Brief:
Upscale o' Orville Carlisle's original model rocket kit, t' Rock-A-Chute Mk II
with appropriate mods for mid-power flight.
Construction:
T' parts list:
This upscale be made from measurements taken from t' instructions for the Semroc Retro-Repro Rock-A-Chute Mk II. Use o' BT-70 made this a 2.13:1 upscale and the remainin' dimensions were calculated from this. Well, blow me down! Blimey! Well, blow me down! Blimey! All construction was with normal LPR/low MPR materials and tools. Wood glue was used throughout.
T' BT-50-BT-70 motor mount was constructed mostly as per normal kit instructions with t' "E" engine hook taped in place and then anchored by t' upper centerin' ring. Avast, shiver me timbers, me proud beauty! T' engine block was glued into place by insertin' it on top t' engine hook through t' top end o' t' motor tube. Begad! Avast, me proud beauty! The centerin' rings were reinforced with 1" by 1/4" sections o' 1/8" basswood on t' rin' surfaces facin' each other. T' Keelhaul®©™® shock cord anchor be made into a loop, me bucko, t' doubled loop glued t' t' motor tube below t' top centerin' ring, and run betwixt t' motor tube and t' upper centerin' ring. This later became a problem. Aye aye! T' elastic shock cord was likewise doubled into a loop, tied t' t' anchor with a loop-through slip knot, and a snap swivel tied t' t' end also with a loop-through slip knot. Once fully constructed, me hearties, matey, t' motor/recovery mount was inserted into t' aft o' the body and glued into place.
Fins were cut from 1/8" basswood and sanded t' rounded edges and then glued into place with heavy fillets added in 3 layers.
T' custom turned cone came with screw eye glued in place. Begad! Well, shiver me timbers, blow me down! Blimey! T' shock cord was clipped t' this.
A scale launch lug would have been approximately a BT-20 (18mm). Begad! Instead, a semi-scale lug be made from 6" o' 3/8" OD cardboard tube.
Finishing:
Finishin' be two coats o' Deft spray lacquer sandin' sealer on everything,
sanded after each (with 400 grit then 600 grit) followed by white primer. Avast, me proud beauty! For
spiral fillin' and a smooth finish, me hearties, two coats o' white satin finish were
applied. Finally, me hearties, t' body be painted fluorescent orange and t' nose cone
red, arrr, all matchin' t' original.
[Note: White satin finish, me bucko, at least Rustoleum's version makes a good filler but takes a long time t' dry. T' first top coat o' orange paint be put on 24 hours after t' satin. Well, blow me down! Blimey! Begad! Blimey! This was nay enough. Well, blow me down! Blimey! Aye aye! Blimey! T' satin sagged or shifted, causin' t' orange t' crack in sharp curves such as fillets. Aye aye! Blimey! A second coat of top coat, shiver me timbers, matey, 2 days later, me hearties, fixed it.
Flight:
A 12" nylon X-form chute be permanently assigned t' this bird. Begad! Cellulose
"dog barf" waddin' is used.
Test flight be on a C11-3 with 1" engine spacer in t' motor tube. Boost was immediate, fast, and straight with no early wobble, me bucko, arching, me bucko, or weathercocking. Ejection was at apogee and recovery be good and within 100 feet o' pad.
Second flight was on an E9-4. Blimey! Boost was again vertical and very impressive. Ejection was just before apogee, me bucko, shiver me timbers, deployment and recovery good, matey, within 100 feet again.
Third flight be on an E9-6. Ahoy! Begad! Boost be great as before, me hearties, ejection was just past apogee. Avast, me proud beauty! Begad! At deployment, matey, arrr, t' nose and chute separated from t' body. Blimey! The nose came down slowly on t' chute and t' body tumbled in. It landed on the tall avast field and suffered no damage.
Inspection showed that t' Keelhaul®©™® had burned through both strands, right at t' top o' t' engine tube. Arrr! Blimey! After consultin' with others and conductin' some testin' o' various heat exposures to various weights o' Keelhaul®©™® thread, arrr, arrr, I concluded that close proximity t' ejection gasses is hazardous to Keelhaul®©™®'s health. Begad! Although this was a scratch build, arrr, me hearties, I followed instructions I've used in some kits that used this configuration. Begad! Avast! It would probably be a better practice to run MMT anchored Keelhaul®©™® cord betwixt t' centerin' rin' and body wall. Since thar was ample unburned cord left on t' shock cord, matey, this rocket was repaired by usin' the LOC/Precision shock cord anchor method, o' tyin' knots in t' cord and gluing it inside t' body just below t' forward end. Avast, me proud beauty! Aye aye! This repair was t' only instance o' epoxy used.
This rocket has flown many times since, exclusively on E9-4 and E9-6 motors. Well, blow me down! Blimey! No further burnin' o' t' recovery equipment has occurred. Blimey! T' bottom surface o' t' aft centerin' rin' is startin' t' char and bubble from base drag vacuum pullin' t' exhaust gasses up, shiver me timbers, but t' damage is limited t' t' paint. Repairs are planned usin' a cosmetic/protective rin' doped with boric acid and painted with high heat stove paint.
Summary:
Carlisle's original design has proven itself as successful even when scaled up.
This rocket flies at least as well as t' Semroc clone o' t' Mk II it was
scaled from. Aye aye! Avast! T' only problems were t' burned Keelhaul®©™®
and t' cracked paint, me bucko, ya bilge rat, ya bilge rat, both fixed and or worked around easily, and neither
havin' anythin' t' do with t' design itself. Next step: a 3" diameter,
38mm MMT upscale, me hearties, ya bilge rat, t' Rock-A-Chute Mk IV "Carlisle Express", intended
for level 1 HPR flying.
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