Counter-rotating props

Jun 13, 2011 No Comments by

Hi, I have a question regarding 2-stoke model aircraft engines,  and multi engine aircarft. Can 2-stroke engine be made to run ccw and just reverse the mounting of the prop? Why do I ask?…aircraft like the P-38 had counter rotating engines, which I assume was to counter the two engine’s torque. Also, why wasn’t this application used in more aircraft and how is engine torque handled in multi-engine aircraft. Anyway, is there an article on
this, and if not can we have one? Note: I am a subscriber to MAN.
 
Thanx, Ed

All of our model engines run counter-clockwise to begin with, but I~understand you mean reverse rotation. Some model engine manufactures offer reverse rotation crankshafts for their engines. Any 2-stroke engine with a removable front housing can have the direction of rotation reversed (clockwise) by rotating the front housing 90° counter-clockwise.

Whether both engines turn the same direction or one the reverse direction doesn’t really make that much difference. Some years back; in a conversation with Tony Lavier who did all the test flying on the P-38, I asked him about this. He said they tried turning both engines to the left, both to the right, both towards the fuselage, and both away, and he couldn’t see much difference in rudder response or flight performance overall. Most twin engine aircraft have both engines turning counter-clockwise for maintenance purposes i.e., the same engine can be used in either position, hence the P-38s that went to England during WW II had both engines turning counter-clockwise.

There have been quite a few articles written on this topic over the years, but I have never kept an index.

Yours,

Clarence Lee

Engine Clinic Ed 

All of our model engines run counter-clockwise to begin with, but I understand you mean reverse rotation. Some model engine manufacturers offer reverse rotation crankshafts for their engines. Any 2-stroke engine with a removable front housing can have the direction of rotation reversed (clockwise) by rotating the front housing 90° counter-clockwise.

Whether both engines turn the same direction or one the reverse direction doesn’t really make that much difference. Some years back; in a conversation with Tony Lavier who did all the test flying on the P-38, I asked him about this. He said they tried turning both engines to the left, both to the right, both towards the fuselage, and both away, and he couldn’t see much difference in rudder response or flight performance overall. Most twin engine aircraft have both engines turning counter-clockwise for maintenance purposes i.e., the same engine can be used in either position, hence the P-38s that went to England during

WW II had both engines turning counter-clockwise.

There has been quite a few articles written on this topic over the years, but I have never kept an index

Yours,

Clarence Lee

Clarence Lee, Dave Gierke, Editors Blogs

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