2 ©2007
MadCow
Rocketry™
MIM-23B
Hawk
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 fit each part before assembly
– some manufacturing tolerances may require light sanding before final 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 finishing and painting.
Step 1 – Motor Mount Assembly
Test fit the tail cone into the aft end of the body tube. Make sure that the tail cone
shoulder does not interfere with the fin slot. If it does, sand the shoulder to the correct
length (the nominal length of the shoulder should be 0.5”). Next, Test fit the tail cone
and centering ring over the motor mount tube and sand if necessary. The centering ring
should have a snug fit but loose enough to move the ring over the motor tube without
deforming it. Also test fit the centering ring in the body tube and sand if necessary.
Spread some epoxy on the outside of one end of the motor tube and slide the tail cone
in place so the motor tube is flush with the aft end of the tail cone. Make sure you clean
the motor tube of any epoxy so
as not to interfere with the fin
tangs later.
After the tail cone is dry, make a
mark 3/8” from the other end of
the motor tube. Spread some
epoxy on the motor tube and
slide the forward ring (with the notch) until it aligns with the mark.
3/8” Exposed
Forward Ring Notch
Step 2 – Shock Cord Attachment
The shock cord in this kit consists of a shorter section of Kevlar and a longer section
of nylon cording. The two sections should be tied together using a single overhand,
ring bend or double fisherman’s knot. The Kevlar section will be attached to the motor
mount and the nylon section will be
attached to the nose cone.
Wrap the end of the Kevlar shock
cord around the forward end of the
motor tube and tie a square knot
or bowline knot near the notch in
the forward centering ring. Apply
some epoxy to the knot to make
sure it doesn’t come loose later.
Make sure the Kevlar loop is seated
against the forward centering ring so that it will not interfere with the fin tangs later. You
can tack with epoxy or CA to hold in place.
Fin Tang
Apply CA or
Epoxy to knot
Push cord in corner
and tack with epoxy
Step 3 – 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. Make sure the cord passes over the notch in the forward centering ring. Test fit the
motor tube assembly into the body tube to ensure a snug fit. Sand the centering rings if
necessary. When you are satisfied with the fit, spread some epoxy on the inside of the
body tube and slide the forward centering ring of the motor assembly into the body tube.
Spread some more epoxy on the inside edge of the body tube before sliding the tail cone
into the body tube. Continue sliding the assembly inside the body tube until the tail cone
