Carb Air light on the Corsair...

[DauntlessDriver546]

Just curious... when I am flying my Corsair at high R.P.M.s, a little red light goes off on the panel... says "Carb Air" above it.

Red lights NEVER mean anything good, so how can I run my engine at combat speeds and not have that light come on? I'm worried about destroying my carberator!

:isadizzy:

[bearcat241]

Carburetor heat lamp...Carb air heater that preheats intake air to prevent carburetor icing at higher altitudes. Doesn't mean much at mid and low levels, but if you fly at high altitudes where carb icing effects performance it can lend a hand in keeping the fight on your side.

This virtual heater and its lamp are activated by record 323 in the air file--->>> 1 = Yes and 0 = No.

[DauntlessDriver546]

So it's NOT a problem then... it's just saying that the Carberator is getting heat through it to warm up? I shouldn't worry about it then???

[bearcat241]

No...its just telling you that the heater is active. I would only be concerned about overheating and engine failure if i were flying a 1% air file with the RealityX.cfg file, which are commonly associated with AVhistory 1% planes. Some addons are also built with the 1% workbook and may use the RealityX.cfg, but these are easily ID'd by the presence of the cfg, the AssemblyLineAero"""".xls, and the AssemblyLineDamge"""".xls in the folder.

[Corsair Freak]

BC,

what ever happened to RealityX? Did people not like it because it was too difficult to fly? I only remember flying with realityx enabled once, in a P-47, and I couldn't keep my engine from over-heating. The cfg files look fairly simple to make.

CF

[bearcat241]

Can't speak for the gang, but its not my stick Junior :d. Like you, i couldn't be bothered with the hassle. The good news is that those text formatted X files are completely customizable to whatever failure tolerances the user wants to put up with.

[Tango_Romeo]

....flight sim panels have a manual Carb Heat switch. However, Carb Heat is an essential in everyday operation of real world aircraft. Carb Heat is engaged for takeoff and landing, and will result in a slight loss of RPM...about 100 RPM in a light plane. Carb Heat is needed on takeoff and landing because even in hot humid weather the air being compressed through a carb gives off heat and becomes quite cold, which causes it to release moisture that can actually freeze-up in the carb because of the very cold air, or add water to the fuel/air mixture. I was always taught by my old flight instructor to use Carb Heat on takeoff and landing as a matter of course. You might not need it, but it sure won't hurt. :d

The principle of compressed gas giving-off heat and decompressed gas absorbing heat is how heat pumps and airconditioners work in your home and car. Compressed Carbon Dioxide in cans is often used as a local anesthetic, as when it is sprayed from a can onto the skin surface it absorbs enough heat to temporarily freeze the area and deaden feeling. :kilroy:

[Pops]

DD546,

I am not sure how the warning light is modeled in CFS2, but on the real Corsair, Carb Air Temp warnings indicated over boosting. The Corsair had a manual "blower" (Super Charger) and if the wrong speed was selected the air sent to the carb would be too hot. I think the second line of the warning plackard said something like "Shift to lower Blower".

[Dirtman]

Whereas I'm not a "real world" pilot (like Tango) I have been an auto mechanic & instructor for the past 35 years. This has an automotive application on older engines equipped with carburetors.

It's termed the "venturi effect". As the air moves through the carb venturi; (a narrow section) it is compressed. As it leaves this area (to a wider section) the air expands which causes a pressure decrease.

The pressure decrease is what causes the fuel to be drawn through the discharge nozzle(s) and then enter the airstream below the venturi. This also causes a temperature drop; which even in moderately cool conditions can cause ice to form in the barrel(s) of the carb resulting in loss of power or even complete stalling of the engine caused by the lack of the necessary air-fuel mixture ratio due to the restriction or blockage of the "low speed" fuel discharge port(s).

If you look at a carb equipped car; (generally built after 1967 thru to the early 90's) you'll see a 1"-2" tube running from the exhaust manifold up to the snout (intake) of air cleaner assembly. Hot air is collected from a tin shield around the exhaust manifold. (this occurs quickly once the engine is started)

Where the tube joins the air cleaner there is a small vacuum operated & temperature controlled valve (flapper) which allows the hot air to be drawn into the carb (while preventing the introduction of unheated outside air) depending upon the intake air temperature that is sensed by a temp. switch located (generally) on the underside of the air cleaner assembly.
This is the function of all those vacuum hoses on the air cleaner assy.

This was often the cause of stalling & performance complaints when the system did not function properly. The vacuum controlled servo usually developed a split diaphragm; the tube was missing or the tin shield had rusted away & fallen off. This did not allow the hot air into the air cleaner - causing carb icing.

If the valve got stuck in the applied position this can result (particularly in hot weather) in "pre-ignition" commonly called "pinging". (this is only one of the many causes of pinging)

In this instance; the incoming air is too hot which causes the temperature in the combustion chambers to exceed the design parameters, resulting in the "pre-ignition" of the air-fuel mixture before the spark plug ignites it.


I was unaware until today of the aircraft applications. I can now fully understand why a heater is used on both takeoff & landing. Two instances where loss of power could really cause you to have a very bad day.


I thought I would add the auto application here as we are heading into the winter months (in the northern hemisphere) & many people still drive carb equipped vehicles which are prone to this problem.

Personal experience has shown that many so-called "good mechanics" completely miss this problem & only discover it after performing other costly and possibly unneeded repairs.

"Backyard" mechanics are generally completely unaware of this problem.


Many Thanks to Tango for his aircraft oriented explanation & to DD for originally posting this thread.

EXCEPTIONAL THREAD DD!!! :medals::medals::medals:
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[Tango_Romeo]

DD546,

I am not sure how the warning light is modeled in CFS2, but on the real Corsair, Carb Air Temp warnings indicated over boosting. The Corsair had a manual "blower" (Super Charger) and if the wrong speed was selected the air sent to the carb would be too hot. I think the second line of the warning plackard said something like "Shift to lower Blower".

...for that information. It makes sense, as internal combustion engines love cold, dense, oxygen-rich air. This seems the best explanation of the warning light. :kilroy: