From: Lehanover@aol.com
Date: 2005/05/06 Fri PM 10:07:24 EDT
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: To Lynn Hanover re: windage trays

 
In a message dated 05/06/2005 06:44 Central Daylight Time,  jerryhey@earthlink.net writes:

Lynn, I  would appreciate your advice.  I am starting out to build wedge oil  pans and wonder about the advisability of having a windage tray at all  since they are not used stock 13-B or Renesis.   The Renesis oil  pan has a sub floor about .75 inches above the actual real bottom where  oil can be trapped and presumably de-frothed.   This might only  be necessary because the pan is so shallow.  I don't know and am  looking forward to hearing your comments.   The wedge oil pans  would be much deeper toward rear and that is where I hope to place the  pick up.    Thanks,  Jerry





The primary reason for the windage tray in rotary racing with the internal  pump, is to keep the entire oil supply from filling up the front cover  and uncovering the pickup under hard braking.  I have thought about the problem of keeping the pickup covered during climb  and descent. How much of a climb angle would be tolerated before a problem develops.  Riding down to Sun&Fun in the Bonanza I decided the angles involved were  just too shallow to be a factor.
 
That only leaves the defoaming as a benefit. We were racing without a tray  for years before adding one. During a race (40 minutes) the oil pressure would  drop from 85-90 PSI to 70 PSI.
 
Some of that from oil temps going up, and some from oil foaming. We were  putting it up into the front cover under braking and foaming the crap out of it  with the front counter weight. This is with a stock pan with a quart of oil  extra added.
 
A conical shaped pan with the pickup at the inverted apex would seem close  to the ideal if you maintain the internal pump. If you want the tray for  defoaming I would suggest a flat plate with a 5/8" gap around the edges the full  size of the pan. Or try the deep pan without any tray at all. If you don't use  steep climb angles the oil will stay off of the front counter weight and  little foaming will occur. Most foaming in the straight line is cooling oil  from the rotors, and that exits at an angle before it gets to the pan and is  just below the breather port.
 
Lynn E. Hanover