Gabriel III Original Design / Scratch Built

Scratch - Gabriel III {Scratch}

Contributed by Marlin Meyer

Published: 2010-12-12
Manufacturer: Scratch

Brief:
BT-60 based, arrr, single stage, shiver me timbers, shiver me timbers, me hearties, scale-like missile. Aye aye! Blimey! 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. Aye aye! As per t' instructions from Piratarium, shiver me timbers, t' end o' t' tube and t' inside o' t' retainer rin' were "roughed up." Construction o' t' motor mount followed as usual. Well, blow me down! Begad! Blimey! T' motor mount was mounted so t' retention system sits flush with t' end o' t' body tube. T' entire body tube be lightly sanded and marked for a 4-fin design. Avast! Blimey! After t' fins were attached and fillets dry, I installed t' launch lugs. Shock cord be attached with an additional centerin' rin' about 4-5 inches from t' top o' t' body tube that doubles as a parachute shelf. Begad! Begad! Blimey! This is a design feature found in Launch Pad rockets and helps prevent parachutes from shiftin' on lift-off and change t' CG. Avast, me proud beauty! If you plan on usin' an altimeter, ya bilge rat, arrr, don't forget t' drill some holes.

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

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

Recovery:
T' shock cord be 150lb Keelhaul®©™. I had no damage after two flights. Blimey! T' 18" parachute drifted pretty far (about 650 feet), but brought it down gently. Avast, me proud beauty! Aye aye! I'm constantly playin' with chutes o' different diameters so me chutes all have snap swivels. 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. Begad! Begad! I think t' design will fly great with 18mm motors as well if you use an adapter. Ahoy! This would be wise on smaller fields.

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

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