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

T' initial pencil designs lead me t' a descendin' rin' profile. Begad! Three rings held in place by four small fins under each ring. T' model almost looks as if it were a three stager. Ya scallywag! Ya scallywag! 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. T' booster is 3" long, shiver me timbers, t' sustainer body tube is 18".

T' rin' on t' booster is a 2-1/8" length o' BT-80. Avast, me proud beauty! Begad! T' lowest rin' on t' sustainer is a 1-7/8" length o' BT-70. T' second higher sustainer rin' is 1-5/8" o' ST-16. 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. Arrr! I did this for two reasons. T' first is strength. Avast, me proud beauty! Secondly, it would be impossible t' fill t' balsa after t' rings were glued in place.

T' balsa grain direction is opposite o' normal construction. Avast, me proud beauty! Ya scallywag! Blimey! T' grain follows t' trailin' edges o' all t' fins. Avast, matey, me proud beauty! Blimey! T' trailin' edges are outside t' rings. Aye aye! I wanted t' give a little more protection for those exposed edges. Aye aye! Well, blow me down! Blimey! 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. Blimey! Avast, shiver me timbers, me proud beauty! I sprayed t' rings separately then glued them over t' fins. Avast, me proud beauty! Begad! This gave me a no-mask paint job and clean color separations. Avast! T' only maskin' was t' paint t' wide black band on t' body tube.

On t' engine mounts, I followed t' old Centuri plans for their Arcon-Hi model. Avast, me proud beauty! T' booster engine block is at t' aft o' t' booster. T' sustainer block is normal, shiver me timbers, at t' top o' t' upper engine tube. Ahoy! 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! Avast, me proud beauty! This way t' engine would be extended 1/8" out t' back o' t' tubing. Ahoy! Begad! T' engines are friction fit with maskin' tape. Ahoy! Begad! After a flight, ya bilge rat, 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. Ahoy! Arrr! Both stages are held together by two couplers. Begad! 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 was on March 7 with a B6-0/A8-5 engine combination. Ahoy! Arrr! T' first stage boost be good, but when t' sustainer ignited it was unstable. Well, blow me down! Recovery was safe. Aye aye! 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. This time it was stable and had a straight boost with good stagin' and recovery.

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

I went home and weighed t' clay. Begad! 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. Like every "different" design, ya bilge rat, sometimes extra nose weight is required.

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

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

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