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 C

  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

  Angle of incidence is also the relative angle of the chord line of
  the wing relative to the longitudinal axis of the fuselage. Angle of
  attack is the relative angle between the airflow and the airfoil
  chord line.

 Jarrett Johnson

 Ah Yes. Come to think of it.
 Very good Jarrett Thanks.
 Well put.


 Paul Lamar


Paul, your proposal for the belt drive in the Coot would be the same for the GlassGoose, NO?

Steve C

It would help but the drag problems would still be there. If you want a side by
side build a gull wing twin tractor. Mazda engines are low cost.

If you want a a single engine build my cat :-)

Here is a narrow tandem seating GG or Sea Hawker. This greatly reduces the
aerodynamic drag problem. It is only 26 inches wide.


Paul Lamar

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