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So do you know the answer - 50 tons of Canaries


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I have actually seen about a thousand budgies flying in a flock. A sight you would never forget.

Yes, if you're ever on the Barkly Highway (Camooweal to Three Ways/Tennant Creek) around sunset near the dams and waterholes, you'll usually see flocks of more than ten or twenty thousand budgies flying in formations. It's a stunning sight, completely mesmerising. The starlings in Europe provide a similar phenomenon.

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Yes, if you're ever on the Barkly Highway (Camooweal to Three Ways/Tennant Creek) around sunset near the dams and waterholes, you'll usually see flocks of more than ten or twenty thousand budgies flying in formations. It's a stunning sight, completely mesmerising. The starlings in Europe provide a similar phenomenon.

Can they talk?

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Any commercial pilot please do not answer this if you know the answer and give it away this is for the guys to exercise their brains in RAA or PPL pilots.

 

This question we got thrown as a hypothetical in one of senior commercial theory licence questions in class it was not in an actual exam – but a bit of fun by the instructor.

 

Accept the premise AND all assumptions.

 

So we have 50 tons of Canaries (yes little yellow birds) sitting in all the seats of a 747. No seats belts.

 

The 747 is flying at 35,000 feet straight and level.

 

Then all 50 tons of Canaries become airborne inside the 747 flying around.

 

The Question

 

  • What happens to the 747 In other words is it 50 tons lighter Or is it the same weight at that point in time.
  • If it is 50 tons lighter does THE 747 climb
  • If the 747 maintains it's flight level without climbing WHY?

 

 

Please explain your logic and process of YOUR answer.

 

No droll smart **** answers I've heard them all before .

If you think of the birds confined in the pressurised space within the 747, then no matter what the birds were doing, sitting or flying, their weight would be the same on the aircraft.

If the birds were out side of the aircraft and hanging on to it, their weight would also be the same, but if they all let go and flew in their own right, then the 747 would experience a weight reduction.

Like if a 747 was piggy backing the Shuttle, on a flight from LA to Florida, the 747 would experience the weight of the Shuttle attached to its back, but if the Shuttle all of a sudden flew off and detached itself from the 747 then there would be a weight reduction on the 747s pay load. So what ever happens inside of the 747 does not alter its overall weight.

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Nev wrote:

If it's in ground effect you will notice it passing overhead and most likely the downwash and wingtip vortices if it's low enough. Nev

 

Back in 1990 the ARDU guys contacted me about a problem they had with the then relatively new Pilatus PC9. The manufacturer had provided them with a position error curve for the airspeed system and had provided the FAA certification people a different one so they decided to measure it themselves. This is easy with GPS but it wasn't available.

It involved flying the aircraft at less than 100 feet (IIRC it was 70 feet) while tracking with a kinetheodolite and filming. In the back seat, in place of the usual altimeter was a precision digital altimeter with one foot resolution that I had built for them. A twin was on the ground under the flight path and they flew over it at speeds from 70 knots IAS up to 240 KIAS By measuring the air temperature, baro pressure and the actual geometric altitude off the films and comparing the static pressure differences the static pressure error at the various speeds could be derived and a position error curve plotted.

I went to Edinburgh base to observe and help which was just as well as I took my handheld aircraft band transceiver and the RAAF didn't have enough of them. It was very interesting observing the 1 to 2 foot jump down in the reading of the ground altimeter as the aircraft flew overhead. Fun times. They tested my altimeters on the bench and found they were more accurate than the expensive bench test gear they had.

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Some of you guys should leave Relativity to the physicists.

Hypothesising non zero mass objects at the speed of light (known as c) isn't useful. Try 0.999c. This is at least theoretically possible. You might like to contemplate what light frequency you'd see. Also search for "starbow". It is quite fascinating.

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If you think of the birds confined in the pressurised space within the 747, then no matter what the birds were doing, sitting or flying, their weight would be the same on the aircraft.

If the birds were out side of the aircraft and hanging on to it, their weight would also be the same, but if they all let go and flew in their own right, then the 747 would experience a weight reduction.

Like if a 747 was piggy backing the Shuttle, on a flight from LA to Florida, the 747 would experience the weight of the Shuttle attached to its back, but if the Shuttle all of a sudden flew off and detached itself from the 747 then there would be a weight reduction on the 747s pay load. So what ever happens inside of the 747 does not alter its overall weight.

Correct, the mass of 50 tons of canaries has displaced the air inside & whether they are sitting down, hanging from the ceiling or flying around does not alter this fact.

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The downward force that the aircraft exerts on the air supporting it will increase! Then as time progresses the aircraft will get lighter!

To raise the potential energy of the birds (increased height above the earth) the birds must exert a force on the floor of the aircraft. This requires a thrust downward from the wings of the birds. The birds will increase the altitude of the centre of gravity of the craft. This has the effectiveness of pushing the aircraft downward, the velocity of the downward force will increase its force under the wings of the craft. When the birds reach a constant altitude they will no longer exert this force and the aircraft thrust downward will return to its previous bird seated value,.......

Well not exactly! The birds will have expended heat in the process of raising their potential energy. This heat will have come from chemical energy, so they will be slightly lighter this reducing the weight of the aircraft.

 

Ever so small changes, but no one said anything about not being precise lol

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I had a good teacher in high school. He used to regularly say - "For all practical purposes" when describing a process involving physics. One day, someone asked, "Sir, what do you mean by the statement, 'For all practical purposes'..?"

 

"Well", he replied, "Let me give you an example. We place a teenage boy and a teenage girl X distance apart. We continually move them closer together, by halving the distance between them, with each physical move".

 

"They will never, ever completely touch! But they'll be close enough, for all practical purposes!" :cheezy grin:

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Many years ago my mates flew our caged canary to Pearce from Richmond.

Later, I was told the canary could withstand a 60 degree bank turn ok, but.... anything more and her little legs collapsed on her perch.

Needless to say after a 3 day Caribou flight to her home the little yellow canary never sang again!

No earmuffs and she was deaf as a post!

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Watched a Caribou Taxi in many years ago next to where I was parked at a small drome thinking WTF he'll corner himself for sure and jam me in too! The noise was deafening! Then I noticed the rear ramp come down and a Aileen looking guy walked down the ramp tethered to the plane via his helmet (reminded me of "Close encounters of the third kind") and the big lumbering noisy bird backed up right into a tight spot! Never seen that, well I had done it a few times in the plane I was driving but that Caribou looked so ugly cumbersome!?

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In the 1980s I was a Musician in the RAAF band. We spent a lot of time touring and our usual mode of transport (other than a bus) was a C130 and occasionally a Caribou as well as other interesting aircraft. The Caribou was USUALLY great fun to fly in. I do remember one occasion though that was not so much fun. It was a flight from RAAF Richmond to RAAF Williamtown. Sometimes they would combine our flight with some kind of training exercise. On this occasion we flew to the coast and then along the coast at low level and it was one of those days. We were tossed around a little too much for most peoples liking. I can remember pretty much all of the band with their heads down and grasping a sick bag. One of our percussionist (we always called him Lurch) claims to have vomited half a dozen times or so.

 

Our band room was at RAAF Richmond was right next to an expanse of grass which was often used for Caribou training. Our old banoom would vibrate pretty badly as they did touch and goes.

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