Just check out Art's swing launcher, or others in and out of the club. These are very good points, Bear.

I have talked to Art with Mark L. present about ways to improve his rail on his tilt up system. Thinking about my previous comments, if the rails come in 20 foot lengths, and considering price and shipping costs, I wonder if it would be more efficient to buy 20 foot rails and cut them to 8' and 12' lengths for our use. Or two 10' rails. Some one has to pay to have a 20' length cut into pieces. We could do it very cheaply with a sawzall and a file, and maybe save $20 instead of 80/20.net doing it. For what it is worth, I have an 8' rail I built with (2) 4' pieces and a splice I made. (Should have bought theirs, it was better and much less time consuming.) The rig works great.

I have been in the position of having to decide how to set and splice the rails. Not fun, but definitely integral to successful launches. No disagreement here, Bear. Art and Mark are two of my favorite people in the club. Listen to them. 😉

Thanks for the advice. I try to do that whenever it applies, especially with those two, or for either of the John's and for the Joe! Their wisdom and experience far surpasses mine. At the time of the discussion with them, I was not asking advice, I was offering suggestion on how to improve the rail and to be able to dis-assemble faster and of course, the reciprocal, how to assemble more quickly. One of my concerns is how to keep the rail from whipping in the breeze, therefore increasing the stiffness, yet at the same time, keeping it light, and yet not so heavy that it damages the uni-ball at the bottom. This is not a concern for Art's launcher, but for the launchers we use that are carried in the trailer, I think it might be a concern. And to get longer rails also, since we seem to keep building larger and larger rockets. On my home made launcher, I found that 80/20 had some brackets that were of 1/4" aluminum anodized black. These brackets have an 180 degree arc machined into them and a 3/8" hole at the center of the arc, that when the bottom is mounted on a piece of strong 1" material, and with a pivot going through the center hole in the bracket which goes through your 10/10 rail, gives you protactor of sorts for changing angles or laying the rail horizontal. If you drill and tap your rail as I did, you can then take some thumb screws, go through the arc in the bracket, and into the 10/10 rail. This allows you to loosen the thumb screws and lower your rail to horizontal. My rigid piece of material that I mounted the brackets onto, has a 1/2" hole drilled through it, perpendicular to centerline. A 1/2" rod was inserted into this, secured with set screws from the sides, and then it goes through a base and is secured from underneath. this allows me to change angles of attack for my rockets and to rotate the base, without moving the tripod, so that which ever direction the wind is coming from, I can move my rocket to the best launch position. But, I do not have to deal with stiffening it yet. This might work for others though if they are building their own rail launchers.

Sounds nice, Bear. But to my knowledge we haven't had that much trouble with our 1010 rails whipping in the wind. But no one will disregard improvement. Jon, John, Joe, Ed, Mark, Art, et al. are all good guys and sources far beyond mine. Crap, I just realized I missed the annual meeting yesterday!

Yes you did. And it was a fine meeting too!
Back at the last Oktoberfest, Joe, myself and some others were standing around on Saturday in the wind and the rain/snow/sleet while watching our tents, tables, awnings, and anything else that was not tied down securely (which was very little after the ground became saturated and our stakes pulled out) take flight and break the binding of earth for a few moments. In the process, we were watching the rails bend in the breeze and made comment about how when it is windy and we are using those rails they tend to whip the rocket a little bit as the bird is leaving the end of the rail, pushing the tail of the rocket into some strange angle other than vertical. This is my reasoning for seeking greater stiffness in those said rails. If it is not important to others, then I guess it probably does not need to be important to me at this time. I guess time will tell.

Very good reasoning, but who would launch in THAT wind?

I've seen them start flexing in about 12mph winds, (the longer they are, the sooner they start flexing and at lower wind speeds also) so that is something that is certainly doable. (I gues it is the aerodynamic drag imposed by a rail an inch wide and 8 feet long is going to give at least 96 sq. inches of surface area to push against.) As for who would fly in that kind of wind? Only a fanatic who has to see things go fast and high, leaving a lot of smoke and noise. It's an addiction, you know.

I'm much more a fan of the 1020 rails - they are 1" wide and 2" deep. Gives you more rigidity in one direction. They also have 2020 rail that is very nice, but the key with any rail is having a good backing to keep it straight.

Edward

I personally agree with you, but I do not recall seeing them on the launch pads. Of course if we are going to get some new rails, then maybe those would be approved.

I've flown off of the 1020 rails a lot at NCR. I think they are on Mark L.'s big pad. The only thing is it sways a lot at the top.

Edward

To eliminate the sway, couldn't you bolt onto the rail at the top, a bar that comes out of it, opposite the side the rocket goes on, and have it come out about 36". (this is so the fins clear the wires) Then you mount 4 guy wires, 90 degrees apart to keep the top from moving? Put quick disconnects on two of them so you can lay the rail down to load the rocket. Stand it back up and resecure the two loose wires. that would be lighter, and less expensive than making a solid stiffener to mount on the back side of the rail. Or something in that direction to add stability.

You can make a swing-set like top guy wire doohickey. I fly off the 16' rail when my hybrids go slower. The key is not needing the 16' 🙂

Edward

Once you get beyond about 12', 1010 or 1515 rail is pretty much unmanageable in a wind unless it is backed by something to stiffen it. Hence we have launchers like Art's Swing Set and Terry Lee's trailer or more elaborately Doug Gerard's amazing launch tower that use a truss or a piece of Rohn antenna tower to stiffen the actual rail. This makes for a much more bulky situation as far as storage and transport not to mention substantial labor in setting it up and tearing it down.

Guy wires, particularly if you're talking some sort of symmetrical arrangement, would put significant limits on what could be flown off the rail.

Our longest launcher is a 16' 1515 rail that is in two 8' sections. It's worked for birds near 100# or more. In cases where project have been built that couldn't use one of these rails, folks have generally built or borrowed pads from others out there. When you step up to projects that require 2020 rail or Unistrut, you also have to realize that commercial rail buttons are pretty much unavailable and need to be machined or fabricated.