Downscales are fun too. 75% Photon Disruptor 1282

I needed a little break from paperwork, so I thought I'd built something that eats small motors.

Neat. So, you downescaled the original Photon Disruptor, correct, not the later (larger) one? Because it seems like scaling that down would bring you back to cloning the original...

Yes, this is a downscale of the #1282 PD. BT50/BT20 down to BT20/BT5. Keeping the external engine hook and strap, since the lower section is minimum diameter.

The #3025 PD II is BT55/BT50. The upper part is about 134% of the original, while the fins are 125% of the original. I built a little table this week to compare them.

Looks like you're right... That would be fun.

Nice work! Can't wait to see the finished project.

Downscaling is something I've only done once. Most of my scaling goes up. But I did this one for a MMX version of the DOM Starship Excalibur. It's almost 7" tall using a BT 4. My last building adventure was a BT 70 version on this design. It actually turned out pretty good, (by my standards) Anyhoo, here's a look-see at it. The second pic is with all my MMX models.

Neat project. I might have to do one myself.

I've done a 24mm downscale of the Optima and a 18mm Cherokee.

Nice rockets all around. That Excalibur is great.

Charles_McG said:

Nice rockets all around. That Excalibur is great.

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Thank you. I know the fin logo is wrong, but it's the same one I did on my upscale version. I didn't know what it was, so I created one. Flies good though.

And decorated.

Charles_McG said:

And decorated.
View attachment 270311
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Very nice work.

Very cool downscales. I have been thinking about doing the same to make a mini engine sized version of the other Excalibur, the Centuri Excalibur. Still working out the body tube ratios, not sure if possible to keep the entire proportional scale while using standard size tubes and nose cones, but I think I can get it pretty close.

GlenP said:

Very cool downscales. I have been thinking about doing the same to make a mini engine sized version of the other Excalibur, the Centuri Excalibur. Still working out the body tube ratios, not sure if possible to keep the entire proportional scale while using standard size tubes and nose cones, but I think I can get it pretty close.

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A close facsimile, would use a BT 20, 7-11/16", a BT 5, 9-7/32", a transition 11/16" long and a nose cone 2-1/8" in length. Quite a task since the nose and tranny are not readily available. You could fabricate the tranny with a paper and you could find a balsa nose cone and shape it down. Or do what I can do and turn one on the lathe. (sorry, don't ask me to do that for you) The fins can also be scaled down, but you need a scaled copy of those to work with.

Charles_McG said:

I built a little table this week to compare them.

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I had a whole spreadsheet going when I was building my 4"/3" version; after about an hour of fiddling with the details, I realized that I really, really needed professional help.

I also built a spreadsheet. That's where I figured out that the PDII isn't an accurate scale of the PD.

So mine isn't perfect. If close is good enough for Estes, it's good enough for me.

Gary Byrum said:

A close facsimile, would use a BT 20, 7-11/16", a BT 5, 9-7/32", a transition 11/16" long and a nose cone 2-1/8" in length. Quite a task since the nose and tranny are not readily available. You could fabricate the tranny with a paper and you could find a balsa nose cone and shape it down. Or do what I can do and turn one on the lathe. (sorry, don't ask me to do that for you) The fins can also be scaled down, but you need a scaled copy of those to work with.

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That would work, but I was thinking even smaller scale, roughly 60 percent, with the bottom tube min dia for the mini engine, so that would be more like a BT5 6 inches on the bottom and a BT4 7.2 inches on top, this nose cone might work, and I could always print up the transition on card stock and roll my own.
https://www.erockets.biz/semroc-balsa-nose-cone-bt-4-1-3-ogive/ (which BT4 nose cone did you use on that Starship Excalibur?)
I might even try to print up the tubes and fins on card stock. I just finished building one of those carded Satellite Interceptors and it was a lot easier than I thought it would be.

I didn't mean to get off on a tangent from your nice work here, but this inspired me, I can start another thread dedicated to this Excalibur downscale project.

That is Really Sweet!

Did you print the decals yourself, or buy them somewhere?

The PD mini, or the Excal being discussed?

Charles_McG said:

The PD mini, or the Excal being discussed?

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mini

Sandman

BT-20X from erockets/semroc

And she flies purty.

This flight had the little black Estes chute. 6"? Could be a bit bigger.

[video=youtube_share;csQzVxVkfvc]https://youtu.be/csQzVxVkfvc[/video]

Next up, A10 to A3 chad staged. The PD mini really wants a 13mm B.

GlenP said:

(which BT4 nose cone did you use on that Starship Excalibur?)

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I turned my own to 1-5/16" above the shoulder. And to solve the next question, each pod is a one piece section of balsa cut and shaped. No cones or tubes used to make them.