PDA

View Full Version : the use of carb heat when stalling?


green dinosaur
12th Sep 2004, 16:45
Is this advisable whilst stalling, as reaching for the carb heat takes a few seconds prior to SSR- versus, limited time at idle power anyway.

what are your thoughts??

FlyingForFun
12th Sep 2004, 18:35
Two thoughts:

First thought: we are teaching people to recognise and recover from an inadvertent stall. If that happens at low, or idle, power, then the pilot will most likely (hopefully) have the carb heat hot. Setting it to cold must, therefore, be part of the SSR, and must be taught. In the real world, pilots don't say "I might accidentally stall during this descent/approach/turn, so I'll leave the carb heat cold for the recovery". So why should we teach students to leave the carb heat cold when practicing stalls?

The second thought is type-specific, but on the Cessna 150/152/172, it is possible to set the carb heat told cold and the throttle to full power with one movement. Just use the palm of your hand to push the throttle right the way in. As the throttle gets near to being fully open, your palm will reach the carb heat knob and push that in at the same time, therefore not adding any additional time to the SSR. Granted, however, that this doesn't work on other types.

FFF
-------------

skydriller
12th Sep 2004, 19:02
FFF,

Of course other instructors state that the stall exercise is a transient manouver and so leave Carb heat cold.

Ive been told the above by some instructors and your theory by others....and been critiqued for doing whichever is not their prefered method:rolleyes: to which I reply the other answer:p

Other opinions?

Regards, SD..

Gertrude the Wombat
12th Sep 2004, 19:20
I'm sure I was never told about carb heat when pulling power back to idle to practice stalls.

So, without being told anything different, I would naturally have pulled the carb heat as well when told to reduce power to idle.

And, being a 152, when applying power to recover I would have put carb heat back to cold in the same movement, as you say, but personally I'm pretty sure I use the thumb rather than the palm.

I have no recollection of an instructor telling me I was doing this wrong so they must have thought I was doing it right.

nosehair
13th Sep 2004, 20:32
Yes, use the carb heat for stalls (power-off). The technique of pushing the throttle, then the carb heat is an automatic habit response that must be built into the student pilot.
Also, some carburetors will develop ice under the right atmospheric conditions at the instant the throttle comes to idle. Play it safe, always apply the carb heat, even though it may be a little of a bother at times.

DeltaT
17th Sep 2004, 04:00
carb heat on first, all the rest of the other things, as the air speed passes back thru 60knts (light aircraft obviously), put to off