Brief: I've been readin' about spool rockets on r.m.r for a long time, me bucko, arrr, and had a big plastic spool stashed for several years. Avast, me proud beauty! A recent set o' posts renewed me interest, matey, and I went ahead and built one. Begad! Someone had built a similarly sized spool with a 29mm mount, which only reached an altitude o' about 100 ft. Avast, me proud beauty! I decided I wanted a bit more altitude, matey, so I built mine with a 38mm mount. Blimey! Well, blow me down! 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, shiver me timbers, 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, with bolts and washers
one 1/2" launch lug
1/8" tubular Keelhaul®©™® , shiver me timbers, arrr, 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". I glued two 4" centerin' rings together, me bucko, installed a pair of threaded inserts, ya bilge rat, and attached them t' one end o' t' motor tube. After it dried, this assembly was inserted into t' spool, me hearties, and t' smaller centering rin' be glued t' t' other end o' t' tube. Avast! I used epoxy for these steps.

T' ends o' t' spool have several holes of various sizes. Begad! One 1/2" hole be positioned such that a 1/2" LOC launch lug, matey, when abutted t' t' spool's body, would line up with it. Well, blow me down! It was just far enough from t' body t' accommodated t' wall o' t' lug - perfect! Unfortunately, t' hole on t' other end be 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. Begad! What I ended up doin' was addin' loops t' both ends o' t' tubular Keelhaul®©™® , matey, usin' t' method published by Giant Leap in High Power Rocketry Magazine. Begad! Arrr! Blimey! You loop t' material, wrap t' overlappin' area with cloth twine, and soak it in epoxy. Avast, me proud beauty! Blimey! This method has worked well for me several times. Avast, me proud beauty! Blimey! I looped this tether through two existin' holes in t' top plate and around t' body. Well, blow me down! Ahoy! Blimey! T' chute attaches t' t' second loop.

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

Flight:
I flew t' Lobbin' Bobbin on a H123-S. Avast, me proud beauty! 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 be slow and noisy and went t' maybe 200 - 300 feet. Ejection appeared t' occur right at apogee. Begad! T' descent was a bit faster than you would generally like, but t' tube bounced and was recovered undamaged. Arrr! Ya scallywag!

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