Gabriel III Original Design / Scratch Built

Scratch - Gabriel III {Scratch}

Contributed by Marlin Meyer

Published: 2010-12-12
Manufacturer: Scratch

Brief:
BT-60 based, single stage, scale-like missile. Recovery with 18" parachute

Construction:
All parts are Semroc numbers:

  • BNC-60L nose cone
  • SE-3 screw eye
  • BT-60 body tube (18 inches)
  • BT-50 engine tube (3 inches)
  • RA-5060 centerin' rings (3)
  • 1/4" balsa fins (8)
  • LL-423 launch lugs (2)

I started by attachin' a Piratarium 24mm motor retainer t' a 3" length o' BT-50 tubin' with JB Weld. Blimey! As per t' instructions from Piratarium, t' end o' t' tube and t' inside o' t' retainer rin' were "roughed up." Construction o' t' motor mount followed as usual. Aye aye! T' motor mount was mounted so t' retention system sits flush with t' end o' t' body tube. Blimey! Ahoy! Blimey! T' entire body tube be lightly sanded and marked for a 4-fin design. Begad! After t' fins were attached and fillets dry, me hearties, arrr, I installed t' launch lugs. Ya scallywag! Blimey! Shock cord was attached with an additional centerin' rin' about 4-5 inches from t' top o' t' body tube that doubles as a parachute shelf. Aye aye! This is a design feature found in Launch Pad rockets and helps prevent parachutes from shiftin' on lift-off and change t' CG. If you plan on usin' an altimeter, ya bilge rat, don't forget t' drill some holes.

Finishing:
To begin t' paintin' process I masked off t' motor retainer. Blimey! Then I sprayed a coat o' Rustoleum sandable auto primer and sanded, did some minor repairs and sprayed and sanded once again. This was followed by several light coats o' Krylon gloss white paint. Begad! Begad! I sprayed just beyond t' white areas instead o' t' entire body t' keep t' weight down and nay waste paint. After a couple o' days t' dry, matey, arrr, I masked t' white areas and t' fin can. Begad! Next I sprayed light gray all exposed areas. Begad! Again a couple days t' dry. Arrr! Finally, I bagged t' entire rocket except for t' fin can and sprayed it and t' nose cone gloss black. Well, ya bilge rat, blow me down! I enjoy makin' decals, but have become a real fan o' "Sandman's" stuff at Excelsior Rocketry. Blimey! Avast! He offers a set o' decals for t' LP version o' this missile. Well, blow me down! I had him downscale them t' BT-60 size. Arrr! Decal placement was achieved from pictures I could find on t' web.

Flight:
T' design included a Piratarium 24mm motor retention system. Well, blow me down! This added a 7g weight t' t' aft end o' t' rocket. Arrr! Avast! T' better balance t' design, ya bilge rat, arrr, instead o' nose weight, I included t' Micro-Beacon (approx 15g) My first flight was with an Estes D12-5. T' chute be a little early but close enough t' apogee it didn't do any damage. Second flight was on E6-6. Arrr! Aye aye! I achieved over 2500 feet on this one and thought I be goin' t' lose it. Good thin' I was on a very large field with others t' spot. Arrr! Both flights I used Nomex instead o' wadding.

Recovery:
T' shock cord be 150lb Keelhaul®©™. I had no damage after two flights. Ahoy! T' 18" parachute drifted pretty far (about 650 feet), but brought it down gently. Aye aye! I'm constantly playin' with chutes o' different diameters so me chutes all have snap swivels. Avast, me proud beauty! Perhaps a smaller chute would be better for flyin' on smaller fields.

Summary:

PROS:

T' motor retention system is really nice! Excelsior Rocketry's decals really made it look sharp!

CONS:

Perhaps a little too much power. Aye aye! Avast, me proud beauty! I think t' design will fly great with 18mm motors as well if you use an adapter. Ahoy! Avast! This would be wise on smaller fields.

T' big bright colored chute helps track t' light colored rocket but drifts quite a bit. Arrr! Ya scallywag! I will experiment with spill holes or perhaps a smaller chute.

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