The Simpliest Launch Pad

 The Thrifty Rocketeer blog continues...

We return to my roots today, with an entry that focuses on saving money. 

I'm always on the lookout for a way to save money, reduce costs, and do something cheaper or less extravagantly. This includes looking at ways to home-build or jury-rig SAFELY,  a more simple system.

In today's world of increasingly computerized Apps, AI and programmed chips, this is harder and harder.

But it's not uncommon to see postings asking: 

  1.  What's the simplest rocket system? 
  2. What's the best glue?  
  3. What's the best painting method?  
  4. What's the best paint?  and 
  5.  What's the simplest launch system?

Recently, someone asked on-line, "What was your first launch system" or "What was your first launch pad?"  Rocketeers of all ages were only too willing to answer, as everyone remembers "their first time"... and not just in rocketry.

Most responses for the first launch system were unremarkably similar... they had or borrowed an Estes Launch controller.  They may have had to replace the batteries... or replace the wires running out to the pad...  but only one talked about having to replace the light bulb, though many said they had to substitute a roofing nail for the firing key. 

But the answers for the launch pad were incredibly varied...from the standard Estes tripod launch pad, rod and blast shield, to the home-brewed systems.

This intrigued me, as several of the launch pads ranged from a rod stuck through an upturned Terra Cota flower pot... to an elaborate saw horse with 4 to 5 launch rods mounted in a row.

One rocketeer even mentioned the PDF file on the NAR website on how to construct a launch pad.

SAY WHAT?!

This was the first that I had heard of it, and I asked for more info.  He supplied a link to the file.  I followed the link and was thrilled to see that someone had invented the wheel before me...(to mix my metaphors).

Now forgive me if you've already read the PDF file or know of this simple launch pad, but I will attempt to summarize it here.

This is a method of constructing identical individual launch pads in a Cub Scout or club setting. It is NOT a sawhorse line of rods nor a launch rail. 

Imaging a string of wooden blocks (triangles, actually) cut from a single 8 ft 2"x'4"  Each triangle, approximately 5" on a side, as the center platform or base for the launch rod.  Drilled into each of the three sides is a single 7/16" hole about two inches deep. Into each of these holes will be turned a "hanger bolt" which consists of a lag screw thread to bite into the block, but instead of a head, it terminates in a 1/4" machine thread screw.  (These are frequently used on wooden kitchen table legs to secure the solid wooden leg to the table top, but with much larger, more sturdy hanger bolts.)

Each bolt that protrudes from one of the three faces has a wingnut then threaded on it. They are used to secure a one foot furring strip (1"x2") to the block base.  All that you need now, is a 36" brazing rod stuck down a very small hole drilled down in the exact middle of the triangle face.  Don't forget your need for a blast shield... either a flattened tin can with a hole drilled in the middle of the flattened face.... or an upturned small flower pot.. or a ceramic tile square (3"x3") with a hole carefully drilled through the middle without breaking it. 

Now, you may say, "Wait a minute...you've described a tippy tripod that can't possibly stand on three narrow legs."   And you'd be right.  Loosen each of the wingnuts slightly, and pivot each of the three legs by the same amount in the same direction.... say, 45 degrees to the left on each leg, then tighten the wingnuts down.  You now have a simple tripod with a wider base between the ends of the three legs, than the extremely small block platform.  It will be stable.  It can be turned or tilted to account for rough ground, or tilting the rod into the wind, etc.

I tried to do them one better, by reducing the furring strip legs to wooden paint stir strips 12" long. I also downsized the 1/4" hanger bolts to #10-40 hanger bolts that come from Lowes 3-in-a-pack instead of two in a pack. Cheaper that way, but the tripod is slightly more flimsy with these adjustments. I also added a washer between the wingnut and the leg for better clamping.

I can't believe that such a simple tripod design exists, but isn't given more exposure.  Then it occurred to me: At $35 each, the plastic Estes rockets launch pad keeps them in business. It wouldn't do to undercut them and slap the company that provides us with motors in the face. 

But for a very simple, easily replicated low launch tripod, I suspect this can't be beat.  Next, the NAR PDF file explains how to build a simple launch controller for pennies on the dollar.

This has been the Thrifty Rocketeer saying, "Can you build a better mousetrap?"


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