Flying in Cold Temperatures

[mrose]

Yeh got lucky, the temp was only -18F instead of the -30 predicted but the winds were 16 -20 kts. We had two r22's flying this morning and noticed some additional vibrations with them. I don't know if it would be the teetering hinge getting a little stiff or what. Also we were looking in the ASA pilots guide on the r22 (the poh didn't have any info on it) and it states "care should be taken when flying in extremely cold ambient conditions, below -10C. In these conditions the use of carb heat may actually raise the temperature in the carburetor to that most conducive to carburetor icing". This sounds like good info that should be in the poh. Still seems like a mystery "to use or not to use carb heat!"

 

Ironranger

 

On carb heat Mr. Robinson relates to an incident where 2 ships made engine-out forced landings right next to each other, later to be determined due to carb ice @ about +40F in ice perfect conditions. This made a light go on in his mind, lets add an inlet temp gauge (30 years after Hiller and Bell determined this) and many unsolved R-22 crashes were now solved. (the 22 carb also hangs in the breeze to cool Vs others).

 

Remember, the lower the outside temp, the lower the humitity and less chance of carb ice. The sweet spot seems to be about 40-50F but up to 70! on humid days as the temp drop in the venturi is the culprit. A fixed wing has a nice prop to keep things spinning and choking for a warning. A helicopter engine has no extenal stored energy direct connection to keep it tuning - it just fails. The FAA has info on this. We flew Alouette turbines in -55. We had a Gazzelle crash in -54, hyd lockup so they made us stop flying @ -41F&C. A good turbine is the perfect low temp heli motor. You have good questions and I could be corrected, which is good for all.

 

Kind regards

 

Mark