Thanks for the tip step. I had never thought about it, as this is the first carbureted plane with a constant speed prop that I have had any experience with. Carb temp gauge is now on my list of upgrades to be made.

In our '55 180 with a J engine I get a rpm drop when checking carb heat. Why would one have a drop in rpm, and not anothier? Not much expierence here but had carb ice once while loffing around at lower power setting and noticed the rough running engine pretty quick. I applied full carb heat and it cleared up in 15 or 20 seconds. Why would you only us 1/2 carb heat?
Thanks, still learning 46tcrft.

One of the more useful additions is a carb temp gauge

Personally I like carb ice detectors. Not horably expensove and let you know early if/when ice is forming.
gary

46TCRFT wrote:In our '55 180 with a J engine I get a rpm drop when checking carb heat. Why would one have a drop in rpm, and not anothier? Not much expierence here but had carb ice once while loffing around at lower power setting and noticed the rough running engine pretty quick. I applied full carb heat and it cleared up in 15 or 20 seconds. Why would you only us 1/2 carb heat?
Thanks, still learning 46tcrft.

Perhaps the carb heat design is different. Mine is a 1967 model. Don't know why they would have made it less effective... About my fourth landing in my 180, after descending from about 13000 ft, I was on short final with winds gusting to 30 in Ely Nevada, when I added power to arrest a high rate of descent and the engine fell flat on it's face. I had carb heat on, and it came back to after about a half second of full throttle.

MTV, what is the flap setting clue in the video? I looked at the shadow before touch down, and didn't see any discontinuity on the trailing edge. That is all I can imagine that you are referring to.

I missed the flap clues too. If the flap handle is where I think it is, he didn't have any, or something hit the handle at impact. Is it an illusion, or did the mains never touch? the divot looks like a nose wheel landing, snap, flip. Even given a do-over, I don't think you can not flip in that much crusty snow.

Just to underscore the importance of a carb air temp. instrument in 182's I will add my comments.
Many of the JP instruments can read the temp too, but I notice some of my students either don't know how to get to that data or pay no attention.
Another caution to throw out there: Out of many many students I have asked to do a ground carb heat check, none have done anything but the standard pull the knob... listen for the drop and shove it back in. On to the next item on the list. So what is WRONG with what all CFI's teach. If you pause for a moment after turning off the carb heat, to see if the RPM returns to where you began.... or possibly returns to a HIGHER setting.. you may get a clue that there is already ICE in the throat while taxiing.
The small amount of heat you applied for a quick check is just enough to melt the surface and probably make things worse. On climbout... you may have a power loss and not enough time to melt it before the unplanned touchdown. It is pretty easy to modify the check. PULL HEAT, WAIT, PUSH HEAT, WAIT.
READ THE RPM. Simple... Good luck out there guys.
(oh.... the obvious.... if you have found some ice, heat it for a while, fully... before takeoff)

I'm not familure with a cessna 175. Do they have cowl flaps, and if so is the control in the open position? Also which control is the carb control and what position is it in. Maybe I should not be asking this. It's easy for us to anilize a forced landing from a key pad. I think the pilot did a good job, as my CFII tells me "fly the airplane first, don't stall it".
46tcrft

No cowl flaps on a 175. Basically a 172 with a geared engine, though this one had a Lycoming conversion.

MTV

Your 180 won't have rpm drop during run-up because of the constant speed prop.

Disagree. I've flown many carbed 182s from 1958 through 1979 models, my P172D has a CS prop and carb, and I've always gotten an rpm drop. At 1700-1800 rpm, the governor won't manage the rpm.

The problem, as flightlogic pointed out, is that many pilots don't test for carb ice--they only test whether the carb heat works. To test for carb ice, you have to leave the knob out long enough for any ice which accumulated during the taxi to melt out. The rpm will drop, then increase as the ice melts, and when the knob is pushed back in, the rpm will be higher than the original run-up rpm.

Cary

Cary wrote:

Your 180 won't have rpm drop during run-up because of the constant speed prop.

Disagree. I've flown many carbed 182s from 1958 through 1979 models, my P172D has a CS prop and carb, and I've always gotten an rpm drop. At 1700-1800 rpm, the governor won't manage the rpm.

Cary

Cary is right on here. You will/should get a drop.

I too am skeptical about the carb ice thing. I was flying the same time that same day not 10 miles north of here. With lots of time in 182s, and until recently it being my primary ride, I'm always thinking of carb ice. This day was not one that was made my Spidy senses go off.

As another post said, that nose is coming over fast and hard regardless of elevator authority. I too will always opt for the slower touchdown speed.

I was going to let that one go... but my CFI conscience got to me right after Cary's post.
Any constant speed prop flyer will know that the governer is not effective at those low power settings.
Otherwise, we would still have 2400 rpms on landing...
A normal runup at about 1700 to 1800 rpms will show the drop during carb heat application... which by the way simply changes the mixture. The crucial thing as I mentioned though... is to leave it out long enough on critical temp days (and that means the temp in the carb throat, not the air temp) to melt any ice.
Another sticky point is runup after taxiing lean. If you are lean enough to taxi... you probably are too lean to do a proper runup. Either the engine will stumble when you add throttle much past idle, or just die. If you richen just a bit... you might get to 1700 rpms, but then your mag drop seems excessive. Just richen some more for the moment and try again. Lean again until you actually get to the hold line for takeoff. Then set for takeoff. All of this can act quite strangely if ice is present. The 180/182 with that cold carb hanging way down there is the worst of the bunch. Carb air temp gauges are cheap.
Don't fly without one!