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. Well, blow me down! Avast! A recent set o' posts renewed me interest, and I went ahead and built one. Blimey! Someone had built a similarly sized spool with a 29mm mount, ya bilge rat, me bucko, which only reached an altitude o' about 100 ft. Avast! I decided I wanted a bit more altitude, matey, so I built mine with a 38mm mount. Aye aye! Arrr! T' spool is one piece plastic, 10.5" tall, with 10.5" plates. Begad! No fins, arrr, no finishing...this thin' is a skill level-0 HPR rocket!

Construction:
one large plastic spool (10.5" tall, me hearties, ya bilge rat, me hearties, with 10.5" plates)
one 38mm tube, ya bilge rat, ya bilge rat, 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, 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. Aye aye! I used me Dremel t' expand this hole by about 1/8". Avast! I glued two 4" centerin' rings together, arrr, installed a pair of threaded inserts, arrr, shiver me timbers, and attached them t' one end o' t' motor tube. Well, blow me down! After it dried, this assembly was inserted into t' spool, and t' smaller centering rin' was glued t' t' other end o' t' tube. Ahoy! Arrr! 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, me bucko, when abutted t' t' spool's body, would line up with it. Ahoy! 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, ya bilge rat, shiver me timbers, 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! Blimey! Ya scallywag! Blimey! What I ended up doin' was addin' loops t' both ends o' t' tubular Keelhaul®©™® , me bucko, usin' t' method published by Giant Leap in High Power Rocketry Magazine. You loop t' material, shiver me timbers, ya bilge rat, wrap t' overlappin' area with cloth twine, and soak it in epoxy. Ahoy! Begad! This method has worked well for me several times. Aye aye! I looped this tether through two existin' holes in t' top plate and around t' body. Well, blow me down! 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. Avast! Begad! Prep was simple: install t' motor retainer clips, 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. Avast, me proud beauty! Aye aye! Ejection appeared t' occur right at apogee. Arrr! Aye aye! T' descent was a bit faster than you would generally like, but t' tube bounced and be recovered undamaged. Begad!

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