head winds

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henryinparadise

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Henry
My cfi is a retired airline pilot.
He says that flying into a headwind, one should push the
plane hard and conversely with a tail wind, coast.
I did the math off of the poh and I concluded that in both
cases, one should not push the plane hard but pick
moderate power settings for economy and time.
I fly a Cessna 210.
Any comments?
 
Are you on a schedule and need a certain ground speed?
Air speed should be the same at a given throttle setting regardless of the wind direction.
 
I don't know what he means. If he means you can take advantage of a tailwind by using a lower acceptable power setting/airspeed/fuel burn and partially overcome a headwind with a higher acceptable power setting/airspeed/fuel burn, I guess the math sort of works.
 
Well, if you slow down in a tailwind, you spend a longer time letting it push your plane and you're usually got better fuel efficiency (less drag) at lower speeds as well.

However, the opposite isn't always true for headwinds. While you probably want to minimize your time in headwinds whether going at a higher airspeed with the incumbent drag increase will result in less fuel burned, you'd need to calculate that for the situation.
 
Suppose you fly a plane that gets 100kts/5gph at normal cruise, 110kts/9gph with the knobs crammed and 1gph at idle. You're trying to fly to an airport 10nm away but there's a 101kt headwind at pattern altitude. Ignoring wind shear effects, you'll take 1.1 hours to get there burning 5.5 gallons if you cram it. You'll burn up all your gas and never arrive at normal cruise. On the return trip, the flight will take 3 minutes/0.25 gallons at normal cruise and 6 minutes/.1 gallons gliding (2.5x better MPG gliding).
 
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thanks guys.
Me, Im never on a schedule.
Thats maybe why he says that.
He couldnt explain the math very well either.
Personally I agree with Baked Potato.
Ground speed is what it is.
No way can you make it up using power
in a C210!
I recently flew 300 miles with a 30 kt headwind.
It was either land or continue onwards.
I had lots of fuel.
 
henryinparadise said:
He says that flying into a headwind, one should push the
plane hard and conversely with a tail wind, coast.
Click to expand...

I find “Reductio Ad Absurdum” can help one visualize these things. It’s what asicer was going for.

Even simpler - and more absurd - imagine a plane with a normal cruise of 60 kts. You need to fly to an airport just a few miles away. Checking winds aloft, you’ll have a 60 kt headwind.

1) How long would it take if you stuck to your normal cruise setting?

2) Might you be better off at full power if it gave you 70 kts?

asicer and your instructor have the right idea: minimize your time in a headwind by flying a bit faster, and maximize your time in a tailwind by flying a bit slower. As the winds aloft get stronger, so will the effect.

I’d say plan out this scenario (faster in headwind/slower in tailwind) with a flight planner on some round trips. I think you’ll find your instructor’s advice results in better efficiency than the same airspeed in both directions.
 
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Works if you are gliding. Mcready did a bunch of study on this. More than just tail/head wind, but same concept. For powered flight, depends on what you are solving for? Fastest time, least fuel etc?
 
August: Flying to Fulton County Airport. About 100 sm.
Out over the Catskill Mountains at 4,500 ft.
Cruising @ 85 mph airspeed. Ground speed was 40.
After 1.25 hours I was still 53 miles short of my destination and down to 1/2 tank (6 gallons).
I turned around and came back at 85 mph airspeed. My ground speed was 120 mph.
Back in 23 minutes.
I came back so fast I landed with almost as much fuel in my tank as when I took off. :devil:
 
Years a go a friend of my Dad was trying to get back for a hot date. He was trying get through Banning Pass in an L19 (O-1 Birddog). He landed at Banning airport 3 times for fuel. And never did get through.
 
What I don't understand about the tailwind situation is why you'd want to pull the power back. Yes, you can get better fuel economy by doing so, but you're ALREADY getting better fuel economy at normal cruise as a result of the tailwind. So you're already saving money by getting there faster (less engine time) and using less fuel, now you want to try to use even LESS fuel, but actually increase the engine time? Makes no sense to me. Of course if you're crossing the Atlantic and every bit of fuel is important, that's one thing. Or if you're trying to skip a fuel stop, maybe. But if you're just flying somewhere well within the range of your airplane, and get a nice tailwind, does anybody decide "yeah, that ground speed is too fast, let me pull the power way back instead"?
 
Sounds like the theory is to spend as little time in a headwind as you can and as much time in a tailwind as you can. I think there's something to the theory. Parasitic drag increases exponentially with speed, so I'd say unless your particular engine does a LOT better at a given setting than the other settings, this would be a sound theory.
 
RussR said:
What I don't understand about the tailwind situation is why you'd want to pull the power back. Yes, you can get better fuel economy by doing so, but you're ALREADY getting better fuel economy at normal cruise as a result of the tailwind. So you're already saving money by getting there faster (less engine time) and using less fuel, now you want to try to use even LESS fuel, but actually increase the engine time? Makes no sense to me. Of course if you're crossing the Atlantic and every bit of fuel is important, that's one thing. Or if you're trying to skip a fuel stop, maybe. But if you're just flying somewhere well within the range of your airplane, and get a nice tailwind, does anybody decide "yeah, that ground speed is too fast, let me pull the power way back instead"?
Click to expand...
But if we're using Tach time, isn't that just based off of percentage of a chosen RPM? i.e. Clock turns faster the more RPM you go? If you are at the reference RPM it's 1:1 for time, but running a few hundred RPM less means you're only recording 0.85:1 and technically turning few revolutions (wear) per unit of time. Pulling back the power in a tailwind saves you fuel and tach time.
 
There has to be a significant amount of wind for this to make a noticeable difference in a piston airplane. As @Hang 4 said, glider pilots adjust their speed based on headwind or tailwind, and also based on the sink rate. But best glide speed in a glider is usually low (compared with airplanes), so the wind speed is a higher percentage of airspeed. And of course glider pilots are a lot more dependent on flying at best efficiency.

In a typical piston airplane we kind of do what the OP's CFI suggested, simply because we tend to fly higher when we can enjoy a tailwind, and lower when flying into a headwind - because typically the wind speed increases with altitude. So while we enjoy as much tailwind as we can at a high altitude, the engine performance (normally aspirated) is reduced, compared with flying lower into a headwind.

My engine monitor has a "NM per gallon" readout. It's pretty easy to see the impact of speed changes on a given flight - make the power change, give it a minute for things to settle down, and see what fuel economy you get. I have yet to experience a headwind where speeding up would help me save gas. It takes a lot of power (and thus fuel) to go fast.

Having said all that: If you are a renter who pays by the hour, then best power is cheapest for you - headwind or tailwind. It just doesn't relate to the actual operating costs of the airplane.

- Martin
 
“Faster in a headwind, slower in a tailwind” starts with long range cruise in no wind.

Since most people fly faster than long range cruise, they’re already “faster in a headwind.”

And unless you’re trying to make your destination without a fuel stop, “slower in a tailwind” from normal cruise is false economy. Especially if you factor in an hourly cost for the airplane.
 
henryinparadise said:
He says that flying into a headwind, one should push the
plane hard and conversely with a tail wind, coast.
Click to expand...

He is talking about maximum efficiency and/or range.

In Gliders we talk about and consider this quite a bit when are trying to get maximum speed and/or distance.
We have fancy glider computers that do the speed to fly calculations for us and even adjust the speed for rising and sinking air masses.

As a general rule we add 1/2 the wind speed to our cruising speed, for speed and maximum range. When racing the pilot that adds the wind speed into the calculation won't have to stop and climb as often and will have a higher average speed than the person just flying the best polar speeds.

Same goes for Tailwinds.

Brian
CFII/AWL

1698694493293.png
 
I agree that in day-to-day flying with moderate winds, varying our power depending on headwind/tailwind is optional, though it may provide some small benefit.

One place it’s good to keep it in mind is when gliding into a headwind, after an engine out, let’s say. Here, adding a few knots - or more - to best glide speed in a strong headwind can easily make the difference between making a runway/field or coming up short.
 
henryinparadise said:
My cfi is a retired airline pilot.
He says that flying into a headwind, one should push the
plane hard and conversely with a tail wind, coast.
I did the math off of the poh and I concluded that in both
cases, one should not push the plane hard but pick
moderate power settings for economy and time.
I fly a Cessna 210.
Any comments?
Click to expand...
If you really want to fly economically delay a day and don’t fly XC into a strong headwind.
 
henryinparadise said:
He couldnt explain the math very well either.
Click to expand...
The idea is to spend more time being pushed forward by a tailwind and less time being pushed back by a headwind.

A headwind increases the air-miles you have to fly to reach your destination. A tailwind decreases the air-miles.
 
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