[C320-list] Perkins Rotation

[Warren Updike]

The name plate on my Hurth:
  MODEL    HBW 50

  RATIO     iA =2.05         iB =1.86

  SER. N.    09-73295

The manual I have says that the "A" ratio is "Transmission ratio propeller rotation opposite engine rotation."  And, the "B" ration is "Transmission ratio propeller rotation same to a engine rotation."  (Exact quote.)

I read the ration as A=2.05:1, to mean that the shaft makes 1 turn to each 2.05 turns of the engine crankshaft.  If the "A" ratio is, in fact, the forward speed, then, indeed the trans does reverse the engine rotation in forward.  Why the reverse, "B" ratio, would be lower than the forward ratio, I can only conjecture.  Certainly, with cars the situation would be reversed, I think.  Perhaps someone with better understanding may enlighten us.

Warren & Pattie Updike
C320, #62, 1994, "Warr De Mar"
Frog Mortar Creek, Middle River
Chesapeake Bay