Wind-chill question

Here is the question:

We have two identical tractors with the same fuel, oil and filters. Temperature is 0 degrees f., wind is blowing 40mph steady. (I know..never happens but this is a hypothetical question).

One tractor is parked in a shop which is closed to the elements but not heated.

The other tractor is parked on a hill facing the wind.

Both tractors sit idle for a month.

Which one will start more easily?

Extra points for why.


Brad
 
No extra points here,but I don't know why one would start any easier than the other. 0 degrees is 0 degrees,shouldn't matter what the wind chill is. Unless one is made of human skin instead of cast iron.
 
My experience is the one in the shed. I know they say that wind should make no difference, but it does. Even if you can park one out of the wind it will make a HUGE difference.
 
Bolonia,
Windchill can freeze up a carburetor in 40* weather. It can freeze a block in colder weather. I looked it up once and the same guy said what you said and in the same sentence said you can get frostbite from windchill in weather above freezing.
The facts need to be proven maybe to settle this but on my car the carb would freeze up in 40* weather until the engine warmed enough cutting my speed to 40MPH. And that's proof enough for me. Ice is Ice try using your blow gun on a cold wet day above freezing and see what happens.
Walt Davies
 
If it"s 0 and the wind is blowing I"ll say the one in the shop. They have set for a month so the battery is dead or close to it. If it"s that cold I"ll hang around and try to get the one in the shop started. Forget that one out in the 40 mph wind unless it"s headed down hill.
 
You did not say how long the wind had been blowing or how long it has been zero. But yes, the tractor out in the open WILL cool off quicker. BUT once both tractors are equally chilled there will be no difference. Neither will start.
 

I always heard wind chill only applied to skin, not to objects, so I agree that 0 is the same to the tractor in a wind or in the calm.
 
Short answer: Thermodynamics.

Longer answer: Adiabatic cooling. The air in the tire is under pressure, you have a large amount of air in a small space. AKA compressed. When you pull the core you are releasing this air to a large area, expanding. When this happens you get heat absorption. When you pull heat out, you get the frosting you see.

Happens the same on an air compressor nozzle.

Rick
Adiabatic cooling explained better than I did
 
(quoted from post at 20:21:30 01/24/13)
That's BS, an open stock tank out in the wind will always have thicker ice than one that is protected.

Yes, Windchill does have somethng to do with evaporation or the cooling of a warm surface. The open stock tank is warmer than the sub freezing air temp and will cool off quicker 'cause the wind-chill is removing the heat. Cold hard steel has no such evaporation issues. Think about an aircraft flying at whatever speed you like. It is not effected by the wind. Only the temp itself

Sounds good to me

Sw
 
Yes a stock tank in the wind will have more ice. The wind will cool an object to zero degrees faster than one out of the wind. The wind blows away the warmer protective layer from the object, skin, water, ect causing it to cool faster and appear to feel colder.

A shed on most days is warmer. It takes a while for the cold to penetrate a building. It does provide some minimal r value.

Clear as mud?
 
It always seems to be warmer in our building then outside. I don't like to let stuff sit out.

Now if those are old JD's with pony motors then I'd go for the one on the hill. Hill starters work the best for them. That's why you used to see them parked on barn banks.
 
Speak for your tractors. My Oliver 1600 has been starting every morining all week unasssisted to feed cattle. lol
 
Brad, you answered your own question. If it is 0 degrees out the one in the shed should start easier because in a closed shed, unheated, will be warmer than 0 degrees. I've lived in the cold climate all my life and worked out in it and I'll take the one inside anytime.
 
If the temp is zero both places wont make any difference. Windchill is only for skin and not anything to do with metal. What are you doing trying to start something.
 
The air excaping does the same thing that an airconditioner does. Compressed air gets hot, thats why there are sometimes fins on the line from the compressor to the tank. Released air gets cold, that's why blow nozzles and air tools freeze.
 

Mine start. In the original post he says the tractors have both been parked a month. If it's been zero for a month it's pretty doubtful either will start.
 
Exactly!!!, so where wind can blow through a small opening say under the hood of a tractor and exits out the other side the temp drops, and thus Adiabatic cooling takes place. So if a fuel filter was in that spot where the wind is passing through will be colder than where the wind can't blow through or pass. The same thing happens to your radiator when the fan sucks air through it or you drive down the road and air moves through the radiator, sometimes causing a radiator to freeze after you are moving. Wind movement and pressure differential cause cooling or what could be called wind chill.
Loren, the Acg.
 
The one in the shed.

Why ?

Because, no one is stupid enough to fart around with the one parked out in the elements.
 

We had two barns on the farm. A brook ran between them. They were probably 100 ft apart and the space faced more or less east-west. When the wind would blow from the west the west end of the space being wider it would compress the air. Or at least it seemed that way. The air coming out from between those barns always seemed colder than anywhere else.
 
It will not matter to the tractor, (the operator would be a different subject!) Wind chill is a calculation taking in to consideration the effect of wind and cold to exposed skin.
The human body loses heat through convection, evaporation, conduction, and radiation.[1] The rate of heat loss by a surface through convection depends on the wind speed above that surface. As a surface heats the air around it, an insulating boundary layer of warm air forms against the surface. Moving air disrupts the boundary layer, allowing for new, cooler air to replace the warm air against the surface. The faster the wind speed, the more readily the surface cools.

For inanimate objects, the effect of wind chill is to reduce any warmer objects to the ambient temperature more quickly. It cannot, however, reduce the temperature of these objects below the ambient temperature, no matter how great the wind velocity.
 
Don't know, don't care.....what I do know is that having to mess with a tractor, outside when it's -20 plus a 15-20 MPH wind is blowing, trying to get it started is a miserable job.

Rick
 
The engines are at the same temperature, will not make any difference. They have no warm blood inside to feel as though it is colder.
However, the one on the hill will start much easier, cause you just roll her down the hill and pop the clutch.
 
Hello Brad Buchanan,

Easy! the one that is in better mechanical shape.
Wind chill is a measure of how it feels on your skin, and it is a combination of temperature and wind speed.

Guido.
 
I agree with the "zero is zero" people. You can set a glass of water on a table outside in 34 degree weather and blow wind at it at 60 mph and it will not freeze. So you can blow zero degree wind at a tractor and it will remain zero. The frost in the venturi of a carb at certain humidity and temp levels does not apply here to this question. An inaminate object does not sense windchill! Another related question I have is why put shutters on a rediator with a properly working thermostat controlled cooling system???
 
Good answer Rick. First time I have seen that word, ( adiabatic ) used since AF tech school. Best I remember, it means a change in temperature without a change in heat content. Thanks for jogging my memory. Joe
 


The other year I posted about wind chill. Many argued with me that wind chill is colder but it isn't.
When we eat a bowl of soup or chili and it's too hot to eat, what do we do? We blow on it to cool it down. Otherwise we would be there an hour for it to cool on its own.

One man posted the other year. Drive down the road at 50mph and 0 degrees and hold a thermometer out the window for a minute and see what it reads. It will be 0.

Wind chill is just a calculated formula on how fast an object cools down, this is why we blow on our bowl of soup. Once the object is cooled to ambient temperature, a wind of 0 degrees and 50mph won't make it any colder. Because heat travels from hot to cold.
 
Hello B-maniac,

Short answer, quicker warm ups with the shutters closed. Also better cooling temperature control.
Thermostat is not an option.

Guido.
 
My cousin proved that one. A guy in the coffee shop swore up and down it made a difference,so they went and got a thermometer and he had the guy hold it out the car window. Drove him five miles without a glove and the thermometer never changed. Louis's hand took a while to recover though.
 
"Thermostat is not an option" , are you saying a modern semi tractor does not have a thermostat? or what are you saying?
 

I think it's because at highway speeds in cold weather you get extreme cooling in the radiator. The thermostat would open as needed and let in a bunch of ice water before it could close again. Not good.
 
The one in the building will start easier because the heat will be disappated faster on the one outside once the firing of the engine has started just like the radiator on the tractor work the faster the air flows through the quicker it will cool. Not sure that I explained it correctly or not.
 
I don't have an answer to your question. What I can tell you is I have started my 806 diesel every day for 20 years in the winter to haul manure. If it is sitting out in the wind 15 above 0 plugged in it will not start. If its in the shed plugged it will have no problem starting at 30 below 0. Keith
 
Hello B-maniac,

I meant to say that you need one. Most people take it off when the engine is overheating. You need a thermostat for proper engine temperature control.

Guido.
 

Obviously the one out doors facing the wind. The wind comes from the southwest. the morning sun comes from the southeast and warms the intake manifold which is almost always on the left so it will fir right up unless you are lazy and don't go out until mid afternoon.
 
(quoted from post at 11:31:12 01/24/13) Here is the question:

We have two identical tractors with the same fuel, oil and filters. Temperature is 0 degrees f., wind is blowing 40mph steady. (I know..never happens but this is a hypothetical question). One tractor is parked in a shop which is closed to the elements but not heated. The other tractor is parked on a hill facing the wind. Both tractors sit idle for a month. Which one will start more easily? Extra points for why. Brad

Okay I'll bite, to your question: You stated both tractors have been idle for a month however you did not state the temperature has been 0 degrees for a month:

Case 1, In the event the weather has been exactly 0 degrees for one month both tractors will be cold soaked to 0 degrees and there should be no difference in how they start.

Case 2, In the event your question assumes normal winter weather patterns where it warms up during the day and dips down at night the tractor exposed to the wind is more likely to be cold soaked to 0 degrees. The tractor in the barn is not exposed to the wind is more likely to be warmer. In this case the tractor in the barn is more likely to start or start more easily.

Why - the average temperature in winter over a 24 hour period will typically be much warmer than the 0 degrees which is likely a night time low. In other words there is more time at temperatures above 0 degrees than the time at or near 0 degrees. The tractor sitting outside in the 40 MPH wind will follow the temperature more closely due to the wind - this is called convective heat transfer. The tractor in the barn lacks the convective heat transfer and stabilizes at a more average temperature. As the temperature falls outside this tractor (metal temperature) will lag behind that of the outside air and the metal temperature of the outside tractor. (Sorry that got a little long)

Case 3, For Case 1) and Case 2) above I assumed the tractors were not "plugged in" since it was not stated. However, lets take the case where the tractors are both plugged in and the heaters are identical. In this case the tractor in the barn is more likely to start since there is no wind to carry away heat as the heater attempts to warm the engine block. Since the tractor is trying to keep warm similar to a human - the 40 MPH wind makes the tractor colder by reducing the effectiveness of the heater.
 
Indiana Ken is keeping more factual matters in mind than many in this thread, which upon reading all of them brings me to the conclusion that several lose sight of the facts &/or don't know what they are talking about & apply wrong example to this situation, such as carb icing or releasing air from a tire.
 
I would have to go with the one inside.
Only a fool would mess around in that wind when he has the option to work inside.
Easier to walk into the shop than it is to walk up the hill to the other tractor.
Real hard to keep a tiger torch lit in 40 mph wind.
Dave
 
I've been starting gas and diesel engines in No. Dak. all my life and you guys say a tractor in a shed won't start any better than one in a windchill have never lived in cold weather. The first thing is--if the temp is zero outside, the temp in that shed out of the wind will be a few degrees warmer. Forget about your books and come up here when the temp is -20 and 20 mph wind. That makes the wind chill around -50 at least. There is no way them two tractors are equal for starting.
 
The one in the barn will start easier because it is going to be hard to spray ether in the air intake of the one sitting outside with a 40 MPH wind.
Tractor facing into the wind, your standing on the steps, spray. Ether in the face. Yuck.
 
(quoted from post at 22:49:59 01/24/13) I've been starting gas and diesel engines in No. Dak. all my life and you guys say a tractor in a shed won't start any better than one in a windchill have never lived in cold weather. The first thing is--if the temp is zero outside, the temp in that shed out of the wind will be a few degrees warmer. Forget about your books and come up here when the temp is -20 and 20 mph wind. That makes the wind chill around -50 at least. There is no way them two tractors are equal for starting.
en, on the scenario that YOU outline, we don't doubt you, BUT & HOWEVER, etc., just like so many others here, you have ignored the basic premises set forth. Both are cold soaked for a month at 0 F, with never any warmer temperatures! Windchill is a human/skin factor.....has absolutely ZERO to do with iron/machinery/etc. Period!
 
Wind chill seems to be the hanging point. As I remember, Wind chill is the feel on your skin as the water in your skin evaporates. Seems like that would also hold true for open water.
Tim in OR
 
Wow! Thanks for the great response.

Some fascinating theories. I will gladly defer to the more educated posters here as I must rely on my high school science classes in the distant past.

Anyway here is my two bit theory:

processes that produce heat are referred to as exothermic as they produce heat ie. fuel being burned in your tractors engine.

Processes that remove heat are referred to as endothermic ie. ice cubes melting in your hand crank ice cream maker or the 40mph wind cooling your tractor on the hill.

In the case of the two tractors the endothermic process continues until all the heat is removed from the machines. The tractor on the hill will indeed cool much faster but over the period of time both will cool to 0 degrees f.

Which will start more easily? Both engines being at the same temperature should start equally well but in my case if I was on the hill cranking the tractor the 40mph wind would blow my mad bomber hat off my head and It would take me 5 minutes to chase it down so....

The tractor in the shed wins!

Thanks for playing.

Brad
 
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