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