I've been flying a PA-18-180 and now I've purchased a PA-18-160....I'm just wondering how critical it the usage of carb heat on the smaller 160 hp engine??? I know the 180 produces enough heat and you basically dont need carb heat......so, how prone is the 160hp to carb icing?? Thanks for any help.
carb heat usage
- Thread starter FlyingY
- Start date
irishfield
Registered User
Penetanguishene, Ontario Canada
FlyingY said:
That belief, and 5 gallons of fuel to get you airborne, will get you killed sooner or later.
ambient temperature and dew point don't care what type or size engine you are using...
had a Chevrolet car that formed carb ice when temp and dew point were conducive.... I would have to stop, shut engine down and let engine/manifold heat melt ice before going again.. Should have seen the look on the GM mechanic's face when I told him... He couldn't comprehend carb ice...
Not a trained pilot obviously...
Treat icing as a probability and not a possibility..
tj.
had a Chevrolet car that formed carb ice when temp and dew point were conducive.... I would have to stop, shut engine down and let engine/manifold heat melt ice before going again.. Should have seen the look on the GM mechanic's face when I told him... He couldn't comprehend carb ice...
Not a trained pilot obviously...
Treat icing as a probability and not a possibility..
tj.
cubpilot2
SPONSOR
Anchorage Alaska
I like the quote someone said on this forum last year... When you find yourself flying along with nothing to do.... pull carb heat.
I started following this advise last year after encountering severe carb ice during a "nice summer day" north of Anchorage. Going to the cabin with a load of freight. 55 deg day and no visible moisture. Everything was normal (no loss of rpm etc) Started to gently throttle back from level cruse and the engine started to pop/backfire. It got worse as I tried to add throttle back. Luckily I had the lake made as I was loosing altitude fast. Engine nearly died when flaring out. I was actually afraid to pull carb heat as I thought it could have gotten worse before clearing up and didn't have a lot of altitude to work with. (don't know if this was the right thing or not). Anyway this cub had not done this at anytime in the 14 years that I have owned it, and hasn't sense. I was a bit complacent about carb ice as I've flown in tons of "visible moisture", cold temps etc without any problems. I am now a believer in "anytime - anyplace!
Would be interested to know of experiences of how an engine acts with heavy carb ice when you pull the carb heat.
I started following this advise last year after encountering severe carb ice during a "nice summer day" north of Anchorage. Going to the cabin with a load of freight. 55 deg day and no visible moisture. Everything was normal (no loss of rpm etc) Started to gently throttle back from level cruse and the engine started to pop/backfire. It got worse as I tried to add throttle back. Luckily I had the lake made as I was loosing altitude fast.
Engine nearly died when flaring out. I was actually afraid to pull carb heat as I thought it could have gotten worse before clearing up and didn't have a lot of altitude to work with. (don't know if this was the right thing or not). Anyway this cub had not done this at anytime in the 14 years that I have owned it, and hasn't sense. I was a bit complacent about carb ice as I've flown in tons of "visible moisture", cold temps etc without any problems. I am now a believer in "anytime - anyplace! Would be interested to know of experiences of how an engine acts with heavy carb ice when you pull the carb heat.
B
bearsnack
On the 160 cub your exhaust and intake filter setup dictates how much ice you build up. I have heard alot of round filter guys say they build it up a lot. My square filter intake hardly builds it at all, but I still use carb heat.
After market exhaust systems do not have as much heat retention in the muffler shroud/ or they have a longer distance to pipe the heat resulting in heat loss (depending on which system you have).
In any case, every engine is a little different in how it builds ice, and it is never fun when you discover you didn't use enough on short final.
Happy New Year! keep the ice in your glass and not in your carburetor.
After market exhaust systems do not have as much heat retention in the muffler shroud/ or they have a longer distance to pipe the heat resulting in heat loss (depending on which system you have).
In any case, every engine is a little different in how it builds ice, and it is never fun when you discover you didn't use enough on short final.
Happy New Year! keep the ice in your glass and not in your carburetor.
Ruidoso Ron
Registered User
Alto, NM
cubpilot2 said:
Ed, that's like the one that they taught us about when to use continuous ignition on the PT6.........
1) In heavy precip,
2) In heavy turbulance, or
3) Whenever it makes you feel better.
Greg Smith
Registered User
Merritt Island, FL
In the J-3 I frequently cycle the carb heat, but the Continental 65 is a notoriously efficient ice maker. The bigger Lycomings mount the carb to ~and route the intake through~ the oil sump (Hotpoint or Hotspot induction, something like that), which warms things up a bit, but not enough to prevent ice accumulation in all scenarios.
Like when you are descending for a long time with the throttle nearly closed, the prop windmilling and acting as a brake. The exhaust cools, and the pistons are sucking lots of air past an almost closed throttle plate. Two old dead guys appear here, named Bernoulli and Charles. Bernoulli says as velocity increases, pressure decreases, and Charles says for a given volume, a decrease in pressure causes a proportional decrease in temperature. Like Bearsnack said, that can make things exciting on short final.
Bearsnack, regarding the round vs. square filters, are you just referring to "impact" ice at the filter, or accumulation in the carb due to Charles law and fuel evaporation cooling? Pulling carb heat will help in the former, but not by melting the ice like it does in the latter. It just allows induction air to be provided form an alternate source, bypassing the clogged filter.
Like when you are descending for a long time with the throttle nearly closed, the prop windmilling and acting as a brake. The exhaust cools, and the pistons are sucking lots of air past an almost closed throttle plate. Two old dead guys appear here, named Bernoulli and Charles. Bernoulli says as velocity increases, pressure decreases, and Charles says for a given volume, a decrease in pressure causes a proportional decrease in temperature. Like Bearsnack said, that can make things exciting on short final.
Bearsnack, regarding the round vs. square filters, are you just referring to "impact" ice at the filter, or accumulation in the carb due to Charles law and fuel evaporation cooling? Pulling carb heat will help in the former, but not by melting the ice like it does in the latter. It just allows induction air to be provided form an alternate source, bypassing the clogged filter.
B
bearsnack
Eddy,
I am referring to ice in the carburetor itself. Its funny that this thread came up because it is just in the last few weeks I have been gathering this information from different cub owners.
It may have something to do with the round filters ability to breathe better, allowing a more favorable condition for icing. Purely speculation on my behalf
I am referring to ice in the carburetor itself. Its funny that this thread came up because it is just in the last few weeks I have been gathering this information from different cub owners.
It may have something to do with the round filters ability to breathe better, allowing a more favorable condition for icing. Purely speculation on my behalf
Greg Smith
Registered User
Merritt Island, FL
Interesting... I'd be interested to know what you find out. It is tickling the back of my brain that the folks on floats were talking about the round vs. square filters awhile back. I can't remember the particulars, whether it is pertinent or not. Gotta go now, but will search tomorrow.
Lowflybye
Registered User
Mount Juliet, Tennessee
I have started to pick up carb ice many times in the PA-18-160 that I used to fly, especially if flying during the humid Memphis summers right after a rain. Carb heat is your friend and pulling it anytime you are not doing something is a good idea.
Earlier this fall while doing some low level river flying in the Maule (O-360) I picked up some carb ice while climbing out of the river over the ridges and forest. This will get your attention in a hurry when you are not equipped with floats and have nothing but trees or water for a few miles.
The outside temp was around 78 degrees and I had been cruising around pretty slowly at 2,500 ft without carb heat and had no trouble. I had throttled way back to slowly cruise the river and enjoying the late afternoon flight. My mistake was that I did not consider the temp /dewpoint spread 10 feet above the water and when I throttles up to climb out my RPM began to drop. I immediately reached for the carb heat and the power returned within a few seconds. Those few seconds seemed like an eternity and I should have known better.
Lesson learned and easily remembered...I won't make that mistake again.
-Chris
Earlier this fall while doing some low level river flying in the Maule (O-360) I picked up some carb ice while climbing out of the river over the ridges and forest. This will get your attention in a hurry when you are not equipped with floats and have nothing but trees or water for a few miles.
The outside temp was around 78 degrees and I had been cruising around pretty slowly at 2,500 ft without carb heat and had no trouble. I had throttled way back to slowly cruise the river and enjoying the late afternoon flight. My mistake was that I did not consider the temp /dewpoint spread 10 feet above the water and when I throttles up to climb out my RPM began to drop. I immediately reached for the carb heat and the power returned within a few seconds. Those few seconds seemed like an eternity and I should have known better.
Lesson learned and easily remembered...I won't make that mistake again.
-Chris
flynlow
FRIEND
Fowler, Ks
Cubpilot2
I think you did good.
Back in the late 70's I was flying a C150 and pulled power and carb heat to do some slow flight and stalls. The temp was 6 degrees F and the engine quit cold after sounding like a snow cone machine. I picked a decent looking field and dove at almost Ne to speed up the fan and got a restart.. Went back up and tried it again, same thing, lost a couple thousand feet each time before it got noisy again. Tried pulling carb heat on the way back to the field with full power and you could hear the ice going through the engine each time so I left it full on. There was no visible moisture and it was very cold.
I believe if you would have pulled carb heat in your situation you would have likely put the fire out.
I think you did good.
Back in the late 70's I was flying a C150 and pulled power and carb heat to do some slow flight and stalls. The temp was 6 degrees F and the engine quit cold after sounding like a snow cone machine. I picked a decent looking field and dove at almost Ne to speed up the fan and got a restart.. Went back up and tried it again, same thing, lost a couple thousand feet each time before it got noisy again. Tried pulling carb heat on the way back to the field with full power and you could hear the ice going through the engine each time so I left it full on. There was no visible moisture and it was very cold.
I believe if you would have pulled carb heat in your situation you would have likely put the fire out.
Greg Smith
Registered User
Merritt Island, FL
Heck, I never learned it from the (early) twentysomenting instructor I had when I got my private 18 years ago. He was just building time at my expense. Looking back, several things he did or allowed me to do could have gotten us killed. It wasn't until later, when I transitioned to a plane with the third wheel on the correct end, that I really began learning how to fly. An wise "old" recovering alcoholic in a Citabria taught me what to do, why, and what would happen if I did otherwise.T.J. said:Do the Instructors today teach this?
Speaking of pulling on knobs, WHY did Bellanca tuck the identical looking front vent and parking brake knobs together under the right side of the instrument panel!?!? That was an exciting landing for a brand new taildragger pilot. Pissed off a bunch of folks in the pattern too when I couldn't get the Decathlon off the runway...
Lowflybye
Registered User
Mount Juliet, Tennessee
Eddy Current said:Heck, I never learned it from the (early) twentysomenting instructor I had when I got my private 18 years ago. He was just building time at my expense. Looking back, several things he did or allowed me to do could have gotten us killed. It wasn't until later, when I transitioned to a plane with the third wheel on the correct end, that I really began learning how to fly.T.J. said:Do the Instructors today teach this?
AMEN!!!
I learned more about flying during my tailwheel instruction from some seasoned tailwheel pilots than I ever learned from a "flight school". My PVT pilot instructor did not know much more about carb ice than it was a knob to pull when entering the clouds or pattern for landing. Carb heat was one of the issues that I learned on my own and from other pilots for the most part. I have spent so much time in recent years flying fuel injected motors that I find myself getting complacent or simply forgetting to pull the carb heat when I fly carbureted...hence the river flight scare. I knew I should be pulling heat ever so often just for good measure, I just got complacent.
-Chris
mvivion
SPONSOR
Bozeman,MT
TJ,
Well said. Seems like a lot of today's pilots act like they are getting charged extra to use carb heat.
I'm with you--pull carb heat on every once in a while, and it'll make your flying a little less exciting at times.
My rule in Kodiak was apply carb heat every time I passed over a bay. That worked out to every five or so minutes in a Cub.
I can't speak for other CFI's, but I sure teach carb heat use.
I doubt that you'll fail the engine with melting ice, but it will certainly sound like it's quitting for a while.
One thing that I emphasize in engine failure drills with students is to get carb heat on RIGHT AWAY, unless you are 50 feet off the ground after takeoff, in which case landing is what should be foremost on your mind.
Switching fuel tanks right away starts getting fuel to a fuel starved engine, so that's an immediate action item, but carb heat is too. Carb heat comes off the muffler shroud. That shroud has cool air moving through it all the time, to prevent overheating.
If the engine fails due to carb ice, and you wait for any substantial period of time (and I don't know what that time period is) you may not have enough residual heat left in that shroud to melt the ice. Note that the manufacturer's certification standard is that the engine has to make adequate carb heat at 75 % power. I have students get out of the plane after a flight and put their hand on the exhaust stack after just a short while. The fact that it's not really hot to the touch reinforces that these systems cool really fast with power back.
If the engine dies on you, switch fuel tanks and pull on carb heat, while you're looking for a place to park.
MTV
Well said. Seems like a lot of today's pilots act like they are getting charged extra to use carb heat.
I'm with you--pull carb heat on every once in a while, and it'll make your flying a little less exciting at times.
My rule in Kodiak was apply carb heat every time I passed over a bay. That worked out to every five or so minutes in a Cub.
I can't speak for other CFI's, but I sure teach carb heat use.
I doubt that you'll fail the engine with melting ice, but it will certainly sound like it's quitting for a while.
One thing that I emphasize in engine failure drills with students is to get carb heat on RIGHT AWAY, unless you are 50 feet off the ground after takeoff, in which case landing is what should be foremost on your mind.
Switching fuel tanks right away starts getting fuel to a fuel starved engine, so that's an immediate action item, but carb heat is too. Carb heat comes off the muffler shroud. That shroud has cool air moving through it all the time, to prevent overheating.
If the engine fails due to carb ice, and you wait for any substantial period of time (and I don't know what that time period is) you may not have enough residual heat left in that shroud to melt the ice. Note that the manufacturer's certification standard is that the engine has to make adequate carb heat at 75 % power. I have students get out of the plane after a flight and put their hand on the exhaust stack after just a short while. The fact that it's not really hot to the touch reinforces that these systems cool really fast with power back.
If the engine dies on you, switch fuel tanks and pull on carb heat, while you're looking for a place to park.
MTV
cabinflyer
Registered User
Lawrence Lake, Mn
TJ,
Excellent advice.... never thought of doing that but always wondered.
I am a little disappointed though.... Weren't you looking for just a little fight??
Happy New Year!!!!
Steve
Excellent advice.... never thought of doing that but always wondered.
I am a little disappointed though.... Weren't you looking for just a little fight??
Happy New Year!!!!
Steve
seaplanepilot
MEMBER
Janesville Wisconsin
If you have carb heat and a mixture control, lean the mixture and the engine will continue to run even with a big load of carb ice. Carb ice makes the mixture too rich and the engine quits. Lean the mixture and the engine will run. The stacks will be hot so there will be plenty of carb heat. When the ice melts the engine may want to quit again because the mixture is too lean, so push the knob in!
Archie
Archie
seaplanepilot
MEMBER
Janesville Wisconsin
fobjob
Back when I was learning to fly, the prewar Military Pilots Training Handbook said exactly that. As a last resort leaning the mixture may cause a backfore that may blow the ice out of the carburetor. Never did figure that one out.
Leaning the mixture will keep an iced up carburetor from killing the engine. Tried it myself many times. Needless to say, over a safe landing area. Never did need it though!
Archie
Back when I was learning to fly, the prewar Military Pilots Training Handbook said exactly that. As a last resort leaning the mixture may cause a backfore that may blow the ice out of the carburetor. Never did figure that one out.
Leaning the mixture will keep an iced up carburetor from killing the engine. Tried it myself many times. Needless to say, over a safe landing area. Never did need it though!
Archie
irishfield
Registered User
Penetanguishene, Ontario Canada
Anyone notice we lost the original poster!!?? 
Not what we intended...don't be scared off...we just like to keep the few that join the great world of flight alive.... to share their tales with us!
Not what we intended...don't be scared off...we just like to keep the few that join the great world of flight alive.... to share their tales with us!
aalexander
Registered User
Anchorage
fobjob said:
seaplanepilot said:
I suppose you could try flipping your mags on and off, if you needed something to keep you entertained. Wouldn't do much for carb ice though as it doesn't produce a backfire at all. The bang you get when you turn your mags on and off isn't a backfire (although it's often erroneously called that) it's properly called an afterfire, it's an explosion that happens after or downstream of the combustion chamber. Makes a big bang, and it might even blow the stacks off your engine, but it won't do a thing to your intake system, ice or not. A true backfire is air/fuel mixture igniting in your in your induction system, ie: fire shoots out your intake. It results from letting the mixture lean out too much on starting (or sticking intake valves). It's the primary cause of DC-6 FEs buying beer for the captain and FO. And yes, it will blow a big ball of fire out the intake scoop under the right conditions.
I think that this "cure carb ice by making it backfire" probably can be traced back to a chapter in Ernest Gann's "Fate is the Hunter" in which he was in severe icing in a DC-2 and losing power because the air scoops were icing shut. His captain blew the ice off the scoops by leaning the mixture until the engines backfired. Did it actually happen? I don't know, maybe. But maybe Gann took some poetic license and turned some crew-room speculation into a good story.
Will it cure Carb ice to lean an engine out and make it backfire ? I don't know, perhaps, but in Gann's story, apocryphal or not, it was induction icing that was the problem, not carb icing. I think you'd have a pretty tough time producing a backfire of any strength in a GA engine. I've leaned GA engines out a little too far probably dozens of times and they've just quitetly lost power. You get a much better backfire in a big radial bacause there a much larger volume of fuel/air mixture contained in the Carb throat, blower tnat intake tubes. For sure, turning your mags on and off won't do anything but perhaps damage your exhaust system.
cubpilot2
SPONSOR
Anchorage Alaska
When I had the "carb ice incident" the popping would have been an "after-fire" condition due to the excessively rich mixture. It was the same reaction you get when pulling the throttle back too quickly at higher altitudes along with a rich mixture, only continuous, and many times more aggressive.
In my situation I didn't think fast enough to consider the mixture leaning idea, (which should work) as things were happening fast, coupled with a rapid "puker factor" increase.
I think that now having experienced this first hand; I will react much more appropriately. It is not something you can forget easily!
In my situation I didn't think fast enough to consider the mixture leaning idea, (which should work) as things were happening fast, coupled with a rapid "puker factor" increase.
I think that now having experienced this first hand; I will react much more appropriately. It is not something you can forget easily!
...I know the 180 produces enough heat and you basically dont need carb heat......
On a beautiful cloudless day this last August, in my PA 14 180, I had just past Port Allsworth when I noticed that the distance between the knob on the throttle and the panel seemed a less than normal for my typical cruise at 2300 rpm (my fingers on the throttle felt a little more crouded than usual). I pulled carb heat and after a short delay, the engine revved up past 2500 rpm. Whew. That got my attention! "Anywhere any time!"
I'm upgrading to an EI UBG-16 this year and I get an additional free temperature gauge as a promotion. It will be a carb temp.
On a beautiful cloudless day this last August, in my PA 14 180, I had just past Port Allsworth when I noticed that the distance between the knob on the throttle and the panel seemed a less than normal for my typical cruise at 2300 rpm (my fingers on the throttle felt a little more crouded than usual). I pulled carb heat and after a short delay, the engine revved up past 2500 rpm. Whew. That got my attention! "Anywhere any time!"
I'm upgrading to an EI UBG-16 this year and I get an additional free temperature gauge as a promotion. It will be a carb temp.
Cardiff Kook
PATRON
Sisters, OR
Reviving a 17 year old thread! Wohooo!
I was always taught to pull carb heat on landing prior to pulling back the power. I keep it on until touchdown. Thats the only time I use it. Maybe I should use it more often?
The only time I ever picked up carb ice was night flying off the coast of Southern California. Recognized it quicky- pulled heat and up went my RPM’s.
perhaps less of an issue in the high desert where I fly now.
do most pull carb heat for landing?
I was always taught to pull carb heat on landing prior to pulling back the power. I keep it on until touchdown. Thats the only time I use it. Maybe I should use it more often?
The only time I ever picked up carb ice was night flying off the coast of Southern California. Recognized it quicky- pulled heat and up went my RPM’s.
perhaps less of an issue in the high desert where I fly now.
do most pull carb heat for landing?
