User manual

Aerosoft PBY Catalina 1.00 Manual
Page 9 of 100
stop. When the carburetors are heated and the ice is removed they will be running normal again (or
can be restarted).
If carburetor air temperature is getting too high, the engine will lose power, because hot air contains
less oxygen. Keep the carburetor air temperature above 32°C and below 50°C.
Structural icing
For an aircraft that was used so much in arctic condition it has rather pitiful de-icing systems. Now
normally this is not a real problem in FSX, but we included an advanced structural icing system.
When you get into freezing rain, ice will build up on your wings, tail and fuselage. Freezing rain is
present when it´s raining and ambient temperature is between +15° and 0°. This will increase drag
and weight and will reduce the efficiency of the wings. The result is that you will lose speed and
eventually will not be able to maintain altitude. Keep an eye on the temperature gauge and when
you run the risk of icing try to stay outside clouds. Icing in the carburetor and the pitot tube normally
starts before structural icing and are serious warning signs of impending problems ahead.
Early
Catalinas had rubber inflatable boots on the wings to break build up ice. Later models fed hot
exhaust gases into the front sections on the wing to avoid icing. This is controlled with a switch on
the back panel. Pitot heat and propeller de-icing are controlled with switches on the control bar.
Fouled sparkplugs
If RPM is kept under 1000 RPM for a longer period the sparkplugs will foul. A coating of half burned
fuel and other material forms on the metal parts and the spark will not be as strong as it should be
and the engine will lose power and will run on lower RPM than expected. In an extreme case the
sparkplugs will fail and will have to be cleaned or replaced by a mechanic. In our model this means
the aircraft has to be reloaded. When the RPM is high this residue will burn off and the sparkplug is
cleaned. A short burst of high revs before take-off is a good remedy to prevent problems.
Shock cooling
Though disputed, shock cooling is a danger to older engines. The situation where rapid cooling arises
is on descent at idle or near idle power settings. In this condition the engine is producing much less
heat. In a descent, the plane's airspeed increases, simultaneously increasing the cooling rate of the
engine. As parts of the engine will cool at different rates the metal gets stressed and may fail.
Cylinder heads and valves are most affected. The most likely scenario of running into this problem is
a full power climb with high Cylinder Head Temperature into a very cold air layer, directly followed
by an idle descent through the same layer. Material failures due to shock cooling accumulate over
time and though you might run into these conditions many times before a failure happens, there is
always a risk. Keep an eye on you Cylinder Head Temperature!