Should I lean mixture while using carb heat?

[KarelPatch]

Hi,
Since mixture rich will cool engine (right?), in case of severe carb icing should I lean my mixture while applying carburetor heat?
In the manual if I remember correctly, it says that in case of icing during low RPM operations I should put the mixture to full rich while applying carb heat.

Thanks a lot.

[Jacques]

The first step in most cases I think would be to apply carburetor heat.

I think I also recall the A2A manual mentions if you are in a low RPM operation (I assume that means descending or landing) increasing manifold pressure and applying carb heat while also enriching the mixture if carb ice is suspected!

[flapman]

Well now THIS is really strange

My (FSX) installation of the T-6 did not include the Manual!
I've just downloaded it... let me check (I've never read the manual in the years I've been flying it )

[KarelPatch]

The first step in most cases I think would be to apply carburetor heat.

Absolutely. But if it isn’t enough, would leaning be helping?

[KarelPatch]

Well now THIS is really strange

My (FSX) installation of the T-6 did not include the Manual!
I've just downloaded it... let me check (I've never read the manual in the years I've been flying it )

Definitely read it, it’s great.
A2A manuals are always really extremely well written and presented.

[flapman]

I found the passage, it only mentions this regarding "low RPM operation." The note about the mixture (it says enrichen not go full rich) is immediately preceded by the instruction to increase manifold pressure and RPM, so my assumption is that the enriching of the mixture is to promote smooth operation (especially considering the engine is about to ingest ice).
That's my best guess for now.

[Jacques]

I “think” carburetor icing can occur anytime conditions allow for it, so according to a T6 manual: carburetor mixture temps of -10C to + 3C and/or free air temps of +4 to +8C and low power or cruise settings are the conditions when ice will form more readily. So using higher power settings when you suspect icing may occur will reduce the chances of it occurring. When I hear the engine begin to slow and lose MP, I use carb heat and it clears quickly.

[KarelPatch]

I “think” carburetor icing can occur anytime conditions allow for it, so according to a T6 manual: carburetor mixture temps of -10C to + 3C and/or free air temps of +4 to +8C and low power or cruise settings are the conditions when ice will form more readily. So using higher power settings when you suspect icing may occur will reduce the chances of it occurring. When I hear the engine begin to slow and lose MP, I use carb heat and it clears quickly.

I 100% understand this.
But now imagine you are flying at low power in carb icing conditions and you forget to use carb heat (big mistake!) Your plane starts to loose power and when you notice it less than a minute later you go full throttle + full carb heat with no immediate effect. You need that motor power back fast because the ground isn’t very far now. Usually in modern planes leaning would help warming the engine faster, but I don’t know about the T-6...

[Oracle427]

Leaning does nothing significant to help with carb icing. The temperature of the cylinder heads and exhaust gas is not going to directly affect the temperature of the fuel/air mixture passing through the carburetor throat. The water vapor in the caburetor throat will condense and freeze under the right conditions.

The T-6 has a carburetor temp gauge and you can use it to maintain a continuous and appropriate amount of carb heat during cruise to ensure carb icing does not develop.

[Jacques]

I see your point, but won’t leaning the mixture also take away from the power you now desperately need? Heat generated by using a lean mixture is generated inside the cylinder, the lack of excess fuel removes any cooling that happens due to excess fuel in the combustible mixture, but I’m not sure how that is going to help when you need warm air to melt ice inside the carburetor?

Coming in late sgain!!

[Oracle427]

Why would it take away power if the act of adding in carb heat has made the intake air density lower and already enrichened the mixture? In order to regain lost power it is now necessary to lean.

This of course assumes that one was running rich of peak and not lean of peak in cruise.

[Jacques]

Thanks Oracle, that’s a good point that I didn’t consider. I got lost in the urgency of regaining power, so I would have left some available power on the table...and probably suffered for it!

[KarelPatch]

In order to regain lost power it is now necessary to lean.

Ok, so there is at least something to do with leaning to regain power? Do you know in what order? Carb heat and leaning at the same time?
I’m trying to find the solution to something that happened to me and a friend flying the T6 in multiplayer yesterday. We had a rainy weather and just after takeoff we began flying slow to try doing some formation flight. Stupid idea. After only 2 minutes I got a complete power loss and basically died. My friend had a power loss 30s later and was able to land back to the runway.
We didn’t use carb heat. When back on the ground I did a complete overhaul and my fellow pilot did try the carb heat but our motors just stopped in the end.

I was wondering:
- what is the fastest way to heat the carb?
- is it possible that our carburetors were iced beyond the point of no return and the only solution was to let the planes a few hours in the hangar? Or what would be the solution in real life to get rid of the ice on the ground? Sorry I’m not a mechanic as you can guess


Thanks

[AKar]

Ok, so there is at least something to do with leaning to regain power? Do you know in what order? Carb heat and leaning at the same time?

You'd probably apply carburetor heat as required, and if necessary, then lean to regain the power lost.

- what is the fastest way to heat the carb?

Full carburetor heat. In theory, if the engine has already quit firing (that is, you're screwed already), pulling mixture to cutoff while windmilling can allow for the ice to melt. But in all realistic situations, your mind should probably be on forced landing and normal loss of power things, not on tricks.

- is it possible that our carburetors were iced beyond the point of no return and the only solution was to let the planes a few hours in the hangar? Or what would be the solution in real life to get rid of the ice on the ground?

Well, if the ice in the carburetor is the reason for hangaring, the airplane would in all probability come there on a truck bed, most likely in more or less mangled condition. By the time the mechanics get a look on it, the ice would have melted already. More seriously, I'm not aware of single instance where carburetor icing would have taken actions on ground to get removed after a successful landing. 'Usual amounts' of carburetor ice melt very quickly after the engine has been shut down. It is, after all, quite warm under the cowl when everything inside there seek their thermal equilibrium. This is also why all reported engine issues that remain unexplained after a technical inspection are typically attributed to carburetor icing, if the circumstances were at least somewhat fitting.

-Esa

[KarelPatch]

Thank you Esa this is super clear, and thank you all for these very instructive answers