Piper Warrior Carb Heat

[Super 27]

Here's a question for you guys that nobody at my flight school can seem to answer:

What is different about the Warrior versus a C152 or C172 that makes it less susceptable to carb icing? I mean, the green arc on the Warrior's tach goes from basically idle all the way to red line. Yes, it has carb heat, but it's not really used much during normal operations. I'm assuming this is due to some difference in the systems that makes the Warrior less likely to pick up carb ice, but none of us can figure out what it is... I was hoping somebody here might know???

-MG

 

[ParrotheadPilot]

The oil pan on the Piper Warriors is right next to the carb. The warm oil gives off heat and warms the carb so carb ice is less of a problem.

The 152s and 172s have the oil pan in a different part of the engine bay. Since it is not near the carb, it is more apt to get carb ice since there is no heat from the carb.

 

[Super 27]

Thanks, that's what I needed to know.

-MG

 

[erj-145mech]

Also look at the engine air filters, the 172 is on the front of the cowling, able to get iced over very easily, the PA-28's goes thru an "S" duct on the right side, not likely to ice up. The oil pan is the same on all of the Lycoming engined airplanes, the carburetor is bolted to the bottom of the oil pan. Only the Continental engined 172's (145hp) versions are different, but has a similar design as the Lyc's.

 

[JediNein]

The oil pan on the Piper Warriors is right next to the carb. The warm oil gives off heat and warms the carb so carb ice is less of a problem.

Just making sure you caught the 'less' of a problem. On certain days the Warriors would get carb ice in the runup area, usually around 50 F and humid with a long wait before takeoff. I've had more than one student surprised by the drop in RPMs and the even-worse drop in RPMs after applying carb heat.

Fly SAFE!
Jedi Nein

 

[A Squared]

The oil pan on the Piper Warriors is right next to the carb. The warm oil gives off heat and warms the carb so carb ice is less of a problem.

The 152s and 172s have the oil pan in a different part of the engine bay. Since it is not near the carb, it is more apt to get carb ice since there is no heat from the carb.

Nope, not true at all, there is no difference between the oil pan in the warrior and the 152 and 172 (except for very early 172's which had the continental o-300. The lycoming engines in the 152 and 172 all have the carb mounted on the oil pan and the intake tubes running through the sump, just like the warrior. In facrt there is very little diference between the warrior engine and the 172 engine.

 

[nosehair]

Nope, not true at all, there is no difference between the oil pan in the warrior and the 152 and 172 (except for very early 172's which had the continental o-300. The lycoming engines in the 152 and 172 all have the carb mounted on the oil pan and the intake tubes running through the sump, just like the warrior. In facrt there is very little diference between the warrior engine and the 172 engine.

OK, so what makes it different - that carb heat in the warrior isn't recommended except in those highly likely carb ice conditions? I've always wondered that myself. I've heard similar "systems" descriptions which seemed to satisfy it - but what do you think, 'Square?
Is it just a hold-over from the old Continental days?

​

 

[TrafficInSight]

OK, so what makes it different - that carb heat in the warrior isn't recommended except in those highly likely carb ice conditions? I've always wondered that myself. I've heard similar "systems" descriptions which seemed to satisfy it - but what do you think, 'Square?
Is it just a hold-over from the old Continental days?

​

If I had to venture a guess I'd say that it's because the induction air on a warrior spends more time inside the cowling before it gets to the carb than on the 172. On the 172 the airbox is right behind the filter, on the warrior it goes through some tubing before it gets there. Susceptibility to it has more to do with installation than anything on the engine itself.

 

[A Squared]

OK, so what makes it different - that carb heat in the warrior isn't recommended except in those highly likely carb ice conditions? I've always wondered that myself. I've heard similar "systems" descriptions which seemed to satisfy it - but what do you think, 'Square?
Is it just a hold-over from the old Continental days?

​

I don't know what the difference is. I do know that if you put the warrior engine and the 172 engine side by side on engine stands, you probably couldn't tell them apart without reading the data plates. It could be cessna being more conservative in thier instructions that piper, and there's no actual difference, or if there is a real difference, it could be the installation, like "traffic in sight" said. I have a friend who has a Piper PA-12 with a 160 hp O-320 which ices up all the time, even on days you wouldn't suspect of causing ice. My guess is that the installation is the root cause.

 

[erj-145mech]

and there's no actual difference, or if there is a real difference, it could be the installation,. My guess is that the installation is the root cause.

The fuel pump on the back of the accessory case is the big difference between the O-320-D2J (Cessna) and the -E3D (Piper), along with the engine driven fuel pump drive components, that are internal, and not externally discernable.

As stated several times in this thread, the difference in the airframe installation is likely the reason for the cause of carburetor icing probability.