By Mark H


This is a four inch scratch build loosely based on the Wildman Punisher.



The red and black fiberglass Wildman Rocketry parts below will be used in this build.  The blue rocket below is based on a 4 inch Wildman Punisher kit, and is the inspiration for the current build.   




The purpose of this build is to give me another 4 inch diameter rocket to bring to a launch that can burn 75-98mm motors.  I decided to make a few tweaks relative to the  previous Punisher Style build. The changes being slightly smaller fins made of solid carbon fiber with the fins being moved up the body tube another 1/2 inch or so.  The fins on the blue rocket have picked up a few knicks from hard landings hence the changes. The new fins will be cut from 0.200" twill weave carbon plate made by RockWest Composites.

Carbon Plate



The nose cone I'm using for this build is a 6:1 VK shape from Wildman (black nosecone at top of photo below).  It is impressively long.  The blue nose cone below is the original fiberglass infused plastic nosecone that came with the Punisher kit in my previous Punisher Style  build mentioned above.  The original plastic/glass Punisher kit nose cone is no longer made. Unfortunately the blue nose cone was damaged when it got wedged in a tree and cracked from tugging on the shock cord in order to free it from the tree.   Too bad the plastic cone was damaged because it had a nice shape and I preferred it to a fiberglass cone.  The gray primer cone at the bottom of the picture below is the Wildman 4:1 fiberglass cone that I got to replace the damaged blue nose cone. 



As usual, I will start the build with the fins.  I cut the fins out using a combination of chop saw, and a Dremel. Here are a few pics.

 Chop Saw

Dremel 1


Fins cut out



After cutting out the fins, I needed to match sand them.  I taped the fins together with double-sided tape and went to work with a belt sander.

 Match Sand



I used a router, and an incline to make the bevels on my fins as shown below.  The router bit is a straight cut bit and 5/8" in diameter.

Router 1

Router 2




It is time to bond the fins to the body tube. I'll be using Loctite E-120HP epoxy like all the  kids are using these days.


 Loctite E120 HP

 Epoxy Mix E120-HP



The fins went on something like this:

Fins 1

Fins 2

Fins 3

Fins 4



I used the typical fillet method as follows:  Tape off fillet area, fill the channel with epoxy, shape the fillet with something cylindrical, remove tape before fillet starts to cure.  I used a 38mm propellant grain to pull the fillet.  The Loctite E-120HP epoxy worked perfectly as can be seen.  






Almost done. Building fiberglass minimum diameter rockets is about the same as building an Estes E2X.  





One set of fillets turn out a little lumpy, so I mixed and applied some Bondo:





The primer went on like this:

primer fin can

Primer 2



Paint:  A combination of carbon fiber metallic, and sublime green.

Paint 4Paint









Here is Build # 1 and 2 side-by-side.



I was planning to launch this on a K680R, but the clouds came before I had it ready, reducing the waiver.  So, until next time here are a few pics.








9600 feet on the Aerotech K680R.



P4 K680 R


P4 Corn



Marsa, Easy Mini, and TeleGPS:






Launched again on an Aerotech L400W:

Video Here: