Multiple Rocket Launcher

I bought the multiple (six pads) launch controller from Pratt Hobbies for about $150, which I think is a good deal. One thing to keep in mind that the electrical and/or extension plugs are packed together closely on the launch controller as shown in the first photo, so only certain extension plugs will work. The controller only comes with about 5' or 7' length wires, so buying more wire is mandatory and can get expensive. I found similar extensions at Lowes, but they had a two outlet plug on one end. I thought that was uncool, so I didn't buy it. In retrospect I probably should have bought it, because it might have been less money and sure would have been less work. This aspect alone shows how the cost of small parts can add up. A 15 foot extension cord is probably around $15, so for 6 pads the cost is already up to $90. I bought a spool of wire (clear insulated wire is cheaper) and many plug connections. It was time consuming to set everything up. The directions stated that about an additional 25' will allow higher power motors. I now realize that I needed to allow for the additional distance for the wire to drop down from the launch controller table and the additional distance to go back up the launch rack, so really more than 25' of wire is required for higher power motors (see last photo).

I bought the Fat Max saw horse from Lowes for around $35. Someone did this on Rocketry Planet several years ago and it seemed to work pretty good. That person went a much easier and less costly route. They put a small diameter PVC pipe in the V-groove in the top of the saw horse and proceeded to drill holes in the PVC pipe for the 6 pads. That would be far easier and cheaper than the route I took. In any case I took 2 L-shaped irons bought from Lowes and bolted them together. I then made a Rube Goldberg wood mounting from 2" x 4" and mounted the now square C-shaped iron on top. I had small brackets made at a local sheet metal from another L-shaped iron.




I took 2 brackets and bolted them together and put a keyless drill chuck in top. This allows different guide wires to be places and the drill chucks can be moved around to point the rocket pad in different directions. Unfortunately, a wing nut cannot fit in the center of my C-iron. I found some U-bolts and plates at Ace Hardware to attach the Rube Goldberg launch assembly to the top of the Fat Max saw horse.

I had some interesting things happen at the launch yesterday. I put a 24 mm C11-3 in my Venus Probe and I took an old D12 igniter (white) plug and forced it into the C11-3. The first time it wouldn't fit with the solar igniter in place, but the second time it did not fall out. When the motor ignited it blew the igniter plug out and burned like a flare on the launch pad. Fortunately, the Venus probe was undamaged and the exhaust deflection place did not burn through. Later, I found the plug on the ground next to the launch pad.




I finally got around to using one of these Estes motor adapters. Previously, I had a model that would take 24 mm D12's. This was too much power for a small field. So, then I put a C11-3 in this model and the model ended up on a golf course adjacent to the park. Yesterday I used the 24 mm to 18 mm adapter in the model with B moor and the flight trajectory was just right for the small field.