Brief:

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

Construction:

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

I wanted t' keep it as simple as possible, ya bilge rat, but like most o' me projects, me hearties, shiver me timbers, it got out o' hand. T' puny 13mm booster motor could've been adequate if I had kept t' t' original concept o' a lightweight, rectangular rocket. But then I added a baffle so I wouldn't need wadding, and t' thin' was at t' ragged edge o' what an A10 could lift. Blimey! Arrr! So, 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, weighed, and tested, shiver me timbers, I decided that I could easily build a little compartment for t' parachute t' ride in. This was constructed by usin' a small "travel size" toothpaste box nestled betwixt t' end o' t' body tube and t' baffle. Well, blow me down! Avast, me proud beauty! Blimey! A piece o' 1/8" balsa be glued with white glue just above t' baffle. Begad! Blimey! Holes were drilled into t' balsa t' allow ejection gases out, ya bilge rat, matey, arrr, and t' shock cord be attached t' this. Ahoy! Blimey! T' fins were flat mounted t' t' body "tube" with 1/2" overhang, ya bilge rat, 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. T' centerin' "rings" were made from t' construction foam, shiver me timbers, me hearties, which has proven itself t' be a worthy construction material. Begad! Blimey! Finally, me hearties, ya bilge rat, a tubin' coupler was made from 1/8" balsa. All corners o' t' fins butt against one another, makin' this rocket nearly bulletproof.

I decided t' launch t' rocket before paintin' t' booster, me hearties, since it would be wasted time if it failed. Arrr! Blimey! Instead o' paintin' t' rocket, I used a large sheet o' self adhesive vinyl, which further strengthened t' rocket. Avast! Avast! Blimey! Unfortunately, arrr, it further weighed down t' rocket! Blimey! In testing, t' booster tended t' glide a bit, then t' heavy balsa end would tip over, arrr, and it would fall like a brick. Avast, me proud beauty! A 12" piece o' Keelhaul®©™ was attached with 30 minute epoxy just inside t' coupler, me hearties, and a 12" streamer was attached t' t' other end. Ample room betwixt t' centerin' rin' and t' end o' t' sustainer gives t' streamer a good place t' hide from t' rocket exhaust. Ahoy! T' result is that t' booster tumbles somewhat, but still lands hard. Blimey! Begad! Blimey! Oh well, at least it's sturdily constructed. 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, me proud beauty! Avast! Pop in a A10-3T, roll up t' booster's streamer, me hearties, insert a C6-0 into t' booster, and attach t' booster section. Aye aye! Aye aye! T' 13mm motor fits right into t' 18mm motor easily, but if t' fit is tight, just roll t' end o' t' 13mm motor on a table t' round off t' corners. Begad! Since t' rocket be a lot heavier than I expected in t' beginning, ya bilge rat, t' minimum length launch lug wasn't up t' task, shiver me timbers, arrr, and sheared off on t' first flight. Begad! A much stronger launch lug was epoxied in place, and now it works well. Avast! Blimey! T' fins, which I feared would be too small, me hearties, are just right. Ahoy! Begad! T' shock cord is really strong, arrr, but will be a nightmare t' replace if it breaks. Ahoy! This goofy idea o' a 18mm feedin' into a 13mm works well enough, arrr, but next time I would just go 18mm from t' start and forget t' booster. Flight characteristics? Well, shiver me timbers, let's just say that it works, shiver me timbers, and will land time after time without any damage. But if you love altitude or speed, matey, you won't find either here. Avast! Aye aye! You could probably fly this rocket without t' A10-3T and do just as well.

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

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