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

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

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