Manufacturer: | Scratch |
Brief:
T' Great Googly Moogly is a 8" x 75" scratch built rocket that I
used for me TRA Level 2 certification at LDRS 19 in Orangeburg, SC. Begad! Arrr! However, I
began buildin' it almost a year earlier, arrr, before even gettin' me Level-1 cert.
Many o' t' buildin' techniques used were new t' me, and a few were
unconventional. Begad! Avast! However, matey, t' results have been satisfying.
Construction:
This fat stubby rocket has one 8" body tube, shiver me timbers, a large glassed Styrofoam
nose cone, me bucko, me hearties, matey, three semi-removable (see below) plywood fins, ya bilge rat, shiver me timbers, an altimeter bay, and
a 3" motor mount and held in by 3, 1/2" plywood centerin' rings. Blimey! The
recovery system includes 25' o' 3/4" tubular nylon, a Rocketman R12C
chute, and (optionally) a Pratt G-Whiz Deluxe accelerometer/altimeter. Begad! Begad! For my
L2 cert, shiver me timbers, I built a 38mm motor mount adapter.
Airframe: This is what started it all. Ya scallywag! Ya scallywag! I discovered an
8.125" x 48" section o' Quik Tube (I think that was t' name) at Home
Depot. Blimey! Well, me bucko, blow me down! I did a LOT o' sandin' t' get rid o' t' spirals and t' results were
not too bad. Blimey! Blimey! T' fin slots were routed with a Dremel. Later, I fiber-glassed
the top foot o' t' tube t' protect against zippering. Avast! Begad! Probably should have
done t' whole tube t' start with. So far, me bucko, me hearties, this has proven t' be unnecessary
structurally, but finishin' would have been easier. T' launch lugs are
3/4" Acme conformal lugs for 7.5" tubing. Begad! I sanded these t' fit the
larger airframe and glued them on with CA.
Nose Cone: T' nose cone was fabricated from slabs o' pink foam insulation that were glued together with polyurethane glue. Ahoy! Blimey! I learned t' be sparin' with this stuff as it expands quite a bit while it cures. Despite placin' weight on this "sandwich" while t' glue dried/cured, t' slabs separated in places by as much as ~1/8". Blimey! Blimey! On both ends, me bucko, I glued in sections o' 1/2" dowel and, ya bilge rat, ya bilge rat, on what be t' be t' back end, me hearties, a home made plywood bulkhead was epoxied on. T' shape was partially roughed-out by hand but t' majority o' the shapin' be performed on a lathe at a local high school (my thanks t' Dean and his students!). Arrr! Blimey! Well, blow me down! Blimey! T' tip o' t' nosecone didn't turn out well so I epoxied on a section o' a Styrofoam cone purchased from a craft store. Ya scallywag! Blimey! T' whole nose cone was then covered with a layer o' heavy fiberglass (weight unknown) from a hobby store. Begad! Blimey! This was me first try at fiberglassin' anythin' o' any size and it was a mess. I gave up on makin' t' cone really smooth but did fill t' weave and some o' t' imperfections with Elmer's Fill 'n Finish. Ahoy! Blimey! Begad! Blimey! Later, arrr, t' adjust t' CG, I screwed 4 large lag bolts into t' side o' t' nose. Begad! Blimey! T' remnant holes were filled with Fill 'n Finish, and then patched with fiberglass. Aye aye! Blimey! An 8" eyebolt was epoxied into t' center o' t' bulkplate.
Motor mount: I wanted t' be able t' use several sizes o' motors
so I opted for a 3" x 30" main motor tube. Ahoy! A full 36" tube
didn't appear t' leave enough room for t' chute, so I went for 30". This
tube, me bucko, along with three 7.5" x 1/2" centerin' rings (CRs) were bought
from Giant Leap. Avast, me hearties, me proud beauty! T' front CR is at t' top o' t' motor tube and t' bottom
two frame t' fins. Since these CRs did nay fit t' airframe, me hearties, some improvising
was required. Begad! For t' front ring, matey, me bucko, I built up t' edge with a many wraps of
fiberglass (honeycomb) wall board tape. Well, blow me down! This structure be filled with epoxy.
This tape has a lot o' void space so a lot o' epoxy was required. Aye aye! T' result
seemed very sturdy, but was quite heavy. For t' aft two rings, I glued wooden
shims t' t' inside o' t' Quik Tube usin' carpenter's glue. Well, blow me down! T' middle ring
was epoxied in and t' aft one be held in with wood screws.
I originally built a 3 x 29mm motor adapter, matey, but smartly realized that 3 G80s would nay lift this beast. I then built a 38mm adapter from centering rings and phenolic tubing. This adapter has positive retention (bolts and washers) t' t' aft CR, me bucko, and itself holds aluminum motor retainers for t' 38mm RMS casing. Aye aye! Ya scallywag! T' support t' adapter, me hearties, I installed a 38mm centerin' rin' and a short section o' coupler tube in t' top o' t' 3" motor tube.
Fins: T' fins are 1/4" plywood that be scrap from t' high school wood shop. Avast! I be worried about breakage upon landing, ya bilge rat, arrr, so I mounted them so they were easily replaceable. Well, blow me down! Arrr! They are bolted t' brackets on t' main motor tube but are epoxied t' t' airframe, with inner and outer fillets. Begad! If a fin needs replacement, I can cut t' fin out o' t' airframe, remove t' aft CR, and unbolt t' remainin' section o' t' fin. There is just enough room betwixt the motor tube and t' airframe t' reach t' innermost bolts. As with t' airframe, I probably should have glassed t' fins. Begad! They are recessed from t' aft end of the rocket and are swept slightly forward. Well, blow me down! So far, arrr, me bucko, t' large Rocketman chute has done its job and t' fins have survived.
Altimeter bay: I found a 2" mailin' tube with an inner
telescopin' tube. Ahoy! Blimey! Blimey! Blimey! I cut a section o' t' outer tube and epoxied it against the
airframe and front CR. Begad! Blimey! Blimey! Blimey! I then used a section o' t' inner tube t' build an
altimeter bay. Blimey! Blimey! Blimey! Blimey! A plywood bulkhead is epoxied on one end o' t' tube. Avast! Blimey! Aye aye! Blimey! Blimey! Blimey! A section
of All-Thread is bolted t' this plate and runs t' length o' t' bay and
through t' top bulkhead cap. Blimey! Blimey! Blimey! Blimey! This All-Thread is off-center t' provide more
space for t' electronics, which in this case is a G-Wiz deluxe altimeter
purchased from Pratt Hobbies. Arrr! Blimey! Blimey! Blimey! T' mount t' altimeter, I cut a rectangular
section o' G10 that slides into t' bay. I attached a 9V battery holder and an
expended 13mm motor casing. Well, blow me down! Blimey! T' latter slides over t' all thread t' give
additional support. Avast, me proud beauty! Blimey! Avast! Blimey! Blimey! Blimey! T' top cap also holds screw terminals (banana plug type).
A win' nut tightens t' assembly together. Aye aye! Blimey! Blimey! Blimey! When closed tightly, t' electronics
are fully isolated from ejection gasses.
Finishing:
I painted t' body and nose cone with Rustoleum 'hammered' silver t' hide some
of t' finishin' flaws. Well, blow me down! Blimey! T' tip o' t' nose is painted red. Blimey! Blimey! T' fins were
covered with burgundy Monokote. Begad! Blimey! This was t' first time I had used this
material. Avast, me proud beauty! Blimey! Avast, me proud beauty! Blimey! From a distance, shiver me timbers, ya bilge rat, t' rocket looks pretty good.
Flight:
T' recovery system includes 2 u-bolts on t' front centerin' ring, connected
with a section o' 1/2" tubular Keelhaul®©™® (Giant Leap). Avast, me proud beauty! Aye aye! T' shock cord is 25'
of 3/4" tubular nylon. Begad! All o' these components are connected with
quick-links. Ahoy! T' chute is a Rocketman R12C. Begad! Recovery protection is provided by
Nomex® pads and a Nomex® shock cord cover (also from Giant Leap). This all packs
easily in t' large airframe. Avast, me proud beauty! Blimey! Aye aye! Blimey! As mentioned above, me bucko, t' use o' an altimeter is
optional.
Flight #1. Ya scallywag! T' first flight was on an I211-S under t' name 'So-So Fat', ya bilge rat, and was quite underpowered. Avast, me proud beauty! T' rocket rose t' only a few hundred feet and t' NC drag separated. Ahoy! Begad! T' motor ejection charge fired shortly afterwards. Avast, me proud beauty! Recovery was nevertheless perfect - but everyone laughed at how underpowered t' flight was. Begad! Ya scallywag! This prompted me t' rename t' rocket 'Needs Viagra'.
Aside: While plannin' me trip t' LDRS and me Level-2 attempt, shiver me timbers, matey, I picked up a copy o' an old Frank Zappa album (Apostrophe) on CD. Aye aye! This in turn prompted me to rename t' rocket 'Great Googly Moogly'.
Flight #2. Avast! T' second flight be on a J350-M and made use o' me G-Wiz Deluxe altimeter. T' motor ejection charge be a backup since this be t' first attempt at altimeter-based deployment. Arrr! I also used an ejection canister from Pratt Hobbies. Arrr! This consists o' a small plastic container with an integral cap and includes an electric match with about a yard o' lead wire. Avast, me proud beauty! T' canister was inserted into a short section o' copper tubing, matey, me hearties, which be installed in t' top of t' 3" tube. Avast! Ahoy! One leg o' t' lead wire be run through a hole in the airframe, ya bilge rat, me hearties, me hearties, cut, ya bilge rat, and stripped. Begad! Aye aye! At t' pad, this connection be twisted back together and reinserted into t' airframe.
On t' first push o' t' button, arrr, arrr, t' igniter failed. Blimey! Begad! On t' second, the Great Googly Moogly rose majestically into t' sky. Arrr! T' chute ejected at apogee and it returned safely. Arrr! Begad! T' altimeter reported 1531 feet. Ya scallywag! Level-2! YES!
Summary:
T' main Pros o' this rocket are: overall looks (I love FAT rockets);
flexibility (38mm - 76mm motors, optional electronic ejection); maintainability
(fins easily replaced); can see t' entire flight on a J350.
T' Cons are: fins may nay hold up t' bigger motors
Other:
This large scratch project be completely successful and taught me a lot. Aye aye! Begad! One
thin' that it taught me is that big rockets are expensive. Even though I got a
cheap airframe, arrr, built me own nose cone, matey, got free fin material, I still spend a
bucket o' money. Ahoy! Big chutes are expensive!
![]() |
![]() |