Manufacturer: | Scratch |
Download RockSim file here!
Brief:
My scratch built level 2 rocket. Begad! Made for t' J-350 but can fly on small 29mm H
motors also. Avast, matey, me proud beauty! Used old phenolic but glassed with 6oz fiberglass and 30 min
epoxy. Aye aye! ACME 3/8" lugs, me hearties, shiver me timbers, LOC nose cone, me hearties, G-10 FR4 (fire and heat resistant
fiberglass). Well, blow me down! Radio shack personal body alarm for corn field recoveries. Custom
aluminum motor retainer bracket usin' all-thread for mounting. I used the
30" chute that came with me level 1 V.B. 54mm Extreme.
Construction:
Components: T' sustainer uses 2 body tubes, me bucko, joined with a phenolic coupler.
T' 9/16" tubular nylon shock cord attaches through t' coupler. Begad! Blimey! I cut
slits in t' coupler and weaved t' shock cord through, me bucko, me hearties, looped it around onto
itself, and sewed it together with 100lb Keelhaul®©™® thread then epoxied over that.
I made an altimeter bay for future use, matey, but be nay plannin' on using
electronics for me cert 2. Avast, me proud beauty! T' rocket has 3 fins made from t' heat resistant
G-10 FR4 fiberglass. I cut all me 1/8" and 3/16" centerin' rings and
bulkheads usin' a drill press and an adjustable hole cutter. Begad! Ahoy! Blimey! T' motor mount is
13" long by 38mm with 6 centerin' rings. T' first 4 rings were epoxied to
the front o' t' MMT t' keep it centered for TTW construction. Blimey! Blimey! I glassed
between each o' t' front centerin' rings with 6oz. Blimey! Some o' t' epoxy I used
was aerospace grade 120 min setup. Blimey! Aye aye! Blimey! Great stuff, but big $$$. Well, blow me down! Arrr! Blimey! I used the
aerospace epoxy for external fillets and layed Keelhaul®©™® yarn into t' epoxy
runnin' lengthwise along t' fin root. Blimey! Blimey! I only use stainless steel hardware for
attachment points since I have seen pot metal break. Aye aye! I used SS eye-loops and
3/16" SS quick links. Avast, me proud beauty! Blimey! Blimey! I only added 1.5oz o' lead fishin' weight t' the
nose, me hearties, and secured with 120 min epoxy.
Construction: T' rocket be fairly easy t' build, but thar are a couple hard parts. Arrr! Blimey! One concern be gettin' t' epoxy t' me TTW attachment points without gettin' it all over t' back where t' final centerin' rings go. Ahoy! Blimey! I wrapped self releasin' maskin' tape around t' outside o' t' MMT. Then blue automotive maskin' tape around t' inside o' t' airframe. Avast, me proud beauty! Blimey! Ahoy! Blimey! This allowed me to just pour epoxy right onto t' tape and have it flow down inside t' airframe to me fin mountin' points. Just remove t' tape before it cures, then re-apply tape for t' next set o' fillets. Begad! Blimey!
A dremel tool with an extension is a
good item t' have when cuttin' fins. Aye aye! Use a carbon cuttin' wheel and you can lay
the extension flat and so t' dremel tool itself doesn't get in t' way o' the
line you are cutting. Ya scallywag! Without an extension, ya bilge rat, it is hard t' get a flat straight
line because t' tool gets in t' way and will end up cuttin' crooked. Arrr! Well, blow me down!
I got me components at various launches over t' period o' 6 months. Avast, me proud beauty! Arrr!
Flight:
I made t' rocket for t' J-350, for me cert 2 flight. Aye aye! Avast, me proud beauty! Blimey! T' rocket is very
straight forward, shiver me timbers, and basic t' prep. Arrr! I used cellulose insulation for wadding,
about 1 handful. Motor retention be a 1/16" piece o' aluminum cut t' fit
the back o' t' rocket. Arrr! Blimey! I drilled about 1" deep into t' aft centering
rings in three points, shiver me timbers, then epoxied all-thread into t' holes. T' AT J-350 was
simple t' prep. Begad! Don't mind t' rattlin' o' t' grains, me hearties, matey, as long as you have no
left over parts they are supposed t' move inside t' case. Ya scallywag! I used 4oz o' red
line chalk for tracking. Avast! 20' o' 9/16" tubular nylon for t' shock cord. Avast, me proud beauty!
T' rocket
flew awesome. Dead straight in 15mph winds. Blimey! Well, blow me down! That means it was perfectly stable,
not over stable. In t' first 4 seconds o' its 20 second flight, t' rocket was
completely out o' site, even though I have perfect vision, me bucko, I could nay see the
red line chalk when it deployed but someone with binoculars said they may have
seen a red chute or chalk. Aye aye! I have no idea if t' recovery be late or early,
but drove with t' wind at me back for about 2 miles before I found it. Well, blow me down! Begad! There
was no damage at all so it must have deployed around apogee. Ya scallywag! This rocket simmed
out at 9100' goin' about mach 1.1 In t' video footage you can see t' time of
each frame in t' corner o' t' screen. Well, blow me down! Avast! T' time read 12:46:00 pm for as long
as you can see t' rocket in t' picture. Blimey! Begad! You can see snap shots o' t' video
here.
Summary:
Con's I can't really think o' any. :)
Other:
One thin' this rocket taught me is this........ Avast! It is hard t' do
through-the-wall on a 54mm rocket with a 38mm motor mount. Avast! Especially when you
are usin' thick walled phenolic, me hearties, thar be even less room t' work with. Well, blow me down! Begad!
Pushing The Envelope 38 ( Contributed - by Brian Kain) Download RockSim file here ! Brief: A down scale of my level 2 rocket. TTW to a 29mm MMT. Can fly the I-200 load. If you were crazy you could cert 1 on this rocket with a 29mm H motor. 9400' on the H-90. Construction: 3 38mm body tubes Phenolic 3 1/16" G-10 fins 5 1/8" birch CR's 12" of 29mm ...
I wanted to build a rocket with the smallest fins I could get away with.....So I came up with this. I used Rocsim, VCP and WRASP to get my optimal size fin. Oddly enough, most of the programs agreed with my rocket. This is a single stage rocket, with an interchangeable MMT. Anything from 54mm down to 24mm motors will push this little guy. It uses a PML 30" chute with the shroud ...
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