Carb heat + Piper?
 

Im new to the piper. I did all my ppl training in cessna...got a quick one hour checkout on an archer and was told that Carb heat isnt needed on a Piper. Now that its cold outside im curious as to why I dont need to use it?


DC10

Some aircraft's carbs are located in more favorable positions on the engine- in locations where the air entering is warmed by engine heat first (Seminole), while some aircraft are the opposite (Old 182's). However, carb ice can occur in some very warm temperatures, and I'd recommend following whatever procedure is stated in the AFM/POH. Enjoy the Archer!

Cold also doesn't play as much a factor in carb ice as moisture content of the air. Be very careful thinking in this way. The only carb ice I ever had was on a 50 degree day.

Same here. Was a 67 degree day in Phoenix. Unless its a fuel injected Archer you never know if you might need it.

So do you guys use it in we theres a change in power in cold and high moisture days? Or should I just not use it? Does it hurt to use it besides using unfiltered air?

I never used it on the ground unless I noticed a drop then increase in performance during the run up. It's normally quite pronounced at that point. If it was a cool/high humidity day I would turn it on after the run up when I was doing the before TO check list and waiting for departure. Then once I was cleared for TO I would go ahead and turn it off.

I was suprised by this whole theory myself when I came from flying at Purdue, where we liberally used the carb-heat abeam the numbers, until we turned off the runway, to when I taught in C152/C172 where I taught to use it abeam until you were on final(My teaching is this would allow max power available for a go around, and in the time it takes to get to the base-final point, everything should be gone if there was contamination anyways). Then I flew with some "ole" boys in an archer who said you don't need to use it.

Honestly, take it for what it's worth, but I'd at least clear the engine for 30 seconds sometime prior to landing. What's it really hurt? When airborn, you are above move particulate matter that the filters are meant to keep out of the engine, so providing some unfiltered air at or above pattern altitude isn't going to threaten the engine. BTW, there's not a fuel-injected archer that I know of. They are equipped with O-360 lycomings, not IO-360's as the Arrow's are.

You'll run into a lot of "old" teachings out there that aren't necessarily true. Like running a constant speed prop engine "over-square." It's actually better to run them that way, but I digress.

thanks ewfflyer thats helps

You wanna elaborate on that a little more?

Whoa guys. CARB HEAT HAS NOTHING TO DO WITH COLD OAT!

When it's cold outside, the air cannot hold much moisture. You worry most about it when its 50-70 degrees out because that temp air can hold much more moisture than 30 degree air. Also important to note is that carb ice does not have much to do with the venturi in the carb, it has a lot more to do with the heat robbed from fuel atomization. The liquid to gas cooling has a lot of effect on the temp of the air going through the carb.

We were also told a very important story in school about someone who did not understand carb ice. Before taking off in a twin on a very cold day, a guy decides he will use the carb heat before takeoff as a precaution. So what happens is he actually heats the air up to a temp that would cause carb ice, ices up his carb on one side and crashes after takeoff.