What speed is your actual speed?

[earl1937]

obviously incorrect.

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?

[Golfer]

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?

[Golfer]

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.

[doright]

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.

[earl1937]

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.

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.

[earl1937]

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.

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.

[doright]

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.

[Golfer]

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.

[earl1937]

Post a video or it never happened.

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.

[Golfer]

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.

[kvuo75]

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

[earl1937]

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

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.

[GScholz]

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!).

[earl1937]

What about the effects on cruise performance if you're not "on the step?"  How's the wind effect you then?

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"!

[Oldman731]

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)