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