I make mine with a 6" or so PVC coupling. First, mark it like a 3 fin rocket. I always number the places the bolts go through before the coupler is sawn in half making 2 rings. Using my drill press I drill a 1/4" holes spaced 120 degrees apart. You can make a large fin marking guide in VCP or other rocket program. Now you will need to give the tower some back bone. I always used a 1"x2"x3" piece of oak lumber, This is the piece that keeps the two rings apart. I've made both 3 and four foot long towers, but the length is up to you. next we need 3 lengths of aluminum tubing abut 3/4" in diameter.these need to be the same length as your strong back. I used a grinder to make 45 degree cuts on the end of every tube so we can thread the head end of the bolt there. You need 6 1/4" -20 bolts 6 inches long. each bolt needs 3 nuts on it. insert the bolt into the aluminum guide rod and tighten the nut, you do the same of each end of the 3 guide rods. You should have a nut on the inside of the PVC ring and another on the outside of the ring. I put a steel plate on the strong back using counter sunk hardware. The plate is at the balance point of the tower and drilled and tapped it with a 1/4"-20 hole so I can use the tower on my Leitz Tilt-All tripod. This makes it very easy to steer to the ideal direction. I keep a chart on the tower that tells me how far the bolts stick out for 13mm, 18mm. or 24mm body tubes, Then you whip out your 7/16th wrench and have at it. This tower design works well , but it is a bit of a PITA to adjust in the field. I made 3 of them so I would be all tuned up for most any contest.
I know that my verbal avalanche is hard to de-cypher, so I will try to post some pictures. As far as the design goes it is nothing new and I make no claim on it, the rocketry public is free to use it and improve it.
I re-read this post, I swear I wasn't drunk when I wrote it! Jeez, I really sounded like the semi-literate knucklehead I truly am!
Dwight
