Madcow Rocketry Cricket User manual

Cricket™
Specications:
Length: 32”
Diameter 4.0”
Weight: 30oz
Recovery: 30” Nylon Chute
Motor Mount: 38mm
Fins: 3 - 1/4” Plywood
CG: 17” from nose tip
Parts List
1. (1) Nose Cone
2. (1) pre-slotted body tube
3. (2) Centering rings
4. (1) 38mm motor tube
 5. (3)laser-cutns
6. (1) Eyebolt, nut and washer
7. (1) Nylon shock cord
8. (2) Rail Buttons and Screws
Optional Recovery
9. (1) 12x12 Chute Protector
10. (1) 30” Nylon chute
Required to complete: 5 minute epoxy,
120/220sandpaper,maskingtape, nishing
ller/paint.
K-141
898666 00141 3

2 ©2008 MadCow Rocketry™ Cricket™ Assembly
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 – some manufacturing tolerances may require light
sandingbeforenalassembly.
Laser cut parts will exhibit varying amounts of charring on the edges
depending on the density of the plywood. The charred edges do not interfere
with bonding and do not need to be cleaned before assembly. In most cases
thecharringwillbecleanedupduringsandingfornishingandpainting.
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.One
of the rings will have a hole for an eyebolt to attach the shock cord - this will
be the forward ring. Spread some epoxy on the outside of one end of the
motor tube and slide the ring (without the hole) until there is approximately
1/4” 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 2 1/2” 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. It is also a good idea to test t
a n to make sure the rings are far enough apart.
Mount the eyebolt using the nut and washer in the forward ring hole. Apply
some epoxy to the nut to ensure it will not come loose later. Attach one end of
the shock cord to the eyebolt using an overhand knott.
1/4” Exposed
2 1/2” Exposed
Forward Ring Hole
Fin
Fin Tang
IMPORTANT: After this assembly cures, cut off any excess motor tube in front of
the forward centering ring to make more room for the recovery components.

Cricket™ Assembly ©2008 MadCow Rocketry™ 3
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aswellasthenrootthatwillcontactthebody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.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 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.
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!
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. Make sure the eyebolt doesn’t interfere with any of the n
slots.
Ensurecenteringringsareclearofthenslots

24338 El Toro Rd #E-134
Laguna Woods, CA 92637
949.547.8847
www.madcowrocketry.com
©2006 MadCow Rocketry™
Step 4 – Rail Button Attachment
Drill a 5/64” hole on the rail button line for the forward and aft rail buttons. The holes
should go into the forward and aft centering rings. 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.
Step 5 – Flying Your Model
At this point, pack the chute and assemble the rocket. 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.Insertthelargestmotorthatyouintendtoy(orsimulatethe
weight with an appropriate substitute) and ensure that the CG is forward of the point
denedinthespecicationsontherstpage.TheCGshouldbemeasuredfromthe
tipofthenosecone.IftheCGisbehindthespeciedpoint,addweightinsidethenose
cone by pouring lead shot into the nose cone tip and adding some epoxy. IMPORTANT:
Screw in several screws through the plastic nose cone into the lead to hold it in
place. Grind or cut of the screw head before lling and applying the nose cone
nish. The epoxy will not stick to the inside of the nose cone and if you do not
anchor with screws, the liftoff force will cause the weight to become dislodged
causing an unstable model. Drill a small 1/8” hole in the chute compartment to allow
venting.
IMPORTANT: always use positive motor retention to secure the motor. Failure to
use motor retention will cause the motor to be ejected instead of the parachute
making for a dangerous ballistic reentry.
IMPORTANT: always remember to check your balance point and ensure your CG
is ahead of the specied 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.