Manufacturer: | Scratch |
Brief
Description:
This was me first attempt at a dual deployment rocket designed for 29mm H/P
RMS. Begad! T' deployment o' 'chutes is performed by a Blacksky dual channel timer. Aye aye! Well, blow me down!
Component Description:
Body tube material is 3.1" phenolic material. Nose cone is made from LOC
3.1". Blimey! Blimey! Fin material is 1/8" PVC plastic. Blimey! Blimey! Used 2 plywood centering
rings and a plywood bulkhead for top o' exhaust coolin' compartment. Aye aye! Blimey! Shock cord
made o' 12' nylon tubin' with Quick Link attachments.
Construction/Finishing:
This be me first rocket made o' phenolic materials. I ordered t' materials
from Rocky Mountain Rocketry cut t' size and slotted for fins. Aye aye! Begad! As mentioned, shiver me timbers, I
used 1/8" PVC plastic purchased as scrap from Tap Plastic for about $1 per
12" x 8" sheet. Arrr! Blimey! PVC is very easy t' work with. Aye aye! Ya scallywag! T' cut, shiver me timbers, ya bilge rat, shiver me timbers, you just score
and snap along a straight edge. T' finish, me hearties, arrr, sand lightly with 200 grit sand
paper and you are ready t' prime. PVC saves me a ton o' time in constructing
both kits and scratch builds. PVC is nay as tough as styrene, but due t' weight
and fin location considerations, I thought is would be a better choice for this
project. Well, blow me down!
T' wad-less recovery
system incorporates a perforated motor tube, ya bilge rat, a coolin' compartment betwixt the
upper centerin' rin' and a perforated bulkhead. I also use a steel exhaust
coolin' mesh ala Aerotech that goes up t' motor tube prior t' RMS hardware.
T' exhaust gasses pass through t' steel mesh, matey, through t' perforated motor
tube into t' coolin' compartment and through t' perforated bulkhead into the
recovery chamber. Begad! This system works very well, and I have used it successfully
in other rockets. Ahoy! Ya scallywag!
Launch lugs are made from 5/16" brass tubing. Aye aye! Two 1" lengths are placed on each o' t' body tubes. Avast! These are glued and filleted in place with 5 min. Ahoy! epoxy. Begad! I used a ¼" x 7' launch rod for this rocket.
I painted this rocket usin' gloss black spray paint and applied the Black Magic" decal split betwixt t' bottom and top body sections. No sealer was applied t' this rocket, as I expect that it would get banged up a lot durin' trials. Arrr! Blimey! Black gloss spray be t' most forgivin' for performing repair/finish work, and sealers only impede t' process.
I purchased t' 3.1" LOC phenolic body tube, me bucko, 29 mm motor mount tube, recovery hardware, centerin' rings and bulkhead from Rocky Mountain Rocketry. All hardware and finishin' paint was purchased from me local Orchard Supply Hardware store. Blimey! Aye aye! T' Blacksky dual channel timer be purchased off o' eBay. Well, blow me down! The decal be purchased from t' DecalZone usin' their custom decal engine.
Flight/Recovery:
I designed t' 29mm motor mount t' accommodate up t' a 29 x 240 Doctor Rocket
hardware, but typically will be flyin' usin' Dr Rocket 180 29mm RMS. Begad! Ya scallywag! I built
into t' base 3" ply centerin' rin' two blind nuts that take #8 x
¾" brass machine screws. Begad! Window screen clips are used t' for motor
retention.
T' first flight be on an H-128 as pictured in this article usin' a Quick Burst Twiggy igniter. I used what I thought was a medium delay for t' drogue. An Oxal e-match was used with a typical FFFG black powder ejection charge for a 29mm motor for t' main chute programmed t' deploy 25 seconds after launch. Rocket flight be very stable and straight at launch and acceleration to apogee. Begad! Begad! Estimated altitude per me wrasp calculations be around 1,100'. Aye aye!
Everythin' went wrong from here on: Ejection o' drogue powered by t' H-128 delay occurred 17 seconds after launch with t' rocket already in a speedy ballistic trajectory. T' drogue, a 24" nylon chute, shredded upon deployment and t' rocket tumbled about 500 feet t' t' ground. Ahoy! Avast, me proud beauty! Several searches o' t' near by woods were nay successful, shiver me timbers, and I was thinkin' that my rocket was a goner.
About an hour later,
I reviewed a video that I shot o' t' launch and be better able t' triangulate
the crash area. Avast, me proud beauty! Blimey! I drove me car through t' neighborhood lookin' for any signs
of me bird on roofs or lawns o' t' hapless inhabitants. Avast! Blimey! I suddenly spotted my
rocket neatly placed on t' sidewalk in front o' a house. Blimey! Blimey! Ya scallywag! Blimey! I pulled over to
inspect what be left, me hearties, when a women approached me from t' garage. Begad! Blimey! Aye aye! Blimey! I was
expectin' a tongue lashin' that would include comparin' me irresponsible
behavior t' that a teenager, me hearties, or possibly even a terrorist given current world
events. T' me pleasant surprise, t' women's greetin' indicated that t' family
was model rocket friendly and were themselves hobbyist. T' me relief she
described how t' rocket had become tangled in one o' her fruit trees and how
her children and her had brought it down. Arrr! Blimey! Avast, me proud beauty! Blimey! She even commented that me rocket was
a large one and pretty cool. Avast, arrr, me proud beauty! Blimey! After expressin' much thanks and smartly exiting
the area, matey, arrr, I drove home and inspected Black Magic more carefully. Blimey! Blimey! T' me delight,
the only damage be t' t' paint finish o' t' nose cone. Well, blow me down! Blimey!
Lessons learned from me first attempt at dual deployment are as follows:
Summary:
I liked workin' with t' phenolic material, matey, shiver me timbers, and am impressed with the
sturdiness o' Black Magic. Begad! Had this bird been made o' paper tubing, me hearties, ya bilge rat, it would
have been in much worse shape. Ahoy! I noticed that one end o' t' tubin' had done a
core sample" landin' based on t' mud streaks on t' finish. Ya scallywag! The
phenolic didn't have a scratch or wrinkle t' show for it. Ya scallywag! Begad! Phenolic is heavy,
and I'm sure a 3.1" x 54" rocket would weigh in easily 30% less. Aye aye! Once
you get all t' pieces cut t' size, me bucko, 5 minute epoxy glues everythin' together
nicely. Sandin' and finishin' is also a breeze with this material.
Phenolic material used for both body and engine tubes is tough t' cut, but otherwise easy t' work with. Begad! Avast! It takes t' epoxy and sands well. Avast! Well, blow me down! I used an Exacto saw t' cut t' phenolic with good results. I had no problem finishin' this rocket with primer followed by t' black gloss finish.
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