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