Ability to do engine static fire in designer

Doing engine static fire in designer gonna be a good addition for the game.
especially for ssto's engines .
How it can be done

1. Activate the engine (The throttle gonna be a fixed 100% for max performance)
2. Use the slider altitude to see how the engines plumes gonna be both in vacuum and atmospheric condition . But with a condition that the player cant configure the engine during static fire.
3. The static fire burn time can be adjusted or fixed time like 10 seconds only or full burn time .
4. Another thing is if the rocket have more than 2 engines ( for a normal two stage rocket),we can choose to do either one or all of them for the engines test
   

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There should be a button saying like "Test stand" or something so we can start the engine test (that's the only thing I could came up with(: ....)
And this can also be apply for all type of engines,including jet engines .