Buzz Nau Omega Centauri Upscale u

[AstroArlo]

I just joined the forum and was in the last stages of an upscale build of a Buzz Nau design called Omega Centauri.

I'm a BAR and since I'm stuck at home, have way more time time to build. Fortunately, I rent so my honey-do list was small and dispatched in the first week of stay at home in Colorado.

I've been building some of my favorites from a long time ago, but got the bug to upscale the models.

So I took Buzz's design and upscaled it in TURBOCAD.

 

[AstroArlo]

All of the tube work is done, and I'm in the process of putting the fins on.

 

[BABAR]

Very cool!

Any chance you can put an external shock cord mount on the rear, so it descends forward body tube down? Those fins look fragile.

 

[AstroArlo]

I agree, I'm a little concerned about the fins. I hadn't contemplated your solution - thanks!

Possible solutions:
1. Lower flight with larger parachute flown on windless days.
2. Reinforce the tiny ends of the fins, and use 1/4" dowel in the fin pods.

 

[AstroArlo]

Added the pods on the fins and the launch lugs :

 

[AstroArlo]

You were prophetic Babar. Was painting the rocket with primer and the wind blew the rocket over, breaking off one of the tiny fin protrusions.

 

[Eagle3]

Hey AstroArlo,

This is Buzz. Steve Kristal told me about your upscale post and it looks great! Rusty Ward built a BT-60 upscale he called the Proxima Centauri Probe five years ago and had the same problem with those swept back fin tips. They're fine on a BT-50 version, but you would need to build it similar to the Estes Constellation and stack some support balsa on both sides. Then sand it to look sort of tear drop shape and I think it would hold up. Rusty replaced those bits with a dowel instead and it looked fine and held up to landings with no damage.

I converted my original model to hang inverted on the way down as I had a problem with the side pods popping off. Rusty built his with through the wall fins on both ends and didn't have that problem. Thanks for sharing the photos and build. Good luck!

Buzz

 

[AstroArlo]

Hi Buzz!

Thanks for your reply - and an interesting design that is fun to build.

I did a simple reinforcement of the tiny fin extensions. I think they are pretty stout now.

I'm in the process of painting/finishing and should be done in a day or so. It's looking really good!

 

[Eagle3]

Hi AstroArlo,

That's exactly what I would do. Great work and can't wait to hear your launch report.

Buzz

 

[AstroArlo]

Finished painting, decals, and monokote. Turned out really nice.

 

[AstroArlo]

I named it "Omega Centauri Heavy - Corona Escape." Called it "heavy" since it's an upscale of Buzz's original design. Called it "Corona Escape" since it was a nice distraction from the pandemic.

 

[Eagle3]

Awesome! Hope she flies great for you!

 

[AstroArlo]

Finally launched the Omega Centauri on an E12-4. Nice straight flight which achieved 599 feet on a relatively calm day.

I wanted to use a 24" parachute, but when I packed it in the limited space for parachute, shock cord, and wadding it seemed really tight and I was afraid it wouldn't deploy.

Consequently, I changed to an 18" parachute. I think it would have been fine, but a gust of wind at the last second made it land hard sideways on one of the vulnerable fin extensions, which broke off in spite of being reinforced. These were made of balsa, so relatively weak anyways.

Thinking about removing the reinforced fin extensions and building them out of 1\8" plywood. Also considering ordering a 24" thin mil nylon parachute to fit better in the parachute compartment.

 

[neil_w]

That's a lovely rocket, glad it's only minor damage.

If you have the means, then I would suggest 3D printing those tips so that they'll slip over the fin. Those will not break. On the other hand, they will transfer the shock to the fins, which will need to be strong.

Or, you could make them friction-fit over the fin tips, in which case they'll simply pop-off on landing.

Just some thoughts. I once made 3d-printed "cuffs" to slide over the leading edge of fins that were prone to landing breakage, and man let me tell you those things will not be breaking any time soon.

 

[Bill S]

Could you rebuild those vulnerable fin extensions with say longitudinal ribs, or put some clear plastic tubing around them to give some extra protection (call them modified engines or something)?

 

[AstroArlo]

The repair is easier than I thought. Easy to remove the broken fin tab.

And replacing with basswood instead of balsa.

Not going to replace the other fin tab until it breaks.

 

[BABAR]

Hotel key cards can be cut to shape and used to reinforce areas where balsa gets stress. May be challenging in this case however to get IDENTICAL pieces cut freehand with scissors. I think epoxy is likely your best attachment method of plastic to wood.