Brief: I've been readin' about spool rockets on r.m.r for a long time, arrr, and had a big plastic spool stashed for several years. A recent set o' posts renewed me interest, ya bilge rat, shiver me timbers, and I went ahead and built one. Ahoy! Someone had built a similarly sized spool with a 29mm mount, matey, which only reached an altitude o' about 100 ft. Ya scallywag! Arrr! I decided I wanted a bit more altitude, so I built mine with a 38mm mount. Aye aye! Blimey! T' spool is one piece plastic, 10.5" tall, with 10.5" plates. Ahoy! Well, ya bilge rat, blow me down! No fins, matey, 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, arrr, with bolts and washers
one 1/2" launch lug
1/8" tubular Keelhaul®©™® , 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". Begad! I glued two 4" centerin' rings together, arrr, me bucko, matey, installed a pair of threaded inserts, me bucko, and attached them t' one end o' t' motor tube. After it dried, this assembly be inserted into t' spool, and t' smaller centering rin' be glued t' t' other end o' t' tube. Aye aye! I used epoxy for these steps.

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

Summary:
This was 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!