Manufacturer: | Vaughn Brothers |
Brief:
Shorter body, Carbon Fibre/Keelhaul®©™ re-enforced airframe, piston ejection system,
extra centerin' ring, all thread reinforcement round central electronics bay.
Replaced recovery shock cord with tubular nylon and replaced motor mount with
PML phenolic motor mount tube.
Modifications:
This would have been an easy kit t' build from stock as it came with easy to
read instructions and contained easy t' build parts. Ya scallywag! Aye aye! Havin' said that, I
promptly put t' instructions in a drawer and begin me kit-bash in earnest. Blimey! Begad! As
always I measured t' components and entered t' data into RockSim. Ya scallywag! I also had
an extra body tube which was slightly shorter and by mistake used this tube
instead o' t' original tube (hence me rocket is slightly shorter than the
kit). Well, blow me down! Usin' RockSim I wanted t' design somethin' which was a little different
than t' usual single deployment blobbo rockets. With this in mind
I decided t' have a central piston which would span t' length o' t' rocket
and create a void which I could use for an electronics bay. Avast, me proud beauty! T' achieve this I
needed extra centerin' rings t' fit t' motor mount and t' piston tube (a
piece o' 2.5" PML QT). Ahoy! A forward centerin' rin' would be removable and
allow for t' placement o' electronics in t' void created by t' piston. Ahoy! Ya scallywag! The
forward centerin' rin' is held in place by t' all thread rods which have
carbon fiber sleaves with washers t' create shelf for t' centerin' rin' t' sit
on (see picture 2). I drilled a very small hole in t' base o' t' piston tube
which allowed for some air t' pass down below t' electronics bay and keep a
vacuum from formin' inside t' piston. Blimey!
T' fins were mounted in t' usual way with extra strips o' carbon fiber and Keelhaul®©™® as re-enforcement.
T' airframe was vacuum bagged usin' me trusty foodsaver and some carbon fiber/Keelhaul®©™® weaved cloth. A further sandin' veil o' fibreglass be applied once t' first layer was 1/2 cured. Well, blow me down! T' result be an airframe which is rock solid. Aye aye! T' body tube was slotted all t' way down so I could mount t' entire motor and piston assembly in one step. Well, blow me down! Blimey! Once mounted onto t' airframe external fillets were created with resin and silica filler. Begad! Ahoy! After this had all dried t' rocket was almost done. Begad!
After measurin' t' center o' gravity against t' CP in RockSim I decided how much weight t' add. Avast! In t' end I used 1.5lbs o' lead along with t' weight of t' hardware and forward bulkhead plus enough resin t' seal it all side the nose cone. Ya scallywag! This left about 3/4 o' t' nose cone as extra room for t' parachute and shock cord (i.e. Avast! I didn't have t' stuff all o' this into t' piston tube). Aye aye!
I was now ready t' finish it.
Construction:
Construction (PROS):
T' extra room a 5.5" airframe gives makes this an easy kit t' build from
stock. Arrr! Well, blow me down! For me sins t' modifications I made took a while as they were somewhat
involved. Avast, me proud beauty! From stock t' kit is complete so no complaints there. Blimey! Since this is
a mod I ignored all instructions and replaced parts as needed.
Construction (CONS):
T' body tube did nay come slotted which isnt a real big problem but does
make for extra work. Begad! Avast!
Finishin' (PROS):
In keepin' with t' idea o' tryin' somethin' different with this rocket I
decided t' use a Monocoat finish. Avast! This be me first attempt at
usin' a Monocoat iron-on finish. Blimey! After some testin' with t' iron and some
samples I decided upon a sky blue airframe with a black and white check trim (a
Z-car effect). Begad! Blimey! I had Scott Binder print up some new decals (as I plannin' to
ultimately launch this on a K550). Its new name was t' be K-Blobbo. Avast, me proud beauty! Blimey! As you can
see in t' picture t' results were nay too bad (see picture 1).
Finishin' (CONS):
As t' Monocoat isnt supposed t' be applied over a prepared surface this
meant that I could nay use a filler primer (UV Smooth Prime) t' create a nice even
surface for t' Monocoat t' cover. Well, blow me down! Blimey! Avast! Blimey! Hence thar are surface ripples from the
composite coverin' showing. Begad! Blimey! Well, me hearties, blow me down! Blimey! I may have a go at finishin' t' composite layer
then tryin' t' apply t' Monocoat again.
Flight:
This kit is suppose t' be t' Kin' o' Blobbos and recommends I and J motors. I
had a couple o' Js left so first off be a long burnin' J185 Blue Thunder
which lifted off t' pad very nicely and burned and burned. Blimey! Ya scallywag! T' parachute
deployed on time but t' surface drag from t' rocket be such that t' delay I
choose was wrong and too long. Ahoy! However, shiver me timbers, ya bilge rat, t' solid build o' t' airframe meant
that even a late and high speed deployment was no problem. Blimey! T' rocket came down
fairly close and all was well. Avast, me proud beauty! A video o' t' launch detected a slight wobble
which t' me meant that I was just too close t' t' center o' pressure so more
nose weight be goin' t' be needed. Begad! Ahoy!
After another 1/2lb o' nose weight I launched it on a J275 White Lightening. Aye aye! This time thar was no wobble and I put in an RDAS in the electronics bay t' ensure deployment at apogee. All went t' plan and t' rocket landed safely nearby. Ya scallywag! T' altitude reached as 1000 feet lower than Rocksim predicted (lots o' drag).
A third launch was performed usin' a Cessaroni Pro38 6 grain (international version) J360 (800ns). Begad! 3. Avast! 2. 1. Arrr! Avast, me proud beauty! launch and up it went t' 2500 feet with the RDAS ensurin' deployment at apogee. Aye aye! Analysis o' t' data indicated that a 10 second motor ejection delay is ideal for this rocket. Avast!
I have since launched this a fourth time on a J360 Pro38 with only motor ejection and it flew as planned with t' 10 second delay providin' t' correct delay for an apogee deployment.
Summary:
A nice rocket with t' internal piston makin' for easy prep. Arrr! T' electronics
bay round t' piston is really handy and allows for a greater range of
motors.
Other:
As always build it like an M and you wont need t' build it again when it
crashes.
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