Read this in the 107 FAA Study Guide...T/F?

[andyimages]

"For example, a tailwind quickly changing to a headwind causes an increase in airspeed and performance. Conversely, a headwind changing to a tailwind causes a decrease in airspeed and performance. In either case, a pilot must be prepared to react immediately to these changes to maintain control of the aircraft."

This is from the FAA study guide.......is the correct or backwards?

 

[Meta4]

"For example, a tailwind quickly changing to a headwind causes an increase in airspeed and performance. Conversely, a headwind changing to a tailwind causes a decrease in airspeed and performance. In either case, a pilot must be prepared to react immediately to these changes to maintain control of the aircraft."

This is from the FAA study guide.......is the correct or backwards?

It's obviously backwards - your Phantom flies slower when fighting a headwind.

 

[N017RW]

It's obviously backwards - your Phantom flies slower when fighting a headwind.

It's not groundspeed...
It's AIRSPEED.

Aircraft performance is dependent on Airspeed not Groundspeed.

Statement is 100% Correct!!

 

[andyimages]

Thanks moderator.......thats what I thought! Aside from this guidebook, are there any free publications that you would recommend to study from......the FAA one seems intentionally confusing. I am just getting into drones and unfortunately I am a professional photographer so it puts me in a bad spot if I fly and take any video or stills at all.

 

[andyimages]

It's not groundspeed...
It's AIRSPEED.

Aircraft performance is dependent on Airspeed not Groundspeed.

Statement is 100% Correct!!

Explain...?

 

[BigAl07]

Remember we're talking Airspeed and not ground speed here.

Going into the wind will give an Indicated Airspeed higher than ground speed and inverse when going downwind.

 

[BigAl07]

Thanks moderator.......thats what I thought! Aside from this guidebook, are there any free publications that you would recommend to study from......the FAA one seems intentionally confusing. I am just getting into drones and unfortunately I am a professional photographer so it puts me in a bad spot if I fly and take any video or stills at all.

FAA Part 107 Ground School
This is an EXCELLENT course and they offer money back guarantee if you don't pass.

 

[andyimages]

That's assuming that the pilot increases the airspeed to compensate for the headwind, right........this was under a discussion about wind sheer, and its effects. It doesn't sound right to me.

 

[BigAl07]

It's not groundspeed...
It's AIRSPEED.

Aircraft performance is dependent on Airspeed not Groundspeed.

Statement is 100% Correct!!

Beat me to it LOL

 

[andyimages]

Beat me to it LOL

]

Ok Al, so if tailwind changes to headwind that wouldn't cause an increase in airspeed----- unless the pilot increased throttle to compensate, correct?

 

[BigAl07]

That's assuming that the pilot increases the airspeed to compensate for the headwind, right........this was under a discussion about wind sheer, and its effects. It doesn't sound right to me.

No... to be fair these questions are for "winged" aircraft which rely upon air going over the wings at a certain speed to produce lift.

You wouldn't need to increase airspeed to compensate for headwind because airspeed is increased with the headwind. Groundspeed would decrease but that's irrelevant at least in the equation above.

 

[N017RW]

Good point Al re: a fixed-wing centric question.

 

[Meta4]

It's not groundspeed...
It's AIRSPEED.
Aircraft performance is dependent on Airspeed not Groundspeed.
Statement is 100% Correct!!

The point about airspeed vs groundspeed is a good one but in the context of a quadcopter, the question is poorly written and confusing or even irrelevant since Phantoms have no way of displaying airspeed.

For example, a tailwind quickly changing to a headwind causes an increase in airspeed and performance.
Conversely, a headwind changing to a tailwind causes a decrease in airspeed and performance.
In either case, a pilot must be prepared to react immediately to these changes to maintain control of the aircraft.​

The only way that a tailwind quickly changes to a tailwind is when the pilot turns the Phantom 180°.
A Phantom dealing with a headwind experiences no increase in performance and if the (now) headwind is beyond the limited ability of the Phantom to counteract the wind any increase in airspeed isn't going to make any difference.

 

[andyimages]

OK, so headwind increase air speed, but decreases groundspeed for fixed wing. And as far as that test there seem to be lots of questions that have nothing to do with flying a drone like a Phantom 4. And you c

The point about airspeed vs groundspeed is a good one but in the context of a quadcopter, the question is poorly written and confusing.

For example, a tailwind quickly changing to a headwind causes an increase in airspeed and performance.
Conversely, a headwind changing to a tailwind causes a decrease in airspeed and performance.
In either case, a pilot must be prepared to react immediately to these changes to maintain control of the aircraft.​

The only way that a tailwind quickly changes to a tailwind is when the pilot turns the Phantom 180°.
A Phantom dealing with a headwind experiences no increase in performance and if the (now) headwind is beyond the limited ability of the Phantom to counteract the wind any increase in airspeed isn't going to make any difference.
Plus Phantoms have no way of displaying airspeed so the whole topic is irrelevant to drones.

Ugh,

 

[sar104]

]

Ok Al, so if tailwind changes to headwind that wouldn't cause an increase in airspeed----- unless the pilot increased throttle to compensate, correct?

The statement is correct. Consider an object moving at constant velocity (not constant airspeed, which is a relative velocity in a variable frame of reference - the surrounding airmass). If a tailwind becomes a headwind, then the airspeed (velocity relative to the airmass) increases. Obviously, if the object is an aircraft, its velocity will then decrease unless thrust is increased, but that will not happen instantaneously due its momentum. Newton's second law (F=ma) tells us that the deceleration will equal the increased drag divided by the aircraft's mass, assuming level flight. So during that resulting deceleration period, the airspeed is higher and the aircraft performance and response are modified accordingly.

 

[N017RW]

Part 107 is not Phantom or MR centric. It is an atmospheric/aerodynamic question and you would have (likely) gotten it wrong if you approached it from a Phantom's perspective.

Due to an adequate headwind, I have actually flown a fixed wing r/c aircraft backwards from the ground perspective.

 

[andyimages]

Wow, I think I got it......thats a tough one, but yes, relative to the increased wind, the aircraft's speed would increase.....thats quite an interesting one,

 

[andyimages]

Part 107 is not Phantom or MR centric. It is an atmospheric/aerodynamic question and you would have (likely) gotten it wrong if you approached it from a Phantom's perspective.

I have actually flown a fixed wing r/c aircraft backwards from the ground perspective.

OK explain how you do that! I am just a photographer, LOL.

 

[sar104]

OK explain how you do that! I am just a photographer, LOL.

As long as the windspeed is higher than the aircraft's stall airspeed, you can just point it into the wind and slow down until the resulting ground speed (airspeed minus windspeed) is negative.

 

[N017RW]

It was prior to a rainstorm. The headwind from the storm's associated downdraft was greater than the necessary airspeed for the model so throttling down such that it was being blown backwards yet adequate air was passing over the control surfaces allowing me to maintain stable attitude.

Strange indeed!