I was first intriguied by the look of a Launch Pad Rockets copy of the AS-17 "Krypton" and immediately knew I wanted to upscale.  First I needed to research the original missile to assure myself of the dimensions needed and not just upscale from the Launch Pad model. My only objective was to make the scale dependent on a four inch diameter body tube. 

I was not able to find scale line drawings so I had to design from sizing and information both from the Launch Pad version to scale up and scale down from what information I could obtain on the web about the original Kh-31 missile.

I carefully measured the parts from the Launch Pad Kit off the instructions and compared them to Kh-31 dimensions found on the web. From these measurements I was able to derive dimensions for my four inch diameter high power rocket scratch build. The only dimensions of usefulness were diameter and length. Specific lengths of ramjet and fins I had to upscale from the Launch Pad kit. In general the scales I used were an approximate 1/3 scale of the original and 1.538 times the Launch Pad kit.  After analyzing the ratio in RocSim I decided it would be more flight worthy to extend the length. It is also more visually appealing.

KRYPTONITE Construction Scale:

My only other clue to design was from available photos of the missile.
 

To make sure that Kyrptonite would fly well, I had to first build the model in RocSim. i have measured all parts of the Launch pad kit and using the supplied kit instruction sheet, upscaled the placement dimensions of parts. The problem with RocSim 3.0 is designing tubular fins. I simply tried to add more parallel fins to replicate the four tube surface area. In a later step I will weigh the rocket to balance the real weight of the rocket in design simulation.
 

Parts used in construction of the Kryptonite:
 

The first construction activity was the sizing and cutting of the outboard fins.  I chose 3/16" 4 ply plywood for the fins as I am not as confident in shaping G10 fiberglass. Also, there is not as much a weight difference between G10 and 3/16" ply as with 1/4" plywood.  Two sets of four fins are required on this project,  I simply copied the fin template from the Launch Pad "Krypton" kit and allowed for the thickness of the ramjet tube, a 38mm paper tube. I sanded the fins with a rounded edge and set them aside while I made a 12.25" hand slot cut in each of the ramjet tubes.  Next I epoxied the fin sets in the ramjet tube. (Fig.1 & Fig. 2). The creation of the ramjet required hand shaping a point on the end of a 1/2"x2" dowel and center mounting it on a 38mm x1/8" bulkhead plate with a small screw and epoxy. The assembly was mounted 1" deep into the forward end of each of the ramjet tubes. (Fig.3).
 
 

Figure 1	Figure 2	Figure 3

The four ramjet tubes were cross mounted 3.9" forward of the tail of the 34" body tube. Heavy epoxy fillets were applied. Side fillets to create a smooth vertial sidewall on the tubes were crafted using wood filler and Kliz paint. Several interations of sanding, kliz, and sandable primer were applied. Tail cones were ordered from Balsa Machine Service.  I ordered four BT-60/50 transition sections and hand sanded them to fit the rear of the ramjet assembly.  Again more sweat effort to kliz and sand and sand and kliz to get a smooth finish. 

Several tries of painting the nose cone with light sanding and repeated paint and sand brings a great smooth paint finish.  Epoxied into the cone a 1/4"x 4" eyebolt. The assembly seems sturdy, but will also loop kevlar thread into the bolt using the normal cord attachment eyes holes on the cone.

I will attempt the color scheme currently shown on the Boeing version , XM-31.
 
 

To be continued ...