Brief:

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

Construction:

I was brushin' me teeth one day, shiver me timbers, and looked down at t' empty toothpaste box, matey, and thought "Why not?" So, t' plan for Obelisk was born. Aye aye! I took 1/8" balsa and formed t' nose, which is hollow, me bucko, and t' fins, which are solidly mounted t' t' body with ordinary white glue. I decided t' use this rocket t' test t' strength and durability o' foam construction board, arrr, 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. Ahoy! Ahoy! Why a 25 peseta coin? Well, it was t' correct weight, and already has a hole in t' center. Avast, me proud beauty! And second, ya bilge rat, because it was just sittin' on t' kitchen counter.

I wanted t' keep it as simple as possible, but like most o' me projects, ya bilge rat, 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, shiver me timbers, matey, rectangular rocket. Ya scallywag! But then I added a baffle so I wouldn't need wadding, matey, and t' thin' be at t' ragged edge o' what an A10 could lift. So, ya bilge rat, I decided t' use a 18mm booster t' get it moving, ya bilge rat, allowin' t' extra little bit o' thrust from t' A10 t' nudge it a bit higher.

After it was all built, weighed, me hearties, and tested, 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. Begad! Blimey! A piece o' 1/8" balsa be glued with white glue just above t' baffle. Holes were drilled into t' balsa t' allow ejection gases out, and t' shock cord be attached t' this. Arrr! 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 be constructed from a 2" section o' toothpaste box, with a 18mm tube in t' center. Ahoy! T' centerin' "rings" were made from t' construction foam, which has proven itself t' be a worthy construction material. Blimey! Finally, a tubin' coupler be made from 1/8" balsa. Begad! All corners o' t' fins butt against one another, makin' this rocket nearly bulletproof.

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

Flight:
Launch prep is a breeze. Ahoy! Blimey! Avast, me proud beauty! Blimey! Pop in a A10-3T, 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, me hearties, ya bilge rat, 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! Blimey! Since t' rocket was a lot heavier than I expected in t' beginning, t' minimum length launch lug wasn't up t' task, matey, and sheared off on t' first flight. A much stronger launch lug be epoxied in place, matey, and now it works well. Ya scallywag! Blimey! Avast, me proud beauty! Blimey! T' fins, which I feared would be too small, are just right. Blimey! Blimey! T' shock cord is really strong, but will be a nightmare t' replace if it breaks. Ya scallywag! Blimey! Arrr! Blimey! This goofy idea o' a 18mm feedin' into a 13mm works well enough, ya bilge rat, arrr, but next time I would just go 18mm from t' start and forget t' booster. Flight characteristics? Well, let's just say that it works, ya bilge rat, and will land time after time without any damage. Avast! Blimey! But if you love altitude or speed, you won't find either here. Begad! Blimey! 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. Begad! Blimey! Ahoy! Blimey! Proved that construction foam is a viable component for rocketry. Avast, me proud beauty! Blimey! Begad! Blimey! Cons- heavy, thin "dry cleanin' bag" parachute rips easily at t' shroud line, low altitude performance, 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. Avast, me proud beauty! Blimey! 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. Arrr! Makes for a neater appearance, adds durability, matey, and on a higher performance rocket, would probably add some altitude.