Unistrut Dimensions?

mtnmanak

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Anyone know what the inside dimensions are of the Unistrut rails we typically see at rocket launches? Is there a standard?

Asking the question because I want to use trolleys instead of buttons on a big rocket and not sure if they will fit in the unistrut rails.

 

H_Rocket

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I'm puzzled,how big of an air frame do you have in mind for a guide that weighs a half a pound, sticks out almost an inch and three quarters, and is designed to suspend 100#?
 

mtnmanak

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I'm puzzled,how big of an air frame do you have in mind for a guide that weighs a half a pound, sticks out almost an inch and three quarters, and is designed to suspend 100#?

12" FG frame, rocket is 20 feet long and will weigh about 250 lbs on the pad
 

mtnmanak

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Look here https://www.unistrut.us/

Over the years, I've seen at least 6 sizes used.

That's the issue... I have a feeling the issue is going to be that different clubs have different rails. I am pretty sure the width of the channel is standard, but the depth appears to range from 13/16" up 1-5/8". That is a big difference. Not sure if trolleys designed for 13/16" rails will work in the 1-5/8" depth rails.
 

H_Rocket

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Unistrut is in no way a precision part. It's intended to hang things from the overhead like welding curtains, hoists, and the like. The most common one Ive seen back east is the 1-5/8 variety. Outside of NY and MD, I've seldom seen it at all. A well mounted 1515 button can hold a pretty good size amount of weight.
 

rharshberger

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Look here https://www.unistrut.us/

Over the years, I've seen at least 6 sizes used.
Other than depth of the rail every Unistrut I have ever seen (used in rocketry )has been the 1-5/8" wide type by 1-5/8" deep standard P1000, and every rail button offered afaik will fit even the 13/16" deep one as long as the mounting screws are flush with the bottom of the rail. Those trolleys are huge.
 

mtnmanak

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Dan Michaels has trolleys on his Patriot, I need to try and get ahold of him and see which ones he used.

A well mounted 1515 button can hold a pretty good size amount of weight.

I am not so concerned with the weight of the rocket when vertical, but when it is laying horizontal on the rail, that is a lot of opportunity for the rocket to roll and tear the buttons out.

Not really concerned about the size or weight of the trolleys. An extra pound or two certainly isn't going to mean much with an O or P in it.

There will be mounts in the frame, so I can remove the trolleys and put buttons on, if I want. Or a T-bracket, if I take the rocket out to the desert.
 

H_Rocket

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It’s gonna be a beast- best wishes on it.

I think Dan is the only guy I’ve ever seen use those trolleys. I’m sure others have done it, just not in my view.
 

mtnmanak

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I think Dan is the only guy I’ve ever seen use those trolleys. I’m sure others have done it, just not in my view.

That's where I got the idea. Delrin buttons have served me well, but this rocket is actually relatively small compared to a couple other projects I have in the works, so would like to try out some rail mounting alternatives before the rockets start getting big.

I also need to talk to Tom Cohen and see what he is using.
 
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