rail button alignment

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watermelonman

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What, if anything, are people using to align rail buttons? I used a doorway to make a straight line then stuck to it best I could. I think I am some percentage of a millimeter off in alignment between the two. Hopefully this is no big deal, like minor imperfections in fins, but I was a little concerned as the buttons closely govern the start of the flight. On the other hand there has to be some give between the buttons and rail itself regardless.
 
Small misalighments are not critical, the rocket will go more in the direction the rail is pointed not where the rocket is pointed. (Newtons law and angle of attack correction at all that....)
 
And if you need to do a third button, put it on a separate section of the sustainer such that it can be twisted into place (i.e. the payload section). Just saying.
 
I use aluminum angle to gat them in a line and confirm it with a 4 foot piece of launch rail.
 
If you have one...... plumb-bob.

Stand rocket vertical hang bob from top.

Can also be done with string and a nut.
 
Small misalighments are not critical, the rocket will go more in the direction the rail is pointed not where the rocket is pointed. (Newtons law and angle of attack correction at all that....)

+1 to this :)

It's best if they are perfectly aligned, but OK if they are off just a smidgen.

>>> There is a bit of tolerance in the "Button - Rail" system. <<<

The buttons are two points on the rocket. Between any two points is always a straight line.
 
The aluminum angle for the line. Then a section of launch railro align the actual buttons. It works I have a couple rockets with three buttons and yes, they work well that way.


Mark Koelsch
Sent from my iPhone using Rocketry Forum
 
My experience is that using anything to get a straight line on the BT will work. A ruler and eyeball will probably get you plenty close. Drilling the hole can be problematic. If you are drilling into a wood block or CR, and don't have the drill perpendicular to the BT, you can get enough misalignment of the buttons to cause problems even if your guide line is perfect.
 
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