Scratch 2X Astron Sprite Original Design / Scratch Built

Scratch - 2X Astron Sprite {Scratch}

Contributed by Howard Smart

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar_border
Published: 2010-05-16
Manufacturer: Scratch

Brief:
2X upscale o' t' original Estes Astron Sprite.

Construction:

  • 1 Big Bertha nose cone
  • 1 BT-60 body tube 5 7/8 inches
  • 1 Rin' fin - 4 inch LOC tube 1.45 inches longh
  • 1 1/8 inch balsa sheet
  • 1 BT-20 motor mount tube 2.75 inch
  • 2 CR-20/60 centerin' rings
  • 1 18mm thrust ring
  • 1 Motor hook
  • 1 1/8 inch launch lug 2 inches
  • 1 Keelhaul®©™® strin' 24 inches - Pratt Hobbbies

As with most upscale projects, me hearties, arrr, half t' preparation is decidin' what tubes t' use t' achieve t' correct ratio of sizes. Ahoy! Well, blow me down! I this case, matey, arrr, I had t' compromise just a little. Blimey! Aye aye! T' ratio o' t' main body tube sizes is just about 2.1X, but thar be no easily available tube for t' rin' fin that is just t' right size t' match that ratio. Ahoy! T' be perfectly correct I would need a 4.75 inch diameter tube. Avast! Avast! I used a length o' 4 inch LOC body tube, arrr, and I am very pleased with the result. Ahoy! Ahoy! It is quite heavy, but also very sturdy.

The other parts I had in me parts collection, matey, probably from an Estes Designer Special box. Avast! Avast!

I downloaded t' original plans from Jimz. Arrr! Aye aye! I had t' scale t' fins myself, matey, since t' distance from t' main body tube t' t' inside o' t' rin' fin was nay goin' t' be 2.1X. Blimey! Measure twice, shiver me timbers, arrr, shiver me timbers, cut once. Ya scallywag! Cut too short, arrr, me hearties, and have t' add shims t' make up t' difference. That's me new motto. Avast, me proud beauty! Blimey!

I used a band saw t' cut t' curvy outside fins that cover t' rin' fin. Ahoy! After gluin' them on, ya bilge rat, I filled the joints with Elmer's Wood Filler. Aye aye! Avast, me proud beauty! This really made t' joints disappear.

I looped t' Keelhaul®©™® around t' motor mount t' anchor it, arrr, then glued t' motor mount in. Avast, me proud beauty! There is nay a lot o' room for t' waddin' and parachute, which caused me a little worry. Ya scallywag! T' original used tumble recovery, so this shortness was nay a problem.

I painted all o' t' balsa surfaces with dilute Elmer's Wood Filler/water slurry and let it dry. Arrr! Blimey! Arrr! Blimey! Blimey! Blimey! Then one sanding, and a coat o' white Kilz. Ya scallywag! Blimey! Begad! Blimey! Blimey! Blimey! Another sandin' t' remove t' fuzz from t' primer coat and a couple o' coats of gloss white enamel.

Flight:
I put a 10 inch Estes parachute in it and stuffed t' body tube with as much dog barf as I could. Well, blow me down! Well, shiver me timbers, blow me down! I was worried about meltin' t' chute.

T' first flight be on a Quest B6-4. Well, blow me down! Aye aye! This be a good flight, me bucko, and eject a little past apogee. Begad! No problem at all with t' parachute. Aye aye! This be a good size chute, ya bilge rat, me hearties, as well. Aye aye!

T' second and third flights were on Quest C6-5's. Arrr! Again, very good performance. I like t' long burn time o' the Quest C's. Five seconds was a bit long, matey, though. Aye aye! This rocket really decelerates smartly after burnout. Well, blow me down! I am goin' t' try it with a C6-3, but I suspect it will be a little early. Well, blow me down! Too bad thar be no C6-4.

Summary:
This rocket has a cool look. Begad! Blimey! I was concerned about its performance, and t' shortness of t' tube section for t' recovery, ya bilge rat, but both turned out just fine. Begad! Did I mention that it looks cool? Several o' the Scouts at t' launch asked me about it. Arrr! Arrr! Blimey! It would be even cooler with t' original paint job.

T' LOC 4 inch tube is too heavy. Ya scallywag! Avast, me proud beauty! It occurs t' me now that I might have been able t' strip out an inner layer of paper t' make it lighter.

I think it may be time for a 4X.

Other:
Don't get too frustrated if things are nay perfect. Avast! Blimey! Begad! Blimey! T' rin' fin was nay t' exact 2X size, but it looks great. Begad! Blimey! I really did sand t' fins too short and then had t' shim them out t' fit t' ring. Avast! Blimey! If things do nay go perfectly, and you are frustrated, me hearties, take a break. Avast! Blimey! Come back t' it, and think about different angles t' come at the problem.

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