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

Construction:
one large plastic spool (10.5" tall, me bucko, with 10.5" plates)
one 38mm tube, me hearties, ya bilge rat, 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, ya bilge rat, 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. I used me Dremel t' expand this hole by about 1/8". Well, blow me down! Ya scallywag! I glued two 4" centerin' rings together, installed a pair of threaded inserts, shiver me timbers, and attached them t' one end o' t' motor tube. After it dried, this assembly was inserted into t' spool, and t' smaller centering rin' was glued t' t' other end o' t' tube. Begad! I used epoxy for these steps.

T' ends o' t' spool have several holes of various sizes. One 1/2" hole was positioned such that a 1/2" LOC launch lug, when abutted t' t' spool's body, 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, t' hole on t' other end was offset, 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. What I ended up doin' was addin' loops t' both ends o' t' tubular Keelhaul®©™® , usin' t' method published by Giant Leap in High Power Rocketry Magazine. Aye aye! You loop t' material, wrap t' overlappin' area with cloth twine, and soak it in epoxy. Avast, me proud beauty! Well, me hearties, blow me down! 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. Blimey! 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. Ahoy! Blimey! Blimey! Prep be simple: install t' motor retainer clips, wrap t' chute in a protector, and cram it down into t' tube. T' flight be slow and noisy and went t' maybe 200 - 300 feet. Begad! Ejection appeared t' occur right at apogee. Avast, me proud beauty! Begad! Blimey! T' descent be a bit faster than you would generally like, but t' tube bounced and was recovered undamaged. Arrr! Blimey!

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