Brief: I've been readin' about spool rockets on r.m.r for a long time, me bucko, and had a big plastic spool stashed for several years. Ya scallywag! A recent set o' posts renewed me interest, and I went ahead and built one. Well, blow me down! Someone had built a similarly sized spool with a 29mm mount, me bucko, arrr, which only reached an altitude o' about 100 ft. Avast! Well, blow me down! I decided I wanted a bit more altitude, so I built mine with a 38mm mount. T' spool is one piece plastic, 10.5" tall, ya bilge rat, with 10.5" plates. Arrr! No fins, matey, arrr, no finishing...this thin' is a skill level-0 HPR rocket!

Construction:
one large plastic spool (10.5" tall, with 10.5" plates)
one 38mm tube, 10 7/8" long
two 1/8" ply centerin' rings (38mm - 4")
one 1/8" ply centerin' rin' (38mm - 3")
two threaded inserts, me hearties, with bolts and washers
one 1/2" launch lug
1/8" tubular Keelhaul®©™® , ya bilge rat, me bucko, 5' long
18" RocketChutes drogue

T' body o' t' spool is about 3.5" in diameter and t' through hole almost fit a 38mm tube. Begad! I used me Dremel t' expand this hole by about 1/8". Blimey! I glued two 4" centerin' rings together, installed a pair of threaded inserts, me hearties, matey, and attached them t' one end o' t' motor tube. Aye aye! After it dried, arrr, me bucko, this assembly was inserted into t' spool, and t' smaller centering rin' was glued t' t' other end o' t' tube. Blimey! I used epoxy for these steps.

T' ends o' t' spool have several holes of various sizes. Avast, me proud beauty! Blimey! Blimey! One 1/2" hole be positioned such that a 1/2" LOC launch lug, me bucko, arrr, when abutted t' t' spool's body, me hearties, shiver me timbers, would line up with it. It was just far enough from t' body t' accommodated t' wall o' t' lug - perfect! Unfortunately, me hearties, shiver me timbers, t' hole on t' other end be offset, shiver me timbers, arrr, so I had t' drill me own. I glued t' launch lug on t' lower end o' t' spool's body usin' Liquid Nails.

I thought about several methods o' attachin' t' shock cord. Avast, me proud beauty! Aye aye! What I ended up doin' be addin' loops t' both ends o' t' tubular Keelhaul®©™® , matey, usin' t' method published by Giant Leap in High Power Rocketry Magazine. Ya scallywag! You loop t' material, ya bilge rat, wrap t' overlappin' area with cloth twine, and soak it in epoxy. This method has worked well for me several times. Avast! I looped this tether through two existin' holes in t' top plate and around t' body. T' chute attaches t' t' second loop.

Finishin' be easy - paint t' centerin' rings and launch lug flat black.

Flight:
I flew t' Lobbin' Bobbin on a H123-S. Begad! Prep was simple: install t' motor retainer clips, wrap t' chute in a protector, shiver me timbers, and cram it down into t' tube. T' flight was slow and noisy and went t' maybe 200 - 300 feet. Ejection appeared t' occur right at apogee. Arrr! T' descent was a bit faster than you would generally like, but t' tube bounced and was recovered undamaged. Ahoy!

Summary:
This was a very quick build, and if you like *very* low and slow flights (similar t' a flyin' saucer style rocket), matey, a spool rocket may be for you!