Why must VTOL engines be larger than normal engines?

[cjl]

It's simple physics. F = ma. In a steady climb, acceleration = 0 so F_net = 0.

 

[davenn]

It's simple physics. F = ma. In a steady climb, acceleration = 0 so F_net = 0.

if you were climbing in zero gravity ?

you are going to have to do a better job of explaining

 

[A.T.]

if you were climbing in zero gravity ?

No, gravity is part of the F in F=ma.

you are going to have to do a better job of explaining

How about you explain what is wrong about it?

 

[David Lewis]

Davenn, I understand your skepticism. According to everyday experience, it may appear that a force needs to be applied to an object in order to make it move -- and that's partly correct. In reality, however, a force only needs to be applied temporarily in order to get it moving. After that, you take away the force and it keeps on moving by itself -- indefinitely. The reason this might be counter-intuitive is that friction and air resistance tend to obscure the underlying law.