Prop stopped.

[facthunter]

Another thing that used to be recommended is to not turn your back on the field.. Nev

[rgmwa]

I remember my instructor telling me to pick a field inside a 45 degree cone around you. Pick anything further away and there’s a good chance you won’t get there. It’s a rule of thumb of course, and there will always be other factors to consider (eg wind), but it’s probably a pretty good guide. 

[pmccarthy]

Hold your arm out straight, put the top of your hand on the horizon, the bottom of your hand is the limit of where you can glide to. Works for normal GA aircraft and their like.

[Garfly]

Juan Browne has just posted his analysis:

 

 

[Roundsounds]

7 hours ago, pmccarthy said:

Hold your arm out straight, put the top of your hand on the horizon, the bottom of your hand is the limit of where you can glide to. Works for normal GA aircraft and their like.

Don’t try that in a Pitts, Victa Airtourer or Beech Bonanza. The rule of thumb I use in these types is to toss a house brick out the window and follow it. 

[danny_galaga]

On 26/02/2022 at 7:56 AM, Garfly said:

Juan Browne has just posted his analysis:

 

 

Wow, how perfect was that?!!

 

Interesting about the manifold pressure

[facthunter]

Why mention it when you still have an altimeter that is far more accurate and incorporates allowance for changing QNH?  Smoke in the cockpit indicates bulkhead damage  as normally it should not be able to happen. as CO would be a risk. Nev

[Garfly]

 

 

[Thruster88]

52 minutes ago, Garfly said:

 

 

He did well, airspeed increased after the engine failed. Not sure it was carb ice, don't think it comes on that suddenly. Cessna piper beech and others must have it wrong with their identical carb heat systems that use hot air in to the carb rather than an electric heater.  

 

His other vid showing the internally cut fuel line is interesting. This type of thing can happen with limited mechanical experience and ageing eyesight.  

[facthunter]

I've used the electric heater that just heats the carb body. Who knows if it works? You don't lose as much power as when you use heat from the Muffler, nor get unfiltered air. Nev

[onetrack]

What's he got powering it? It looks like a V-twin, is it a Briggs & Stratton Vanguard? That thing is so tiny, 240kg MTOW, it must be the equivalent of a Hummelbird.

[facthunter]

There's a few horizontal shaft Vee Twin Industrial motors that it could be.    Nev

[Old Koreelah]

1 hour ago, facthunter said:

I've used the electric heater that just heats the carb body. Who knows if it works? You don't lose as much power as when you use heat from the Muffler, nor get unfiltered air. Nev

I know a well-respected LAME who always flies his Jab with a little bit of carb heat.

[facthunter]

That's not the advised procedure. It's usually to use the lot before you descend and reduce power.  Nev

[kgwilson]

I was a bit surprised when he said it was icing. The engine was at idle so the airflow through the carb would have been minimal with the venturi throttle flap closed. It is the compression and expansion of the air which causes cooling and the condensation of the water vapour. The ice takes a little while to develop & although low engine speeds will disguise the onset of icing it happened pretty fast. I don't know what the OAT was or the humidity level so I don't know.

 

Usually the engine will cough and run rough & carb heat will worsen this momentarily as the ice melts and gets ingested then gets better. Engines don't like hot air though. My 3300A won't develop much power if I leave the carb heat on & apply full power.

[turboplanner]

13 hours ago, Old Koreelah said:

I know a well-respected LAME who always flies his Jab with a little bit of carb heat.

Power output is directly related to the amount of air each piston compresses.

The warmer the air, the less gets into the combustion chamber, so less power is produced so the engine has to work harder to get the same result, and has a shorter life, or produces a lesser result.

Intercoolers and aftercoolers cool air before it enters the combustion chamber, so more gets in and there's more to expand and push the pistons down, so power is increased.

 

There is plenty of information available on identifying conditions where carb icing may occur in transit so I won't cover that.

 

When power is reduced, vacuum in the carby increases, dropping air pressure, and we know from physics that this lowers the air temperature immediately.

 

It's effectively the same as a refrigerator valve. If you've ever fitted a vacuum gauge on a petrol engine as a fuel saver, you'd be familiar with the slow movement of the needle at cruise, falling back slowly with power demands into wind and on hills and snapping to maximum instantly when you lift your foot to slow down. The temperature drop is instant when the throttle butterfly valve is snapped shut, and you can see the carb body instantly ice up, then thaw when power is applied then ice up again when you close the valve.

 

The potential is there for icing when you pull the throttle back pre-landing which is why you apply full carb heat for the downhill run, then turn it off around 300' so you'll have full power for a go round.

 

 

It does get mixed up in the diagnosis on recreational aircraft where there may be issues with fuel supply lines, float levels, jetting and ignition being less than optimum.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[APenNameAndThatA]

On 15/5/2022 at 7:06 AM, turboplanner said:

Power output is directly related to the amount of air each piston compresses.

The warmer the air, the less gets into the combustion chamber, so less power is produced so the engine has to work harder to get the same result, and has a shorter life, or produces a lesser result.

Intercoolers and aftercoolers cool air before it enters the combustion chamber, so more gets in and there's more to expand and push the pistons down, so power is increased.

 

There is plenty of information available on identifying conditions where carb icing may occur in transit so I won't cover that.

 

When power is reduced, vacuum in the carby increases, dropping air pressure, and we know from physics that this lowers the air temperature immediately.

 

It's effectively the same as a refrigerator valve. If you've ever fitted a vacuum gauge on a petrol engine as a fuel saver, you'd be familiar with the slow movement of the needle at cruise, falling back slowly with power demands into wind and on hills and snapping to maximum instantly when you lift your foot to slow down. The temperature drop is instant when the throttle butterfly valve is snapped shut, and you can see the carb body instantly ice up, then thaw when power is applied then ice up again when you close the valve.

 

The potential is there for icing when you pull the throttle back pre-landing which is why you apply full carb heat for the downhill run, then turn it off around 300' so you'll have full power for a go round.

 

 

It does get mixed up in the diagnosis on recreational aircraft where there may be issues with fuel supply lines, float levels, jetting and ignition being less than optimum.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I think four “i” symbols in response to a post is a record. 

[facthunter]

Latent heat of vaporisation also lowers Carb temp. Put you hand in avgas and move it in the wind. Injection almost eliminates icing. Nev

[Garfly]

There was some discussion on the pilot's diagnosis - and carb ice in general - in the YouTube comments.

(Click "Watch on YouTube" on the vid to check it out.)

Here are a few excepts:

 

 

 

Mike Wood

1 year ago

...    I can only "suspect" carb ice since, as usual, the evidence tends to disappear quite quickly after landing! However, since the engine had been performing normally prior to the failure and ran perfectly the next day once we had recovered the aircraft, combined with the local (RAF) met office opinion of likelihood of Moderate to Severe icing conditions, I'm happy that was the cause. There's a discussion on the remedy on the Yahoo groups page: https://groups.io/g/SD-Planes

Robert Borchert

1 month ago (edited)

Brilliant emergency landing!    Carburetor icing? Indeed!

I rebuilt carburetors professionally for some time, years ago. This process was different from mere cleaning. Service included taking care of the bore and throttle plate, bearings if fitted, seals, linkages, jetting, emulsion tubes, bypass fuel and air jetting.

The reason carburetors ice is a combination of two factors, Boyle's Law and atomization of the fuel. On the engine side of the throttle, pressure is lower than at the inlet. The air now occupies an area where it can expand. In doing so, it absorbs energy. At this point, we introduce fuel. The fuel is drawn inward and vaporized. In doing so, it also absorbs energy. The net result is a rapid drop in temperature. The throttle plate becomes much cooler than the ambient temperature. Moisture in the air rapidly condenses, cooling to ice. You can count on a 40 degree drop or more at this point.

Carburetor icing is critical at low power settings when landing. You are at idle power. Less volume of air is passing through the bore, that air has a wee bit more time to cool, and the pressure differential is at its highest. The solution is to give that incoming air mass more thermal energy. This is why we have carburetor heat systems. Fuel injection systems have the primary advantage in this case of moving the fuel atomization much further downstream of the throttle. Years ago, throttle body injection systems were more common, injecting the fuel directly down onto the throttle plate. The fuel sure kept the plate shiny, but the assembly was very cool in operation. In some installations, an electrically heated grid was fitted in line with the bore, to help completely vaporize the fuel droplets for cleaner emissions.

 

 

Mike Wood

1 month ago

Thank you, Robert. A useful reminder of how it all happens. I initially set up a system that would warm the inducted air but decided that this was not as efficient as warming the carb body (and, by conduction, the throttle plate) since this is where the ice would form. Obviously, warm dry air into the carb would be best (from an icing point of view), but since I couldn't arrange that I went for the "hot carb" option. Any thoughts?

Edited May 17, 2022 by Garfly

[facthunter]

Raising the air temp will decrease power, often so much the motor won't safely get you into the air with carb heat on.. Often the heated air is unfiltered coming from a muff around the muffler, which could also have accumulated dust in it and if there's any exhaust leaks/cracks have a lot of carbon monoxide with it . Mufflers can also get detached baffles and blockage and engine overheating and power loss due extra back pressure. Nev

Edited May 17, 2022 by facthunter

[Blueadventures]

On 14/05/2022 at 4:42 PM, Old Koreelah said:

I know a well-respected LAME who always flies his Jab with a little bit of carb heat.

Maybe worth a try for him to check the carby up inside where the main jet screws in as there may be some build up of deposits there.  I had this happen on a rotax 80hp UL in a skyfpx with fibre glass tanks.  Took 6 weeks of trial, parts and hair pulling to find the issue.  When cleaned the engine ran smoothest it had ever.  Before that always had a slight bump at cruise rpm and if I pulled the carb heat about 2mm it would go away.  Always thought of adjusting or placing a spacer on the back of the carb heat knob.  Maybe what's happening in his single carb Jab.

[spacesailor]

Does ' carbon monoxide ' have any effect, on an IC motor.

AND

IF. Exhaust gas is so bad for an engine !,

why have " Reticulated Exaust Gas " systems on motor vehicles .

AND

If those engine manufacturers make/endorse  a modification. 

WHY

Does this government refuse to allow modifications. 

spacesailor

 

[facthunter]

 Exhaust recirculation To reduce combustion temps which cause Nitrous oxides. Carbon monoxide stops the blood carrying oxygen. Nev

[spacesailor]

Due the extra power,  used to overcome the R E G pollution in the air inlet, 

Are more oxides produced, than if  there cleaner air is used, 

That is a 64 thousand $ question.

spacesailor

[facthunter]

There is some loss of efficiency due to the LOWERED combustion temperature and therefore more CO2 is produced. There is no question about that. It's a fact.. Nev