rharshberger
Well-Known Member
Over the Labor Day Weekend, Steve Thatcher of SMT Designs was one of the vendors at SodBlaster 2018, while he was there I was looking at his products and the 38mm bay kit caught my eye as I have a 38mm MD project in the works. So for the price of $22.95 I picked up a 38mm Compact Bay Kit (knowing I was going to need the longer sled), Steve and I talked about the product and I asked him to make a long sled for the MissleWorks RRC3 (which he already had, just no stock on hand iirc), and a new sled for the Eggtimer Quantum in a long variety, my coupler is 8" long so the compact sled is too short, but all other components are the same. Regrettably I did not take pictures of the bay components in their bags but its lots of screws, washers, eyelets for wiring, 3D printed parts. Each part is bagged with its fasteners and components.
Here is the fully assembled Rabid Weasel MD (Blue Tube clone of the Loc Precision Weasel)
The upper airframe is secured to the altimeter bay by 3 button head 6-32 x .5" machine screws (shorter woud be better but .5" long is all I had on hand), two of the button heads are visible in the picture, the third screw (phillips head) is actually the arming screw. Steve's design uses a slide switch that is activated by the screw being inserted and tightened, the design works very well IMO as the switch cannot move once secured by the screw. Steve includes a 3" long 6-32 screw that can be cut to proper length for your bay application, in my case the screw needed to by 13/16" long, which allows me to snug the screw just as the switch bottoms out. Static ports are visible in center of coupler. As for drilling all these precisely located holes its easy, I also picked up a coupler drilling guide a airframe drilling guide, it was super easy and the holes lined up nearly perfectly the first time ( due to the fact I drilled my holes slightly undersized it was necessary to open some of them up to get the screw into the hole).
Button heads removed and the arming screw, lower airframe has been removed as well showing the end of the bay (drogue side), the three holes in the coupler are for the screws to secure the lower bay cap, I did not have any 6-32 undercut head screws on had so I have been working around that for now, the charge well is my own design/manufacture and is made of .5" 6061 aluminum bar stock, but the mounting location is part of SMT's design. The undercut screws when they arrive will be countersunk into the coupler and then profiled to match the coupler OD as the lower bay will be secured by a single shear pin to the airframe.
Bay removed from airframes, alternate view of end cap and charge well, the charge well mounting post also doubles as the ematch wire terminal point and the shorter post as the other ematch wire terminal.
Yet another view of endcap.
What are these two holes for you ask? Well they are to access the two screws that secure the sled to the end cap assembly so that the end cap can be removed. Steve prefers to use a larger window in his couplers than I do, so I just made two holes to access the screws. The smaller screw hole is where the undercut head 6-32 screw will eventually go (I have to open the hole up some and then profile the screw to match the couplers OD). The blue tape is friction fit of course.
Window number two, what is it for? Well that so I can attach and detach the wiring for the drogue bay end cap (yellow and orange wires), there is enough room in the bay that I was able to pretty easily push the wires from the opposite end to the window and using tweezers tuck the wires into the terminal block and secure them (the wires are actually about 2" longer than necessary).
The end cap from above with the charge well, the second wiring post is just peeking out from behind the charge well at about the 1130 position, the three smaller screws are what attaches the shock cord anchor plate and terminal pass through plates to the bays mounting ring, the shock cord anchor plate is design to be easily replaceable as the BP firing will eventually damage the surface. The shock cord anchor plate and the pass through plate aslo form the groove for the o-ring seal on each bay cap.
Fully assembled bay with charge wells removed.
Here is the fully assembled Rabid Weasel MD (Blue Tube clone of the Loc Precision Weasel)
The upper airframe is secured to the altimeter bay by 3 button head 6-32 x .5" machine screws (shorter woud be better but .5" long is all I had on hand), two of the button heads are visible in the picture, the third screw (phillips head) is actually the arming screw. Steve's design uses a slide switch that is activated by the screw being inserted and tightened, the design works very well IMO as the switch cannot move once secured by the screw. Steve includes a 3" long 6-32 screw that can be cut to proper length for your bay application, in my case the screw needed to by 13/16" long, which allows me to snug the screw just as the switch bottoms out. Static ports are visible in center of coupler. As for drilling all these precisely located holes its easy, I also picked up a coupler drilling guide a airframe drilling guide, it was super easy and the holes lined up nearly perfectly the first time ( due to the fact I drilled my holes slightly undersized it was necessary to open some of them up to get the screw into the hole).
Button heads removed and the arming screw, lower airframe has been removed as well showing the end of the bay (drogue side), the three holes in the coupler are for the screws to secure the lower bay cap, I did not have any 6-32 undercut head screws on had so I have been working around that for now, the charge well is my own design/manufacture and is made of .5" 6061 aluminum bar stock, but the mounting location is part of SMT's design. The undercut screws when they arrive will be countersunk into the coupler and then profiled to match the coupler OD as the lower bay will be secured by a single shear pin to the airframe.
Bay removed from airframes, alternate view of end cap and charge well, the charge well mounting post also doubles as the ematch wire terminal point and the shorter post as the other ematch wire terminal.
Yet another view of endcap.
What are these two holes for you ask? Well they are to access the two screws that secure the sled to the end cap assembly so that the end cap can be removed. Steve prefers to use a larger window in his couplers than I do, so I just made two holes to access the screws. The smaller screw hole is where the undercut head 6-32 screw will eventually go (I have to open the hole up some and then profile the screw to match the couplers OD). The blue tape is friction fit of course.
Window number two, what is it for? Well that so I can attach and detach the wiring for the drogue bay end cap (yellow and orange wires), there is enough room in the bay that I was able to pretty easily push the wires from the opposite end to the window and using tweezers tuck the wires into the terminal block and secure them (the wires are actually about 2" longer than necessary).
The end cap from above with the charge well, the second wiring post is just peeking out from behind the charge well at about the 1130 position, the three smaller screws are what attaches the shock cord anchor plate and terminal pass through plates to the bays mounting ring, the shock cord anchor plate is design to be easily replaceable as the BP firing will eventually damage the surface. The shock cord anchor plate and the pass through plate aslo form the groove for the o-ring seal on each bay cap.
Fully assembled bay with charge wells removed.
