Double check the fit around a body tube. I painted my competition models and the fit was a little tight. The rail guides didn't immediately fly off the tube when released.
I wrapped some 220 grit sandpaper around a body tube and sanded the inside diameter slightly larger.
The instructions recommend painting the guides a bright color. Apparently they can fly off and land 10 feet from the launcher. A bright fluorescent color will be easier to find on the ground.
After painting the small rubber bands were pulled into the slots to join the two halves.
Here's how they fit around a BT-20 tube.
Notice the stretched rubber band at the bottom.
At the center top is the "T" shaped halves that slide into the launch rail.
These fly-away rail guides are another great example of what can be made using a laser cutter.
I've never seen one of these in action. It seems like the rubber-band would cause the part that fits inside the rail to be tight against the rail and this friction would be worse than the air friction of a launch lug, and at the time when the engine has most of it's thrust?
ReplyDeleteJust curious.
Hi Bill,
DeleteThere wasn't any real friction on the 1010 rail. I was surprised by how easily it slid up and down the rail.
I'm sure the piston launched models got better altitude than my fly-away guide models did. But the fly away guides would result in less drag than a rocket with launch lugs.
Hello Chris,
ReplyDeleteI've just come across your great blog and I'm enjoying all of your past blog posts. Luckily, there's plenty to catch up on! I came across this one and it caught my attention because I hate launch lugs. I'd like to eventually convert my rockets (most are BT-50. 55 and 60 in diameter) to fly-away rail guides. But it turns out that I need a special launch rail, such as the Standard 1010.
Here's my question: If I launch a typical LPR (say, a stock Alpha III or Big Bertha), how long does the launch rail need to be? My online research finds discussions about 8 foot tall rails, but those are for really tall rockets or higher-powered rockets. So could I get away with a shorter guide for my intended rockets? If so, how short? For example, would 4 feet suffice?
Hi J.L.,
DeleteFor standard LPR rockets, I would think a four foot length of rail should be plenty! I don't think I've ever seen an eight foot long rail. Most were three feet.