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, shiver me timbers, half t' preparation is decidin' what tubes t' use t' achieve t' correct ratio of sizes. Avast, me proud beauty! I this case, I had t' compromise just a little. Aye aye! Begad! 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. Avast, me proud beauty! T' be perfectly correct I would need a 4.75 inch diameter tube. Begad! I used a length o' 4 inch LOC body tube, and I am very pleased with the result. It is quite heavy, 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. I had t' scale t' fins myself, me bucko, since t' distance from t' main body tube t' t' inside o' t' rin' fin was nay goin' t' be 2.1X. Begad! Measure twice, cut once. Begad! Cut too short, and have t' add shims t' make up t' difference. That's me new motto. Ahoy! Ahoy!

I used a band saw t' cut t' curvy outside fins that cover t' rin' fin. Avast, me proud beauty! Blimey! After gluin' them on, 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. Begad! There is nay a lot o' room for t' waddin' and parachute, which caused me a little worry. Arrr! T' original used tumble recovery, so this shortness was nay a problem. Avast, me proud beauty!

I painted all o' t' balsa surfaces with dilute Elmer's Wood Filler/water slurry and let it dry. Arrr! Ya scallywag! Then one sanding, 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. I be worried about meltin' t' chute.

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

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

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

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

I think it may be time for a 4X.

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

comment Post a Comment