Carb heat, while enroute

[JoeSelch]

Every R-22 runs at least partial carb heat at ALL times!

Are you speaking of R22s with an O-360 (which are equipped with a correlated carb heat assist)?
The pilot may override the assist as desired.

So, it's not "every" R22. Nor is it "ALL" the time.
Still, it's there in some. And a welcome feature, as carb ice in a helicopter is rather intractable.

 

[Dan Thomas]

If you need carb heat in cruise, it will cost some powere even if leaned. But that's no different than cruising much higher, in which case we open the throttle more to account for the thinner air, so do that when using carb heat, too. When the air is that thin, and that cold to start with, detonation is no threat because you can't get high enough cylinder pressures or high enough induction temperatures.

 

[petrolero]

With my turbo I regularly see carb temps in the 20 to 30 C range even when OAT is way below freezing. So "carb heat" is pretty much a constant for me.

 

[Caramon13]

I would say it "depends". While I agree with everyone's assessment about WHEN carb heat may be necessary, my POH expressly says that while it's ok to use it, it should be used off and on, not left on (unless conditions are severe enough for it).

Specifically: "Unless icing conditions in the carburetor are severe, do not cruise with the heat on. Apply full heat slowly and only for a few seconds at intervals determined by icing severity".

I never use it at full power due to the possibility of detonation.

And of course, if icing is that big of a problem anyway, why are you flying at that altitude or at all?

 

[petrolero]

I'd use it in IMC and when T/D spread is low.

 

[hindsight2020]

I would say it "depends". While I agree with everyone's assessment about WHEN carb heat may be necessary, my POH expressly says that while it's ok to use it, it should be used off and on, not left on (unless conditions are severe enough for it).

Specifically: "Unless icing conditions in the carburetor are severe, do not cruise with the heat on. Apply full heat slowly and only for a few seconds at intervals determined by icing severity".

I never use it at full power due to the possibility of detonation.

And of course, if icing is that big of a problem anyway, why are you flying at that altitude or at all?

Um, because Carb icing also occurs in conditions otherwise not conducive to structural or induction scoop icing? By your logic, in the continental US , carb engines shouldn't fly 3/4 of the year to include summer.

I don't agree with your logic, but I do happen to agree with the spirit of what you attempted to convey, which is why I now fly behind an injected engine and not going back.

I don't consider carb icing blasphemy as a generality, but I do consider the occurrence of carb icing in a full operating temperature engine at WOT where the conditions are not conducive to structural icing, an unacceptable condition to have to monitor and compensate for. So I fly FI.

 

[kgruber]

Are you speaking of R22s with an O-360 (which are equipped with a correlated carb heat assist)?
The pilot may override the assist as desired.

So, it's not "every" R22. Nor is it "ALL" the time.
Still, it's there in some. And a welcome feature, as carb ice in a helicopter is rather intractable.

Good to hear they have fixed that. The R22s I flew were strictly manual carb heat.

 

[Dan Thomas]

And of course, if icing is that big of a problem anyway, why are you flying at that altitude or at all?