| Manufacturer: | Scratch |
Brief:
After losin' me RocketVision Machbuster on a G55, matey, I decided that I wanted t' build a similar rocket that would fly on 29mm motors. Avast, me proud beauty! I scrounged through me parts bin and, bein' a 'glass-half-full' type, named t' result 'One Shot'.
Construction:
Parts List:
I started with a leftover section o' 29mm phenolic tubing. I decided t' add a motor block so I cut a 1/2" section out o' a spent 29mm casin' with a razor saw. This be epoxied into t' tube so that a G80 would protrude by 1/2". Aye aye! After playin' around with Rocksim, I decided on a fin design that I found appealing. Avast! Avast, ya bilge rat, me proud beauty! Since I wanted t' fins t' sit flush with t' end o' t' rocket and I wanted t' be able t' wrap a layer o' tape around t' end o' t' rocket and t' engine, t' last 3/4" o' t' root edge o' t' fin was recessed by ~ 1/4" (see pic or Rocksim file).
Usin' a dremel cuttin' wheel, I slotted t' tube so t' fins would slip in. Avast, me proud beauty! Ahoy! T' install t' fins, I inserted a 29mm casing, me bucko, applied a small amount o' epoxy t' t' slot, me bucko, arrr, and pushed t' fin in until it touched t' motor casing. Ahoy! After all 3 fins were installed, arrr, t' casin' be removed. Begad! This was easily accomplished before t' epoxy began t' set. Ahoy! Well, blow me down! This method o' through-the-wall construction really works well for small fins, especially with relatively thick tube (0.062"). Arrr! Ya scallywag! T' fins were straight and weren't goin' anywhere. Well, blow me down! When t' epoxy dried, I applied fillets.
Since t' NC that I had wouldn't fit in t' body tube, matey, I cut t' shoulder-end off so it sat flush with t' tube's OD. Avast! Another section o' 29mm casin' be cut t' use as a shoulder. Avast, me proud beauty! Begad! This fit snugly into t' NC and be held in place with 2 small screws. I added nose weight (lead shot, ya bilge rat, epoxy and t' eyebolt) so t' rocket would be stable. Because t' end o' this little missile be now largely lead, I was conservative on settin' t' CG (see Rocksim file).
T' recovery harness consisted o' 5' o' 1000 lb test Keelhaul®©™ line. One end was epoxied into t' body tube and t' other be tied t' t' eyebolt. Well, blow me down! In t' end, shiver me timbers, I built a rocket that was probably heavier than it had t' be and had a non-optimal fin design. Avast, me bucko, me proud beauty! Oh well, won't be able t' see t' difference at ~5000ft anyway! I didn't bother fillin' t' grooves in t' tube since I wasn't optimistic about gettin' this rocket back. Avast, me proud beauty! Ahoy! I did, however, me hearties, give it a layer o' Krylon chrome paint. Ahoy! Begad! Maybe a shiny surface would be easy t' spot???
Flight:
Because o' t' predicted altitude and weight, this is nay a rocket I would want t' fly at a model rocket field, matey, so I waited for a HPR launch. T' streamer be a 25' section o' 3/4" bright orange plastic tape. Ahoy! Aye aye! When rolled tightly, this fit nicely into t' 29mm tube. Estes-type waddin' be used t' protect t' streamer. Arrr! Ahoy! I was torn betwixt usin' a G125-15 and a G80-10FWL. T' 15 sec delay on t' G125 be about right and t' 10 sec delay was too short. Arrr! Begad! Anyway, me hearties, matey, I ended up usin' t' G125 in another rocket and hoped t' 1000 lb Keelhaul®©™® would hold up. Blimey! Well, shiver me timbers, matey, One Shot exploded off t' pad and, ya bilge rat, ya bilge rat, like me Machbuster, shiver me timbers, was never seen or heard from again.
Summary:
PRO's 1. High performance rocket built from leftovers in t' parts bin. Ahoy! CON's 1. Avast! Ahoy! Another non-recoverable rocket (when flown on big engines)
Other:
When surface mountin' small fins on minimum diameter rockets, shiver me timbers, you can get added strength by slottin' t' tube and gluin' t' fins into t' slots. An engine casin' is inserted t' keep t' fin flush with t' inside o' t' tube. Ahoy! You must make sure you work fast and don't glue t' casin' in. Arrr! In me case I used epoxy and a phenolic motor casin' (AT SU). Aye aye! T' thicker t' tube, t' better this will work. Begad! Begad! (Idea 'borrowed' from t' RocketVision Machbuster.)
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