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#1
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Carb heat: my new policy. Any comments
Flying a lot of 152s and 172s with carb heat lately. When inbound, I've
been taught to pull the carb heat "on" downwind, hey actually use it as a power control to slow the plane just a bit mid-field, and then more importantly, just leave the thing on till clear of the runway and cleaning up. No matter what the temp, humidity. And to have it on at all times when the RPM is less than the green band. Kind of a preventative. A few times I have been coming in on short final and needed a burst of power due to a sudden downdraft, or needed to pour on a little juice cause my approach was coming up just a bit short. Moving the throttle forward 1/4 to 1/2 inch, i.e. giving it a little juice but certainly not a go around type of thing, often times I would get a stumble, hicuup, drop in RPM'S for 2-3 seconds before the horses responded. Lot of convective turb lately and that power really comes in handy at times on mid to short final. Kind of a shocker when the engine doesn't respond quite nicely. This has happened on a few birds, especially on hot days. I think what's happening is the engine is just too rich, hey I've got the mixture all the way in, it's hot (air less dense), and it's (way) hotter with the carb heat on ( air much less dense), all enriching the mixture, and when I put on a little power the accelerator pump in the carb over-enriches the engine for just a little bit; causing the stumble. Other pilots and the A&P just tell me to pour on the power a little slower. I think I'm going to follow a new SOP. Turn the carb heat off on mid-final. Reasoning: no carb, esp a warm one is going to ice up in 30 seconds, sets me up better for a go-around, and will prevent this stumble business (I did test it out at altitude, and it prevents or at least seriously mitigates the stumble). thoughts? T |
#2
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Carb heat: my new policy. Any comments
"Tman" x@x wrote in message . .. Flying a lot of 152s and 172s with carb heat lately. When inbound, I've been taught to pull the carb heat "on" downwind, hey actually use it as a power control to slow the plane just a bit mid-field, and then more importantly, just leave the thing on till clear of the runway and cleaning up. No matter what the temp, humidity. And to have it on at all times when the RPM is less than the green band. Kind of a preventative. A few times I have been coming in on short final and needed a burst of power due to a sudden downdraft, or needed to pour on a little juice cause my approach was coming up just a bit short. Moving the throttle forward 1/4 to 1/2 inch, i.e. giving it a little juice but certainly not a go around type of thing, often times I would get a stumble, hicuup, drop in RPM'S for 2-3 seconds before the horses responded. Lot of convective turb lately and that power really comes in handy at times on mid to short final. Kind of a shocker when the engine doesn't respond quite nicely. This has happened on a few birds, especially on hot days. I think what's happening is the engine is just too rich, hey I've got the mixture all the way in, it's hot (air less dense), and it's (way) hotter with the carb heat on ( air much less dense), all enriching the mixture, and when I put on a little power the accelerator pump in the carb over-enriches the engine for just a little bit; causing the stumble. Other pilots and the A&P just tell me to pour on the power a little slower. I think I'm going to follow a new SOP. Turn the carb heat off on mid-final. Reasoning: no carb, esp a warm one is going to ice up in 30 seconds, sets me up better for a go-around, and will prevent this stumble business (I did test it out at altitude, and it prevents or at least seriously mitigates the stumble). thoughts? T Shouldn't be a problem, but sometimes it happens. Apply power a little slower. or Carry just a tiny bit of power on final. Sounds like you might be approaching at cut off. or Bump a little power every 15 to 20 seconds to keep the engine clear. Personally I wouldn't cut the carb heat. |
#3
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Carb heat: my new policy. Any comments
On Sep 6, 12:58*pm, Tman x@x wrote:
Flying a lot of 152s and 172s with carb heat lately. *When inbound, I've been taught to pull the carb heat "on" downwind, hey actually use it as a power control to slow the plane just a bit mid-field, and then more importantly, just leave the thing on till clear of the runway and cleaning up. *No matter what the temp, humidity. *And to have it on at all times when the RPM is less than the green band. *Kind of a preventative. A few times I have been coming in on short final and needed a burst of power due to a sudden downdraft, or needed to pour on a little juice cause my approach was coming up just a bit short. *Moving the throttle forward 1/4 to 1/2 inch, i.e. giving it a little juice but certainly not a go around type of thing, often times I would get a stumble, hicuup, drop in RPM'S for 2-3 seconds before the horses responded. Lot of convective turb lately and that power really comes in handy at times on mid to short final. *Kind of a shocker when the engine doesn't respond quite nicely. This has happened on a few birds, especially on hot days. *I think what's happening is the engine is just too rich, hey I've got the mixture all the way in, it's hot (air less dense), and it's (way) hotter with the carb heat on ( air much less dense), all enriching the mixture, and when I put on a little power the accelerator pump in the carb over-enriches the engine for just a little bit; causing the stumble. Other pilots and the A&P just tell me to pour on the power a little slower. |
#4
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Carb heat: my new policy. Any comments
Tman wrote:
Flying a lot of 152s and 172s with carb heat lately. When inbound, I've been taught to pull the carb heat "on" downwind, hey actually use it as a power control to slow the plane just a bit mid-field, and then more importantly, just leave the thing on till clear of the runway and cleaning up. Never heard of this before. I think I'm going to follow a new SOP. Turn the carb heat off on mid-final. Tha't what I've always been taught. Actually, I do it on short final. There will come the day when you need full power for the go-around. Too silly if you then have the carb heat on. |
#5
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Carb heat: my new policy. Any comments
I was taught to push in the carb heat with my thumb while advancing the
throttle for a go-around. "John Smith" wrote in message ... Tman wrote: Flying a lot of 152s and 172s with carb heat lately. When inbound, I've been taught to pull the carb heat "on" downwind, hey actually use it as a power control to slow the plane just a bit mid-field, and then more importantly, just leave the thing on till clear of the runway and cleaning up. Never heard of this before. I think I'm going to follow a new SOP. Turn the carb heat off on mid-final. Tha't what I've always been taught. Actually, I do it on short final. There will come the day when you need full power for the go-around. Too silly if you then have the carb heat on. |
#6
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Carb heat: my new policy. Any comments
"Lonnie" @_#~#@.^net wrote in message
... "Tman" x@x wrote in message . .. Flying a lot of 152s and 172s with carb heat lately. When inbound, I've been taught to pull the carb heat "on" downwind, hey actually use it as a power control to slow the plane just a bit mid-field, and then more importantly, just leave the thing on till clear of the runway and cleaning up. No matter what the temp, humidity. And to have it on at all times when the RPM is less than the green band. Kind of a preventative. A few times I have been coming in on short final and needed a burst of power due to a sudden downdraft, or needed to pour on a little juice cause my approach was coming up just a bit short. Moving the throttle forward 1/4 to 1/2 inch, i.e. giving it a little juice but certainly not a go around type of thing, often times I would get a stumble, hicuup, drop in RPM'S for 2-3 seconds before the horses responded. Lot of convective turb lately and that power really comes in handy at times on mid to short final. Kind of a shocker when the engine doesn't respond quite nicely. This has happened on a few birds, especially on hot days. I think what's happening is the engine is just too rich, hey I've got the mixture all the way in, it's hot (air less dense), and it's (way) hotter with the carb heat on ( air much less dense), all enriching the mixture, and when I put on a little power the accelerator pump in the carb over-enriches the engine for just a little bit; causing the stumble. Other pilots and the A&P just tell me to pour on the power a little slower. I think I'm going to follow a new SOP. Turn the carb heat off on mid-final. Reasoning: no carb, esp a warm one is going to ice up in 30 seconds, sets me up better for a go-around, and will prevent this stumble business (I did test it out at altitude, and it prevents or at least seriously mitigates the stumble). thoughts? T Shouldn't be a problem, but sometimes it happens. Apply power a little slower. or Carry just a tiny bit of power on final. Sounds like you might be approaching at cut off. or Bump a little power every 15 to 20 seconds to keep the engine clear. Neither of which would do anything to prevent potential problems. Personally I wouldn't cut the carb heat. Because flight sim doesn't care either way. |
#7
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Carb heat: my new policy. Any comments
"Tman" x@x wrote in message
. .. Flying a lot of 152s and 172s with carb heat lately. When inbound, I've been taught to pull the carb heat "on" downwind, hey actually use it as a power control to slow the plane just a bit mid-field, and then more importantly, just leave the thing on till clear of the runway and cleaning up. No matter what the temp, humidity. And to have it on at all times when the RPM is less than the green band. Kind of a preventative. A few times I have been coming in on short final and needed a burst of power due to a sudden downdraft, or needed to pour on a little juice cause my approach was coming up just a bit short. Moving the throttle forward 1/4 to 1/2 inch, i.e. giving it a little juice but certainly not a go around type of thing, often times I would get a stumble, hicuup, drop in RPM'S for 2-3 seconds before the horses responded. Lot of convective turb lately and that power really comes in handy at times on mid to short final. Kind of a shocker when the engine doesn't respond quite nicely. This has happened on a few birds, especially on hot days. I think what's happening is the engine is just too rich, hey I've got the mixture all the way in, it's hot (air less dense), and it's (way) hotter with the carb heat on ( air much less dense), all enriching the mixture, and when I put on a little power the accelerator pump in the carb over-enriches the engine for just a little bit; causing the stumble. Other pilots and the A&P just tell me to pour on the power a little slower. I think I'm going to follow a new SOP. Turn the carb heat off on mid-final. Reasoning: no carb, esp a warm one is going to ice up in 30 seconds, sets me up better for a go-around, and will prevent this stumble business (I did test it out at altitude, and it prevents or at least seriously mitigates the stumble). thoughts? T What's going to happen if you actually do have carb ice which hasn't burned off by the time you turn carb heat off? I'd much rather attempt a go around with the carb heat initially on than attempt a go around with the lingering effects of carb ice. I have no idea what DA you're talking about, but what you're describing is trying to correct a problem with the mixture by controlling it with the carb heat. If you're landing at a high DA airport, you shouldn't have the mixture full rich. Setting the mixture on downwind is the solution to the problem. On a 152 or 172 you can also have your hand on the throttle with your thumb on the carb heat. It should be a natural reaction to push both in together or push the carb heat in first on a go around. |
#8
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Carb heat: my new policy. Any comments
On Sep 7, 2:58*am, Tman x@x wrote:
Flying a lot of 152s and 172s with carb heat lately. *When inbound, I've been taught to pull the carb heat "on" downwind, hey actually use it as a power control to slow the plane just a bit mid-field, and then more importantly, just leave the thing on till clear of the runway and cleaning up. *No matter what the temp, humidity. *And to have it on at all times when the RPM is less than the green band. *Kind of a preventative. A few times I have been coming in on short final and needed a burst of power due to a sudden downdraft, or needed to pour on a little juice cause my approach was coming up just a bit short. *Moving the throttle forward 1/4 to 1/2 inch, i.e. giving it a little juice but certainly not a go around type of thing, often times I would get a stumble, hicuup, drop in RPM'S for 2-3 seconds before the horses responded. Lot of convective turb lately and that power really comes in handy at times on mid to short final. *Kind of a shocker when the engine doesn't respond quite nicely. This has happened on a few birds, especially on hot days. *I think what's happening is the engine is just too rich, hey I've got the mixture all the way in, it's hot (air less dense), and it's (way) hotter with the carb heat on ( air much less dense), all enriching the mixture, and when I put on a little power the accelerator pump in the carb over-enriches the engine for just a little bit; causing the stumble. Other pilots and the A&P just tell me to pour on the power a little slower. |
#9
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Carb heat: my new policy. Any comments
"Jon Woellhaf" wrote in message . .. I was taught to push in the carb heat with my thumb while advancing the throttle for a go-around. "John Smith" wrote in message ... Tman wrote: Flying a lot of 152s and 172s with carb heat lately. When inbound, I've been taught to pull the carb heat "on" downwind, hey actually use it as a power control to slow the plane just a bit mid-field, and then more importantly, just leave the thing on till clear of the runway and cleaning up. Never heard of this before. I think I'm going to follow a new SOP. Turn the carb heat off on mid-final. Tha't what I've always been taught. Actually, I do it on short final. There will come the day when you need full power for the go-around. Too silly if you then have the carb heat on. Yeah, same here. |
#10
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Carb heat: my new policy. Any comments
On Sep 6, 9:58*am, Tman x@x wrote:
I think I'm going to follow a new SOP. *Turn the carb heat off on mid-final. *Reasoning: no carb, esp a warm one is going to ice up in 30 seconds, sets me up better for a go-around, and will prevent this stumble business (I did test it out at altitude, and it prevents or at least seriously mitigates the stumble). Don't put any money on that bet. I've had carbs freeze up on me during stop-n-goes from the time it takes to kick off the heat to the time it takes to pour on the coals. The carb can freeze in seconds. -Robert, CFII |
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