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T' MegaBlast is me first High Power rocket o' me own design. Avast, me proud beauty! This is the "journal" o' its construction. Ya scallywag! Hold your mouse over t' photo t' read the description. Click on t' photos t' view t' larger picture. Begad! Ya scallywag!
T' MegaBlast is
constructed out o' LOC 4" tubing, shiver me timbers, and uses a single 38mm H motor.
Original, me plans called for 1/8" plywood fins, ya bilge rat, but I could nay find any
sheets that were nay warped. Aye aye! So I decided t' go with 1/4" plywood. Avast! The
fins were cut usin' a razor saw. Ahoy! After all three fins were cut, arrr, arrr, matey, it was time to
do t' air foiling. I marked where I wanted t' tapers t' begin, and used
maskin' tape as a guide. Blimey! Blimey! I clamped a belt sander t' t' workbench, and used it
to taper t' leadin' and trailing. Avast! I be impressed how well I did on the
tapers. Begad! I guess buildin' t' THOY Phoenix a couple years ago gave me a lot of
practice. Ahoy! Begad!
Once the
fins were done, it was time t' make t' motor tube. Begad! Begad! I used VCP t' print out
some fin location guides and wraps. Ahoy! Well, me hearties, blow me down! Since t' rocket features T3F, I marked the
fin locations on t' motor tube. Blimey! I also marked t' locations on t' centering
rings. Begad! Aye aye! I drilled holes in t' aft centerin' rin' for t' motor retention bolts,
and a hole in t' forward centerin' rin' for t' shock cord anchor. Aye aye!
Then, usin' balsa strips, arrr, I glued guides on t' two aft centering
rings. Avast! Blimey! Well, blow me down! Blimey! T' purpose o' these guides is t' ensure t' alignment o' t' fins, and
to help hold them in place as t' epoxy cures. Begad! Blimey! Apparently, everythin' turned
out great since it can hold itself together without any glue. Ahoy! Blimey! Begad! Blimey!
I used 2 Ton Epoxy t' assemble t' mount. Well, blow me down! First I secured t' three centerin' rings. I had t' fins in position so t' rings would be aligned properly. Begad! Begad! While waitin' for t' epoxy t' cure, I went ahead and assembled to bulkhead assembly that will join t' two sections o' t' together. Ya scallywag! After the epoxy cured, me bucko, I epoxied t' fins into their proper position
After all t' epoxy was cured, matey, arrr, I attached t' motor
mount t' t' airframe. Avast! Then I used angle bar t' draw t' slot lines onto the
airframe. I then removed t' motor mount, arrr, me hearties, and extended t' lines t' 8".
Then I used a razor blade t' cut out t' slots. Avast! When all three slots were cut,
I test fitted t' whole assembly. I be pleased with t' results. Aye aye!
I then took t' whole assembly apart and concentrated on finishing
the motor mount. Blimey! Blimey! I took some 100 grit sandpaper and roughed up t' motor
tube/fin tab joint. Begad! Blimey! Begad! Blimey! I then cut out some fiberglass strips and epoxied them to
the joint. Well, matey, blow me down! Blimey! While lettin' t' undercoatin' o' epoxy t' soak in, I applied epoxy
fillits t' all remainin' joints, and installed t' shock cord anchor. Avast, me proud beauty! Blimey! Epoxy was
used t' set t' nuts on t' eye-bolt. T' fiberglass was then coated with
another layer o' epoxy. Arrr! Blimey! When t' epoxy was cured, arrr, matey, I used trimmed away any
"hairs" that be stickin' out from t' fiberglass. Avast, me proud beauty! Blimey! Well, blow me down! Blimey! Then I attached a
piece o' tubular nylon t' t' shock cord anchor. T' motor mount/fin unit is
now finished.
I then took some two ton epoxy, matey, and smeared it 16 inside the
rear end o' t' tube, ya bilge rat, shiver me timbers, and smeared some more epoxy just above t' fin slots. I
then inserted t' motor mount assembly into t' airframe tubing. Avast! Avast! After the
middle centerin' rin' entered t' tube, me hearties, arrr, I added some more epoxy t' t' end of
the tube. Avast, me proud beauty! Avast! Then I slid t' motor mount all t' way into t' airframe. Aye aye! I then
used t' remainin' epoxy t' saturate t' leadin' and trailin' edges o' t' fins
to make them less prone t' denting. Ahoy!
After
the epoxy cured, I sanded all t' epoxy on t' fins. Ahoy! Avast, me proud beauty! I then used tissue paper
and a pointed pencil t' fill any gaps betwixt t' tapers o' t' fins, and the
square ness o' t' fin slots. Avast, me proud beauty! A mixture o' 2 ton epoxy and microballons was
then used t' create fillits on all t' fin and body tub joints. Well, blow me down! After the
fillets dried, and sanded, me bucko, arrr, shiver me timbers, I applied t' first coat o' Bondo glazin' and spot
putty t' t' fin fillets. Avast! I also used t' Bondo t' fill t' spiral on the
airframe tubes.
After several application o' Bondo, shiver me timbers, with sandin' betwixt each application, the MegaBlast be ready for priming. Begad! Blimey! Aye aye! Blimey! I used Rust Oleium Grey Automotive primer. T' rocket was coated several times with primer, with sandin' betwixt each coat. Begad! Blimey! Blimey! Blimey! T' rocket be now ready t' paint, shiver me timbers, but what colors should I paint it?
At this time, me hearties, I began t' think about usin' this rocket t' obtain me Level 2 certification flight. Arrr! I passed t' written exam at a recent CMASS meeting, and the MegaBlast would make an ideal vehicle t' fly on a 38mm J motor. Blimey! It will go a little over 4,400 ft with a J350 motor a bit high for t' CMASS launch site, but doable for t' field in Hallifax, me bucko, me bucko, MA. T' next Frontier launch was May 25th, arrr, 2002. T' date was set. Begad!
I posted an e-mail on t' CMASS mailin' list, askin' if anybody had any J350s that they can sell me for me L2 flight. Begad! Nobody responded about the J350, arrr, but Tony Brock-Fisher replied that he had a J570 load, and asked if I could use that. I loaded up me RockSim file again, selected t' J570, launched t' rocket on t' computer and t' software predicted that t' rocket would go over 5,650 feet OVER A MILE!!!! I accepted t' motor offer. Begad! I then gave a call t' Magnum and ordered a Transolve PK Altimeter kit, me bucko, a new tube coupler, me hearties, a 45 parachute, me hearties, and a couple bulkheads. Well, blow me down! I also went t' a local hardware store and bought some threaded rods, bolts, arrr, me hearties, nuts, and other various hardware. Begad! Avast, me proud beauty! It be time t' build me first rocket that uses Dual Deployment. Aye aye!
Fortunately, HobbyTown USA in Plaistow NH offered t' sponsor me L2 project, arrr, so
some o' me expenses be covered. Begad! Now I have a paint scheme t' color me rocket
with
t' HobbyTown colors :-). Avast! I painted t' body o' t' rocket white,
the nose cone blue, arrr, arrr, and t' fins red. Well, blow me down! I used black vynal letterin' t' mark the
name on t' rocket, matey, me bucko, me hearties, and I used a HobbyTown decal t' advertise t' sponsor. Now
I must admit that I am a beginner at usin' electronics in rockets
I have
no experience mountin' electronics in t' rocket, and this be t' first time I
used Dual Deployment. Avast! I decided that I wanted t' altimeter t' go in an
enclosed central modual that can be interchanged easily betwixt 4
diameter rockets. Both recovery systems will attach t' t' module, ya bilge rat, matey, so strength
is important. Avast! Ahoy! So I built an assembly that consisted o' three threaded rods
connectin' two plywood bulkheads. T' rods will support t' stresses o' both
recovery systems. Blimey! T' assembly then slides into a tube coupler, where it is
fastened down with four screws. Avast, me proud beauty! Well, blow me down! I be concerned that t' wood used for the
bulkheads be on t' thin side, but I decided that it was good enough. Blimey!
Once t' altimeter module was built, it was time to
balance t' rocket. Ahoy! I put t' rocket together like I was goin' t' fly it. Avast! Ahoy! I
loaded t' recovery system, and installed t' loaded J570 motor. Avast, me proud beauty! I hung the
rocket on t' ceiling, and started addin' weight t' t' nose cone until the
center o' gravity was where I wanted it t' be. I ended up installin' almost a
pound o' clay into t' nosecone, but t' rocket was now balanced. Arrr! Begad! It now
weighed close t' 6 pounds empty, a little on t' heavy side for a H.
T' flight profile o' t' MegaBlast with a J570 is as
follows. Blimey! Begad! At ignition, t' rocket will accelerate off t' launch pad quickly. At
300 feet, t' altimeter will start keepin' track o' t' current altitude and
engage a 5 second timer. Ahoy! Aye aye! This is called t' mach inhibiter, and it prevents the
sudden increase in pressure o' t' shock wave caused by a object breakin' the
speed o' sound from foolin' t' sensor t' fire t' parachute charges. Ya scallywag! Ahoy! This
rocket is subsonic, ya bilge rat, so this feature is nay mandatory. After 5 seconds of
flight, t' mach inhibitor is turned off, me hearties, and both charges are armed. Begad! Begad! When the
rocket reaches apogee (over 1 mile with t' J570), t' altimeter will deploy
the drogue chute. Ya scallywag! T' drogue chute allows t' rocket t' freefall in a
controlled manner. When 600 ft is obtained, t' altimeter will fire t' last
charge t' deploy t' main chute. Blimey!
May 24th came, ya bilge rat, and I loaded me car with me MegaBlast, me hearties, ya bilge rat, me hearties, and a few other rockets.
I drove 50 miles t' Marlbourgh, where I spent t' night at a friends house. Begad! Blimey! The
next morning, me hearties, we traveled t' additional 50 miles t' t' Frontier field in
Hallifax
but I be sick. Aye aye! Blimey! I only launched one rocket
I decide to
test t' altimeter in me EZI-65 with a H242-10T. By t' time I got t' rocket
back after me first, me bucko, and successful two stage recovery, I was too sick t' fly
any more rockets. Well, blow me down! Blimey!
T' next
opportunity t' launch t' MegaBlast came on August 24th, 2002. NARRRRR decided to
accept t' Canadian certification o' t' Pro38 J class motors. Arrr! Begad! I traded me J570
for a Pro38 J285 load and borrowed a case. Well, blow me down! I also made some minor modifications
to t' recovery system. I replaced t' 22 Aerotech chute that I was using
as a drogue with a RocketMan 28 X-form chute. Avast! I also added a nylon rope
backup t' both bungee cords in case they snap. Begad! Arrr! Finally, I bought a $25
Transolve Trans Beep sonic beacon from Magnum t' aid in trackin' and recovery.
T' new altitude estimate for t' MegaBlast with t' Pro38 J285 is 3,800 -
4,200 feet. Blimey!
Robert DeHate, me hearties, Olga Glotova, and Mishka (Olga's friend visitin' from Russia) helped me prep t' rocket for flight. Well, blow me down! Begad! We placed t' rocket on t' launch pad, installed t' igniter, ya bilge rat, armed t' altimeter, me hearties, me hearties, and moved back a safe distance. Robert and Peter Chestna were t' witnesses. Aye aye!
5 . Begad! Blimey! 4 . Well, blow me down! Blimey! 3 .. Avast, me proud beauty! Blimey! 2 .. Blimey! Blimey! 1 .. KAPLUNK!!!!
T' Pro38 motor detonated. Aye aye! T' casin' o' t' motor shot
into t' drogue compartment, shiver me timbers, wedgin' t' recovery system into a tangled mess
inside t' tube, causin' major damage t' t' airframe, me bucko, and completely
destroyin' t' Trans Beep buzzer. Aye aye! Avast, me proud beauty! T' altimeter bay assembly be ripped from
the tube coupler, which confirmed some fears that t' thin centerin' rings and
tube coupler would nay hold. Avast, me proud beauty! Aye aye! T' catoin' motor also destroyed t' motor
retention system, arrr, shiver me timbers, damaged t' motor tube, and blew apart t' aft centering
ring. Avast! Ahoy!
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Bob Krech and Robert DeHate suggested that we repair the altimeter bay, me bucko, and use t' EZI-65 as a booster, t' try again at achievin' Level 2. Ya scallywag! Well, ya bilge rat, blow me down! I decided that since I had little over an hour left o' t' launch, me hearties, me bucko, that would be rushin' it. I did nay want t' rush it. Begad! T' much loot is on t' line. Aye aye! I told them I did nay want t' rush it. Avast, me proud beauty! Avast, shiver me timbers, me proud beauty! They agreed. Well, blow me down! Ahoy!
Robert DeHate offered t' fix t' booster for me, and he gave me a J350 reload
to replace t' blown J285. Avast! He coated t' damaged section o' t' body tube with
fiberglass, arrr, me hearties, and use Keelhaul®©™®
to repair t' motor tube. Avast! I sent t' Trans Beep back t' Magnum for repairs, and
ordered a LOC 4 Electronics bay. T' solve a concern that t' shockcord
anchor on t' nosecone was nay strong enough, matey, shiver me timbers, I took a pice o' tubular nylon,
ran it through t' cone, me bucko, tid several knots in it, rammed t' end o' t' nylon
into t' clay, then filled t' cone with expandin' foam. There is no way this
shock cord anchor is goin' t' fail. Begad! I was hopin' that t' MegaBlast would be
ready t' launch again for t' September 14th launch. However, t' order from
Magnum did nay arrive till t' 16th, which be t' Monday after t' launch. Aye aye!
Missin' t' 14th launch probably worked out for t' better anyway. Well, blow me down! Ahoy! It gave me
time t' repair t' rocket t' way I wanted to. Blimey! Well, blow me down! I built t' LOC electronics bay
and added some bevels so t' bolts have somethin' t' screw into besides paper.
I also replaced t' nylon rope that I used t' back up t' bungee cord with
tubular nylon. This stuff is stronger, and less likely t' tangle. Avast, me proud beauty! I also took
advantage o' t' extra time t' get some replacement grains for me J350. Aye aye! Begad! The
J350 I had had t' 7/16 core in t' propellant grain, which has been
known t' cato. Arrr! Ahoy! So I called Aerotech and they ordered me a set o' the
½ core grains. Blimey! Ya scallywag! I also ordered two inert sets so I could make two
I161 reloads out o' t' older J350 grains. Arrr! I managed t' get t' grains a week
before t' Oct 27th CMASS launch. Avast! Ahoy! Perfect timing. Begad!
The
weather on t' October 27th was perfect. Blimey! Begad! T' club was nay expectin' that many
people t' show up t' this launch, so they did nay set up a launch site for a J
motor. So I set up me Super Pad at t' High Power C site, me bucko, and set up t' wires
and battery for t' site. Avast! Ahoy! Once that was completed, arrr, I launched me Electronics
bay on me EZI-65 rocket with an I161-14 motor t' test out t' altimeter, which
reported 1,500 ft. Arrr! T' flight was perfect, ya bilge rat, me bucko, but t' Trans Beep buzzer was
damaged durin' recovery. Avast! Then t' moment o' truth, My L2 flight :-D. Steven Boy
(same guy who did me L1) and Robert DeHate as a witness. Arrr! T' J350 came t' life,
and t' MegaBlast left me launch pad in a hurry, trailin' behind a thick white
smoke trail, me hearties, and a very loud thunderous roar. Ahoy! T' Drogue deployed on time at
2,500 ft, arrr, but due t' inertia, t' main be also deployed. Begad! However, me hearties, t' rocket
was recovered, and I passed me Level 2 Cert flight!
Overall, arrr, me bucko, matey, this project be a success. This was me first
High Power rocket o' me own design, me bucko, and it achieved its purpose. Aye aye! Blimey! I now have my
level 2 license. Begad! Avast! What is me future plans. Well, t' MegaBlast is a perfectly
good launch vehicle, shiver me timbers, so I plan t' get many more launches out o' it. Regarding
my L2? I am thinkin' about buildin' a LOC Magnum that will air start its
outboard motors. Well, blow me down! I also might get into t' hybrid motors offered by t' various
companies out there. Begad! Ya scallywag! I feel that this is necessary due t' t' increased
regulations on our hobby. When I get me Level 3, me bucko, matey, I may have t' use a hybrid,
since it may be a long time before I can get t' unnecessary LEUP t' store
those larger motors. Begad! Arrr! And if things go t' way they are, ya bilge rat, maybe even for the
stuff I currently use
but that is another story
.
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Olga Glotova For bein' a friend, an inspiration, shiver me timbers, someone to
talk to. Robert DeHate Your support, advice and effort is so much appreciated. Frank D'Aloisio Thanks for your support and financial contribution. Ryan Sebastian and Family For helpin' me out at t' launches. Bob Krech For supportin' me crazy ideas. William Gardei For talkin' me out o' me crazy ideas. |
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