Hi, are you talking about AOI ?

   Steve Carlisle

   No :-)

   "Angle of Incidence (or AOI) is the angle between the blade chord line and the
   plane of rotation of the rotor system." ???

   I am talking about the panels behind the cockpit relative to the direction of flight
   that are greater than 7 degrees. The Glass Goose is an example.

   There are a limited number of single engine sea plane configurations that minimize drag.
   None of them have that configuration.

   Lake, Coot and Sea Wind. High mounted engines that allow more or less perfectly stream lined
   fuselages.  The High mount is necessary to keep the prop out of the water spray.

   The Coot did not take full advantages of the possibilities. Also the prop could have been
   driven by a longer belt lowering the weight of the engine and moving the prop higher.
   See the attached picture. These airplane have rather bad handling due to the
   weight and thrust  of the high mounted engines relative to the wing. More power causes
   a nose down moment as does landing in water due to the inertia of the high
   mounted heavy engine.


   IMHO the Sea wind is the best of the group.

   For twins there is more variation. Gull wings are a good one Dornier DO 26, Martin PBM,
   and an Italian lite sea plane  that I don't remember the name of.

   The next category  is pylon mounted wings with multiple engines. The PBY is the best example.
   Dorneir D18D is another.  These usually  have some high drag strut bracing.

   BTW if the pilot and passenger are semi reclined the cabin top of the Glass Goose AKA
   Sea Hawker could be lowered and the wing supported with a short pylon
   above the cabin top which would benefit the aerodynamics some what.

   Then the deep fuselage with wing mounted engines.  There is a whole raft of those including
   the Spruce Goose and the Martin Mars. The only feature that causes extra drag is
   the step and the extra deep or high fuselage. As they get bigger this is less of a problem.

   All the older  strut mounted high wing sea planes are high drag.
   The Dorneir Wal was the best of the group.

   Sea planes are a difficult design problem due to the two mediums it must operate in.


   Paul Lamar


   Thanks for the info Paul, sorry about the confusion, I was meaning AOI in regards to airplanes.

   Steve Carlisle

   What is your definition?


   Paul Lamar


   Hi Paul, just learning this stuff, but angle of incidence  and angle of
   attack seem to be one in the same, is that right?

   Steve Carlisle

   They seem to be but AOI is associated with propellers however it is rarely used
   Pitch is used most often. That is not an angle per se. It is far the propeller will
   go in one revolution.

   AOA is used very very frequently to refer to wings. In fact there is an AOA instrument
   to warn the pilot of a stall among other uses. Navy pilots were taught to use
   an AOA instrument as I recall .

   Paul Lamar


Okay, thanks Paul.

Steve Carlisle

I can't stop myself from inventing things. A rate of AOA change would be a good
addition to the instrument. That would tell you how fast you are going to stall :-)

Paul Lamar


   The Rotary Engine free News Letter. Powered by Linux. If you want off
   the list PLEASE let me know and I will remove  you.  ACRE NL web
   site. http://www.rotaryeng.net You Tube http://tinyurl.com/beqqxas
   Copyright 1998-2016 All world wide rights reserved.