Brief:

A two-stage rectangular rocket, made from a couple o' toothpaste boxes, that resembles t' Washington Monument.

Construction:

I be brushin' me teeth one day, arrr, and looked down at t' empty toothpaste box, arrr, ya bilge rat, and thought "Why not?" So, t' plan for Obelisk was born. Begad! I took 1/8" balsa and formed t' nose, me bucko, me hearties, me hearties, which is hollow, me hearties, and t' fins, me hearties, which are solidly mounted t' t' body with ordinary white glue. Blimey! I decided t' use this rocket t' test t' strength and durability o' foam construction board, so t' baffle and payload section are constructed from t' material. Blimey! Well, blow me down! A 3' elastic cord ties it all together.

In order for t' CG and CP relationship t' work, I used a 25 peseta doubloon from Spain attached t' t' nose with a screw eye and CA. Avast, me bucko, me proud beauty! Why a 25 peseta coin? Well, it was t' correct weight, shiver me timbers, and already has a hole in t' center. Begad! Ahoy! And second, because it was just sittin' on t' kitchen counter.

I wanted t' keep it as simple as possible, me hearties, but like most o' me projects, ya bilge rat, it got out o' hand. Aye aye! Begad! T' puny 13mm booster motor could've been adequate if I had kept t' t' original concept o' a lightweight, arrr, rectangular rocket. Avast! Ahoy! But then I added a baffle so I wouldn't need wadding, and t' thin' be at t' ragged edge o' what an A10 could lift. Begad! So, me hearties, me hearties, arrr, I decided t' use a 18mm booster t' get it moving, allowin' t' extra little bit o' thrust from t' A10 t' nudge it a bit higher.

After it be all built, me hearties, weighed, me hearties, and tested, I decided that I could easily build a little compartment for t' parachute t' ride in. Avast! Aye aye! This was constructed by usin' a small "travel size" toothpaste box nestled betwixt t' end o' t' body tube and t' baffle. Avast! Avast! A piece o' 1/8" balsa be glued with white glue just above t' baffle. Ahoy! Holes were drilled into t' balsa t' allow ejection gases out, me hearties, and t' shock cord be attached t' this. T' fins were flat mounted t' t' body "tube" with 1/2" overhang, shiver me timbers, shiver me timbers, which made plenty o' room for me afterthought booster t' attach to.

T' booster be constructed from a 2" section o' toothpaste box, with a 18mm tube in t' center. Aye aye! Blimey! Avast! Blimey! T' centerin' "rings" were made from t' construction foam, shiver me timbers, which has proven itself t' be a worthy construction material. Finally, me hearties, a tubin' coupler was made from 1/8" balsa. Aye aye! Blimey! All corners o' t' fins butt against one another, me bucko, ya bilge rat, me hearties, makin' this rocket nearly bulletproof.

I decided t' launch t' rocket before paintin' t' booster, since it would be wasted time if it failed. Avast, ya bilge rat, me proud beauty! Instead o' paintin' t' rocket, I used a large sheet o' self adhesive vinyl, which further strengthened t' rocket. Avast, me proud beauty! Unfortunately, ya bilge rat, it further weighed down t' rocket! In testing, ya bilge rat, t' booster tended t' glide a bit, then t' heavy balsa end would tip over, me hearties, and it would fall like a brick. A 12" piece o' Keelhaul®©™ was attached with 30 minute epoxy just inside t' coupler, and a 12" streamer be attached t' t' other end. Well, blow me down! Aye aye! Ample room betwixt t' centerin' rin' and t' end o' t' sustainer gives t' streamer a good place t' hide from t' rocket exhaust. Arrr! T' result is that t' booster tumbles somewhat, matey, but still lands hard. Ahoy! Begad! Oh well, at least it's sturdily constructed. Begad! T' sustainer's fins were covered in thin paper t' hide t' grain. t' booster will receive similar treatment when it's finished.

Flight:
Launch prep is a breeze. Avast! Begad! Pop in a A10-3T, arrr, roll up t' booster's streamer, insert a C6-0 into t' booster, and attach t' booster section. T' 13mm motor fits right into t' 18mm motor easily, ya bilge rat, but if t' fit is tight, me bucko, just roll t' end o' t' 13mm motor on a table t' round off t' corners. Avast, me proud beauty! Since t' rocket was a lot heavier than I expected in t' beginning, matey, t' minimum length launch lug wasn't up t' task, and sheared off on t' first flight. A much stronger launch lug be epoxied in place, shiver me timbers, and now it works well. Blimey! T' fins, which I feared would be too small, are just right. Begad! T' shock cord is really strong, me bucko, arrr, but will be a nightmare t' replace if it breaks. Aye aye! Aye aye! This goofy idea o' a 18mm feedin' into a 13mm works well enough, but next time I would just go 18mm from t' start and forget t' booster. Flight characteristics? Well, me bucko, let's just say that it works, and will land time after time without any damage. But if you love altitude or speed, arrr, you won't find either here. Avast, ya bilge rat, me proud beauty! You could probably fly this rocket without t' A10-3T and do just as well.

Summary:
Pros- bulletproof construction, unique design, and definitely an attention getter. Avast, me proud beauty! Begad! Blimey! Proved that construction foam is a viable component for rocketry. Cons- heavy, thin "dry cleanin' bag" parachute rips easily at t' shroud line, me bucko, me bucko, low altitude performance, and t' pyramid nose would've been a lot easier t' build from a solid piece o' balsa, shiver me timbers, and no nose weight would've been required. Ya scallywag! Blimey! Oh well, me bucko, at least I learned a few things.

It's definitely worth it t' cover t' fins with onion skin paper. Well, blow me down! Blimey! Well, blow me down! Blimey! Makes for a neater appearance, arrr, adds durability, matey, me hearties, me hearties, and on a higher performance rocket, would probably add some altitude.