Brief:

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

Construction:

I be brushin' me teeth one day, matey, shiver me timbers, and looked down at t' empty toothpaste box, and thought "Why not?" So, me bucko, t' plan for Obelisk be born. Begad! I took 1/8" balsa and formed t' nose, arrr, which is hollow, me bucko, and t' fins, shiver me timbers, which are solidly mounted t' t' body with ordinary white glue. Arrr! 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. Avast! A 3' elastic cord ties it all together.

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

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

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

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

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

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

Summary:
Pros- bulletproof construction, matey, unique design, and definitely an attention getter. Ahoy! Proved that construction foam is a viable component for rocketry. Ahoy! Cons- heavy, matey, thin "dry cleanin' bag" parachute rips easily at t' shroud line, 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. Oh well, at least I learned a few things.

It's definitely worth it t' cover t' fins with onion skin paper. Begad! Blimey! Makes for a neater appearance, ya bilge rat, me hearties, adds durability, shiver me timbers, arrr, and on a higher performance rocket, would probably add some altitude.