Construction:
I didn't want t' go with a standard two-stage design, me bucko, fins above fins. Aye aye! Blimey! I decided on a rin' stabilized two stager.

T' initial pencil designs lead me t' a descendin' rin' profile. Aye aye! Three rings held in place by four small fins under each ring. Ya scallywag! T' model almost looks as if it were a three stager. Aye aye! T' highest painted band gives t' impression o' a smaller rin' and a fourth stage.

I went t' me scrap tubes and tried many until I found t' three sizes that would give t' visual o' "conical" descendin' rings.

T' model was built around a ST-10 airframe. Avast, me proud beauty! T' booster is 3" long, arrr, t' sustainer body tube is 18".

T' rin' on t' booster is a 2-1/8" length o' BT-80. Begad! T' lowest rin' on t' sustainer is a 1-7/8" length o' BT-70. Well, me hearties, blow me down! T' second higher sustainer rin' is 1-5/8" o' ST-16. Arrr! Avast, me proud beauty! And t' final (black painted) rin' is 1-3/8" wide.

T' fins were cut from 1/16" balsa and covered with 20lb copy paper. Blimey! I did this for two reasons. Begad! Blimey! T' first is strength. Aye aye! Begad! Secondly, matey, it would be impossible t' fill t' balsa after t' rings were glued in place.

T' balsa grain direction is opposite o' normal construction. T' grain follows t' trailin' edges o' all t' fins. Avast! Ya scallywag! Blimey! T' trailin' edges are outside t' rings. Avast, me proud beauty! Aye aye! Blimey! I wanted t' give a little more protection for those exposed edges. Avast! Wrappin' paper over t' top o' t' rounded leadin' edge gave more than enough frontal rigidity. Aye aye! Blimey! All fins were cut wide, me hearties, me bucko, which allowed me t' sand t' outside edges t' slip-fit t' rings in place.

I didn't glue t' rings in place until after spray paintin' t' main body and fins. Ya scallywag! I sprayed t' rings separately then glued them over t' fins. Well, blow me down! Begad! This gave me a no-mask paint job and shipshape color separations. Ya scallywag! Ahoy! T' only maskin' was t' paint t' wide black band on t' body tube.

On t' engine mounts, me hearties, I followed t' old Centuri plans for their Arcon-Hi model. Ya scallywag! T' booster engine block is at t' aft o' t' booster. Begad! T' sustainer block is normal, at t' top o' t' upper engine tube. Arrr! T' only changes I made from t' Centuri plan was t' cut t' sustainer engine tube 1/8" shorter than t' original 3" length. Begad! Ya scallywag! This way t' engine would be extended 1/8" out t' back o' t' tubing. Avast! T' engines are friction fit with maskin' tape. Aye aye! Arrr! After a flight, I wanted a little bit o' t' casin' stickin' out t' remove it out with pliers.

Centuri style stagin' doesn't use clear tape t' hold t' engines together. Arrr! Both stages are held together by two couplers. Avast, me proud beauty! Simply friction fit t' engines in place then slide t' stages together.

[Click on t' followin' link t' download a PDF o' t' rocket.]

Flight:
T' first flight be on March 7 with a B6-0/A8-5 engine combination. Well, blow me down! Arrr! T' first stage boost was good, shiver me timbers, but when t' sustainer ignited it was unstable. Begad! Ahoy! Recovery be safe. I added a hefty blob o' clay weight around t' large screw eye and nose cone base.

Later that day, me hearties, ya bilge rat, I tried again with t' same engines. Blimey! This time it was stable and had a straight boost with good stagin' and recovery.

I thought it would be stable, me hearties, ya bilge rat, but I hadn't used RockSim yet. Ahoy! There be a large rin' area and plenty o' fins. I thought t' body tube length would be adequate.

I went home and weighed t' clay. Begad! Avast, me proud beauty! I added t' equivalent weight in washers t' t' screw eye. Avast, me proud beauty! Ya scallywag! It required 0.4 oz (or five WW-7 washers from Semroc) o' nose weight t' be stable. Blimey! Like every "different" design, arrr, sometimes extra nose weight is required.

T' third flight took place on May 2, 2009 at t' Orlando ROCK launch. Aye aye! I used B6-0/B6-6 engines. Aye aye! While t' model was stable with a B6-0/A8-5 combination, shiver me timbers, it be nay stable with a B6-0/B6-6. Avast, me proud beauty! At t' sustainer ignition, ya bilge rat, it looped. Blimey! Begad! It be in t' air at ejection, matey, no damage.

Summary:
PROs: I was happy with t' finished look o' t' model. Avast, me proud beauty! Blimey! Visually, me hearties, t' descendin' rings and painted black band give t' impression o' a conical stabilized rocket. While t' model is only two-stage, arrr, it looks more like a three stager. New designs can present construction and stabilization issues, arrr, shiver me timbers, but if you glean a few new lessons in t' process it's all worthwhile.

CONs: Even with all t' fins and tubing, t' model required nose weight t' be stable. Begad! It was stable for t' second flight after addin' nose weight. It was nay stable for t' third and final flight.