Aces High Bulletin Board
General Forums => Aces High General Discussion => Topic started by: Tinkles on September 25, 2013, 08:29:40 PM
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Just for clarification.
Was in a 110G-2 today at 23k and was watching the E6B since I was low on fuel.
When I looked at the E6B I noticed this.
229 Indicated
339 True
351 Ground
So what speed was I actually going? And what is the significance of all three?
Thanks for the info.
Tinkles
<<S>>
P.S. Yes I knew these existed looong before this topic was posted. But I was just curious as to what each one means and it's relevance to my plane.
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True speed if your actual speed, but fly by your indicated.
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There are actually 4 types of airspeed (3 in AH)
This will clear it up for you :aok
http://www.golfhotelwhiskey.com/understanding-the-four-types-of-airspeed/
:cheers: Oz
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True speed if your actual speed, but fly by your indicated.
that can be dangerous in certain planes.
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True speed if your actual speed
this has been my understanding since 2002. However, when bombing the calibrated airspeed number tends to ground speed. Granted, I've not spent as much time in buffs of late and made notes during the flight as I should.
It's confusing.
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True air speed is the speed of the air passing your aircraft. Ground speed is your speed relative to the ground, and is important for navigation. Indicated is what you should worry about if you're slow and about to stall. True air speed is what you need to worry about going fast in a dive close to compressibility.
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Btw. true air speed (TAS) is the little red arrow on your speedo.
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Btw. again... Indicated is actually a measure of the air pressure exerted by the air hitting your aircraft. That's why it is important when you're slow, because your wings are held up by air pressure, not air speed.
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There are actually 4 types of airspeed (3 in AH)
This will clear it up for you :aok
http://www.golfhotelwhiskey.com/understanding-the-four-types-of-airspeed/
:cheers: Oz
I think you could argue that we have all 4 types but since there isn't any error in our IAS it matches CAS.
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Btw. true air speed (TAS) is the little red arrow on your speedo.
How do you know about the red arrow on my speedo? :uhoh
:neener:
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Determining your actual speed is very complex. I think we don't know exactly how fast the Sun is moving in space while we orbit it.
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I think you could argue that we have all 4 types but since there isn't any error in our IAS it matches CAS.
We model CAS and IAS. I know the needle shows IAS not CAS. I would have to look at code to be sure which one the E6B is showing.
HiTech
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We model CAS and IAS. I know the needle shows IAS not CAS. I would have to look at code to be sure which one the E6B is showing.
HiTech
That is amazing that you would model the IAS errors. So we do have all 4 types in AH. :D
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this has been my understanding since 2002. However, when bombing the calibrated airspeed number tends to ground speed. Granted, I've not spent as much time in buffs of late and made notes during the flight as I should.
It's confusing.
I am sure that I am over simplifying this but, calibrating to ground speed is correct basically because your target is on the ground. the ballistic arc of your bombs has to be callculated using 2 parts. 1:the speed of the bomb at release point (I.E. the speed of your bomber) in relation to your desired impact point; and 2: the release platform's altitude over the desired impact point at the point in space of bomb release. This is why when the bombsight is calibrated it accounts for aircraft altitude and ground speed (and target altitude when bombsight calibration is set to "manual" in the arena settings)
At least this is how my meager physics knowledge justifies it. Somebody smarter or more informed than me might come along and let me know how wrong I got it though :D
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So your True air speed can only be slower than your Ground speed if there is a tail wind? :salute
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So your True air speed can only be slower than your Ground speed if there is a tail wind? :salute
Correct.
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True air speed is what you need to worry about going fast in a dive close to compressibility.
The gist of one of my favorite things I ever saw Hitech post to someone talking about flight modeling was, 'You are trying to apply broad general logic in an arena where it is not detailed enough to apply.'
With that in mind, I'm curious how this applies. To me, compression would seem to me to be a similar thing to a stall, just at the other end of the spectrum. Why would IAS not apply in compression like a stall? Not challenging the truth of the statement, it just seems counterintuitive to me.
Wiley.
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True speed if your actual speed, but fly by your indicated.
:airplane: Not quite true, but close! Your ground speed is the speed at which your aircraft is moving over the ground and that is the one which you must use to compute time to your destination! Your true airspeed is just indicated airspeed, corrected for altitude and temperature! Your indicated airspeed is the speed at which the air is flowing over your pitot tube and wings. Your calibrated airspeed is the airspeed corrected for any instrument errors.
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Wiley, stalling is the abrupt loss of lift as the angle of attack increases beyond the wing's ability to keep the airflow from separating from the wing surface. Indicated airspeed is the raw data that comes from your instrument, which is connected to a pressure sensor in the Pitot tube. This device measures the pressure exerted on it by the flow velocity of the air. The higher you fly the thinner the air gets and thus the faster you need to fly to get the same indicated airspeed; there are fewer air molecules hitting the Pitot tube sensor for any given unit of speed and time, so speed must be increased to achieve the same reading. IAS thus also neatly indicates the mass of air flowing past your wing in any given unit of time, which is what you need to generate lift. In thinner air you need more speed to generate the same lift, and in general, without going into extreme detail, the IAS you need to keep flying changes little with altitude, because you need to increase speed with altitude just to get the same IAS reading.
At the other end of the speed spectrum you are facing compressibility, or in other words, speeds where the air molecules are beginning to have trouble getting out of the way quick enough, and start forming shock waves. Compressibility is a Mach effect and thus directly linked to the speed of sound, so the true airspeed is what is important in that end of your aircrafts speed range.
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Compressibility is a Mach effect and thus directly linked to the speed of sound, so the true airspeed is what is important in that end of your aircrafts speed range.
Ah! Makes perfect sense now. I didn't quite understand the general idea of compressibility. Thanks for the answer.
Wiley.
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So your True air speed can only be slower than your Ground speed if there is a tail wind? :salute
:airplane: An example of your question is this: You are flying on a 090 degree heading, and your true airspeed at, say, 15,000 feet is 330MPH true! Now, with the wind 270 degrees at 30MPH, then your aircraft would be moving over the ground at 360MPH. If you were heading 270 degrees with your aircraft, with the same 30MPH wind, and 330MPH true air speed, you would now be moving 300MPH over the ground, which is what is referred to as ground speed. Another effect of wind, which a lot of people do not notice is this: your aircraft will climb faster in feet per minute into the wind than it will climbing down wind.
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a TA152 at 40k the speed!!!!!!
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So what speed was I actually going? And what is the significance of all three?
Hi Tinkles, this should help.
Airspeed is measured by determining the difference between 2 air pressures about the aircraft. One pressure measurement is taken on the side of the aircraft, or on the side of the pitot-static tube (e.g. a small tube sticking out of the aircraft with its axis parallel to the direction of flight ), and indicates the static air pressure at your current altitude. The other pressure measurement is taken in the front, open end of the pitot tube, and indicates the total air pressure acting on your aircraft as you fly through the air mass. The difference in these 2 measurements is indicated airspeed (IAS). Airspeed gauges are only calibrated for sea-level, standard-day atmospheric conditions. So. unless you are at sea level and the atmospheric conditions match standard day conditions, your airspeed indicator is not indicating true airspeed (TAS), ie your true speed with respect to the air mass. That's why this value is called IAS, it’s what is indicated on the airspeed gauge.
Calibrated airspeed (CAS) is IAS corrected for what is called "position error". This error is due to local airflow effects about the static measuring source. As the aircraft moves through the air, it changes the pressure field around itself. So, you don't get an accurate static pressure reading from the static source. This error is different for every aircraft type, and usually changes for each aircraft with airspeed and configuration (e.g. gear up or down) changes. Through flight test, you can determine what these position errors are, and then determine the necessary corrections to get CAS from IAS. The reason this is called CAS, is because this is what you would read if the airspeed indicator was "calibrated" perfectly, i.e. no position errors.
Equivalent airspeed (EAS) is CAS corrected for what is called "compressibility effects". As you go higher and/or faster, individual air molecules can be compressed as they come to rest inside the pitot tube. This "compressing" has the effect of causing the pressure sensor inside the pitot tube to indicate a total pressure higher than the actual value. These compressibility corrections are independent of aircraft type, and depend only on CAS and pressure altitude. They only come into play if you exceed 0.6 Mach number and/or 30,000 ft pressure altitude. The reason this is called EAS, is because this is your TAS equivalent at sea level. That means, take whatever value this is at your current altitude, Star Trek transport your aircraft to sea level, and this will be your TAS. The term is important because for a given angle of attack (AOA), an aircraft behaves the same aerodynamically (ie. it generates the same amount of lift, drag, etc.) at a given EAS regardless of altitude, discounting Mach number effects.
TAS is EAS corrected for air density at your current altitude. Air density is a function of pressure and temperature. Ground speed is TAS corrected for wind velocity.
At sea-level, standard-day atmospheric conditions all of these airspeed measurements will be equal, well except for IAS which is still dependant on those position errors, which are different for each aircraft type. An easy way to remember how their magnitudes relate to one another at higher altitudes is by using the square root symbol as shown in the diagram below:
(http://www.badz.pwp.blueyonder.co.uk/images/Speedtype.jpg)
IAS and CAS are usually very close to one another. For most aircraft, usually within 10 to 20 knots or less. EAS is always less than CAS. For airspeeds of Mach 1.0 or less, the maximum difference will be 30 knots. TAS is always greater than all the other airspeeds, at altitudes above sea level.
An important note, IAS/CAS tells the pilot how the aircraft will behave regardless of what altitude he's at. The same aircraft at 200 KCAS at sea level behaves just like it does at 200 KCAS at 30,000 feet. Remember what I said about a given AOA and EAS above? IAS/CAS is very close to EAS, much closer than TAS even at moderate to low altitudes, much less high altitudes. Therefore, since the aircraft behaves the same for the same airspeed even at vastly different altitudes, this makes flying one a lot easier when referencing IAS/CAS which is why when pilots talk speed, they talk IAS/CAS and in WWII that would have just been IAS. On the other hand if you want to compare different aircraft or know which aircraft is faster you need to know their TAS and so aircraft data and performance reports are normally provided in TAS.
Hope that helps…
Badboy
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Hi Tinkles, this should help.
Airspeed is measured by determining the difference between 2 air pressures about the aircraft. One pressure measurement is taken on the side of the aircraft, or on the side of the pitot-static tube (e.g. a small tube sticking out of the aircraft with its axis parallel to the direction of flight ), and indicates the static air pressure at your current altitude. The other pressure measurement is taken in the front, open end of the pitot tube, and indicates the total air pressure acting on your aircraft as you fly through the air mass. The difference in these 2 measurements is indicated airspeed (IAS). Airspeed gauges are only calibrated for sea-level, standard-day atmospheric conditions. So. unless you are at sea level and the atmospheric conditions match standard day conditions, your airspeed indicator is not indicating true airspeed (TAS), ie your true speed with respect to the air mass. That's why this value is called IAS, it’s what is indicated on the airspeed gauge.
Calibrated airspeed (CAS) is IAS corrected for what is called "position error". This error is due to local airflow effects about the static measuring source. As the aircraft moves through the air, it changes the pressure field around itself. So, you don't get an accurate static pressure reading from the static source. This error is different for every aircraft type, and usually changes for each aircraft with airspeed and configuration (e.g. gear up or down) changes. Through flight test, you can determine what these position errors are, and then determine the necessary corrections to get CAS from IAS. The reason this is called CAS, is because this is what you would read if the airspeed indicator was "calibrated" perfectly, i.e. no position errors.
Equivalent airspeed (EAS) is CAS corrected for what is called "compressibility effects". As you go higher and/or faster, individual air molecules can be compressed as they come to rest inside the pitot tube. This "compressing" has the effect of causing the pressure sensor inside the pitot tube to indicate a total pressure higher than the actual value. These compressibility corrections are independent of aircraft type, and depend only on CAS and pressure altitude. They only come into play if you exceed 0.6 Mach number and/or 30,000 ft pressure altitude. The reason this is called EAS, is because this is your TAS equivalent at sea level. That means, take whatever value this is at your current altitude, Star Trek transport your aircraft to sea level, and this will be your TAS. The term is important because for a given angle of attack (AOA), an aircraft behaves the same aerodynamically (ie. it generates the same amount of lift, drag, etc.) at a given EAS regardless of altitude, discounting Mach number effects.
TAS is EAS corrected for air density at your current altitude. Air density is a function of pressure and temperature. Ground speed is TAS corrected for wind velocity.
At sea-level, standard-day atmospheric conditions all of these airspeed measurements will be equal, well except for IAS which is still dependant on those position errors, which are different for each aircraft type. An easy way to remember how their magnitudes relate to one another at higher altitudes is by using the square root symbol as shown in the diagram below:
(http://www.badz.pwp.blueyonder.co.uk/images/Speedtype.jpg)
IAS and CAS are usually very close to one another. For most aircraft, usually within 10 to 20 knots or less. EAS is always less than CAS. For airspeeds of Mach 1.0 or less, the maximum difference will be 30 knots. TAS is always greater than all the other airspeeds, at altitudes above sea level.
An important note, IAS/CAS tells the pilot how the aircraft will behave regardless of what altitude he's at. The same aircraft at 200 KCAS at sea level behaves just like it does at 200 KCAS at 30,000 feet. Remember what I said about a given AOA and EAS above? IAS/CAS is very close to EAS, much closer than TAS even at moderate to low altitudes, much less high altitudes. Therefore, since the aircraft behaves the same for the same airspeed even at vastly different altitudes, this makes flying one a lot easier when referencing IAS/CAS which is why when pilots talk speed, they talk IAS/CAS and in WWII that would have just been IAS. On the other hand if you want to compare different aircraft or know which aircraft is faster you need to know their TAS and so aircraft data and performance reports are normally provided in TAS.
Hope that helps…
Badboy
Lots.. of... words.. :rolleyes:
Thank you guys for all the info.
Tinkles
<<S>>
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Another effect of wind, which a lot of people do not notice is this: your aircraft will climb faster in feet per minute into the wind than it will climbing down wind.
Are you sure this is what you meant to write?
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Are you sure this is what you meant to write?
In reference to the ground.
- oldman
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Compressibility is a Mach effect and thus directly linked to the speed of sound, so the true airspeed is what is important in that end of your aircrafts speed range.
For Mach effects the mach number is what is important (duh). It is displayed on the E6B. For each airplane mach buffet always occurs at the same mach number no matter the altitude. Same with control lockup. Mach changes with temperature and therefore altitude. Where as TAS is, well true airspeed, independent of altitude and temperature changes.
So say your cruising along at the edge of Mach buffet at .79 mach in a ME163. You increase throttle and now your controls lock up at .83 mach.
At 24,000 feet these occur at a TAS of 549 (375 ias) and 577 knts (394 ias), and throttle is 33%.
At 1,000 feet these occur at a TAS of 600 (593 ias) and 630 knts (620 ias), and throttle is 77%.
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In reference to the ground.
- oldman
I would hope so but that's not what he wrote. It reminds me of the old question if an aircraft turns faster with a headwind or a tailwind.
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Your indicated airspeed is the speed at which the air is flowing over your pitot tube
:huh
obviously incorrect.
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I would hope so but that's not what he wrote. It reminds me of the old question if an aircraft turns faster with a headwind or a tailwind.
:airplane: Regardless of what you may think or have heard, just try this in a real aircraft: takeoff into a 20MPH headwind and time your self to 500 feet. Then land, turn around, takeoff downwind and time yourself to 500 feet. You will see that there is considerable difference in the amount of time it took to climb into the wind and the time it took to climb downwind.
Maybe I need to state it in a different way: We want to climb to 10,000 feet, and we are climbing at a 1,000 feet per minute rate of climb, that would be 10 minutes, say into a constant 20MPH headwind, correct?
Now, reverse the climb into a downwind, same 1,000 feet per minute, 20MPH tailwind, climbing to 10,000 feet, should take 10 minutes, right? Sorry Charlie, in the real world, it won't arrive at 10,000 feet in 10 minutes, like you think it would. A lot of the books and so called experts say that you will, but try it and you will find that what I just told you is correct. The bottom line to the statement is just this: An aircraft will climb more efficiently into the wind than downwind. The aircraft will move further away from point of departure when climbing downwind, when it arrives at 10,000 feet, than it will climbing into the wind, because of the difference in ground speed.
The old argument of turns into and downwind is really very simple: turns into or downwind, when started directly into or downwind, will be the same, as the wind effect is canceled because of the same amount of time into and downwind. Now, if you really want to discuss turns into and downwind, consider this: you are flying on a heading of 360 degrees and the wind is from 270 degrees at 30 knots, and you want to make a 180 degree turn to the left, which 90 degree segment of the turn will have the greatest radius of turn?
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:huh
obviously incorrect.
:airplane: Just where does your airspeed instrument pick up the airspeed at which you use to control the aircraft? Or, maybe I should have said, the device which is being impacted by the oncoming air and is transferred to the airspeed indicator is called what?
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:airplane: Regardless of what you may think or have heard, just try this in a real aircraft: takeoff into a 20MPH headwind and time your self to 500 feet. Then land, turn around, takeoff downwind and time yourself to 500 feet. You will see that there is considerable difference in the amount of time it took to climb into the wind and the time it took to climb downwind.
Maybe I need to state it in a different way: We want to climb to 10,000 feet, and we are climbing at a 1,000 feet per minute rate of climb, that would be 10 minutes, say into a constant 20MPH headwind, correct?
Now, reverse the climb into a downwind, same 1,000 feet per minute, 20MPH tailwind, climbing to 10,000 feet, should take 10 minutes, right? Sorry Charlie, in the real world, it won't arrive at 10,000 feet in 10 minutes, like you think it would. A lot of the books and so called experts say that you will, but try it and you will find that what I just told you is correct. The bottom line to the statement is just this: An aircraft will climb more efficiently into the wind than downwind. The aircraft will move further away from point of departure when climbing downwind, when it arrives at 10,000 feet, than it will climbing into the wind, because of the difference in ground speed.
The old argument of turns into and downwind is really very simple: turns into or downwind, when started directly into or downwind, will be the same, as the wind effect is canceled because of the same amount of time into and downwind. Now, if you really want to discuss turns into and downwind, consider this: you are flying on a heading of 360 degrees and the wind is from 270 degrees at 30 knots, and you want to make a 180 degree turn to the left, which 90 degree segment of the turn will have the greatest radius of turn?
What about the effects on cruise performance if you're not "on the step?" How's the wind effect you then?
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An aircraft will climb more efficiently into the wind than downwind.
I agree with you, when you measure using gradient alone or feet per nautical mile to measure efficiency. Specific fuel consumption, no. Time over a distance, no. I also don't agree with you that if I spin my VS bug to a 1000'/min climb heading westbound that those 1000'/min are different eastbound. Feet per nautical mile, absolutely but not on the clock.
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:airplane: Regardless of what you may think or have heard, just try this in a real aircraft: takeoff into a 20MPH headwind and time your self to 500 feet. Then land, turn around, takeoff downwind and time yourself to 500 feet. You will see that there is considerable difference in the amount of time it took to climb into the wind and the time it took to climb downwind.
Maybe I need to state it in a different way: We want to climb to 10,000 feet, and we are climbing at a 1,000 feet per minute rate of climb, that would be 10 minutes, say into a constant 20MPH headwind, correct?
Now, reverse the climb into a downwind, same 1,000 feet per minute, 20MPH tailwind, climbing to 10,000 feet, should take 10 minutes, right? Sorry Charlie, in the real world, it won't arrive at 10,000 feet in 10 minutes, like you think it would. A lot of the books and so called experts say that you will, but try it and you will find that what I just told you is correct. The bottom line to the statement is just this: An aircraft will climb more efficiently into the wind than downwind. The aircraft will move further away from point of departure when climbing downwind, when it arrives at 10,000 feet, than it will climbing into the wind, because of the difference in ground speed.
The old argument of turns into and downwind is really very simple: turns into or downwind, when started directly into or downwind, will be the same, as the wind effect is canceled because of the same amount of time into and downwind. Now, if you really want to discuss turns into and downwind, consider this: you are flying on a heading of 360 degrees and the wind is from 270 degrees at 30 knots, and you want to make a 180 degree turn to the left, which 90 degree segment of the turn will have the greatest radius of turn?
I'm calling BS. You ain't flying a kite. Your rate of climb indicator doesn't give a rats bellybutton which way the wind is blowing. If the little dial says your climbing at 1000fpm, in 10 minutes you'll add 10000' feet to your altitude.
As for as your t/o climb performance difference in time to an altitude depending on wind. Well ya, duh. You have a 40 knot wind difference. A 20kt headwind is going to decrease your t/o roll. A 20kt tailwind will hugely increase your t/o roll (hope the runway is very long with no trees at the end). With a 20kt headwind, you have 20kt airspeed just sitting there. With a 20kt tailwind your airplane has to accelerate to 20mph ground speed just to have 0 airspeed, then accelerate to t/o airspeed. All that time accelerating on the ground is going to impact your total time to altitude. But once you are airborne headwind/tailwind makes no difference to the rate of climb.
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I agree with you, when you measure using gradient alone or feet per nautical mile to measure efficiency. Specific fuel consumption, no. Time over a distance, no. I also don't agree with you that if I spin my VS bug to a 1000'/min climb heading westbound that those 1000'/min are different eastbound. Feet per nautical mile, absolutely but not on the clock.
:airplane: Didn't address fuel consumption, was only making the statement, based on experience, that the aircraft, climbing at a ROC of 1,000 feet per, will arrive at 10,000 feet, quicker into the wind than downwind, because of the difference in angle of climb to 10,000. While you are cruising around in your kerosene burner, check your AOA instrument into and downwind. Might be of interest to you. The best test is the radar altimeter, check it both ways and see what you get.
Not being familiar with the current crop of jet aircraft and the latest, greatest instrumentation available to the PIC, not sure how vertical speed get its info, from pressure system, using static port, or raw data from radar altimeter, but the AOA of any aircraft climbing into the wind is greater than downwind, so there for, into the wind, it will get to 10,000 feet quicker in time, regardless.
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I'm calling BS. You ain't flying a kite. Your rate of climb indicator doesn't give a rats bellybutton which way the wind is blowing. If the little dial says your climbing at 1000fpm, in 10 minutes you'll add 10000' feet to your altitude.
As for as your t/o climb performance difference in time to an altitude depending on wind. Well ya, duh. You have a 40 knot wind difference. A 20kt headwind is going to decrease your t/o roll. A 20kt tailwind will hugely increase your t/o roll (hope the runway is very long with no trees at the end). With a 20kt headwind, you have 20kt airspeed just sitting there. With a 20kt tailwind your airplane has to accelerate to 20mph ground speed just to have 0 airspeed, then accelerate to t/o airspeed. All that time accelerating on the ground is going to impact your total time to altitude. But once you are airborne headwind/tailwind makes no difference to the rate of climb.
:airplane: Never said that the wind direction made a difference in what the ROC indicator shows you, just that it will take you longer to get to 10,000 downwind than up wind. Your are right about the vertical speed not giving a "rats" bellybutton about which way the wind is blowing, but your aircraft does.
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:airplane: Never said that the wind direction made a difference in what the ROC indicator shows you, just that it will take you longer to get to 10,000 downwind than up wind. Your are right about the vertical speed not giving a "rats" bellybutton about which way the wind is blowing, but your aircraft does.
Post a video or it never happened.
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:airplane: Didn't address fuel consumption, was only making the statement, based on experience, that the aircraft, climbing at a ROC of 1,000 feet per, will arrive at 10,000 feet, quicker into the wind than downwind, because of the difference in angle of climb to 10,000. While you are cruising around in your kerosene burner, check your AOA instrument into and downwind. Might be of interest to you. The best test is the radar altimeter, check it both ways and see what you get.
Not being familiar with the current crop of jet aircraft and the latest, greatest instrumentation available to the PIC, not sure how vertical speed get its info, from pressure system, using static port, or raw data from radar altimeter, but the AOA of any aircraft climbing into the wind is greater than downwind, so there for, into the wind, it will get to 10,000 feet quicker in time, regardless.
Radar altimeter only gives a reading below 2500'. If I'm only doing 1000'/min up below 2500 I've got an engine failure.
I see what you're saying. When the winds are out of a certain direction when I left my home airport I'd be level at cruise altitude by the time I passed Washington Dulles airport. If they were out of another direction I wouldn't quite be up there yet. Temperature relative to standard mattered, weight mattered however we typically left at the same weight on this particular flight. That wasn't a function of time, but of distance. I simply hadn't traveled the same ESAD (Equivalent Still Air Distance) without the headwind "helping" me get up "faster" which again, was a function of distance rather than time. I'd still be level at cruise in the same amount of time, since we'd note the information which was displayed right in front of us on the clocks which start at weight off wheels. The biggest factor would be temperature. At ISA+10 it takes longer to climb than it does at ISA.
My AOA comes from one of two vanes on either side of the airplane. Rate of climb which come from an Instantaneous-VSI integrated with 2/3 Air Data Computers which are using a regular static system and probes to gather its information.
1000 feet per minute is 1000 feet per minute. How many units of lateral measure it takes to climb that 1000 feet will change with wind. How many seconds it takes to climb those 1000 feet will remain the same.
It'll take more than an anecdote to change my opinion.
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Post a video or it never happened.
:airplane: Unfortunately, or fortunately, depending on which way you look at it, at my age, 80 the 9th of Oct, I don't have to prove anything to anybody. Body is worn out, but mind is still just as sharp as in my 20's and 30's. My problem is that I do not have enough command of the English lang. to better explain experience in my head! Didn't mean to create a up roar, but has been an interesting discussion.
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Earl I'm not beating up on ya buddy! Like I said I think I know what you're getting at but then you say something that definitively isn't what I think you were saying I keep my dissenting opinion.
I'm not even saying you're outright wrong because you may adapt your technique without realizing it but also may appeared to have been so using older instrumentation.
Let's leave the Invader/Maurader discussion aside too ;)
Happy Friday.
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:airplane: Just where does your airspeed instrument pick up the airspeed at which you use to control the aircraft? Or, maybe I should have said, the device which is being impacted by the oncoming air and is transferred to the airspeed indicator is called what?
you said indicated airspeed was a measure of the speed of the air past the pitot tube.
it is not, because it is measuring pressure on the tube compared to the ambient pressure.
if it was measuring speed, it would show the same # at 1000msl and 10000msl
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you said indicated airspeed was a measure of the speed of the air past the pitot tube.
it is not, because it is measuring pressure on the tube compared to the ambient pressure.
if it was measuring speed, it would show the same # at 1000msl and 10000msl
:airplane: Sorry Charlie, you get your indicated airspeed from the PIDOT tube, coupled with a static port! explanation by the Federal Aviation Agency:
Along with the altimeter and vertical speed indicator, the airspeed indicator is a member of the pitot-static system of aviation instruments, so named because they operate by measuring pressure in the pitot and static circuits.
Airspeed indicators work by measuring the difference between static pressure, captured through one or more static ports; and stagnation pressure due to "ram air", captured through a pitot tube. This difference in pressure due to ram air is called impact pressure.
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It's "Pitot", not "Pidot" after the French engineer Henri Pitot who invented it. His name is pronounced "pee-toe".
You won't climb faster in ft/min in a headwind. Your climb will be steeper relative to the ground, but not relative to the airflow around your aircraft. Time to altitude will be the same no matter which way the wind blows. From a standstill on the runway taking off into the wind will result in a shorter time to altitude, but that's only because of the shorter ground roll; in essence you're starting with an airspeed equal to the wind speed, while with a tail wind you have to catch up to the wind first. Once you're airborne there is no difference because the ground then becomes irrelevant (unless you hit it!).
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What about the effects on cruise performance if you're not "on the step?" How's the wind effect you then?
:airplane: Being on "step" is a matter of AOA of the wing, relative to direction of flight and the "separation" point of lift on the wing is slightly further to the rear of the wing. I have flown aircraft which I couldn't tell hardly any difference in speed and other aircraft which would show an increase of 5 to 8 MPH. I have always felt that being able to "step" an aircraft in cruise is more of a wing design thing than pilot skill. Most aircraft which I could quickly identified its ability to get on "step" were single engine aircraft with cruise speeds under 200 MPH IAS. A dentist down in Marietta, Ga, had a old "N" model Bonanza, built by Beechcraft, which was the old "V" tail setup and there was about 8MPH difference when comparing to just pushing over in level flight and setting up cruise power, and climbing up an additional 100 feet and gradually descending back to desired cruise, while slowly bleeding MP and RPM settings. After arriving at the desired throttle and prop settings, then, consult your EGT to "tweak" best performance from the engine.
Of course, there is one school of thought which says there is no "step"!
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:airplane: Regardless of what you may think or have heard, just try this in a real aircraft: takeoff into a 20MPH headwind and time your self to 500 feet. Then land, turn around, takeoff downwind and time yourself to 500 feet. You will see that there is considerable difference in the amount of time it took to climb into the wind and the time it took to climb downwind.
I will try this, Earl, hopefully within the next few days. Will post results here.
- oldman (although I am not eager to take off with a 15 knot tailwind)
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<S> To OP. You have asked an honest and apparently difficult question for some.
Only took three pages so far to try to answer your question...
I look forward to pages to come, so I may learn as well.
Coogan
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I will try this, Earl, hopefully within the next few days. Will post results here.
- oldman (although I am not eager to take off with a 15 knot tailwind)
You needn't risk taking off with a tailwind. Nobody disputes the advantage of taking off into the wind.
The claim was that your feet per minute climb rate varies with wind direction but Earl often argues a different point then the one being discussed, even if he brought it up.
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I will try this, Earl, hopefully within the next few days. Will post results here.
- oldman (although I am not eager to take off with a 15 knot tailwind)
:airplane: I had rather you not try that! Many people are missing the point I am making, but we are having a good discussion about the effects of wind on climbing. The whole discussion is about getting to 10,000 feet the quickest! I will post the CORRECT answer to this discussion in time, but first, lets see what other "pilots" in here have to say about this subject.
Don't want anything to happen to you, sir, as you are one of the knowledgeable people who make good posts in this forum. :salute
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It's "Pitot", not "Pidot" after the French engineer Henri Pitot who invented it. His name is pronounced "pee-toe".
You won't climb faster in ft/min in a headwind. Your climb will be steeper relative to the ground, but not relative to the airflow around your aircraft. Time to altitude will be the same no matter which way the wind blows. From a standstill on the runway taking off into the wind will result in a shorter time to altitude, but that's only because of the shorter ground roll; in essence you're starting with an airspeed equal to the wind speed, while with a tail wind you have to catch up to the wind first. Once you're airborne there is no difference because the ground then becomes irrelevant (unless you hit it!).
:airplane: Si, 18 hour days on this ole body is getting me. You are right, it is PITOT, can't believe I typed what I did! :old: You are getting real close to the correct reply to my statement which a lot of people are taking exception with. BTW, I know you are in Norway, but are you of German decent?
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You needn't risk taking off with a tailwind. Nobody disputes the advantage of taking off into the wind.
The claim was that your feet per minute climb rate varies with wind direction but Earl often argues a different point then the one being discussed, even if he brought it up.
:airplane: Being in the trainer corp, you should know that different points of view about aviation related subjects, usually ends up educating people on the subject at hand, no matter what the original statement made was.
A good instructor is one who can draw a verbal description of subject at hand and the student can mentally draw a picture of what you said. Any student will learn faster if he or she sees the whole picture of matter being discussed. I am not an aviation engineer by any stretch, I just try to convey real life situations which I have experienced my self. I did not claim that climb rate varies with wind direction, Time to climb does vary with wind direction.
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Another effect of wind, which a lot of people do not notice is this: your aircraft will climb faster in feet per minute into the wind than it will climbing down wind.
This was the statement and it does not mention any takeoff or time to 10000ft, only feet per minute also known as ROC. I am with doright on this one.
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:airplane: Being in the trainer corp, you should know that different points of view about aviation related subjects, usually ends up educating people on the subject at hand, no matter what the original statement made was.
A good instructor is one who can draw a verbal description of subject at hand and the student can mentally draw a picture of what you said. Any student will learn faster if he or she sees the whole picture of matter being discussed. I am not an aviation engineer by any stretch, I just try to convey real life situations which I have experienced my self. I did not claim that climb rate varies with wind direction, Time to climb does vary with wind direction.
Actually you did make that claim which is why I asked if that's what you meant to say. :aok
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I want to go on record I'm not okay with people taking off in light airplanes with 15 knot tailwinds for the sake of an Internet board discussion.
And define "time to climb"
If you're talking about brake release to 10,000 headwind vs tailwind it's different than being level at 5 climbing to 15.
Your example was that a 1000ft/min climb will result in two different times to climb to a predetermined altitude based on wind direction. I disagree.
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:airplane: Sorry Charlie, you get your indicated airspeed from the PIDOT tube, coupled with a static port! explanation by the Federal Aviation Agency:
Along with the altimeter and vertical speed indicator, the airspeed indicator is a member of the pitot-static system of aviation instruments, so named because they operate by measuring pressure in the pitot and static circuits.
Airspeed indicators work by measuring the difference between static pressure, captured through one or more static ports; and stagnation pressure due to "ram air", captured through a pitot tube. his difference in pressure due to ram air is called impact pressure.
that's what I said all along.. :huh
you're the one who said the pitot tube measured velocity.
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I did not claim that climb rate varies with wind direction, Time to climb does vary with wind direction.
that is self contradictory.
btw.
how does an airplane know which direction the wind is coming from.. say.. above a cloud deck with no nav instrumentation at all.
magic?
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I want to go on record I'm not okay with people taking off in light airplanes with 15 knot tailwinds for the sake of an Internet board discussion.
Yes. In the light of day the notion does not appear as sensible as it did at the time.
Further proof of the wisdom of the bottle-to-throttle regulation.
- oldman (plus I'd need a really long runway)
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The whole discussion is about getting to 10,000 feet the quickest!
I think I see the problem. Define quickest.
If you mean look at the clock and measure time and multiply it be the rate of climb then it will exactly equal the altitude gained (assuming you start the clock after liftoff) no matter the wind direction.
If by quickest you mean look out the window and see how far the point below you is from your t/o position when you reach 10000' then wind definitely has a role. The ground distance traveled while climbing into a head wind is a lot less then the ground distance traveled while climbing with a tail wind. But at the same time the time to altitude will be the identical.
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Always remember in the main arena settings the time speed multiplier is set to 2.0. So you're actually only going half as fast as your indicators indicate.
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Always remember in the main arena settings the time speed multiplier is set to 2.0. So you're actually only going half as fast as your indicators indicate.
:headscratch:
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:headscratch:
No kidding :lol
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Check your humor detectors.
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One vital point in this is the wind gradient. Whatever the wind is doing on the ground, it is doing more of it at altitude. Because your aircraft has inertia, it does not simply ignore this change in velocity, it responds to it as an acceleration. Climbing into wind, this acceleration is positive and your aircraft gains energy from the airmass as it climbs, and thus climbs faster. Climbing downwind the accelleration is negative, you lose energy and you climb slower. The reverse is true when descending, which is why you'd better carry a little extra on approach, because the wind gradient can leave you short of both airspeed and altitude in a hurry if you don't.
To visualize this, imagine an absolutely sharp wind shear layer of twenty knots. Below it, you're cruising along straight and level. Climb two feet, the wings are in the new airmass and they're flying twenty knots faster than they were a second ago. That extra airspeed immediately turns into extra altitude as your aircraft (still trimmed for S&L twenty knots slower) slows down.
With a sharp enough shear a skilled glider pilot can maintain altitude simply by pulling up and turning into the gradient and then pushing over and turning out of it. Such shears are rare, but condors use the same effect close to the ocean to soar for hours without flapping a wing.
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One vital point in this is the wind gradient. Whatever the wind is doing on the ground, it is doing more of it at altitude. Because your aircraft has inertia, it does not simply ignore this change in velocity, it responds to it as an acceleration. Climbing into wind, this acceleration is positive and your aircraft gains energy from the airmass as it climbs, and thus climbs faster. Climbing downwind the accelleration is negative, you lose energy and you climb slower. The reverse is true when descending, which is why you'd better carry a little extra on approach, because the wind gradient can leave you short of both airspeed and altitude in a hurry if you don't.
To visualize this, imagine an absolutely sharp wind shear layer of twenty knots. Below it, you're cruising along straight and level. Climb two feet, the wings are in the new airmass and they're flying twenty knots faster than they were a second ago. That extra airspeed immediately turns into extra altitude as your aircraft (still trimmed for S&L twenty knots slower) slows down.
With a sharp enough shear a skilled glider pilot can maintain altitude simply by pulling up and turning into the gradient and then pushing over and turning out of it. Such shears are rare, but condors use the same effect close to the ocean to soar for hours without flapping a wing.
:airplane: :banana: You, sir, air correct!
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You can test it. Using a pt boat and timing yourself on the ingame clock go 50mph, after a half hour on the clock you will have only traveled 12.5 miles, not 25 miles.
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Always remember in the main arena settings the time speed multiplier is set to 2.0. So you're actually only going half as fast as your indicators indicate.
That's not the time speed multiplier, that is the fuel burn multiplier. You are going just as fast as your indicators indicate, but you are burning fuel twice as fast as you would in real life.
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Because your aircraft has inertia, it does not simply ignore this change in velocity, it responds to it as an acceleration. Climbing into wind, this acceleration is positive and your aircraft gains energy from the airmass as it climbs, and thus climbs faster.
the air is less dense though? does it have the same inertia?
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That's not the time speed multiplier, that is the fuel burn multiplier. You are going just as fast as your indicators indicate, but you are burning fuel twice as fast as you would in real life.
Wrong, the time speed in arena settings is set to 2. Check the clock, check how fast the sun moves.
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Wrong, the time speed in arena settings is set to 2. Check the clock, check how fast the sun moves.
That is only game time,I.E. how fast the sun moves. and nothing to do with plane performance.
If you time with your watch the game is completely real time for performance. I.E. if you climb rate is 1000 ft per min, and you are at 5000 feet, looking at your watch (oops I'm old school , I mean your cell phone) you will see in 1 min you are exactly at 6000 ft.
HiTech
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One vital point in this is the wind gradient. Whatever the wind is doing on the ground, it is doing more of it at altitude. Because your aircraft has inertia, it does not simply ignore this change in velocity, it responds to it as an acceleration. Climbing into wind, this acceleration is positive and your aircraft gains energy from the airmass as it climbs, and thus climbs faster. Climbing downwind the accelleration is negative, you lose energy and you climb slower. The reverse is true when descending, which is why you'd better carry a little extra on approach, because the wind gradient can leave you short of both airspeed and altitude in a hurry if you don't.
To visualize this, imagine an absolutely sharp wind shear layer of twenty knots. Below it, you're cruising along straight and level. Climb two feet, the wings are in the new airmass and they're flying twenty knots faster than they were a second ago. That extra airspeed immediately turns into extra altitude as your aircraft (still trimmed for S&L twenty knots slower) slows down.
With a sharp enough shear a skilled glider pilot can maintain altitude simply by pulling up and turning into the gradient and then pushing over and turning out of it. Such shears are rare, but condors use the same effect close to the ocean to soar for hours without flapping a wing.
I of course agree, but for every one else, NOTE the key to his statement is the wind is not constant speed, but is continually increasing speed as the altitude is increased.
HiTech
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I of course agree, but for every one else, NOTE the key to his statement is the wind is not constant speed, but is continually increasing speed as the altitude is increased.
HiTech
:airplane: Hooray! Someone finally got it right! The wind is never constant from sea level to 10,000, feet, changing usually to a more or faster speed as altitude is gained. That does not affect the climb rate like it does when climbing downwing, with the same wind gradient in place. That was my point all along, but no one ever mentioned it, except Hi Tech! When climbing into the wind, as the wind speed increases with altitude, your AOA will change slightly and become a little steeper, in order to maintain the 1,000 foot rate of climb, therefore you will get to 10,000 feet quicker.
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That is only game time,I.E. how fast the sun moves. and nothing to do with plane performance.
If you time with your watch the game is completely real time for performance. I.E. if you climb rate is 1000 ft per min, and you are at 5000 feet, looking at your watch (oops I'm old school , I mean your cell phone) you will see in 1 min you are exactly at 6000 ft.
HiTech
So the minute hand on the cockpit clock is moving at least 1000 feet per minute, and the minute hand on the cockpit clock in the plane sitting in the hangar is only moving a few centimeters per minute, should Bustr make a gunsight that compensates for time dilation?
(http://upload.wikimedia.org/wikipedia/commons/7/72/Nonsymmetric_velocity_time_dilation.gif)
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your aircraft will climb faster in feet per minute into the wind than it will climbing down wind.
Excellent point about wind gradient and inertia of the aircraft.
Only point I would make is if your holding a 1000fpm climb, the wind still wont make a difference. If you're holding a climb speed that approximates 1000fpm then the wind profile will make a difference.
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your aircraft will climb faster in feet per minute into the wind than it will climbing down wind.
Excellent point about wind gradient and inertia of the aircraft.
Only point I would make is if your holding a 1000fpm climb, the wind still wont make a difference. If you're holding a climb speed that approximates 1000fpm then the wind profile will make a difference.
Earls statement is 100% incorrect. The basic statement that a head wind increases your climb rate is completely inaccurate. Stating so is completely ignoring the basic definitions of distance , velocity and acceleration and time.
Winds speeds do not always increase as altitude increases,and rarely stay the same direction as altitude changes. Hence if the wind speed is decreasing with altitude your climb rate would be slower if climbing into the wind.But no matter WHAT the wind is doing , if your climb rate is showing 1000 FPM, it will take exactly 1 min to climb 1000 feet.
In either case it is not the velocity of the wind that is effecting your climb rate, it is the ACCELERATION.
Had Early originally stated that if wind speed is increasing with altitude, climbing into the wind will increase you climb rate he would have been correct, and I don't believe a debate would have followed.
HiTech
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Thanks Hitech. You want to clear up adverse yaw now? :D
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Just to make things more interesting....
Note that wind speed and direction will affect your ground speed. The other day (in game) I was headed north, so I climbed to 14K where the wind was blowing to the north. Although my air speed was the same, my ground speed was higher, and I got to the target quicker. :banana:
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...if your climb rate is showing 1000 FPM, it will take exactly 1 min to climb 1000 feet.
Assuming calibration, no turbulence and stabilized climb.
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yada yada yada....don't listen to any of this crap! There is ONE speed baby....
The Speed of Heat!! :rock :airplane:
Bwamp bwamp!
Boo
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yada yada yada....don't listen to any of this crap! There is ONE speed baby....
The Speed of Heat!! :rock :airplane:
Bwamp bwamp!
Boo
I believe you Boo but what direction does heat travel??
:salute
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I believe you Boo but what direction does heat travel??
:salute
Conducted, convected or radiated?