Carb Heat Problem????

Carb Heat Problem????

Carb Heat Problem?

Hello All,

Im a new cessna owner ,, cessna 150D 1964 MOD. Heres the problem I have experienced. Im currently a student pilot when flying at aprox. 2500 feet asl my instructor advised me to make a slow approach. I pulled the carb heat out and instead of pulling the throttle out I pushed it in with the instructor immediately saying something is wrong with the plane.. what was heard was a slight engine .. i shouldnt say sputter but just a little different sound.. when we pushed the carb heat off it went away.. we landed the airplane and the next day did the same thing and it was there again very minor..

I had another pilot fly the plane (a.p) And he thought the plane was fine.. any suggestion what may have happened?


N4277U

Barry G. Beaver

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Re: Carb Heat Problem????

Barry:

What happened was to be expected!  When you add the carb heat, it effectively richens the mixture.  When you went full rich, with full carb heat and the throttle back, with it cold outside, the mixture became very rich.  Very rich mixtures do not ignite as quickly as proper mixtures so you feel a stumble in the engine.

This can be avoided in the winter by not pulling ALL of the carb heat on.

There is much more to the use of carb heat that generally is not being presented in early flight training.

Walter Atkinson
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Re: Carb Heat Problem????

I've always subscribed to the theory that carb heat, if used, must be used full on, ... unless the airplane is equipped with a carb air temp gauge.  Partial carb heat may actually melt frozen moisture in the air...only to have it re-freeze within the cold carb throat.  THEN you are really in trouble.
If you have to fly with full carb heat continuously for some reason, then it's permissible to lean (or re-lean as the case may be) for the new operating condition.  This will alleviate the overly-rich condition caused by the carb heat application. 
Don't forget to undo it all if you subsequently turn carb heat off.

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Re: Carb Heat Problem????

George Horn wrote:

> I've always subscribed to the theory that carb heat, if used,
> must be used full on, ... unless the airplane is equipped with
> a carb air temp gauge.  Partial carb heat may actually melt
> frozen moisture in the air...only to have it re-freeze within
> the cold carb throat.  THEN you are really in trouble.
> If you have to fly with full carb heat continuously for some
> reason, then it's permissible to lean (or re-lean as the case
> may be) for the new operating condition.  This will alleviate
> the overly-rich condition caused by the carb heat application.
>
> Don't forget to undo it all if you subsequently turn carb heat
> off.


This is EXACTLY the way I was taught and still practice.

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Re: Carb Heat Problem????

if you have a darburated engine you need a carb temp. gage,
to proprely manage the engine, including to avoid having to use full carb heat .  that gage is not an expensive item

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Re: Carb Heat Problem????

George:

*I've always subscribed to the theory that carb heat, if used, must be used full on, ... unless the airplane is equipped with a carb air temp gauge.*

I agree, but there are actually TWO issues to clarify:

1) Carb heat for the purpose of clearing carb ice.  This is the most commonly held concept for the purpose of even HAVING carb heat.  It is a good idea to use it FULL ON for that purpose as you have suggested.  Doing so may make the mixture so rich as to make the engine stumble.  Being prepared for that possibility and being willing to lean the mixture if it occurs is helpful.

2) Carb heat for the purpose of balancing F:A ratios.  This concept in GA engines sorta has been lost to time and has just recently re-discovered.  In the old radial books, an optimum IAT is listed and the flight engineers would set the manifold heat (carb heat) to attain that temperature for optimum engine operation, F:A ratio balance, and smooth operation.  The GA flat engines also have optimum IATs and the carb heat should be used for all of the same purposes listed above.  This is very hard to do without a Carb Temp gauge.


I have found it *possible* to do, but very difficult without a ccareb temp gauge.  As it turns out, if the optimum temp is used as a matter of routine, I don't think it is possible to get carb ice since the coldest part of the entire system is kept above freezing.  That has been my experience since I have been using the Optimum Carb Temp concept in all carbureted engines.

Again, if using the Carb temp for ice removal, use it ALL.  Don't mess around! <g> Partial carb heat used as a matter of routine to attain smooth operation by balancing F:A ratios is very good for the engine and is how it was designed to be operated.

Walter Atkinson

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Re: Carb Heat Problem????

Walter,

A while back you reported reading about the use of partial carb heat to smooth out engine operation.  I was wondering if you researched when "they" dropped the use of partial carb heat and why?   I find it curious that this technique to facilitate smooth engine operation would just be forgotten.

Maybe some old timers might remember this?  Unfortunately we have no "old timers" in this forum, just very mature pilots.

Barry

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Re: Carb Heat Problem????

Barry:

As to WHY the science was lost, I have no solid proof.  I do have a guess that seems reasonable until proven otherwise!  Adding partial carb heat was SOP in the BIG radials.  It was DEMANDED to be accomplished in the 3350s.  It is referred to in the manuals of smaller radials (that's where I first read about it).  Radials SEEM to run smooth and the issue was not a big deal to pilots operating the small radials so they just kinda didn't mess with it. Pilot's being a lazy lot and all. In reality, radials run a LOT smoother when the optimum carb temp is used.  That came as a surprise to me when I discovered this.

I think what happened was that flat engines came along and wouldn't run smooth LOP like all of the radials seemed to do, so people just ran 'em rich so they would run smooth.  In doing so, the ill affects of running with poor F:A ratios were masked.  Adding carb heat was an extra step that  didn't *appear* to make a difference, so the art was lost.

The only people who seemed to appreciate the importance of operating a spark ignition, internal combustion engine with even F:A ratios were the researchers like Charles Fayette Taylor of the SLoan Lab at MIT and the engineers who DESIGNED the engines.  The Flight Engineers had some appreciation of what they were doing, but the pilots were not so well educated. Now, of that group  who became CFIs in the 50s and 60s?  Why, of course, the less educated among them!  It's not their fault; it's just the way it happened.

A HUGE turn-around has occurred as a result of the internet and froums like this one.  The pilots are now the better educated of the group when compared to the mechanics.

Another thing that has come a a big surprise to me was the discovery that the POHs were NOT written by the people at the OEMs who KNEW what was right.  POHs were more frequently written by the guy with the least senority who got stuck with that dirty job.  I learned this from one such guy, who says he'd like another shot at fixing what he wrote so poorly 50 years ago and is STILL found as boilerplate wording in today's POHs.

This path of discovery over the last few years has left me with some interesting observations concerning reality and what I had perceived as reality.  Arrrrgh!

Walter Atkinson
Barry Schneidman wrote:

> Walter,
>
> A while back you reported reading about the use of partial carb
> heat to smooth out engine operation.  I was wondering if you
> researched when "they" dropped the use of partial carb heat and
> why?   I find it curious that this technique to facilitate
> smooth engine operation would just be forgotten.
>
> Maybe some old timers might remember this?  Unfortunately we
> have no "old timers" in this forum, just very mature pilots.
>
> Barry

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Re: Carb Heat Problem????

Why do we keep referring to radial engines as if they have anything to do with the engines we are operating in this forum?  And why do "old timers" seem to have had all the magnificent knowlege about present-day operations, but are no longer around?  "Old Timers" also thought it was cool to wear riding boots, spurs, and breeches and that airspeed alone affected stalling speeds.
  How 'bout we try to keep to real situations, facts, and not anectdotes and smoke/mirrors?
  All present-day engines and their carburetors are designed to operate quite normally and pretty efficiently in cool air, in fact, the colder the better.  Freezing temps do not suddenly make an engine (that's already flying) a haphazard gizmo with poor FA ratios (whatever THAT's supposed to mean to a 172 pilot!)  Otherwise they'd have prohibitions and placards in their AFM's and POH's about keeping them tied down and in the hangar in cold weather, and they'd certainly be prohibited from flying at high altitude.         AFMs/POHs these days are not haphazardly constructed.  Since the mid '70's they have been carefully scrutinized not only by the engineering departments but also the legal dept's and the FAA or other certifying body for accuracy and soundness of operating procedures.  To operate contrary to an approved AFM/POH document in any but an emergency is dangerous and illegal.
  Those references to radial engines, as if all their quirks of operating techniques had some magical applicability to horizontal engines, are like comparing apples-to-oranges.  Those references don't really illustrate anything.  All they do is add a lot of verbage to muddy up the water.  You might as well talk about steam engines and how the hot steam is better than the cold steam. : {
  The average 172/182 has a simple engine, well designed, and pretty basic.  I feel that recommendations to run around toying with partial carb heat is going to get someone in trouble.  We're not running these engines in a laboratory with a test stand....we're hurtling through the atmosphere with other airplanes and trying to navigate and that's where most of our attention should be directed.
  If your engine is running poorly, then regardless of the OAT something's wrong that should be fixed,...not twiddled with in flight where insufficient instrumentation exists anyway.
  My 2 cents.

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Re: Carb Heat Problem????

George's comments notwithstanding, I was interested in why the change in philosophy of operation from using carb heat in radials to no carb heat in Lycomings or Continentals.  Personally, I dislike not knowing the reason.  It is difficult to justify a change without knowing the basis.  Not impossible, but difficult.  In my opinion, the case for making the change in operation requires a solid basis be established.  Unfortunately, in so doing, it is important that all the relevant information is known and we know what is relevant.  Sounds like double-talk, but it's not.  Logical arguments are fallible.  They fail because of wrong or poor assumptions, faulty logic, or not including all relevant information.

For now, I am convinced that you, Walter, have available data to support the information regarding details of engine operation.  Developing the engine data is not an easy task and it is an excellent and necessary achievement.  The information I'm concerned about is other than engine operating data.  Your experience in flying is a great asset in developing this basis and identifying other information.  Items that I would like to hear about are:

-  potential for developing carburetor ice that can’t be overcome due to partial carburetor heat operation
-  Required instrumentation – CHTs, EGTs, carbuerator venture-throat temperature, etc. (We did hear about this.)
-  Are there deleterious effects from operating for extended periods without the benefit of filtered or partially, filtered inlet air.
-  Number of accidents where partial carb heat was a contributing factor.
-  Cockpit distraction and added work load (affected by available and suggested instrumentation)
-  Airbox failures due to excessive operation of the butterfly valve – operating the equipment in a manner not envisioned by the designers/engineers.
-  Pilot knowledge and experience required for safe operation

I’m sure there are other factors to consider, and that were considered, but not delineated or discussed (yet).   

Has a formal, comprehensive study been done on this suggested operating strategy and critiqued by independent groups?

Perhaps this is overkill, perhaps not.  I really didn’t mean to preach or “rain on anybody’s parade”.  It just seems that changing our manner of operation without this basis could be hazardous.  So far, we are all free to do as we think.  We just don’t want to stop and think, but forget to start again!  (I just had to say that; read it somewhere and it stuck.)

Thanks to all for the info and lively discussions….

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Re: Carb Heat Problem????

Barry S.,
I think that George and Walter are both right, in a way. The problem seems to be that each of them present their opinions without allowing the rest of us the privilage of reviewing any document or data to form our opinion. Which one do we believe?

Everyone,
Read the following and form your own opinion.

FAA Advisory Circular AC-113 dated 10/22/81
"... It is usually preferable to use carb heat or alternate air as an ice prevention means, rather than as a deicer...   ...The use of partial heat for ice prevention without some instrumentation to gauge its effect may be worse than none at all under the circumstances...  ...The use of partial heat when the temp is below 32 dF may, for example, raise the mixture temp up to the danger range, wheras, full heat would bring it well above any danger of icing...  ...With instrumentation such as carb or mixture temp gauges, partial heat should be used to keep the intake temp in a safe range. Without such instrumentation, full heat should be used intermittently as considered necessary.
...When no carb air or mixture temp instrumentation is available, the general practice with smaller engines should be to use full heat whenever carb heat is applied. With higher output engines, however, especially those with superchargers, discrimination in the use of heat should be exercised because of the possible engine overheating and detonation hazard involved... ... A pilot of an airplane equipped with a carb air or mixture temp gauge should make it a practice to regulate his carb heat by reference to this indicator..."

Barry B.,
It does sound like you experienced a normal response when you applied carb heat. But you do need to realize that there are other factors that can cause problems. First to mind is a crack in the exhaust system. Leaking exhaust gases into the airbox when carb heat is applied can dilute the induction air sufficiently to cause poor combustion. If you ever suspect a problem, by all means, have a mechanic look at it, and don't ever hesitate to ask questions.

And last, but not least, refer to your POH. Mine says this.

"Carb ice, as evidenced by an unexplained drop in RPM, can be removed by application of full carb heat. Upon regaining the original RPM (with heat off), use the minimum amount of heat (by trial and error) to prevent ice from forming..."

Your POH or FAA approved AFM is the supreme document in operating your aircraft. I'm not saying I think that it is 100% accurate, and would agree with anyone that might say that it has incorrect and obsolete information. Thus the need for the FAA's Advisory Publications. In these publications you will often find that "old" information has been reviewed and then revised to reflect our increased knowlegde through human experience (trial and error) and research and developement.

I am not aware of an FAA publication endorsing or instructing pilots how to use carb heat for improving F/A ratios, but I do agree that it does work. I wouldn't suggest anyone trying it without a carb temp indicator, but that's just my opinion. If there is such a document or FAA publication, I would be very interested in reading it.

Del

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Re: Carb Heat Problem????

Barry:

*  Your experience in flying is a great asset in developing this basis and identifying other information. *

Thank you, but don't believe me... believe the data!

-  potential for developing carburetor ice that can’t be overcome due to partial carburetor heat operation

If the coldest part of the system(right behind the venturi, inside the carburetor) is above freezing, it is not possible (according to Newton) to have carb ice at normal pressures.  The key  is KNOWING that temperature... with a carb temp gauge.

-  Required instrumentation – CHTs, EGTs, carbuerator venture-throat temperature, etc. (We did hear about this.)

Yes, we agree that a carb temp gauge is very important.  I consider it a necessity.  Although not necessary, an engine monitor PROVES to the pilot with DATA that he has set the optimum temperature.  I use the engine monitor fo rthis purpose.

-  Are there deleterious effects from operating for extended periods without the benefit of filtered or partially, filtered inlet air.

Of course--in dusty conditions.  You will notice that I have recommended this practice in cruise, at altitude, where there is not much dust.  There are no air filters at all on my Twin Beech!

-  Number of accidents where partial carb heat was a contributing factor.

I know of none.  I have not done an NTSB search on this either.

-  Cockpit distraction and added work load (affected by available and suggested instrumentation)

I find it less distracting than a rough running engine! <g>  Seriously,. it's like any other issue.  Once you are comfortable that you understand the procedure, there is no untoward distraction.

-  Airbox failures due to excessive operation of the butterfly valve

???  Should we quit checking the carb heat and no longer use it before landing because it might wear it out?

– operating the equipment in a manner not envisioned by the designers/engineers.

Hmm?  Did the designer say the engine could not be operated when the OAT is above 90 degrees F?  Let's THINK about this.  When the OAT is 92dF, the temp after the venturi in my Twin Beech carb is 36dF.  That is the optimal temp according to the designer.  Now, when the OAT is 25dF and carb heat is added to attain a temp of 36dF at the same place in the induction system, the engine thinks it's summer time!  So what?  As it turns out, the optimal temp is differnt from engine to engine.  IN a 182, it seems to be about 45-50dF.  Somebody needs to explain how in the world you could have carb ice when the coldest temp in the entire system is 50dF.  IT's HOTTER than that everywhere else.

-  Pilot knowledge and experience required for safe operation

OK, here's the rub.  You do have to understand what you are doing.  That is also true of stalls and putting the stupid gear down before you land.  This is SIMPLE.  It's just no longer commonplace.

When I flew the other day in a 182 with the OAT below freezing with carb heat set to attain 50dF, the airframe thought it was winter time while the engine thought it was summer.  So what's the big deal?  Now, I agree, if you do not have a carb temp gauge, and you don't understand what you are doing, you could set the temp to a bad range and get carb ice and die.  OTOH, if you don't have an airspeed indicator and you don't know how to recover from a stall you could die.

I can accomplish this repeatably.  Anyone can.  There is no need to argue about anything which can be MEASURED by ANY independent observer.  The laws of physics are everywhere the same.

Walter Atkinson

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Re: Carb Heat Problem????

George:

You are an interesting gentleman.  I'm going to take the time to answer you. There may be something to learn here.

It is important to understand that the combustion event is IDENTICAL in all spark ignition, internal combustion, piston engines.  Stating that there is no similarity of radials to flat engines is simply incompatible with ALL of the known engineering data from ALL observers.  A Sears lawnmower engine will exhibit IDENTICAL pressure traces of the combustion event as an O-300, IO-540, 985 or 3350.  This is well established knowledge that ALL engine designers, engineers, and manufacturers are familiar with. You are making statements which are incompatible with their observations.

With all due respect, your understanding of these issues may be incomplete.  Please allow me to elaborate.  Consider that an O-470 as in a 182 is not ONE engine, but rather six engines all sharing the same crankshaft which are flying in close formation.  All multi-engine pilots know that it is good to have equal power from all engines so good thrust balance is achieved. The same can be said of these six engines sharing the single crank.  The designers want all six of these engines to produce the same horsepower.  I think we would both agree that that is desirable.  It decreases vibration.  It lowers stress on main bearings, it lowers stress on the crankshaft.  The engine will run smoother if all of those engines are producing the same HP.  Smoother is better, right?

Anyone who thinks that these six little engines actually produce the same horsepowers have never seen one instrumented up.  Different volumetric efficiencies provide differing amounts of air to each engine (cylinder). Why else would people flow balance cylinders?  Differing F:A ratios can make HUGE differences in HP output.  The spark timing event is not even the same on every cylinder!  I'll bet you didn't know that?  Well, four months ago, neither did I.  It is a recent discovery that I think the engine manufacturers don't even know.  Are you aware that there is even cycle to cycle variability within ONE cylinder?  Neither was I until recently.

Anyone who thinks that a carbureted engine (or any engine for that matter) automatically gets even F:A ratios is simply uninformed and has not seen them run instrumented.

* Freezing temps do not suddenly make an engine (that's already flying) a haphazard gizmo with poor FA ratios*

That statement is absolutely, 100% false.  With all due respect, you simply do not know that that is 100% incompatible with ALL of the KNOWN and OBSERVED engineering data since 1927.  You obviously have not SEEN this.  Otherwise, you would not make such an incorrect statement.  Remember, this can be PROVEN to ANYONE who is interested in SEEING it with their OWN eyes. Lindbergh knew it.  He balanced his three carburetors to get as perfectly even F:A ratios as he possibly could so he could run LOP and not have to swim the last 150 miles! (reference:  Captain John Miller, personally witnessed the event and assisted in the set-up in 1927 and told me of the process last year at OSH.  He is 98 and still flying.  BTW, He claims to have run every airplane he has owned LOP since he bought his first Jenny in 1929.)

Now, specifically, in answer to your incorrect statement above.  Temperature has more effect on F:A ratios than any other factor in a carbureted engine.  The purpose of the carburetor is to atomize the fuel into as small a droplet size as possible.  The purpose of this is to aid in the VAPORIZATION of the fuel so it can, in fact, be evenly spread throughout the induction system.  The designer plans on the fuel being VAPORIZED so it will be evenly distributed.

When it is colder than the optimum temperature (as outlined by the design of the engine) vaporization is inadequate.  Droplets of liquid fuel move through the system. These are not vaporized and represent a very rich mixture locally.  Because of their weight, they move to different places than small droplets and vaporized fuel.

Anyone with an engine monitor can see this F:A imbalance as displayed as a high DIFF number.  Don't believe me; believe the engine monitor. That's data, not an opinon.

George, I have taken the time to try to explain this for several reasons.  First and most importantly, I think you're a pretty smart guy and obviously have a wealth of experience as a mechanic.  Secondly, I want others who do respect your opinion to know the truth and not believe incorrect information coming from an otherwise very trustworthy source.  Rather than argue with each other, why don't we simply observe the event?  What do you have to lose?

The above explanation of the physics of the events discussed is not my opinion.  Do not believe me.  It is the repeatable, confirmed observations of all of the known data from all observers. (reference: Taylor--MIT engine lab, P&W, Wright, Lycoming, TCM, NACA and NASA, and the Carl Goulet Engine Test Facility) I will be more than happy to demonstrate this to anyone who would like to SEE it for themselves.  Heck, if they've got an engine monitor, they don't need me.  They can see it for themselves.

The laws of physics are everywhere the same. You are no more interested in my opinion than I am of yours.  Neither of our opinions are worth anything to the laws of physics.  I am interested in what I can repeatably observe as fact.  If your statement were correct, adding carb heat to an engine when the OAT is low would not change the DIFF number on an engine monitor.  It does.  EVERY time!

We all have a choice. We can educate ourselves or we can remain uninformed.  You may find the article on page 119 of the Feb., 2004 AOPA Pilot interesting.

Walter Atkinson
Advanced Pilot Seminars

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Re: Carb Heat Problem????

* Has a formal, comprehensive study been done on this suggested operating strategy and critiqued by independent groups?*

Oops, forgot to answer that one.  Sorry.

The answer is a definite yes.  The study consisted of at least 400 MILLION flight hours.  Yep.  That's a Four with EIGHT zeros.  (Gee, I hope that's enough hours of data to satisfy the naysayers!) Data collected by American Airlines and published by Wright Aeronautical Division of Wright Aircraft.  It's a really incredible work.  I last read it sometime around October 2003.

Walter

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Re: Carb Heat Problem????

Good evening Del:

I hope it's not too cold up there in Mena! <g>

*I am not aware of an FAA publication endorsing or instructing pilots how to use carb heat for improving F/A ratios, but I do agree that it does work. I wouldn't suggest anyone trying it without a carb temp indicator, but that's just my opinion. If there is such a document or FAA publication, I would be very interested in reading it.*

The FAA does not do research and does not endorse ANY operating technique of ANY kind.  That is not their function.  FAA approval of a POH in NO WAY suggests that they agree or disagree with the recommendations found within.

Walter

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Re: Carb Heat Problem????

Walter, I'm pretty sure I know why you gave that kindergarten course, and I'm hopeful you feel better now.  Let's don't patronize.  It's unbecoming.

George wrote-Freezing temps do not suddenly make an engine (that's already flying) a haphazard gizmo with poor FA ratios.

Walter wrote-"That statement is absolutely, 100% false."

=======
Well, I guess we'd better quit flying in cold weather since our engines become haphazard gizmos.  The mfr's better hope the FAA doesn't find out about this and revoke thousands of airworthiness certificates.

Walter, The advice you offer is so frequently beyond the instrumentation of the average Cessna.  Of the thousands of single-engined Cessnas produced, exceptionally few have engine monitors, and even FEWER have carb air temperature gauges.   
  The advice you usually offer require those types of accurate instrumentation yet the aircraft airworthiness does NOT.  Virtually NONE of them left the factory with that kind of equipment.  How EVER did they get airworthiness certificates awarded so dangerously ill-equipped?
   
Walter wrote-"Anyone who thinks that a carbureted engine (or any engine for that matter) automatically gets even F:A ratios is simply uninformed and has not seen them run instrumented." 
  When I made that premise the point of my message not too long ago YOU took exception to it, Walter.  I had pointed out the difficulty of accurately leaning a carbureted engine (due to poor fuel atomization and distribution) and your response at the time was to discount that statement and boasted of accurately running a 182 LOP.  But You didn't emphasize the equipment required to accomplish that feat, and I feel this is a reason for our opposing positions on many of these issues.   
  You simply MUST recognize that few 172/182 aircraft are adequately instrumented to effectively utilize the advice you offer.  In light of that, I feel it is dangerous to advise pilots to attempt procedures for which they are not properly equipped.

  You and I should remember the majority of the guys here are interested in knowing how to operate safely, legally, and efficiently, ....within the capabilities of their average, stock-equipped airplanes.  While "fine tuning" techniques are always fun and rewarding, I feel it's important to emphasize basics to pilots only equipped with basics.
 
  (And the reason I referred to the earlier radial engines examples offered, as if they were "smoke-and-mirrors" is because you seem to offer such examples as a method diversion and of self-promotion.  I'm just trying to keep the discussion germane to the engines and airplanes at hand,...not Lindbergh's carburetors.   

I resent your attacks that imply I'm a promoter of Old Wives Tales. Del makes a good point about supporting documentation.   (Due to time contraints I felt folks could log onto the appropriate free website (FAA or otherwise) and click on "Search" on their own.  I don't try to sell anything here.)
Since Del admonished us about documentation, I'll remind you of an exchange regarding this topic of carb heat and my comment about  "leaning to backfire".  You attacked me and my comment, called it an OWT, and implied I didn't know what I was talking about, and that I must have meant "afterfire".  (Another ploy of yours to discredit.)  See AC 20.113, where it specifically recommends as a carb ice corrective action , "a severely iced engine may sometimes be relieved by inducing backfiring with the mixture control."  Seems I'm not the only one to know of the technique, or to have experienced leaning that can cause backfire.
  I believe the reason you and I clash Walter has less to do with the mechanics (physics was the word you used) of these matters, than it does about the motives of our participation.   I want to offer good advice based of legal, safe, and sound operating practices.  You appear to be interested in selling something, and there's the rub.

  I won't be confrontational with you anymore.  It does neither of us credit and it's a bore to our friends.

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Re: Carb Heat Problem????

I will neither make any claims to know 1/2 of what you gentlemen know about aircraft engines. My expertise is in servo motors. What did grab my attention was the comments on entities not researching or endorsing certain requirements.

As always there has to be a governing body and expecially when the machines fly several thousand feet above the ground. Im glad there are procedures and SOP's that we as pilots must adhere to ie: airworthy or not airworthy... A&P, AI. I have to agree with George somewhat with his comments about certain procedures that must be performed and certain practices thats better left along or maybe stated in a different manner. Im a student pilot who doesnt want to experiment with procedures that may or may not cause an engine out. I can see Walters side also.. hes very well knowledged and im sure has the experience to voice his opinion as he sees.. but lets please let it remain an opinion and not advise...

You guys are great.. I have learned quiet a bit in my short time here..

Thanks for all your post

heated arguments arent always bad.. it gets us to think and be creative


Barry

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Re: Carb Heat Problem????

   This has been a great thread and I love to see the different views on seemingly simple subjects.
  I tell customers to go by the book when operating their airplanes and systems. While this doesn't always squeese the most performance out of that powerful O-300D or IO-520 I've never felt bad about saying "what does the POH say?".
  The POH, while not usually an engineering textbook, does contain enough information to operate the aircraft in a consistantly safe manner with enough margin for error to preclude most inadvertant, and scary, "moments of silence".
  However, rather than being just a "driver" up in the cockpit, pilots need to understand what happens when they flip switches and push-pull engine controls. Teaching pilots (and mechanics) to recognize the real problem and take appropriate corrective action is a tough job.
  So, my suggestion to the list is for EVERYONE to take their POH home and re-read that silly thing! Amazing how many jewels of wisdom are in there that may have been glazed over. Read that thing like you're taking a test and try to memorize the emergency proceedures. Keep it out and open to the page that reflects the portion of flight you're conducting and use it.
  Sit in the cockpit, look at all the shiny switches and knobs and ask yourself if you really know what they all do, when they should and shouldn't be used and what happens if they fail. What happens if that mixture cable comes out in your hand? Or that tach cable breaks, or the fuel starts leaking out of the pressure gage in cruise?! If you aren't sure when, or how much carburetor heat to use....RTFB (Read the F****** Book).   
  My opinion only ;^)

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Re: Carb Heat Problem????

Walter wrote:
"A HUGE turn-around has occurred as a result of the internet and froums like this one. The pilots are now the better educated of the group when compared to the mechanics."

....hhhmmmmm......kind of a blanket "mechanics are stupid" statement that gets my hackles up so I'll assume I'm way out of my league when talking this airplane stuff to you real wizards, right?! Sure hope someone developes a "Professional Mechanics Seminar" so I can get competent........hah!

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Re: Carb Heat Problem????

Gregg:

*  ....hhhmmmmm......kind of a blanket "mechanics are stupid" statement *

No, it's not a mechanics are stupid statement.  The proof is in the pudding.  When given and ENGINE MANAGEMENT test, pilots do a lot better than mechanics.  The FAA was there to see this and THEIR a7ps did poorly as well.  The test scores don't lie.  The following was received this moring from an A&P who had worked for Cessna, TCM and now works for Superior:

John:

I have been out traveling since attending the advanced pilot training seminar. What a great program! I have been involved in aviation for over 35 years, flew for Cessna, product support for Teledyne Continental Motors and now at Superior. What I learned in those two and a half days at APS was mind boggling, too say the least. It's depressing also. I spent over 10 years at TCM working with the experts and getting incorrect information.

More depressing is the fact that for 3 of those years, my office was right next to Carl's! He spent a great deal of time explaining the various vibration orders and the affects of counterweights and dampeners. He was the best!

Please pass on my thanks to George and Walter. I will now go into hiding for all the mis-information I have been giving pilots for the last 20 years!!

Name withheld

HE has seen the data.  Others who have not have a hard time understanding some of the statements those make who have seen it.

To each his own level of comfort with his own level of knowledge.  Here's the good news. No one MUST learn.  Read the article on page 119 of the Feb. 2004 AOPA Pilot.  Most of you get that magazine.  See what they say.

Walter Atkinson.

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Re: Carb Heat Problem????

Well Walter, since every post of yours tends to drift into your seminars and how the rest of the world is befuddled by misinformation I'll add this... my level of comfort with my knowledge isn't narrowed to how well I do on YOUR engine management test but rather how well I perform complicated, often life-critical maintenance on a variety of aircraft. I didn't get that in 3 days of a seminar...just seemed to accumulate it over 31 years of professional aircraft maintenance on GA and Military hardware..from restoring classic warbirds, making fan speed on a TF34-GE-100A on an A-10, to pumping life back into a Polish MiG-17. Come change the engine hoses on a Klimov VK-1F, overhaul a 3000 PSI dual-power brake control valve...or something simple like set up and adjust the fuel pressures on a Continental IO-520D. That's the kind of stuff I'm "comfortable" with. I'm sure your seminar has tremendous value for fine-tuning engine managment...I just find your constant assertion that only those who've paid the price of your seminar are worthy of respect to be...hhhmmm...arrogant. You may not mean it but every post you make, backed up by your reams of data and testimonials, is just another plug (read SPAM) for your services.
  This will be my last reference to your seminar...as I'm convinced this list has heard quite enough.
  Gregg Horrell
  Refusing to learn the real truth ;^)

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Re: Carb Heat Problem????

It's been interesting reading all the posts concerning carb heat and such. I've yet to figure out how any of Walter's technology applies to my 40+ year old 0300 in my equally old C172. Maybe I'll continue what I was taught. Apply full heat when necessary. And when in cruise flight lean the mixture.

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Re: Carb Heat Problem????

Gregg:

I am quite certain that your extensive experience is very valuable and variable.  As such, you are a treasure to the Aviation world.  It is the men and women like you who keep the rest of us flying and we all appreciate your skill, experience and knowledge.  I have a tremendous respect for that experience and knowledge.  Assumning otherwise is to misunderstand my appreciation and respect for you and the other A&Ps sharing your day to day experiences.

*I just find your constant assertion that only those who've paid the price of your seminar are worthy of respect *

I have NEVER asserted that.  That is not my opinion.   Anyone wishing to build a $700,000 engine test stand as GAMI has done can run their own tests to prove that TCM, Lycoming, P&W and Wright all had it right.  If you develop a heretofore never constructed computerized facility and invent a system which measure 50,000 samples per second of the combustion event you too can collect the same data.   For about 1.5 MILLION you could learn what we have already learned and are continuing to learn.  Gregg, this is the most advanced engine test facility in the world.  PERIOD.  They are seeing things NOBODY has ever seen before.  Do you not find that interesting?

This brings up an interesting issue.  I have very little knowledge of some of the experience you have had (particulary in the jets and miltary world) and would not assert to have any opinion as worthy as yours in those areas of expertise.  Why?  Well, I have not SEEN those things and have no experience in those areas.  In those areas, I hope I could turn to you and those like you for advice.

If you have not seen a fully instrumented piston engine run and seen the data for yourself (which is not possible anywhere in the world other than at the Carl Goulet Memorial Engine Test Facility), how can you make definitive statements contradicting that which others have seen and are reporting.  There is much being learned (and re-learned) in this area.  I am an A&P as well.  I cannot tell you how much I knew to be true from my A&P experience which is just, plain wrong.  I've learned the taste of crow.  It could be that some people are not interested in expanding their knowledge in this area.  I would hope that those who wish to be considered as experts and keep their knowledge abreast of the latest understanding IN THIS AREA would be interested in seeing the information for themselves... particulary when not one single soul who has seen this has ascerted it was wrong or claimed it was reported with bias.  On the contrary, reporters from Aviation Consumer, Light Plane Maintenance, Plane and Pilot, Private Pilot, Cessna Owners(your own organization magazine), Piper, AOPA Pilot, and Air & Space Smithsonian have universally reported positively about their experience and new knowledge.  Most of these reporters have said that they had never seen anything like it anywhere.  One gentleman who has worked in the industry for 27 years for Cessna, TCM, and now Superior stated that he could not believe how wrong he had been for so long about so many piston engine management issues.  That was HIS opinion about what he learned when he saw the data.  Of the dozens of A&Ps who have seen the data, not one--not a single one--not once--has said we are wrong.  Not one.  Wouldn't you think ONE of them would call BS if there were a hint that we are wrong?

The people from the FAA Engine Directorate are changing some of the ways they do things based on what they've seen and recently learned from us.  The folks in charge of the FAA A&P testing have seen this data and have decided that they have some of the answers wrong on some of the questions on the FAA tests (specifically the A&P test).  I have been asked to review these test questions for accuracy and make suggestions for improving the test questions and bring them more into harmony with the known engineering information.  Wouldn't it make sense that if they had ANY concern that ANY of our information was even possibly wrong, they wouldn't stick their necks out to ask me to review their battery of test questions?  Are these stupid people?  I hope not.  They are in charge of the testing.

This would indicate to casual observer that what I am saying has merit and has been proven to be in harmony with the laws of physics since those who are in a position to call BULLSHIT (if we were in fact wrong) have not done so, but rather been quite complimentary concerning their experience after seeing the data.

Of course, if one has not seen the data, one may still pontificate.  The question is, "Will they be correct?"  There are people who are convinced that the world is flat and that O.J. didn't do it, so nothing surprises me.

I do respect your experience.  I do feel compelled to point out what I have observed as repeatable scientific facts--even when I used to agree with your current position. 

Gregg, I am, hereby, publically offering to show you personally the data.  What do you have to lose?  Are you interested? 

Walter Atkinson

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Re: Carb Heat Problem????

Jay:

*I've yet to figure out how any of Walter's technology applies to my 40+ year old 0300 in my equally old C172.*

Well, most of this was known 60 years ago when your engine and aiframe were being designed.  So what's the big deal?  This is stuff all pilots and mechanics should know.

Walter Atkinson (BTW, it's not MY technology.  It's TCM's as well as others.)

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Re: Carb Heat Problem????

I for one am appreciative to Walter and others knowledge. I cannot understand why so many are so irate to argue to ones data that proves valuable. I do agree sometimes opinions become opinated facts and should have been left as maybe a hypothesis. But guys you are the brains and I for one appreciate the information..

Barry

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