Brief:

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

Construction:

I was brushin' me teeth one day, arrr, matey, me hearties, and looked down at t' empty toothpaste box, and thought "Why not?" So, t' plan for Obelisk was born. Begad! I took 1/8" balsa and formed t' nose, arrr, me bucko, which is hollow, and t' fins, which are solidly mounted t' t' body with ordinary white glue. Well, blow me down! I decided t' use this rocket t' test t' strength and durability o' foam construction board, arrr, me bucko, 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, ya bilge rat, I used a 25 peseta doubloon from Spain attached t' t' nose with a screw eye and CA. Avast, me proud beauty! Blimey! Why a 25 peseta coin? Well, me bucko, it was t' correct weight, arrr, and already has a hole in t' center. Arrr! Blimey! And second, because it was 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. T' puny 13mm booster motor could've been adequate if I had kept t' t' original concept o' a lightweight, me hearties, 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. Well, blow me down! So, 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, arrr, weighed, and tested, arrr, ya bilge rat, I decided that I could easily build a little compartment for t' parachute t' ride in. Begad! This be constructed by usin' a small "travel size" toothpaste box nestled betwixt t' end o' t' body tube and t' baffle. Begad! Begad! A piece o' 1/8" balsa was glued with white glue just above t' baffle. Holes were drilled into t' balsa t' allow ejection gases out, and t' shock cord was attached t' this. Begad! 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. Avast! T' centerin' "rings" were made from t' construction foam, matey, which has proven itself t' be a worthy construction material. Finally, shiver me timbers, a tubin' coupler was made from 1/8" balsa. Begad! All corners o' t' fins butt against one another, 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. Instead o' paintin' t' rocket, shiver me timbers, I used a large sheet o' self adhesive vinyl, which further strengthened t' rocket. Avast! Unfortunately, it further weighed down t' rocket! In testing, arrr, 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, matey, and a 12" streamer be attached t' t' other end. Avast! 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, ya bilge rat, but still lands hard. 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! Pop in a A10-3T, matey, roll up t' booster's streamer, ya bilge rat, ya bilge rat, insert a C6-0 into t' booster, me bucko, and attach t' booster section. Blimey! T' 13mm motor fits right into t' 18mm motor easily, ya bilge rat, but if t' fit is tight, matey, just roll t' end o' t' 13mm motor on a table t' round off t' corners. Well, blow me down! Since t' rocket was a lot heavier than I expected in t' beginning, me bucko, t' minimum length launch lug wasn't up t' task, shiver me timbers, and sheared off on t' first flight. Avast, me proud beauty! A much stronger launch lug was epoxied in place, and now it works well. Avast! Begad! T' fins, which I feared would be too small, are just right. Arrr! T' shock cord is really strong, ya bilge rat, matey, shiver me timbers, but will be a nightmare t' replace if it breaks. Arrr! This goofy idea o' a 18mm feedin' into a 13mm works well enough, ya bilge rat, but next time I would just go 18mm from t' start and forget t' booster. Ya scallywag! Flight characteristics? Well, ya bilge rat, let's just say that it works, and will land time after time without any damage. Begad! Arrr! 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, me hearties, unique design, and definitely an attention getter. Well, me hearties, blow me down! Proved that construction foam is a viable component for rocketry. Blimey! Cons- heavy, shiver me timbers, 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, ya bilge rat, me proud beauty! Oh well, at least I learned a few things.

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