User manual

Section Appendix A.4 Part B
Down wind taxiing
is possible but getting the aircraft to turn downwind is difficult in all but the lightest
conditions. Once directed downwind, short burst of power alternately applied can be used
to keep the aircraft straight. If the tail is allowed to wander out of a strictly down wind
position considerable power may be needed to correct the aircraft's path. A higher taxi
speed will also occur and engine overheating is likely. Lowering the landing gear adds
drag to overcome this problem as can streaming a drogue from each side of the aircraft.
With drogues and landing gear down it is possible to taxi a Catalina down wind in quite
strong wind conditions.
Note: If good control can not be maintained taxiing down wind, allow the aircraft to turn
into wind and "sail" it backwards, tacking sideways a little as required.
Lowering the landing gear helps in all displacement taxiing since it improves lateral
stability, tightens the radius of a turn and provides protection against shallow water, sand
bars, reefs etc. PBY has a nose gear isolation system to allow lowering of the main wheels
alone, but after use, landing gear hydraulic sequencing problems are more likely.
WARNING: Always ensure that landing gear is UP at the end of water taxi
03 SAILING
This is included here because it is one way of controlling the aircraft's movement across
the water and is therefore technically a form of taxiing. The aerodynamic and
hydrodynamic principles have been covered in section 02.10.
Sailing may be achieved with power off or power on. With power on sailing the advantage
is that the engine power will counter the wind force moving the aircraft downwind, so better
control on the water is possible.
In general to, sail the aircraft, these guidelines should be followed:
1) Allow the aircraft to weathercock into wind. The aircraft sails downwind backwards.
2) To sail in a direction other than directly downwind turn the rudder direction of the turn
required and the ailerons in the reverse direction make use of rudder and aileron drag
effects. The aircraft should proceed downwind and to the desired side. (Keel sailing)
3) Add a small amount of power to overcome the down wind component of wind allowing
more cross wind heading to be maintained.
4) In strong wind conditions alternately sail down and across wind and taxi under power
as much up and across wind as possible, thus tacking the aircraft in the desired
overall direction.
04 HIGH SPEED (STEP) TAXI
While a very good way of covering distance over the water quickly, the step taxi has
limitations as well as advantages. This procedure is done with the floats selected in the UP
position.
The main practical uses of the step taxi are fast taxiing to reposition the aircraft for take-off
or to travel from a landing area to a beaching or mooring area. These can be
accomplished quickly and without overheating the engines taxiing on the step.
Step taxiing is also a good training manoeuvre since it allows practice of the correct
Minimum Drag /Maximum Acceleration trim angle for the take-off run avoiding porpoising
during the take-off run. If not current on the water some taxi practice is very useful before a
full take off run is initiated.
Rev No: 02 Stichting Catalina PH-PBY
Page: 2 01 April, 2006