When landing, what does "reverse thrust" actually do? On the 737-800NG aircraft on Wednesday, landing at Seville as soon as the wheels were on the ground the reverse came on? Then the noise built up, and there was some vibrations, slight shudders of lockers? And then the plane came to a stop pretty soon?
Designs vary from engine to engine but essentially "clam-shell" style doors open when reverse is activated shutting off the rearward thrust flow and re-directing it forwards. It doesn't actually "spin the engine backwards" (as I thought when I was little
) but it uses the engine's thrust against the aircraft to help it decelerate. This does inevitably make the cabin fittings shake quite a lot.
The vibrations in the in 737NG aren't too bad....but some older types can be positively teeth shattering!