Hi ya'll,
Seems I should add to previous post on basics
First on aileron differential, this applies to ANY style airplane, but
need is more apparent with pattern because the desire is to
maneuver precisely, slight maneuver misalignment with a sport
style is usually not a concern, however with pattern it would cost
points.
The reason for the differential is complex. but the resultant is
simple. Down aileron simply creates more drag than up, so the
up aileron movement is increased to equalize drag.
Some examples to illustrate the basics given previously.
'twas said: aerodynamics is created by the airplane moving thru
air. it moves so regardless of it's attitude.
Consider: craft is trimmed for level flight, the wing incidence is
set relative to the line of flight, not the horizon. The gravity forc is perpendicular to the line of flight. The nose is raised for a climb,
the gravity force vector is now angled back reducing the thrust
force which slows the craft. To maintain the climb angle some
elevator is used which increases the angle of attack relative to
the line of f light. Additional lift created offsets the loss due to the slower air speed. Gravity has simply upset the previous
aerodynamics which are still created by movement.
Similarily take a powerull craft and pull it from level flight into
vertical, aerodynamics remain the same, only change is gravity
now opposes only thrust.
Another consideration: inverted flight. with a symmetrical airfoil
slight down elevator is usually required to maintain level. Know
some positive incidence to the line of flight was required upright,
in relation to the LOF when inverted this becomes negative and
must be raised to positive.
Also: a flat bottom airfoil. inverted requires considerable elevator
force. Two reasons are envolved. First is same as with symmetrical. 2nd is gravity again. Upright the airfoil lift equals gravity, inverted the lift generated adds to gravity, It is possible
for this airfoil to create lift when upside down by using a high angle of attack, again relative to the line of flight.
If you have flown a flat bottom inverted you may have noted that
the attack angle required is at or close to the stall angle. This may
be a rather low angle brcause inverted this airfoil is inefficent
Observation is the craft "mushs" or flounders
Note mysteries become more clear when we remember that
aerodynamics always relate to the line of flight no matter what
direction it might be. Plus the application of the gravity force
changes with the craft's attitude.