DragonWorks Rocketry

        It was one of those designs that kept me up late one night in 2003, staring at the ceiling; I could see it so clearly in my head that I could virtually touch it!  Nonetheless, if I did not get it on paper, it was going to fly right out of my head!

          Early in my model rocketry years, I wanted to build a simple launch pad using the simplest of tools with most all of the components purchased from local hardware stores.  The exception was the extruded rail, which was ordered off the Internet.  No welding, or extravagant “one-off” machine shop fees, just a unique design from standard PVC.  Many of the PVC designs I searched all followed a standard formula for design, three or four legs, and some mechanism to support azimuth and direction adjustments.  The problem I had with these designs is that they had to support the full weight of a rod or rail from the very end of the rail.  Coupled with a rocket, there is some strain on that “mechanism”.  I watched a commercial J570 (38mm Aerotech reload) take just such a design to the ground at launch.  Luckily, the rocket left fast enough for a stable flight path, but the pad was rendered garbage from the blast (except for the rail).

          The AMEX/PVC launch pad described here, trades functionality for brawn.  The pad sits firmly (flat) on the grand, tilts for ease of loading, and has a very low center of gravity.  It is rock solid and shoots straight, and that is it.  There is no azimuth, and no tilt, although using a longer piece of PVC in the rail mast, will allow some angle to aim away from spectators.  However, it supports ten feet of rail, which is bolted to four feet of mast for strength and stability.  To date, this pad has not been taken down by any large motors; it has handled H thru J-class, and one small K motor.

 Materials: 

• I chose 1.5″ PVC from local home improvement center.  The beauty here is that this design can be scaled up or down by merely choosing a smaller or larger diameter PVC tube, and matching components (i.e. elbows, end caps and couplers etc.) 

  

  Click Here for Design Drawing Package

• Standard PVC pipe Joint adhesive

 Tools: 

• Hack saw
• Design Drawings

The best advice I can give when building this pad, is to make sure all cuts are as square as possible.  Moreover, do not glue any parts until the pad has been fully test fit to ensure it is built true.  Tolerance stack up is not an issue, however, most stack-ups from PVC will come from non-square cuts.

          To mount the 1010 rail to the rail mast, I drilled three holes, evenly spaced, from the back of the mast through the front.  I used 2″ long round head machine screws and wing nuts to secure the rail.  The round head fits snugly in the rail slot, and then the wing nuts are tightened to secure the rail.  That is it, there really is not much to building a PVC launch pad, unique or not.

          Total price for the pad circa 2003, was $48 and some change.  The rail cost more to ship than I paid for it, and totaled right at $40 to $50 as well.

 Pro and Cons: 

Pros: 

• Easy to build using simple tools
• Strong
• Low center of gravity
• Tilts for ease of rocket loading
• Disassembles for storage
• Semi-light weight (For large dia. PVC)

 Cons: 

• Zero functionality, shoots straight, and that is about it 
• No Azimuth
• No Angle adjustment
• Needs a relatively flat surface to base on
• Disassembles into six fairly large/long pieces (not including rail) 

4" Rocket Loaded on AMEX/PVC Pad

Mast Tilted For Loading

          So why even bother with a launch pad that is devoid of frills?  Simple, I am of the opinion that angle and azimuth are for low – mid-power rockets.  If you are launching high power or amateur motors in large rockets, then straight up and away from spectators is the way to launch.  Most high power, and all amateur fliers use some sort of close proximity recovery device (altimeter or timer etc) so wind drift issues can be kept to a suitable minimum (don’t fly on windy days).  Finally, unless you are launching from a hillside, it is not that difficult to find a flat surface to base the PVC pad from.  The PVC launch pad will ensure that your flights are straight and true.

See you on the field,

 Johnnie