Gabriel III Original Design / Scratch Built

Scratch - Gabriel III {Scratch}

Contributed by Marlin Meyer

Published: 2010-12-12
Manufacturer: Scratch

Brief:
BT-60 based, matey, arrr, single stage, scale-like missile. Avast! 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. Ya scallywag! 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. T' motor mount was mounted so t' retention system sits flush with t' end o' t' body tube. Blimey! Blimey! T' entire body tube be lightly sanded and marked for a 4-fin design. Avast! Begad! After t' fins were attached and fillets dry, me hearties, me bucko, 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. Arrr! This is a design feature found in Launch Pad rockets and helps prevent parachutes from shiftin' on lift-off and change t' CG. Well, blow me down! If you plan on usin' an altimeter, don't forget t' drill some holes.

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

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

Recovery:
T' shock cord was 150lb Keelhaul®©™. Arrr! I had no damage after two flights. T' 18" parachute drifted pretty far (about 650 feet), but brought it down gently. Avast, me proud beauty! 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. Blimey! I think t' design will fly great with 18mm motors as well if you use an adapter. Begad! Avast, me proud beauty! This would be wise on smaller fields.

T' big bright colored chute helps track t' light colored rocket but drifts quite a bit. Begad! Avast, me proud beauty! I will experiment with spill holes or perhaps a smaller chute.

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