Build a Cheap Launch Pad
by Andy Hofle
I recently went looking on the web for a decent launch pad that could withstand larger rockets, allow 360 degree swiveling of the launch rod, hold a variety of launch rod diameters, and collapse for easy storage and transport. I was disappointed with the results and was shocked to find some pads costing well over $200!!! During my search I found a few useful sites with instructions for building your own, but most were insufficient or were barely better than the cheap pads that Estes puts out. So I decided to design and build my own.
One site I stumbled upon had a good design (by Bill Owen) for the launch pad legs, which are made out of standard PVC with 45 degree elbows. But the rest of the pad, in particular the attachment of the launch rod, was not very accommodating. I based the design of my pad on this base, but added the ability to swivel the rod attachment both left and right as well as forward and backwards. Here are the plans.
Let's start with the materials you will need to buy for this project, most or all of which can be found at your local Home Depot or other hardware store:
|8 foot long, 1 inch diameter PVC pipe
|1 inch 4 way PVC coupler section
|1 inch 45 degree PVC elbow section
|1 inch PVC end cap section
|1 inch PVC extension section
|1 inch PVC 90 degree elbow
|8 foot long 3/4 inch diameter PVC pipe
|3/4 inch 90 degree PVC elbow
3/4 inch 90 degree PVC elbow with flush end.
This might be hard to find (I got them at Home Depot), but the flush end
makes securing the swiveling section to the frame with a carriage bolt
easier. One end should accept 3/4" PVC and the other end should fit into a
3/4" elbow. If you can't find this part, a reader made the following suggestion:
I bought a couple of t-connectors and sawed off one extension from each, then epoxied a washer into the opening (there's a little lip left, just beyond the cut, to snug the washer into). I then dremelled the hole in the washer into a square shape for the carriage bolt.
Another great alternative: 3/4" PVC plugs are flush - drill a hole into one and epoxy a 3/8" lock nut. Then mount it into a 3/4" Tee. Use 3" of threaded 3/8" rod instead of the carriage bolt.
Another reader had good luck simply dremmeling the end plug directly and attaching the carriage bolt that way.
|3/8" wing nuts
|3/8" diameter 3" long carriage bolt
|3/8" diameter 4" long bolt
All of the PVC connectors should NOT have threads and should have smooth receptacles for inserting and gluing PVC pipe. Other materials you will need: PVC cement, ruler, needle nose pliers, hacksaw or PVC pipe cutter, Dremel rotating tool, and a power drill with a 3/8" bit, and whatever bits necessary to drill holes for your launch rod sizes.
OK let's begin. I will loosely quote the info-central website for the bottom/base section of the pad instructions. Take an 8 foot section of 1" PVC pipe and cut four 2 inch sections of pipe with a hacksaw or PVC cutter. Take the remaining pipe and cut four 23 inch sections of pipe. Take the 4 way pipe coupler and use PVC joint cleaning compound to get the joints ready to join. Do the same to the 2 inch sections you just cut. Coat the joints according to the instructions on your PVC cement compound. Insert the 2 inch sections in each of the four holes in the 4 way. Let that set for as long as the instructions on the cement label suggest. Take the four 45 degree elbows and clean up one of the ends and prepare them for gluing to the remainder of the 2 inch sections that are sticking out of the 4 way. Test fit each of the 45 degree elbows and make sure they can all be pushed completely on and make sure you can get them all lined up straight down, before applying any glue. Use a pencil to mark the best alignment on each if that will help keep them straight. Apply the PVC cement and attach the 45 degree elbow with the ends facing directly down on each of the four ends. Make sure they are as straight as you can make them and do it quickly, since the glue sets up rapidly. Let the assembly dry with the open ends up as in figure 1 so the glue doesn't run into the elbows (a mistake I made). When it's dry, take a 3/8 inch drill and drill a hole directly through the top and bottom walls of the middle of the 4 way, then test fit the 4" by 3/8" bolt. You should have a set up that ends up looking like this (except with a hole in the center):
Figure 1 (Click thumbnails to enlarge)
Attach 4 of the 1" end caps to the 4 23" PVC sections to make the legs. Pound them all the way on (you probably don't need to bother with the glue). Do not glue the legs to the center section -- taking them off and on makes the pad very portable. I suppose if you don't care about that and you want a small amount of additional stability, you could glue them.
Cut two pieces from the 1" PVC about 5 5/8 inches long each. Cut another two pieces about 4 5/8 inches long each. Use the 1" extension to glue both 5 5/8" pieces inline with each other. Now attach the two 1" 90 degree elbows to each end (don't glue yet), making certain that they are both aligned and pointing in the same direction. You can do this by pressing the assembly open-elbow-end-down onto a hard surface. Then draw marks where the elbows meet the PVC. Take the elbows off, apply glue, and then glue them back on making sure the marks align. Again, while drying, try leaving the open ends of the elbows pointing up so glue doesn't run out of them. You'll end up with this:
Take the last two 1" end caps and glue them to one end of the 4 5/8" PVC pieces you just cut. Make sure the caps go all the way over the pipe equally for both pieces so they are the same height. Drill a 3/8" hole right through the end caps on both pieces. Make sure they are even from the top of the cap on both. Then glue those to the open ends of the elbows from figure 3. Again, make absolutely certain that the holes line up with each other and are parallel with the elbow assembly 'crossbar'. You now have the U-shaped frame that will hold the swiveling launch rod mount:
Figure 4 Figure 4.1
Drill a hole in the middle of the crossbar from figure 4 which will allow attachment to the base. The hole should be parallel with the two arms of the U-frame so that the arms will point straight up when attached to the base.
Figure 5 Figure 5.1
Now to the only really tricky part of the pad. You will need to dremel out a square hole from the middle of the end of both flush 90 degree elbows. This allows the carriage bolt to grip the inside of the elbow so you can tighten it down with a wing nut without worrying about the bolt slipping around inside the elbow. It doesn't have to be too exact, just enough so that the carriage bolt catches. Start by drilling small hole (1/4" or 1/8"), then gradually trimming down to fit the bolt. Use the bolt to test fit periodically while you are grinding. I'm sure there is a better way to do this, but I'm not an expert on carpentry so I wouldn't know. :-) When you are done the bolt should stick out of the flush end like in figure 6.2.
Figure 6 Figure 6.1 Figure 6.2
Cut two pieces of 3/4" PVC pipe a tad over 9 inches each. I apologize that this step doesn't have an exact measurement for you to make, but I had to just eyeball it so that it would fit snugly between the posts of the U-shaped frame. You can test fit (i.e. don't glue) one of the 9" PVC pieces to each of the flush 90 degree elbows and make sure it fits snugly in between the U frame. Don't forget to take into account the two 3/8" washers that will be between the elbow and the U-frame. Once you have a good tight fit, leave the carriage bolts sticking out of the elbows and glue the elbows to one of the 9" pieces of 3/4" PVC. As in figure 3, make certain the elbows are exactly aligned and watch for glue drippage. Repeat this step with the other 9" by 3/4" piece, except use the two regular/rounded 90 degree elbows. DO NOT glue the two 9" assemblies together yet -- you'll see why in the next step. You should now have the following 3 pieces:
Take the piece with the carriage bolts sticking out, and insert one end into the U frame (the carriage bolt should go all the way through), making sure a washer is on both sides of the U-frame end cap hole. Secure in place with a wing nut. The other side is trickier to attach since the bolt is sticking out. You will need to push the bolt so it's flush with the end of the elbow, move the elbow into position next to the hole on the other end cap, and then use a needle nose pliers to slowly work the bolt through the end cap. This is why you need the hole in the elbow to access the bolt. Secure the other carriage bolt with another wing nut. You should end up with a piece like in figure 8.3.
Figure 8 Figure 8.1 Figure 8.2 Figure 8.3
Now before gluing the remaining part of the rod attachment, you will need to test fit it and see if you have a drill bit long enough to drill holes for your launch rod (I recommend drilling your largest rod diameter hole in the middle for weight and balance issues). The drill bit should be able to go completely through the top pipe, and only half through the bottom pipe (so the launch rod can rest on the bottom of the bottom pipe). If not you will have to drill the holes separately like I did. For me, the drill bit was barely short, so I attached the pieces (without glue), drilled through the top, and pushed the bit as far down as possible, then marked the bottom pipe. I then disconnected the bottom piece and drilled on the marks. You could also drill the top pipe, then insert your launch rod through the top hole and mark exactly where it touches the bottom pipe, disconnect, and drill half way through the bottom piece. Finally, when your holes are drilled, you can glue the bottom section to the top section.
Figure 9 Figure 9.1 Figure 9.2
Attach the assembly from figure 9 to the base using the 4" by 3/8" bolt, a couple of washers, and the remaining wing nut. Put on the legs and then throw in a launch rod. If you drilled the holes perfectly straight, the rod might be loose, and will need to be secured in place so it doesn't fly up with your rocket and skewer some poor spectator's eye balls. You can buy these little tiny clips at Home Depot in the tools section for about 50 cents each. They are strong enough to lift the entire pad by the rod. Attach the clip as in figure 10.
Lastly, you will need a blast deflector. You have several options. I used the blast deflector that came with my friend's Aerotech Mantis launch pad (whose demise necessitated this design, he he). You can also use a standard Estes deflector (figure 11.1). If you are better than I am at bending metal, you can cut a 1/3 section from a coffee can, bend one end over the top of the pad, drill a hole for the rod, and secure it with a couple of screws. Figure 11.2 shows my pathetic attempt at a coffee can deflector plate.
Figure 11 Figure 11.1 Figure 11.2
And there you have it. The pad is quite sturdy -- it can hold Aerotech and The-Launch-Pad rockets easily, not to mention Estes and Quest rockets. The pad comes apart into several sturdy pieces that can be tossed into an old gym bag for storage and transport. I haven't tested the maximum weight so don't blame me if your 20 pound sounding rocket collapses the pad. Adjust the launch angle by loosening the two side wing nuts and repositioning the swiveling rod holder. Retighten when finished. You can also loosen the bottom wing nut to turn the entire U-frame left or right. I usually just lift the whole pad.
Feel free to email me with any questions, comments, or improvements to the pad, or just to say hi. If you are a millionaire or just extremely appreciative for this design, you can Paypal me a few bucks. Enjoy the pad!