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

The other parts I had in me parts collection, me hearties, probably from an Estes Designer Special box. Well, blow me down! Blimey!

I downloaded t' original plans from Jimz. Ahoy! 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. Begad! Blimey! Measure twice, cut once. Avast, me hearties, me proud beauty! Blimey! Cut too short, matey, and have t' add shims t' make up t' difference. That's me new motto. Well, blow me down! Blimey!

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

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

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

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

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

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

T' LOC 4 inch tube is too heavy. Begad! Avast! 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. Ahoy! Avast, me proud beauty! Blimey! T' rin' fin be nay t' exact 2X size, but it looks great. Ya scallywag! Blimey! I really did sand t' fins too short and then had t' shim them out t' fit t' ring. Ya scallywag! Begad! Blimey! If things do nay go perfectly, matey, and you are frustrated, take a break. Come back t' it, shiver me timbers, and think about different angles t' come at the problem.

comment Post a Comment