Is carb heat really necessary when 80F?

[Racerx]

You mean like FADEC stuff? It's here, it's just not retrofitted to our 1930s era engines.

Lycoming's ie2 is still a 540. Twin turbo, single lever, push button start. It's retrofitted to the engines...just no STC for the type certificate. Would love to see them drop the turbos and somebody come up with the STC for an engine swap. Even runs on unleaded.

 

[noahfong]

Might want to double check your math there

Ouch! You're so right! Mea Culpa.

 

[David Megginson]

How much does pulling the carb heat really hurt on every descent...like the POH says? How much time does it take? Should be reading a checklist so you shouldn't forget. It should be second nature. Like getting in and buckling up. If you don't fully grasp the how or why that's fine, just defer to the checklist. The air compressor analogy was one that resonated with me. Dump all the air through a tiny orifice at high pressure and it will ice up. I work well with real world application stuff over the theoretical. Makes me think less when Ive seen it happen and now I understand the why it happened.

I think the concern is forgetting to turn the carb heat off again before advancing the throttle in a go-around. Some POHs recommend carb heat for every low-power descent (which makes sense for something like the Continental O-200 ice machine in the Cessna 150, for example), and others recommend using it only when you have reason to suspect carb icing (e.g. in the Piper PA-28 with a Lycoming O-320). I think each manufacturer does their best to balance the two risks. Like you wrote, follow whatever the POH says.

 

[samiamPA]

Exactly, the answer to the question is simple - follow the POH, which follows the physics/math.

Look at the percentage of Cessna 150 accidents attributable to carb ice, then decide if it's "worth it" or not to pull the knob when the power is less than 55%.

 

[MBDiagMan]

The best solution is a quality carb temp instrument. My 140 has one and my C model Mooney had one. If it showed in the yellow when on downwind, I pulled carb heat when I chopped power abeam the numbers. Works great!