Astron Sprite Upscaled To BT-80H

[lakeroadster]

Here's an Estes Astron Scout upscaled to a BT-80H, about a 3.45 : 1 upscale.

29mm Power​

Rear Eject​

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I used Bruce Levinson's Ring Fin Haack with Open Rocket to check stability.​

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Looks like a fun build!​

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Ring Fin Haack

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[lakeroadster]

I modified the Open Rocket model, using an actual "Tube Fin" and the stability looks similar to the "Ring Fin Haack". Cool!

 

[John Kemker]

May I pretty please (with whipped cream and a cherry on top) get a copy of the ORK file?

 

[lakeroadster]

CAD Model and Drawings, Rev 00

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[bjphoenix]

I had one of the originals back in the day when they were selling them, occasionally they would give out a kit like this as a freebie with your order.

 

[Imaknow]

So, if no tumble recovery, would this be a Semi-upscale?

 

[lakeroadster]

So, if no tumble recovery, would this be a Semi-upscale?

There's just something about 19 ounces without any recovery device that just says "No".​

 

[Imaknow]

There's just something about 19 ounces without any recovery device that just says "No".​

Fully understand, just poking fun.
Streak, Sprite, Wac Corporal, Scout were my first 4 rockets way back when.
Only one I lost was the Corporal, stupid 12" chute drifted off 30 yards into a cotton field and was never found.
Tumble recovery for the win.

 

[Glasspack]

I am a big fan of BT-80 Tubes. That my friend is pretty cool ................

 

[lakeroadster]

How about an X-Wing Sprite?

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[Back_at_it]

I have wanted to build a BT80 version of these for literally years. I have everything laid out and the fins ready to cut but I haven't pulled the trigger as I haven't found a ring that would fit around the fins.

 

[neil_w]

How about an X-Wing Sprite?

View attachment 677538View attachment 677539​

Excellent.

 

[lakeroadster]

I have wanted to build a BT80 version of these for literally years. I have everything laid out and the fins ready to cut but I haven't pulled the trigger as I haven't found a ring that would fit around the fins.

That's my 1st order of business...​

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I'm on the hunt for plastic, paper, cardboard or wood. But if I can't find it, I'll build it from scratch.​

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[neil_w]

What diameter ring do you need? I've been through this routine before.

 

[Back_at_it]

What diameter ring do you need? I've been through this routine before.

7.1 inch

 

[neil_w]

7.1 inch

Hmm, that's pretty big.

Well, what I did was go through Home Depot with a ruler and look for every cylindrical object they had until I found something that would work as a mandrel for my bent balsa rings (I need 5") Took a while but I eventually found that 4" PVC couplers were just right. 7" might be a bit tougher but there could be something out there.

 

[Back_at_it]

Hmm, that's pretty big.

Well, what I did was go through Home Depot with a ruler and look for every cylindrical object they had until I found something that would work as a mandrel for my bent balsa rings (I need 5") Took a while but I eventually found that 4" PVC couplers were just right. 7" might be a bit tougher but there could be something out there.

Uline sells 8" cardboard mailer tubes that are .125 wall thickness. With it being oversized, I could slit it and make it fit but .125 wall is crazy heavy but right now it seems like my only option.

I'm thinking I might be able to carefully unroll a BT101 and make three sections that would fit between the fins.

I'll figure it out someday. I have about 20 builds planned and the list isn't getting any shorter. There are way too many good ideas on this site

 

[neil_w]

Uline sells 8" cardboard mailer tubes that are .125 wall thickness. With it being oversized, I could slit it and make it fit but .125 wall is crazy heavy but right now it seems like my only option.

.125 wall cardboard is indeed pretty darn heavy. Slit and shrink is doable but in this case might be rather difficult to make a round ring out of it. Maybe three separate sections would work.

I'm thinking I might be able to carefully unroll a BT101 and make three sections that would fit between the fins.

My guess is that getting a 4" tube to be 7" is too much of a stretch.

 

[Back_at_it]

My guess is that getting a 4" tube to be 7" is too much of a stretch.

I would cut up the BT101 into sections to fit in between the fins so it would be three individual pieces.

 

[neil_w]

I would cut up the BT101 into sections to fit in between the fins so it would be three individual pieces.

I think they will look too small.

Anyway, back to @lakeroadster 's thread.

 

[K3LAG]

Nice! I have an upscale Astron Sprite on my to do list as well. It's no where near the top though. I haven't decided on a size.

 

[lakeroadster]

The kicker here, for the ring, is it needs to be about 1/8" thick. As a tumble recovery, the Astron Sprint was built strong, so an upscale needs to look the same.

On my CAD model I used 1/8" thick.

Here's Grant Edwards Vintage Sprite... beefy!

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[kuririn]

3D Rocketry made upscale versions of the Sprite.
It was called the Circulus.
3 and 4 inches I believe.
29mm motor mount.
They used Sonotube for the rings.


That reminds me, I have to paint and fly this puppy.

 

[BEC]

The kicker here, for the ring, is it needs to be about 1/8" thick. As a tumble recovery, the Astron Sprint was built strong, so an upscale needs to look the same.

On my CAD model I used 1/8" thick.

Here's Grant Edwards Vintage Sprite... beefy!

View attachment 677656​

Well, "beefy" for such a small model. The fins are 1/8 inch balsa and the tail ring is a bit of BT-70 in the original Sprite. Plans/instructions: http://spacemodeling.org/jimz/estes/k-15.pdf

The K-15 Sprite was the first use of the EH-2 engine hook which, used here, allowed the engine to slide back 1 inch to effect the CG shift for proper tumble recovery. It was first used to hold a full-length 18mm motor in the K-25 Alpha....and set the standard for quick-change motor mounts for a large percentage of model rockets to come.

 

[lakeroadster]

Well, "beefy" for such a small model.

Indeed. Estes Astron Sprite, The Original Gene Street Design Circa 1966​

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[heada]

Hawks Hobbies had a Super Sprite kit. I had one until it came in with a tangled 'chute and disassembled on impact. I wish Hawks Hobbies was still around, they made good kits.

 

[DTRocket]

The kicker here, for the ring, is it needs to be about 1/8" thick. As a tumble recovery, the Astron Sprint was built strong, so an upscale needs to look the same.

On my CAD model I used 1/8" thick.

Here's Grant Edwards Vintage Sprite... beefy!

View attachment 677656​

Have you seen this before. It says to use a peace of 7.5 lock tubing for the BT-80.
I have built a BT-60 and a 3inch sprite and had the same problem with the ring. I finally found a tube that was close to the size I needed and used it as a mandrill. Got some heavy card stock and built the mandrill up to the size I needed then used the same card stock to build the ring to the right diameter & thickness. Use spray glue on the back of each strip as you go. On the 3inch model I covered the ring with fiberglass. Hope this helps. I searched for years before I thought of this, it works pretty well.

 

[lakeroadster]

Have you seen this before. It says to use a peace of 7.5 lock tubing for the BT-80.
I have built a BT-60 and a 3inch sprite and had the same problem with the ring. I finally found a tube that was close to the size I needed and used it as a mandrill. Got some heavy card stock and built the mandrill up to the size I needed then used the same card stock to build the ring to the right diameter & thickness. Use spray glue on the back of each strip as you go. On the 3inch model I covered the ring with fiberglass. Hope this helps. I searched for years before I thought of this, it works pretty well.
View attachment 677831

Thanks @DTRocket.​

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I really need a ring just a bit smaller than the 7.515" I.D. x 7.675" O.D. LOC 7.5" Tube.​

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The Ring on my BT-80H is 6-7/8" I.D. x 7" O.D.​

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I built a Ring Fin for my Ahpla Booster from regular paper and Gorilla Wood Glue. On this one though I'm thinking of going with pine sections glued and then turned on my wood lathe. I've never done that, I think it would be a challenge.​

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[Mward]

Everyone realizes that the SEMROC 13mm engined Sprite is still available?

https://www.erockets.biz/semroc-flying-model-rocket-kit-sprite-sem-kv-86/

 

[lakeroadster]

Everyone realizes that the SEMROC 13mm engined Sprite is still available?

https://www.erockets.biz/semroc-flying-model-rocket-kit-sprite-sem-kv-86/

We can build it..... better, stronger, faster and bigger, like 3-1/2 times bigger...​

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The Bionic Sprite​

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