Scratch Stink Bomb Original Design / Scratch Built

Scratch - Stink Bomb {Scratch}

Contributed by Dick Stafford

Manufacturer: Scratch
(Contributed - by Dick Stafford - 09/07/09)

Brief:
This be an experiment in makin' a paper mache rocket usin' a latex mold. Ya scallywag! I built a mold from a Toypedo pool toy usin' 2-part latex. I had originally planned t' make fiberglass shells. Avast! However, me first attempt turned out poorly. Soon, me mind wandered and I got t' harebrained idea o' makin' a pair o' shells from paper mache. Avast!

T' quality o' t' surface continued t' deteriorate as, shiver me timbers, I guess, t' middle layers totally dried. Aye aye! I started to try t' clean it up but ended up throwin' in t' towel. Well, blow me down! I then started wonderin' about paint and a name. Avast! Motivated by t' movie Caddyshack. Ya scallywag! Avast! I was thinkin' about paintin' it brown and namin' it Is that a Baby Ruth in your pool? Or, maybe just Baby Ruth. Ya scallywag! Ya scallywag! I found that me existin' brown paint was unusable and went with a camo scheme. Ya scallywag! T' name became Stink Bomb.

Construction:
T' needed parts include:

  • Newspaper
  • Scrap junk tubin' (roughly BT-60)
  • Thick card stock (for rings)
  • 18mm Estes motor mount (tube, block, sleeve, hook)
  • Clay nose weight
  • Foam board
  • Telescopin' inside tube from a 3” mailin' tube
  • Elastic shock cord

T' body is two paper mache half-shells joined by more strips o' paper mache. Ya scallywag! Aye aye! Blimey! Each half-shell was formed from multiple layers o' newspaper soaked in Mod Podge, ya bilge rat, which is a thin white glue. Ahoy! Blimey! Blimey! When they seemed t' have dried, I removed them from t' mold and trimmed t' edges with a pair o' scissors.

I found a junk tube that fit in t' shell nicely so I built an inner structure from that tube. Begad! Blimey! T' motor mount is surplus from an Estes kit and t' rings were made from thick card stock usin' a circle cutter. I glued this in one half and carefully trimmed off t' nose section flush with t' tube. I added t' second and sealed t' edges with more layers o' paper mache. Ahoy! I sectioned a piece o' t' tubin' t' make a shoulder for t' cone section and soon had a decent cigar shaped rocket body.

Initially, ya bilge rat, things looked OK but, as t' paper mache continued t' dry, shiver me timbers, matey, it continued t' warp. Begad! Blimey! Blimey! Blimey! Blimey! Blimey! I started fillin' and sandin' but soon realized this was a losin' proposition. Avast! Blimey! It was then that I named it as described in t' intro, ya bilge rat, matey, shiver me timbers, above.

However, once I had a body completed, me hearties, I though I should fly it. Blimey! Blimey! Aye aye! Blimey! I played with V-2-like fins, shiver me timbers, built a RockSim Model, me bucko, added some clay as a nose weight, and decided makin' it stable would be a problem. Aye aye! Blimey! Avast, matey, me proud beauty! Blimey! I could add more weight, ya bilge rat, me hearties, add bigger fins, arrr, ya bilge rat, etc. Avast! Blimey! Avast! Blimey! But suddenly, shiver me timbers, me bucko, arrr, I had an epiphany! Blimey! A rin' fin would help stability a lot and I had recently found how well t' inside telescopin' tube from a 3” mailin' tube fits inside a 3” window tint tube (plastic, ya bilge rat, kind of like Quantum tube – but free). After another round with RockSim, I had me design – an ugly, matey, matey, ring-finned, tube-launched rocket!. Ahoy! Blimey! Avast, me proud beauty! Blimey! This was a really junky el-cheapo design, so foam board seemed t' be a quick and easy source for t' fins.

When I can’t decide on t' color scheme for a rocket, I find myself fallin' back on a camo scheme. Ahoy! I used three colors from t' Rustoleum camo set. Avast! Aye aye! Finally, I touched it up with some day-glo green ‘Mr. Arrr! Yuk’ poison warnin' stickers

Flight:
T' launch tube is a piece o' window tint tube with a Firstfire igniter tube duct taped on. Ahoy! This fits on a standard 3/16” or 1/4” rod.

For t' first flight, I chose a Quest ‘long burn’ C6-3. It was windy on launch day and it weather-cocked soon after it left t' tube. What should have been ejection was a tad late. Arrr! Didn’t matter much since t' cone stuck. It core sampled, totally destroyin' t' cone section. Avast, me proud beauty!

But, I wasn’t goin' t' give up. Arrr! Arrr! I replaced t' cone with half o' a pink plastic Easter Egg. Ya scallywag! Now, the Stink Bomb really looks goofy! I also made a cap for t' bottom o' t' tube. Begad! Arrr!

On t' second flight, I opted for a good ol’ Estes short burn C6-3. Aye aye! Aye aye! I used a Quest Q2G2 igniter and twisted on some scrap wire t' extend t' igniter through t' launch tube’s cap. Avast! This time, ya bilge rat, matey, t' flight was great. Blimey! Well, blow me down! Ejection was early and it recovered unscathed. Ahoy! Ya scallywag! There is even a movie here.

Summary:
There is nay much you can learn from this build, shiver me timbers, except maybe how poor a material paper mache is for rocketry. On second thought, me bucko, it may be poor for ‘normal’ rockets but may have a place in odd-rocketry. Avast, me proud beauty! This one actually flies well and I think I may make more rockets t' launch from me tube launcher.

comment Post a Comment