flight and I took it out for the J510 flight. I had cut the bottom off my nose cone so that everything would fit, so the only way to attach a shock cord to it was to use the (now empty) payload section.

Ari.

wfcook said:

How good have the predictions been?

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It's hard to say. On the one flight where I have data, they are significantly higher than OR predictions. OR predicts 3,200', altimeter shows 5,000. I don't know how much I trust a single data point though.

Ari.

Thank you Jim. I think this project overlapped with your medical issues. I'm glad you're feeling better now.

Ari.

iter said:

Thank you Jim. I think this project overlapped with your medical issues. I'm glad you're feeling better now.

Ari.

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I was at the Snow Ranch launches, my medical problems started on May 1. I don't remember seeing you launch it though. Maybe I was busy with lunch. You know how us fat guys are. :tongue:

I saw the BFT launch at Snow Ranch but lost it overhead..geezerly eyes and I didn't have my little 10x23 Nikon binocs with me.

It's quite an impressive project.

iter said:

I'm building a minimalistic 38mm MD tube-fin rocket out of Blue Tube. If you think the name is a bad pun, I challenge you to come up with a better one!

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Inspired by Ari's efforts, I'm working up a variant of this on my own. 31" body tube, mitered fin leading edges, and a Giant Leap slimline retainer.

Ari, how did you end up dealing with the rail buttons? Did you just use a tube fin as a guide?

Yes, one of the fins is the mother if all launch lugs. The top button is a button, and doubles as shock cord attachment point.

Ari.