Potential problem with rail button binding?

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billdz

billdz

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The rocket pictured below has a 24" long, 5" diameter lower air frame with a transition to a 62" long, 4.5" upper section. The rail buttons are on the shorter, 5" section, about 18" apart.

The thought occurred to me that, since there is so much of the rocket above the rail buttons, it's possible the rocket may lean during liftoff and cause the buttons to bind on the rail. I can't place the top button any higher, because the top part has a smaller diameter.

Is this something to worry about? If yes, any fix? I can't think of any way to arrange the buttons differently, except maybe by adding a standoff on the upper section.

Thanks for any thoughts,
Bill
Black Panther.jpg
 
billdz said:
The rocket pictured below has a 24" long, 5" diameter lower air frame with a transition to a 62" long, 4.5" upper section. The rail buttons are on the shorter, 5" section, about 18" apart.

The thought occurred to me that, since there is so much of the rocket above the rail buttons, it's possible the rocket may lean during liftoff and cause the buttons to bind on the rail. I can't place the top button any higher, because the top part has a smaller diameter.

Is this something to worry about? If yes, any fix? I can't think of any way to arrange the buttons differently, except maybe by adding a standoff on the upper section.

Thanks for any thoughts,
Bill
View attachment 405202
Click to expand...
Boy that booster sure looks nice. Could you put a stand off on upper section to have button higher? It would not take much of a stand off. 1/2" maybe. But I believe you would be ok with the 18" point for upper rail button.
 
I say leave it.. you want buttons close together, so they are on the rail for the longest time. Not like we had with lugs & rods, where you wanted them far apart to minimize rod whip..

My buttons are always on the lower 1/3 or 1/4 of the rocket..
 
Bill, the rocket shown below has only 2 rail buttons and has launched fine on both flights. Buttons are located by yellow paint marks.

upload_2020-2-1_12-5-19.jpeg
 
I think the most important thing to avoid binding is to clean the rail before you fly. There should be WD-40 and plastic scrub pads ("Scotch Brite") near the pads to clean the rails. There's generally gunk from prior flights on the slot which could bind, so I generally spray on a bit of WD-40 and then run the pad in the slot a few times to make sure there are no rough spots.
 
This is true John, but I think the OP was worried about a "tall" rocket tilting and then wedging on the rail. I may be wrong though, my wife says I am a lot!
 
JohnCoker said:
I think the most important thing to avoid binding is to clean the rail before you fly. There should be WD-40 and plastic scrub pads ("Scotch Brite") near the pads to clean the rails. There's generally gunk from prior flights on the slot which could bind, so I generally spray on a bit of WD-40 and then run the pad in the slot a few times to make sure there are no rough spots.
Click to expand...
Respectfully, John ... Our feeling is that WD-40 can cause dust and dirt to stick to rails and we don't recommend it's use at our site where there is a lot of dirt/dust. YMMV.

Hoping down the rail with a dry cloth is recommended.

As to the OP ... if you use two buttons you should be just fine with no binding, even if they are relatively close together.
 
llickteig1 said:
Respectfully, John ... Our feeling is that WD-40 can cause dust and dirt to stick to rails and we don't recommend it's use at our site where there is a lot of dirt/dust. YMMV.

Hoping down the rail with a dry cloth is recommended.

As to the OP ... if you use two buttons you should be just fine with no binding, even if they are relatively close together.
Click to expand...

If you do use WD-40, you have to use it for every flight. I’ve done it both ways. The first flight after cleaning with WD-40 works great, but a Lance points out if there’s blowing dust (and there almost always is if you’re on the playa) any kind of oil just acts as a binder for the dust.
I like to use a dry piece of scotchbrite in the groove of a rail when it gets sticky.
 
Good questions. We've used WD-40 at the launches I'm familiar with, but it wouldn't surprise me if there are other options. No matter what, I clean the rail before using it.

And of course one should follow the guidelines of the club putting on the launch as to how to clean the rails.
 
Thanks for the replies. I launched the rocket with the buttons as-is, and there were no problems.
 

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