engine alternate air

[ntme9 3]

I decided to fly the mission civil air patrol, and I noticed that the (engine alternate air) switch had no effect in the 3d cockpit of my maule. It would turn/move but had no effect. I had to switch to 2d mode to get it to function properly.

 

Is anyone else having this issue? Is this a known issue?

 

Thanks

[geolpilot 88]

Having the same in the Mooney Acclaim. Can't find a switch in the VC either. BTW what does Alternate Air do, and when should it be on?

 

Rob

[ntme9 3]

Its to combat icing issues, like carb heat for carbureted engines.

[NikkiA 7]

Having the same in the Mooney Acclaim. Can't find a switch in the VC either. BTW what does Alternate Air do, and when should it be on?

 

Rob

 

The way a pitot tube works is that it compares pressure of the air hitting the front of the pitot tube (which is forward facing in the airstream), with a reference 'static' source of air (ie, just the regular outside air pressure, but not moving in the airstream - hence the name static). This is usually done by an air resevoir somewhere on the body of the aircraft, that has a vent to the outside. Because vents tend to freeze over, a second air resevoir is often fitted that becomes the 'alternate static source' or 'alternate air'. I believe the alternate port is usually heated to avoid the vent icing over, but I'm not certain.

 

Anyway, having two static sources in case of the primary freezing is a requirement for IFR equipped aircraft.

[ntme9 3]

Pitot heat does what you are talking about, we are talking about engine alternate air not pitot alternate air.

[n4gix 4,947]

An alternate air door is used to supply an alternate source of induction air to an aircraft reciprocating engine. The engine needs to breath to function. If the air intake were to become clogged during flight (say, bird strike?) a small spring loaded door on the rear side or the Air Inlet Scoop will open. This will draw warm, unfiltered air into the induction system for combustion.

Most aircraft have an automatic spring loaded alternate air door such as the one described above which are opened by the sucking or vacuum force of an oxygen starved engine. Another type which a few aircraft have is manually controlled from the cockpit with a cable linkage. This allows the pilot to select alternate air if needed.

Now, with regards to your actual question, the 2d gauge in the Maule (besides animation) simply toggles on/off the

ANTI_ICE_TOGGLE event. The 3d interior model does not have this switch scripted at all, which is of course why it "doesn't work..." :unsure:

 

BTW, this ANTI_ICE_TOGGLE is simply carburetor heat anyway...

[ntme9 3]

Thanks for the reply, good, its not just my setup. Can we expect this to be corrected in V2.1 ?

[n4gix 4,947]

I have no idea whatever. It wasn't present in the FSX version for that matter. You always have the option to use the keyboard to turn it on and off though: Ctrl-H

[geolpilot 88]

Thanks Bill for your explanation.