Madcow Rocketry Tomach FIBERGLASS KIT User manual

Specications:
Length: 63”
Diameter 2.6”
Weight: 28oz
Recovery: 30”/14” Nylon Chutes
Motor Mount: 38mm or 54mm
Fins: 3 - 1/16” G10
CP: 48” from nose tip
Parts List
1. (1) Fiberglass nose cone
2. (1) Fiberglass nose cone coupler
3. (1) G10 nose cone bulk plate
4. (1) Pre-slotted body tube (33”)
5. (1) Payload tube (16”)
5. (2) G10 centering rings
6. (1) 38mm (8”) or 54mm (12”) MMT
 7. (3)G10ns
8. (2) Eyebolts (4) nut, (1) washer*
9. (2) Nylon shock cords
10. (2) Rail Buttons and Screws
11. (1) Fiberglass Removable A-Bay
* 54mm version has (1) Eyebolt and (2) nut and relies on motor
forward closure anchor for shock cord.
Optional Recovery System
 1. (2)9”x9”ameproofchuteprotector
2. (1) 30” Nylon chute (Main)
3. (1) 14” Nylon chute (Drogue)
Required to complete: 5 minute epoxy,
120/220sandpaper,maskingtape, nishing
K-193
898666 00193 2
®
FIBERGLASS KIT
™
Tomach

2 ©2014 MadCow Rocketry™ FG Tomach™ Assembly FG Tomach™ Assembly ©2014 MadCow Rocketry™ 3
Please make sure you read all directions and understand how to assemble your model
beforeyoustartconstruction.Itisalsoagoodideatotestteachpartbeforeassembly.
Fiberglass parts still contain small amounts of mold release and other materials on the
surface that will inhibit adhesives and/or paint. It is important to clean each part prior
to assembly with a solution of 1 part rubbing alcohol, 3 parts water and a drop of dish
washing soap. IMPORTANT: do not sand any parts until after you have cleaned them -
youwillembedthematerialsyouaretryingtocleanmakingitdifculttoclean.
The G10 parts will have holding tabs left over from the CNC machine. These small tabs
will need to be sanded off before assembly. Before assembling any part with epoxy,
rough up the surface to be epoxied using course sandpaper. The scratches in the G10
surface will give the epoxy something to grab onto.
Step 1 – Motor Mount Assembly
Testtthecenteringringsoverthemotormounttubeandsandifnecessary.Alsotest
tthecenteringringsinthebodytubeandsandifnecessary.Theringwiththe1/4”hole
for an eyebolt will be the forward ring (38mm version only). Spread some epoxy on the
outside of one end of the motor tube and slide the ring (without the hole) until there is
approximately 1/2” of motor tube exposed. Make sure you clean the motor tube of any
epoxysoasnottointerferewiththentangslater.Aftertheaftringisdry,makeamark
1” from the other end of the motor tube. Spread some epoxy on the motor tube and
slide the forward ring until it aligns with the mark. VERY IMPORTANT: make sure there
is not any epoxy on the motor tube that would interfere with the n tangs later
on. Also test t one of the ns to make sure there is enough room for the n tang
between the centering rings.
38mm Version: Mount the eyebolt
using the two nuts as shown in the
forward ring hole. Apply some epoxy
to the nuts to ensure they will not
come loose later. Attach one end of
the shock cord to the eyebolt using
an overhand knot. IMPORTANT:
Make sure the eyebolt and nut
are aligned properly so the motor
assembly can slide into the body
tube.
54mm Version: Use the motor’s
forward closure retention eyebolt for the recovery attachment point.
Step 4 – Rail Button Attachment
Drill a 5/64” hole on the rail button line for the forward and aft rail buttons. The aft hole
should be 1/2” from the aft end of the aft body tube and the forward hole should be near
the center of pressure (CP). Apply a small amount of epoxy in the holes and attach the
rail buttons using the supplied #6 wood screws. Make sure the screw is loose enough
for the rail button to spin freely - this ensures the button is not compressed to the point it
will hang on the rail guide.
IMPORTANT: Make sure the forward rail button screw protruding through the body
tube doesn’t snag the chute. Epoxy over the screw to provide a smooth surface.
The screw can also be cut shorter.
Step 2 – Insert Motor Tube Assembly into Body Tube
Wrap the shock chord into a small bundle and stuff it inside the motor tube for this next
step.Testtthemotortubeassemblyintothebodytubetoensureasnugt.Sandthe
centeringringsifnecessary.Whenyouaresatisedwiththet,spreadsomeepoxyon
the inside of the body tube and slide the forward centering ring of the motor assembly
into the body tube. Make sure you have the motor assembly facing the right way!
(38mm version only) Spread some more epoxy
on the inside edge of the body tube before
sliding the rear centering ring into the body tube.
Continue sliding the assembly inside the body
tube until the aft end of the motor tube is even
with the aft end of the body tube. It’s a good
ideatotesttanineachslotherebeforethe
epoxy sets. Hold the body tube with the motor
tube assembly down until the epoxy sets. Make sure the weight of the motor assembly
doesn’t cause it to slide out of alignment.
Step 3 – Fin Assembly
Using a door jam or small section of angle stock, pencil a line halfway between two of
thensthatextendsfromthefronttothebackofthebodytube.Thislinewillbeused
latertoaligntherailbuttons.Testteachofthensintotheprecutnslots.Then
shouldseatrmlyagainstthemotortube-sandeachnifnecessary.Whenyouare
satisedwiththet,applysomeepoxytotheendofthentangthatwillcontactthe
motortube.Also,spreadathinlayerofepoxyoneachsideofthentang.Slidethen
intoplaceandcheckthealignment.Continuerecheckingthenalignmentuntilyouare
suretheepoxyhasset.Cleananyexcessepoxyfromaroundthenjoint.Repeatfor
theremainingns.Next,applyepoxylletstobothsidesofeachnbyapplyingathin
beadofepoxyatthen-bodytubejoing.Carefullysmooththeepoxylletswithyour
ngerbeforetheepoxysets.Alloweachllettosetbeforerotatingtheairframeforthe
nextllet.
Step 6 – Balance and Nose Cone Assembly
Epoxy the shorter coupler into the nose cone. Insert the nose cone and coupler into
the forward body tube to make sure the coupler is aligned properly. BE CAREFUL not
to glue the nose cone to the body tube. Mount the remaining eyebolt using the nut and
washer in the nose cone bulkplate. Apply some epoxy to the nut so it will not come loose
later.Testtthebulkplateinthebaseofthenoseconeandsandifnecessary,butdon’t
glue it in yet.
At this point, pack the chute and assemble the rocket. Assemble your model and insert
thelargestmotoryouintendtoy(orsimulatetheweightwithasubstitute)andensure
thattheCGisatleast1bodydiameterinfrontoftheestimatedCPpointspeciedonthe
rstpage.TheCPpointismeasuredfromthetipofthenosecone.IftheCGisbehind
the desired point, add weight inside the nose cone by pouring lead shot into the nose
cone tip and adding some epoxy.
Whenyouaresatisiedwiththebalanceoftherocket,epoxythebulkplateintothebase
ofthenoseconeleavingatleasta1/4”liptoapplyallet.Next,applyalletofepoxy
around the bulkplate and nose cone shoulder joint.
1/2” Exposed
1” Exposed
Forward Ring Hole
Fin Tang
Step 5 – Altimeter Bay Assembly
Refer to the Fiberglass Removable Altimeter Bay instructions and assemble the altimeter
bay.
Ensureringsareclearofthenslots

IMPORTANT: always use positive motor retention to secure the motor in the motor
tube. Failure to use motor retention may allow the motor to be ejected during the
ejection charge instead of the parachute, making for a dangerous ballistic reentry.
IMPORTANT: always remember to check your balance point and ensure your CG
is forward of the recommended CG point.
IMPORTANT: Always follow the NAR safety code and remember that rockets
are not toys and can be dangerous if not prepared and used properly. If you
are a beginner, it is a good idea to y with a club or other group of experienced
rocketeers until you have gained some experience.
IMPORTANT: In no event shall Madcow Rocketry be liable for any direct, indirect,
punitive, incidental, special consequential damages whatsoever arising out of
or connected with the use or misuse of it’s products. The buyer assumes all
risk and liability resulting from ANY use of any and all products sold by Madcow
Rocketry. Your purchase and use of any Madcow Rocketry product constitutes
your agreement to and acceptance of these terms. If you do not agree to these
terms and conditions, you must return the unused product in resalable condition
for a refund or credit.
IMPORTANT: Please contact us via phone or email if you have any questions about
constructing or ying your model.
24338 El Toro Rd #E-134
Laguna Woods, CA 92637
949.547.8847
www.madcowrocketry.com
©2006 MadCow Rocketry™
®
Step 6 – Flying Your Model
Attachtheendoftheshockcordfromthencantotheafteyeboltofthealtimeterbay.
Also attach a second shock cord from the forward eye bolt of the altimeter bay and the
nose cone eyebolt. Attach your parachutes and chute protectors to the approriate place.
When packing your chute, wrap the chute protector around the chute with the opening in
the chute protector facing forward. Always make sure your chute is well protected as the
hot ejection motor gasses will melt the nylon chute.