Résultats de la recherche (Page 2) / Pilote-Virtuel.com - Forum de simulation aérienne

Salut Brice,

non j'ai pas éssayé de l'enlever, mais a quoi pense tu, car sans carte video dans un Pc il y a pas grand chose a faire.

The following failures are simulated:

Engine failure due to excessive CHT (Cylinder head temperature)
If CHT gets above 260°C (the exact temperature depends on how fast temperature is rising), the engine will fail, cause the aluminium weakens when reaching these temperatures.
During Take off and climb, it is important to open the cowlflaps to keep the engines cool.
You will see that failure is eminent, when power quickly starts to decrease. If You can manage to get the engine cooled down again before it seizes, You might safe the engine. Otherwise it´s dead.
Airspeed is another factor as well as mixture setting. The faster You fly, the better the cooling. Rich mixture also helps cooling.

Engine failure due to excessive oil temperature:
If oil temperature gets above 100°C, the engine will fail. Again the exact number depends on how fast the temperature is rising.
The reason for failure is that as oil temperature increases, the lubrication effect gets less when too hot. Remember that the quality of the oil used at that time wasn´t as good as lubrication oil is today !
The cooling of the oil is dependent on the same factors as the CHT, though airspeed has a bit more effect, cause oil is cooled by an oilcooler. Cowlflaps has less effect, but is still important for proper cooling.

Shockcooling:
Shockcooling happens when a hot engine get´s cooled too fast. This causes the materials of the engines to be cooled down unevenly, wich leads to cracks.
You might get away shockcooling a number of times, but there is a certain risk that something eventually breaks and the engine fails.
To prevent shockcooling - allways reduce throttle input gradually to let the engines cool down slower, especially when engine temperatures are very high.
Cowlflaps should also be opened gradually.

Sparkplug fouling:
If the engines are run with too few RPM´s, the sparkplugs will gradually be sooted and foul.
You will see that the engines starts to loose RPM and run uneven after some time when RPM is below 1000 RPM.
To clear the sparkplugs - add some power to burn the soot away.
If You don´t do that, then the engine will fail, requiering maintance personel to remove the sparkplugs and clean them (In FSX - Re-load the Catalina)
Assure that when idle, that RPM stays above 1000 RPM !

Carburretor Icing:
FSX's own carburretor icing only occurs very rarely (I think I only have seen it once).
Therefore have we implementet a custom carburretor icing routine.

When air is flowing through the venturi of the carburretor, temperature drops. If the air contains moisture and the temperature reaches the freezing point, ice build-up wil occur inside the caburretor. Also the throttle valve can ice up.

To prevent this, aircraft are equipped with carburretor heat.

On the Catalina carb heating is done by diverting the intake air through a heat exchanger, wich simply is a kind of duct around the exhaust, heating the air.
This can be applied gradually by opening a damper. This way the amount of heated air can be controlled.

On the Catalina there are two switches, one for each engine. These switches controls an actuator that opens or closes this damper.

Carb air temperature is measured in the manifold on the Catalina. The carb air temperature gauge will normally indicate a value close to the outside temperature.
The reason it doesn´t show a lower temperature, after having been cooled in the venturi, is that it is heated again by the compression done by the supercharger. This means that actual temperature inside the carburretor is much lower than indicated on the carb air temperature gauge.

On the Catalina, icing can occur at carb air temperature gauge readings below appr. 26°C.
When outside air temperature is below -5°C then icing will selvdom occur, cause the air will be dry.

Carburretor heat should never bee used during take off, since high carb air temperature also reduces engine power.
Only use carb heat when icing is anticipated.
Icing can occur inside clouds (they are moisture) or when visibility is low (less than appr. 20 km).

By opening the carb heat dampers, the amount of heat can be controlled.
Open them to keep an carb air temperature of about 32°C.

Be aware that the temperature, when using carb heat, will change with engine power setting, cause the air heated by the exhaust becomes hotter.

Power reduction due to excessive carburretor air temperature:
Warm air is les dense and contains less oxygen than cold air. This means that as air gets hotter, engine power decreases.
Checking that the carburretor heater works is infact done bu turning carb heat on and then check that engine RPM drops a bit.
If Carb air temperature gets above 50°C, the engines will certainly start to show this reduced power.
So if You use Carb heat, ensure that carb air temperature doesn´t exceed 50°C.
Also be aware that when power is apllied after the carb air temperaure has been set, will increas - meaning that You need to re-adjust carb heat.

Engine vibrations at certain RPM's:
Not an failure, but still something to be concerned about...
When RPM´s are in the region between 1750-1800 RPM or 2450-2550 RPM, engine resonance will occur on the Catalina.
These are RPM regions that should be avoided by the pilot.

This conludes the failures.