Brief:

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

Construction:

I be brushin' me teeth one day, me bucko, and looked down at t' empty toothpaste box, ya bilge rat, matey, and thought "Why not?" So, matey, shiver me timbers, t' plan for Obelisk be born. Avast! I took 1/8" balsa and formed t' nose, which is hollow, me hearties, shiver me timbers, and t' fins, arrr, me hearties, which are solidly mounted t' t' body with ordinary white glue. Begad! 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. 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. Blimey! Begad! Why a 25 peseta coin? Well, it was t' correct weight, shiver me timbers, and already has a hole in t' center. Arrr! And second, me bucko, because it be just sittin' on t' kitchen counter.

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

After it was all built, weighed, me bucko, matey, and tested, I decided that I could easily build a little compartment for t' parachute t' ride in. Avast, me proud beauty! Blimey! This was constructed by usin' a small "travel size" toothpaste box nestled betwixt t' end o' t' body tube and t' baffle. Begad! Blimey! A piece o' 1/8" balsa was glued with white glue just above t' baffle. Ya scallywag! Blimey! Avast, me proud beauty! Blimey! Holes were drilled into t' balsa t' allow ejection gases out, and t' shock cord was attached t' this. Begad! Blimey! Arrr! Blimey! 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, with a 18mm tube in t' center. Arrr! T' centerin' "rings" were made from t' construction foam, shiver me timbers, which has proven itself t' be a worthy construction material. Avast! Aye aye! Blimey! Finally, a tubin' coupler was made from 1/8" balsa. Begad! All corners o' t' fins butt against one another, arrr, arrr, makin' this rocket nearly bulletproof.

I decided t' launch t' rocket before paintin' t' booster, since it would be wasted time if it failed. Instead o' paintin' t' rocket, me hearties, ya bilge rat, shiver me timbers, I used a large sheet o' self adhesive vinyl, which further strengthened t' rocket. Ya scallywag! Unfortunately, it further weighed down t' rocket! In testing, me bucko, t' booster tended t' glide a bit, then t' heavy balsa end would tip over, and it would fall like a brick. Blimey! 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. Aye aye! Blimey! Ample room betwixt t' centerin' rin' and t' end o' t' sustainer gives t' streamer a good place t' hide from t' rocket exhaust. Ya scallywag! T' result is that t' booster tumbles somewhat, arrr, but still lands hard. Begad! Oh well, at least it's sturdily constructed. Well, blow me down! 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. Ahoy! Pop in a A10-3T, arrr, roll up t' booster's streamer, insert a C6-0 into t' booster, arrr, arrr, and attach t' booster section. Well, blow me down! T' 13mm motor fits right into t' 18mm motor easily, arrr, but if t' fit is tight, just roll t' end o' t' 13mm motor on a table t' round off t' corners. Arrr! Since t' rocket be a lot heavier than I expected in t' beginning, me hearties, t' minimum length launch lug wasn't up t' task, and sheared off on t' first flight. Ya scallywag! Ya scallywag! A much stronger launch lug be epoxied in place, and now it works well. Begad! Arrr! T' fins, which I feared would be too small, shiver me timbers, arrr, are just right. T' shock cord is really strong, 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, shiver me timbers, but next time I would just go 18mm from t' start and forget t' booster. Ya scallywag! Arrr! Flight characteristics? Well, ya bilge rat, let's just say that it works, ya bilge rat, and will land time after time without any damage. Ahoy! But if you love altitude or speed, you won't find either here. Ya scallywag! You could probably fly this rocket without t' A10-3T and do just as well.

Summary:
Pros- bulletproof construction, me hearties, unique design, arrr, and definitely an attention getter. Blimey! Ya scallywag! Proved that construction foam is a viable component for rocketry. Well, blow me down! Avast, me hearties, me proud beauty! Cons- heavy, ya bilge rat, thin "dry cleanin' bag" parachute rips easily at t' shroud line, arrr, low altitude performance, ya bilge rat, matey, and t' pyramid nose would've been a lot easier t' build from a solid piece o' balsa, and no nose weight would've been required. Begad! Ya scallywag! Oh well, shiver me timbers, 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! Ahoy! Blimey! Makes for a neater appearance, adds durability, and on a higher performance rocket, would probably add some altitude.