Thursday, January 29, 2015

Build It Yourself - Quickie Launch Pad

Sometimes you find you need a new piece of equipment in rocketry, because what you have isn't the right piece for a particular rocket. Or maybe you want an extra this or that. Launch pads are one of those - maybe you want to be able to set up multiple rockets at one time, or you need a pad with a fatter launch rod.

If you go with building Estes kits, and you build a larger rocket with an E-sized motor, the kit instructions tell you to launch it only on an Estes E-sized launch pad. The basic launch kit has a 1/8 inch rod. Rockets with an E motor really should be launched with a 3/16 inch rod.

The Estes V2 - a semiscale model of the historical rocket - uses E motors
and needs a larger launch rod than your typical Estes Skill Level 1 kit.

Great, you think, now I gotta go out and get a whole new launch pad!

Not so.

There are a lot of things you can build yourself in rocketry - most things, in fact, once you get enough experience and know how things work. Launch pads are particularly easy.

I realized I needed a launch pad with a 1/4 inch launch rod - and quickly, for a launch the next day. For most of my rockets, I use a camera tripod with the Odd'l Rockets Adeptor - a kind of threaded rod connector with a thumbscrew in the side.


You screw one end of the Adeptor to the tripod, stick the launch rod in the top, and use the thumbscrew to secure the rod in place. It's great! And only about 10 bucks from JonRocket.com. However, it only takes up to a 3/16 inch rod.

No problem! I threw together a little list, ran to Lowe's and Michael's Crafts - I needed to go anyway - and built a new launch pad. Whole thing took me 15-20 minutes to build, plus an hour to allow some glue to dry.

There are a lot of cool launch pad plans on the internet - with legs, adjustable rod holes, swivels for changing the angle of the rod. But if you just need something basic, this works great. It only takes one sized rod, but you can make multiples of these for different sized rods, easily and quickly.

Here's how you build mine. You can design your own - it just needs to be wide enough to be stable, and thick enough to hold the launch rod securely. I designed this on the fly, and it's really easy.

What You Need
  • 12-inch square plywood base, 1/2 inch thick (Michael's Crafts - $5)
  • 4-inch square wooden plaque, about 3/4 inch thick (Michael's - $0.99)
  • 1/4 inch steel rod - you can use whatever size rod you need for the rockets you're launching. (Lowe's - price varies depending on thickness and length of the rod. Mine was less than $4)
  • Steel electric box cover plate (Lowe's - $0.50)
  • Pencil
  • Straightedge (I needed an 18-inch ruler. Didn't have one, so I used a piece of basswood I had)
  • Wood glue
  • Drill with a bit the same size as the launch rod - 1/4 inch, in my case
  • Steel wool
  • Paper towels
  • WD-40
 Step 1: Use the straightedge to mark diagonal lines from the corners on the plywood base:


Step 2: Place a ring of glue around the center:


Step 3: Line up the corners of the small wooden plaque with the diagonal lines on the base, and glue the plaque to the base. Place a heavy book on top and allow it to dry for 30 minutes:

While the glue dries, it's time to clean up the launch rod.

The steel rod is found in a section labeled "metal shapes and rods," and I think it's for welding or something. I don't know - I only use it for rockets. In the same section, you'll find aluminum angle - useful for lots of applications in rocket building. For this pad, I used a 1/4 inch rod, but you should get whatever thickness rod you need. For your basic kits, a 1/8 inch rod is standard. Just make sure it's long enough - a 3 foot rod is right for most low power kits with A-C motors. I have a 3/16 inch rod which is 4 feet long for slightly bigger stuff.

Note: I do have to get a longer launch rod for this pad - the rocket I built it for needs a 4-foot-long rod, and all they had in stock that day were 3-foot. Easy fix.

The rod is covered with some nasty black oils, and may be a little rusty. This is fine. Just make sure you get the straightest rod you can find - some of them are a little bent.

The rod is covered in oils which will turn your hands black, and may be a little rusty.
You'll need to remove the label.
First, you remove the paper label on one end of the rod. Then you'll get out some steel wool, paper towels and a can of WD-40.

You're going to rub the rust and oils off the rod with the steel wool. Work from one end to the other - this doesn't take too long, but you want to scour the rod until it looks shinier. It took me perhaps five minutes.

Now the rod is shinier and smoother.
After that, you need to clean the rod. Spray some WD-40 onto one paper towel, and begin rubbing down the rod. All the oils and steel shavings will be collected onto the paper towels - it gets pretty messy.


Once one paper towel is thoroughly dirty, switch to a new one. Spray on some more WD-40 and repeat the process. You'll repeat this a couple of times with a new towel until the towel remains clean, and doesn't show any oils when you rub it down with the WD-40.

Finally, with a clean, dry paper towel, rub off the excess WD-40. Just rub the rod down until it doesn't feel greasy any more.

Now, let's go back to the base of the launch pad. Take the book off the top, and with a pencil and straightedge, extend the diagonal lines from the corners of the wooden plaque so that you find its center.


With a hand drill, drill as straight as you can down into the center, through the block and a little into the base.

If you have access to a drill press, that's even better. I do not, so I had to eyeball it.


Check the fit of the launch rod. It should go right into the hole. Then, see how easily it comes out. If it comes out too easily, just drill a little deeper into the base - but not all the way through. That will provide more friction against the launch rod, so it doesn't accidentally pop out of the hole at launch.

The electric box cover serves as your blast deflector. If it's large enough, you can drill a hole in the center, and it will be perfectly centered on your launch pad.

But mine came with a screw hole on one corner, which was perfect.

Insert the launch rod into the hole on the base, and slide the blast deflector down over it. If you use a corner screw hole like I did, then it will hang off at an angle - this is great. It'll direct the blast away from the pad, and not just back up at the rocket. Just make sure you place your rocket over the blast deflector when you launch!


Boom. You're done. Launch pad.


If you need to angle the pad at launch, or you didn't get the center hole perfectly straight, you can adjust the angle of the pad by placing a small rock underneath one side.

Like my Facebook page for blog updates.

No comments:

Post a Comment