The kit is a Semroc x-kit and came with the pieces shown here (except for the coupler/kevlar at left). Included was the balsa motor block. It fit snugly in the airframe, but I opted to not use it. I'm sure it was included because that's how the original Mark was done (I assume), but I'm not that faithful. When I was a kid, there was a guy up the street who would drag rusty piles of junk into his garage and turn them into Hot Rod Magazine quality vehicles. And, while the 1940 Ford he built looked exactly like a '40 Ford, it contained a 1970 small block Chevy under the hood and had front disk brakes So, my Mark may look like the one G Harry designed, but it includes some bits that are a little more contemporary The fins are laser cut, and thus needed no effort to prepare them for gluing. I mounted the launch lug in the stock position, but did bevel the ends. They look so draggy when they're square cut With some filler and paint applied, the launch appears molded into the fin root:

Since I wanted to anchor the recovery harness at the forward end of the motor, I substituted a length of BT-20 coupler for the wooden unit. A wrap of kraft paper brought the coupler's outside diameter up to the Mark's BT-30 size. A slot was cut the length of the coupler on the outside for the kevlar to sit in, then the kraft paper was applied over it. The kevlar travels down the outside and back up thru the inside of the coupler, and then a knot with a bit of yellow glue secures it in place. From there, I had several options, but I chose to use a nomex ribbon thru the opening.

The ribbon is made from a strip of nomex cloth folded double, then stitched around its perimeter with a leather stitch.  Next, each end of the ribbon is folded thru the loop in the kevlar.  The folds are then stitched on all four sides.  The side over the kevlar is actually stitched around the kevlar (like a tunnel) such that the kevlar can slide back and forth to even itself. This is probably overkill for this rocket.  Little, light rockets are much more tolerant of high speed deployments - they can be slowed down in a hurry without zippering - so this much anti-zipper protection is probably uncalled for, but this is my current recovery harness construction technique, so that's what I implemented

The nosecone was absolutely beautifully turned. I can't get over how nice Semroc's balsa pieces are. Nothing that nice ever comes out of my lathe  (Fortunately, I'm an executive chef when it comes to applying Fill 'n Finish  )

The rocket is a minimum diameter 18mm airframe, meaning it can fly on BP motors up to C impulse.  I considered building a 13mm motor mount into the bird. I've done that before with some of these 18mm birds, but have since learned that mustering the self control to not overpower them is not that great a challenge. Besides ½A6-2's and A8-5's, I can use T-motors glued into spent 18mm casings to give me plenty of suitable motor choices that should be readily recoverable, without resorting to higher impulse motors that might take it out of sight and cause it to be lost.

I hope to post some flight  pics soon.

8-16-2010