Originally Posted by james ozzie
I think many of the posts above are incorrect (now thats asking for it!)
James,
I would say we simply shouldn't have dragged rocket engines into the discussion....
Rocket engines carry their own 'reaction mass' with them, which is then accelerated rearwards "from standstill" (relative to the vehicle).
Jet engines differ in that they get their 'reaction mass' from the outside (neglecting the tiny mass contribution of the fuel), coming in a the speed of the vehicle. So it
has to be accelerated to a greater speed at the exhaust to provide a reaction (thrust). The thrust formula is fundamentally different.
CJ