"lift off" definition

[dr wogz]

What is considered "lift off"?

When the first or last rail button / lug has cleared the rail /rod / tower?

(At what point is the rocket considered 'on it's own'?)

I just want to get the terminology right. And I've always considered it when the last lug / button has left the rail / rod.. When the rocket is no longer in any contact with the launch device.. (But I can see where the upper / first button leaving can be considered 'on it's own'..)

 

[shreadvector]

First movement. When thrust exceeds weight and it starts to move.

For NASA , it is when the hold-downs release and it starts to move upwards.

it “lifts off”. Pretty simple term.

 

[heada]

First sustained forward movement. I added sustained to avoid a chuff.

 

[dr wogz]

yeah, I'm reviewing a student paper, and English isn't their first language. So am trying to deduce / decipher what they mean, and what term they should be using.

they state "lift off" as being the moment the first button leaves the rail; the first moment the rocket is 'unguided and on its own' for the flight..

 

[JohnCoker]

As far as ThrustCurve.org goes, it's the first time simulated velocity is positive.

 

[shreadvector]

yeah, I'm reviewing a student paper, and English isn't their first language. So am trying to deduce / decipher what they mean, and what term they should be using.

they state "lift off" as being the moment the first button leaves the rail; the first moment the rocket is 'unguided and on its own' for the flight..

“lift off” is different than “free flight”.

starting to move upward is liftoff.

leaving a launch rod or rail is free flight. And that does not address if the Rocket is fin stabilized or uses a guidance system.

 

[Sooner Boomer]

“lift off” is different than “free flight”.

starting to move upward is liftoff.

leaving a launch rod or rail is free flight. And that does not address if the Rocket is fin stabilized or uses a guidance system.

I think that's the perfect definition.