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, half t' preparation is decidin' what tubes t' use t' achieve t' correct ratio of sizes. I this case, me hearties, I had t' compromise just a little. Ya scallywag! 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. Ya scallywag! T' be perfectly correct I would need a 4.75 inch diameter tube. Begad! Avast! I used a length o' 4 inch LOC body tube, and I am very pleased with the result. Avast! It is quite heavy, ya bilge rat, me bucko, but also very sturdy.

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

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

I used a band saw t' cut t' curvy outside fins that cover t' rin' fin. Blimey! After gluin' them on, arrr, I filled the joints with Elmer's Wood Filler. Begad! This really made t' joints disappear.

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

I painted all o' t' balsa surfaces with dilute Elmer's Wood Filler/water slurry and let it dry. Ahoy! Then one sanding, me bucko, me bucko, and a coat o' white Kilz. 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. Aye aye! Arrr! I was worried about meltin' t' chute.

T' first flight was on a Quest B6-4. Avast, me proud beauty! This was a good flight, and eject a little past apogee. Well, blow me down! No problem at all with t' parachute. Begad! Blimey! This was a good size chute, arrr, as well. Avast, me proud beauty!

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

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

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

I think it may be time for a 4X.

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

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