Measuring distance on launch rail

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highflyer1968

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Just wondering when setting up Rocsim for how long the rail is, do you just enter the length of the rail or from where the last rail button is? I have an 8 foot rail and the first button is about 75 inches from end of rail and second one is about 86 inches from the end.

thanks for any help
 
I would consider the length of the rail to be 75 inches, the rocket is only guided while both buttons are in the rail.
 
mbeels said:
I would consider the length of the rail to be 75 inches, the rocket is only guided while both buttons are in the rail.
Click to expand...
I think a lot of folks overlook this. I've seen tall rockets on 6' rails where the top button is only about 3' down the rail. Or sometimes the rail stop will be set a good foot or more up the rail which of course shortens the guidance. For my taller rockets I try to use an 8' rail whenever possible, especially if I know the launch speed is on the low side or if it's windy.

That does raise a good question - in OpenRocket I don't need to add rail buttons to a rocket to sim it. So when it computes the speed off the top of the rail what actual distance is it using - the entire 6 or 8 feet? If so, it is overestimating the speed. Hmm.


Tony
 
manixFan said:
I think a lot of folks overlook this. I've seen tall rockets on 6' rails where the top button is only about 3' down the rail. Or sometimes the rail stop will be set a good foot or more up the rail which of course shortens the guidance. For my taller rockets I try to use an 8' rail whenever possible, especially if I know the launch speed is on the low side or if it's windy.

That does raise a good question - in OpenRocket I don't need to add rail buttons to a rocket to sim it. So when it computes the speed off the top of the rail what actual distance is it using - the entire 6 or 8 feet? If so, it is overestimating the speed. Hmm.


Tony
Click to expand...

You can change the effective length of the rail in OR as well.
 

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