Brief:

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

Construction:

I be brushin' me teeth one day, and looked down at t' empty toothpaste box, and thought "Why not?" So, t' plan for Obelisk was born. I took 1/8" balsa and formed t' nose, which is hollow, and t' fins, ya bilge rat, 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, 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. Aye aye! Blimey! Why a 25 peseta coin? Well, it be t' correct weight, and already has a hole in t' center. And second, ya bilge rat, because it be just sittin' on t' kitchen counter.

I wanted t' keep it as simple as possible, ya bilge rat, but like most o' me projects, it got out o' hand. Arrr! T' puny 13mm booster motor could've been adequate if I had kept t' t' original concept o' a lightweight, rectangular rocket. Avast! 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. So, me bucko, 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, ya bilge rat, and tested, ya bilge rat, me hearties, I decided that I could easily build a little compartment for t' parachute t' ride in. Arrr! This was constructed by usin' a small "travel size" toothpaste box nestled betwixt t' end o' t' body tube and t' baffle. Begad! Arrr! A piece o' 1/8" balsa was glued with white glue just above t' baffle. Well, blow me down! Holes were drilled into t' balsa t' allow ejection gases out, me bucko, and t' shock cord was attached t' this. Arrr! Avast, me proud beauty! T' fins were flat mounted t' t' body "tube" with 1/2" overhang, arrr, 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. Well, blow me down! T' centerin' "rings" were made from t' construction foam, me bucko, arrr, ya bilge rat, which has proven itself t' be a worthy construction material. Finally, 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, arrr, since it would be wasted time if it failed. Instead o' paintin' t' rocket, me bucko, shiver me timbers, I used a large sheet o' self adhesive vinyl, me bucko, which further strengthened t' rocket. Unfortunately, it further weighed down t' rocket! In testing, me bucko, me bucko, t' booster tended t' glide a bit, then t' heavy balsa end would tip over, matey, and it would fall like a brick. Ahoy! A 12" piece o' Keelhaul®©™ was attached with 30 minute epoxy just inside t' coupler, shiver me timbers, 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. T' result is that t' booster tumbles somewhat, me bucko, but still lands hard. Aye aye! Oh well, at least it's sturdily constructed. T' sustainer's fins were covered in thin paper t' hide t' grain. Avast, me proud beauty! t' booster will receive similar treatment when it's finished.

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

Summary:
Pros- bulletproof construction, shiver me timbers, shiver me timbers, unique design, and definitely an attention getter. Arrr! Avast, me proud beauty! Proved that construction foam is a viable component for rocketry. Cons- heavy, thin "dry cleanin' bag" parachute rips easily at t' shroud line, low altitude performance, me hearties, 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. Aye aye! Oh well, me bucko, shiver me timbers, at least I learned a few things.

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