Let's see your Jawstand - Rail adapters

[SMR]

While I like this design, as it fully utilizes the whole rail length, when I tried this, for 4+-fin rockets, you can get fin interference with a backing board. I had to put the stop near the top of the Jawstand, rather than near the bottom. Nike Smoke fins would hold the rocket up, because the fins would interfere with the Jawstand, unless the rail was moved away from the flat flange of the stand..

This is a non-issue with small rockets. Just watch your fin clearance.

What are you using for a spacer between the rail and the backboard? That will solve a lot of problems. But you are correct, more fins / long fins / tube fins do create issues anytime the rail is attached to a support structure.

I no longer use that pad (8' rail did not come off and transporting it was a pain), but IIRC the back board was less than 8" wide, or 4" either side of centerline. I used a 1 1/2" spacer behind the 1" rail. Worst case scenario would be a small diameter rocket with the fin root right against the rail (the orange dot in my rough sketch), which is 1/2" from centerline of rail, leaving 3 1/2" to clear the edge of the backboard. A four fin rocket spaced 2 1/2" away from the backboard (with spacer) and fins longer than 3 1/2" long ( = 2.5" / cos 45° ) with the root right against the rail would not clear the backboard. But that would be the exception. Realistically, even a 54mm diameter rocket gives extra room, both because the root is further away laterally from the rail (y axis), and because the body curves away from the rail, giving extra longitudinal room (x axis). The larger the diameter, the more clearance you have from the backboard. Love the Jawstand for ease of setup, but the weight and footprint of these small pads quickly become limiting factors. We use beefier pads for large / heavy rockets, but flew 2.6" to 4" rockets off the Jawstand without ever having a clearance issue. (4 fin max, 2 fin min. YMMV with 5 or more.)

 

[Donnager]

What are you using for a spacer between the rail and the backboard? That will solve a lot of problems. But you are correct, more fins / long fins / tube fins do create issues anytime the rail is attached to a support structure.

I no longer use that pad (8' rail did not come off and transporting it was a pain), but IIRC the back board was less than 8" wide, or 4" either side of centerline. I used a 1 1/2" spacer behind the 1" rail. Worst case scenario would be a small diameter rocket with the fin root right against the rail (the orange dot in my rough sketch), which is 1/2" from centerline of rail, leaving 3 1/2" to clear the edge of the backboard. A four fin rocket spaced 2 1/2" away from the backboard (with spacer) and fins longer than 3 1/2" long ( = 2.5" / cos 45° ) with the root right against the rail would not clear the backboard. But that would be the exception. Realistically, even a 54mm diameter rocket gives extra room, both because the root is further away laterally from the rail (y axis), and because the body curves away from the rail, giving extra longitudinal room (x axis). The larger the diameter, the more clearance you have from the backboard. Love the Jawstand for ease of setup, but the weight and footprint of these small pads quickly become limiting factors. We use beefier pads for large / heavy rockets, but flew 2.6" to 4" rockets off the Jawstand without ever having a clearance issue. (4 fin max, 2 fin min. YMMV with 5 or more.)

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Another

Mine is actually a 2x2 piece of aluminum square tubing. If I put a Nike Smoke on mine, the fins would actually hit the Jawstand flanges, unless I move the rail center away from the Jawstand flanges. It holds heavier weight when centered, so I just took the loss of the 12" of rail.

 

[SEWAR]

Just bend the deflector and we’re done!

 

[gdjsky01]

I took a 24 inch (60cm) length of 1010 rail and attached it to the side of the main rail. You loosen two screws (with the hex wrench you see clamped in a drill chuck on the 2x4) and it slides on or off the bottom for transport.

My idea initially was to have the drill chuck you see holding the rod slide as well, so I could set up multiple rods. Alas I could not find a fastener that fit in the 1010 channel and in the drill chuck. So I drilled a fixed hole. There is nothing stopping me from drilling one or two more...

Still you can see how one jawstand might support 2 or more rods and still have the rail. MPR only. I mean an H is probably all a jawstand should use anyway... I guess. But the outriggers on either side could handle 2 or 3 small rods...

BTW: My jawstand is always staked into the ground. YMMV

 

[SEWAR]

Just bend the deflector and we’re done!

Decided not to bend and added some wing nuts for transport.

 

[cautery]

Started the preliminary design process for my Rockwell JawStand launch pad...

Calculated the minimum 4FNC airframe diameters for 1010 vs. 1515 based system, and decided that it is best to go 1515 first.

Using 1020 as the base piece: Approximately a 55mm diameter airframe with 4 fins assuming the fins are no thicker than the rail-button stand-off distance.
Using 1530 as the base piece: Approximately 38mm diameter airframe, 4 fins </= thickness of rail button stand-off.

If thicker fins, then increment the airframe diameter by the fin thickness delta above the rail button stand-off dimension.

Design Goals:
1) Easy deployment and recovery.
2) Easy to clean up.
3) Light w/ minimum volume.
4) Transportable in short bed truck or car.
5) Scalable.... going to build it, then break it, then engineer in solutions to failures.... rinse and repeat.
6) Keep thrust vector induced moments as close to tripod center-line as practicable.
7) Configurable to length
8) Ability to guy at the top and at about 48 inches.

So, a base piece of 1530 about 2-3 feet long. Then patch in piece(s) of 1515 above the base piece to meet the length requirement. The base piece of 1530 will be affixed to the jaw FACE using 1-1/2" x 1-1/2" 90 degree aluminum angle with a square inside corner. NOT as it is oriented in the drawing if I can help it. I believe I have room to reverse the angle leg 180 degrees and affix it to the rear half of the 1530 base piece.

This opens up an additional opportunity for boxing in and reinforcing if necessary by adding 0.125" x 3" plates to each side and extending the angle bracket fastener chain with a longer bolt and bushings to clamp the 1530 to BOTH the front flange via the angle bracket, but also clamped between the sides of the jaws, forming a very strong and rigid "box".

The camming jaw clamp will be removed. Eventually, the fine adjustment mechanism will be removed. As time permits and need/want arises, I will be progressively eliminating plastic pieces, beginning with the tubing saddles.

A clinching ring will be added to the bottom of the center tube between the legs. To the cinch ring will be three adjustable tethers with rings on the ends. The leg spikes will go through the legs AND the tether rings and thence into the earth. The tethers will be tensioned sufficiently to assist in the weight/thrust loads operating down on the stand.... essentially forming 3 supported triangles between the center tube, legs, and tethers.

More to come....

 

[cautery]

Machined base rail to rail extension brackets from 3" x 6" x 0.125" 6061 aluminum. Did it with a drill press and a simple fence/stop with 2 setups. Mine cost $5.02 in materials and about 1 hour labor. OE brackets are about $50.00 shipped and twice as thick and heavy.... unnecessarily so.

The Rail Base is 3 feet long 1530 stock. Rail extensions can be any length of course. I have a 6 foot piece that I will likely shorten some (need a short piece to use for the detachable leveling tool).

Still working on some of the "down the road" design decisions. Definitely decided to reverse the 1.5"x1.5"x0.125" angle back into the stand bracket as the best compromise that is also easily achievable.

 

[cautery]

Machined 2 brackets to connect the 1530 Base to the Jawstand Bevel Head.... No OE comparable part, but figure 3-1/3 x a 3 hole inside bracket @ $12... So, about $40.00 per bracket... $80.00 plus shipping.

I made them on the SAME setup as yesterday for about $12 each, so $24 in materials and about 1:15 labor total. Used 1.5" x 1.5" x 0.125" thick 6063 aluminum with square inside edge.

Now, I need to mate the assembly to the "bevel head" with appropriate stainless hardware.... was thinking 3/8", but I think I will stick with the largest bolt I can get with the same socket head wrench size as the 5/16"-18 screws/bolts in the 1515 hardware to keep the number of tools to a minimum.

I put the standard 1.5" spacing on the 15" brackets with a 0.75" standoff at the ends, so 10 screws/bolts on the 1530 side. Don't NEED 10, but I can use them as needed to set the base higher/lower, and if I slot the bracket on the 1530 side, I can adjust the rail assembly "IN and OUT" relative to the center-line.

 

[cwbullet]

Nice, but is that 1970s carpet?

Can you show an image of it installed on a jaw stand?

 

[cautery]

Nice, but is that 1970s carpet?

Can you show an image of it installed on a jaw stand?

I have no idea. It's the loading room and was here when I got here.

EDIT: As to the provenance of the carpet in our loading room, amateur radio shack, engineering space, etc. I am fairly confident that it is NOT 1970s carpet. The house was built in November or December of 1982. THAT carpet was installed in the house when my darling bride bought the house in 1998 or so. So, unless the carpet was several years old when it was installed new as the house was constructed, "No. The carpet is not from the 70s" It is from the early 80s to late 90s somewhere...

Of course, when it is mounted, I will.

 

[cautery]

Here's the Rail Base Assembly mounted to the Bevel Head on the Jawstand. I machined the bracket to Bevel Head holes at two lateral distances: a) 0.750" (std 80/20), and b) 0.400" from outside edge which is the measured distance to center of the OE hexagonal holes on the bevel head faces. That way I can use it with a Jawstand or with standard 80/20 materials and accessories. I chose to add the "missing" 4th hole, and will drill/fill it as soon as the next materials order arrives.

BELOW: Caliper, pencil, drill press, fence, magnification, and patience... Custom brackets.



LEFT: The brackets will remain attached to the "bevel head" via 4 x 5/16"-18 1515 fastener sets. Properly torqued and blue threadlocker.

RIGHT: If I were to produce these in any numbers, I would convert the 2 holes to a slot at those 4 stations. And add perhaps 3/16" or 1/4" radius cuts on the 4 corners.... I'll do that anyway. The lone 5th hole? Yeah, I briefly contemplated adding additional holes, but reconsidered after drilling that one. Prototyping.



LEFT: Side view reveals that the base is relatively close to the shaft centerline. I could make it closer with a deeper leg and slotted hole on the 1530 side of the bracket, but that would start increasing the minimum airframe diameter for 4 fin rockets pretty quickly. The path to a closer to coincident rail/shaft centerlines leads through a new bevel head bracket design.

RIGHT: Love that the standard stainless steel 1515 fastener sets happen to work here, too. ONE 3/16" hex wrench to disassemble the entire thing. I like that.



BELOW: I need to do some analysis, but I am pretty sure that I will be drilling access holes over the rail base fastener driver holes so that the rail base assembly may be adjusted up and down in the field. May need to refer to the images above, but you could drop the rail base to the ground if you wanted to. Or raise it until the bottom is flush with the bottom of the bevel head. Very adjustable.


Working on the blast shield, blast skirt, and various methods to increase stability for larger rockets to include guy "wire" points and base extensions. And I am proceeding with an eye towards progressively replacing OE parts with better parts/designs as the funds and ideas become available. Big(ger) rocket pad; compact/light stand is the goal.

EDIT: Designed an entirely new shaft and bevel head design to put between the rail assembly and the tripod. Should be lighter, remove airframe diameter restriction almost entirely, and be hella rigid.... There is a LOT of play IMO in the OE head design, and bulk, and... and... and...