Project Overview:

The goal of the launch pad project was to build a lightweight, yet sturdy and strong PVC launch platform for flying Level 1 and lower impulse Level 2 flights.  For higher impulse flights, the steel "Medium High Power Pad" from A Launch Pad Co. will still be used.  However, several features of the steel pad were incorporated into the PVC pad including leg levelers, use of the same blast plate, and a rail mount in similar fashion as the rail adapter that came with the larger, heavier pad.

Design:

The pad uses 3/4" Schedule 40 PVC, 1/2" x 6" steel carriage bolts, and 1/4" x 2" steel bolts (plus all related hardware.  i.e. washers, nuts, etc.).  I found the original idea for this pad on www.rocketryforum.com in the thread PVC HPR Pad. The pad there seemed rather sturdy, but I wanted my pad to have some launch angle adjustability and the ability to set it so it launches level and not just at the angle of the ground beneath it.  This design is a result of those design goals.   A mechanical drawing is attached below as well as a complete parts list.  If there is interest, I would be willing to pre-assemble some pads for $80.00 each plus S&H or 65.00 each plus S&H without the leg levelers (Rail NOT included).  If interested, contact me at JAllen@JoesRocketry.com.  However, you MAY build your own at no charge (from me at least :) )

Click the image to enlarge it.

Construction:

The first step was to cut all the pipe to appropriate lengths using a circular pipe cutter.  After the pipe lengths were cut, the PVC fittings were lightly sanded with a Dremel rotary tool so the pipe segments would sit flush at the base of the grooves in the fittings.  Thirdly, each of the 4 leg levelers were constructed using 2 3/8" washers drilled out to 1/2" (this was because the 3/8" washer OD matched the ID of the fittings), 2 1/2" hex nuts, and 1 1/2" x 6" carriage bolt, 1 3/4" T PVC pipe fitting, 2 3/4" x 0.8", and some JB Weld to hold the washers and nuts together.  See the construction pictorial below for more details on the construction of the leg levelers. 

Once all the pieces were cut and prepared, the first dry fit of the pad was made.  It went together beautifully, and even unglued (minus the leg levelers) the pad held my full body weight.  At this point I marked the locations where I would need to drill holes in the Ts for assembly and disassembly of the legs.  The second step in this process was to build a drilling jig so that I could (in theory) drill holes so when assembled, the legs would be interchangeable.  This would have worked, in theory, however the drill press's plate was ever so slightly angled and resulted in several pieces being cut at angles.  Now, all 4 legs are labeled and belong to a specific part of the pad assembly.  The same principle was applied to drilling holes for the rail attachments and swing arm lock. 

After a successful dry fit, the pad was disassembled, the parts labeled, and the pad was reassembled with PVC cement.  Then all the bolts were re-attached and the pad was tested again with myself as a weight.  I decided that in order for the central tower to maintain its structural integrity, I would need to place a fifth "leg leveler" in the center to transfer the pad weight to the ground as the legs were only stiff enough to support the pad and keep it upright. 

Pictures:

coming soon!