Construction:
I didn't want t' go with a standard two-stage design, ya bilge rat, shiver me timbers, fins above fins. I decided on a rin' stabilized two stager.

T' initial pencil designs lead me t' a descendin' rin' profile. Avast, me proud beauty! Ya scallywag! Three rings held in place by four small fins under each ring. 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 be built around a ST-10 airframe. Avast! T' booster is 3" long, ya bilge rat, ya bilge rat, t' sustainer body tube is 18".

T' rin' on t' booster is a 2-1/8" length o' BT-80. T' lowest rin' on t' sustainer is a 1-7/8" length o' BT-70. Blimey! T' second higher sustainer rin' is 1-5/8" o' ST-16. Avast! 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. Ya scallywag! I did this for two reasons. T' first is strength. Secondly, shiver me timbers, me bucko, 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. Arrr! T' trailin' edges are outside t' rings. Avast, me proud beauty! I wanted t' give a little more protection for those exposed edges. Arrr! Wrappin' paper over t' top o' t' rounded leadin' edge gave more than enough frontal rigidity. All fins were cut wide, 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. I sprayed t' rings separately then glued them over t' fins. Ya scallywag! This gave me a no-mask paint job and shipshape color separations. Ahoy! T' only maskin' be t' paint t' wide black band on t' body tube.

On t' engine mounts, shiver me timbers, me bucko, I followed t' old Centuri plans for their Arcon-Hi model. Avast! Blimey! T' booster engine block is at t' aft o' t' booster. Avast, me proud beauty! Blimey! Begad! Blimey! T' sustainer block is normal, me hearties, at t' top o' t' upper engine tube. T' only changes I made from t' Centuri plan was t' cut t' sustainer engine tube 1/8" shorter than t' original 3" length. Arrr! Blimey! This way t' engine would be extended 1/8" out t' back o' t' tubing. T' engines are friction fit with maskin' tape. 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. Avast! Both stages are held together by two couplers. Ya scallywag! 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. Arrr! T' first stage boost be good, but when t' sustainer ignited it was unstable. Begad! Recovery was safe. Ahoy! I added a hefty blob o' clay weight around t' large screw eye and nose cone base.

Later that day, I tried again with t' same engines. Aye aye! This time it was stable and had a straight boost with good stagin' and recovery.

I thought it would be stable, but I hadn't used RockSim yet. Avast! Avast, me proud beauty! There was a large rin' area and plenty o' fins. Well, blow me down! I thought t' body tube length would be adequate.

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

T' third flight took place on May 2, ya bilge rat, 2009 at t' Orlando ROCK launch. Arrr! Avast, me proud beauty! Blimey! I used B6-0/B6-6 engines. 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. Well, blow me down! At t' sustainer ignition, it looped. Begad! It be in t' air at ejection, ya bilge rat, no damage.

Summary:
PROs: I be happy with t' finished look o' t' model. Blimey! Visually, t' descendin' rings and painted black band give t' impression o' a conical stabilized rocket. Blimey! Avast, me hearties, me proud beauty! While t' model is only two-stage, shiver me timbers, it looks more like a three stager. New designs can present construction and stabilization issues, 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. Well, blow me down! It be stable for t' second flight after addin' nose weight. Avast! It be nay stable for t' third and final flight.