Wouldn't you know it. After 20 years of flying and never having this occur during taxi and takeoff (only had it in cruise), I had this very thing happen to me a couple of days ago. Needless to say, it got our attention. As soon as we rotated, it felt like a cylinder was missing, then about 2 seconds running very rough. The funny thing is the runup, including the carb heat RPM drop, was normal and smooth. I figure that it must have formed quickly from the time we taxied onto the runway to the time we rotated due to going to full throttle and the increased air flow/moisture being pumped into the carburetor. Interesting experience. I'll be more mindful of this in the future.
Skystrider wrote:I had an interesting experience Monday afternoon. My friend and I got the plane out about 5:00 pm for a couple practice T & L's. We had not flown for eight weeks because of the weather and the runway conditions. After start up we let it run at about 1400 rpm for a few minutes to warm up and then did a taxi down the turf runway and back checking for soft spots. We then did a run up and everything checked out normal so off we went. The plane accelerated a bit slowly and we took maybe half the runway to get off the ground as opposed to a few hundred feet. I noticed that it was not climbing with the speed it normally does. So I stuck close to the airport and landed. Once again I did a runup and everything checked out. I then held the brakes and did nearly a full power runup to check where the RPM's were. Again, it appeared normal. So off we went again. Same result.
This time however, I was paying such close attention to the instruments that I was a bit high and fast on final so rather than force it, I went around. When I shoved the power in, it responded like it always does and really climbed! So I went around and landed and put her away till I had more time to make checks.
It occurred to me today that I had pulled carb heat on the downwind leg rather than on base/final because I was trying to be more cautious. Maybe there was carb ice that melted and that resulted in the normal power when I went around?
Anybody had any experience with carb ice while waiting for the plane to warm up? Could that be it?