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### Re: What-If 0149: "Pizza Bird"

Posted: Wed Apr 13, 2016 7:01 pm UTC
This assumes an airplane in straight and level flight. Deviations from this make it rather easier on the bird.

At one extreme, a circling aircraft with the tether attached to it(and a small weight) could simply have the pizza attached at leisure by someone on the ground.

And tie the bird on as well, for completeness, I suppose.

### Re: What-If 0149: "Pizza Bird"

Posted: Wed Apr 13, 2016 8:42 pm UTC
Re: alt text on last pic- pure nonsense. if you don't have to fold the slice to eat it, it's not good NY style pizza.

### Re: What-If 0149: "Pizza Bird"

Posted: Wed Apr 13, 2016 11:25 pm UTC
operagost wrote:if you don't have to fold the slice to eat it, it's not good NY style pizza.
Much like if you pay less than \$5 for something, it's not a real perpetual motion machine.

### Re: What-If 0149: "Pizza Bird"

Posted: Thu Apr 14, 2016 1:15 am UTC
Still, I've never heard of criticizing someone for eating a slice of pizza correctly. It's not like the eagles used a fork and knife.

### Re: What-If 0149: "Pizza Bird"

Posted: Thu Apr 14, 2016 9:22 am UTC
One important follow-up question is:
To which temperature must the pizza be pre-heated to be edible (not frozen) on arrival?

### Re: What-If 0149: "Pizza Bird"

Posted: Thu Apr 14, 2016 12:23 pm UTC
catnipper27 wrote:One important follow-up question is:
To which temperature must the pizza be pre-heated to be edible (not frozen) on arrival?

Cold pizza is generally considered to be as edible as hot pizza.

By induction, any temperature should serve equally well.

### Re: What-If 0149: "Pizza Bird"

Posted: Thu Apr 14, 2016 12:38 pm UTC
I would expect a few practical problems when you eat a pizza that's 0 kelvin. So there is a minimum temperature.

### Re: What-If 0149: "Pizza Bird"

Posted: Thu Apr 14, 2016 12:48 pm UTC
Tyndmyr wrote:
catnipper27 wrote:One important follow-up question is:
To which temperature must the pizza be pre-heated to be edible (not frozen) on arrival?

Cold pizza is generally considered to be as edible as hot pizza.

By induction, any temperature should serve equally well.

But it's quite cold up there; the temperature at a jet's cruising altitude will be 60-80C colder than at the surface. And "cold pizza is edible" stops somewhere in the neighborhood of 0C, as catnipper implied.

### Re: What-If 0149: "Pizza Bird"

Posted: Thu Apr 14, 2016 3:24 pm UTC
Tyndmyr wrote:By induction, any temperature should serve equally well.
By induction, you could probably keep it at a the same desirable temperature even as it travels, with a few electrical components and a small power-pack.

### Re: What-If 0149: "Pizza Bird"

Posted: Thu Apr 14, 2016 5:44 pm UTC
Well played.

### Re: What-If 0149: "Pizza Bird"

Posted: Fri Apr 15, 2016 10:42 am UTC

### Re: What-If 0149: "Pizza Bird"

Posted: Fri Apr 15, 2016 10:57 am UTC
Copper Bezel wrote:Still, I've never heard of criticizing someone for eating a slice of pizza correctly. It's not like the eagles used a fork and knife.

Fork and knife? What abomination is this? You mean a knife and fork.

### Re: What-If 0149: "Pizza Bird"

Posted: Mon Apr 18, 2016 2:21 am UTC
Hmm. I can't help but think of this:

Fulton Surface-to-Air Recovery System FTW!

### Re: What-If 0149: "Pizza Bird"

Posted: Mon Apr 25, 2016 1:17 am UTC
keldor wrote: https://www.youtube.com/watch?v=u4xlYpKrCnU Fulton Surface-to-Air Recovery System FTW!

Way cool - an airplane snagging a line lofted by a balloon! So why not a line lofted by a kettle of vultures?

A column of Rüppell's vultures climb a thermal carrying a 10 km carbon nanotube filament, very light and very thin. It is attached to a few hundred kilometers of exponentially widening CNT filament, at the end of which is the pizza inside a strong metal box (cardboard pizza boxes fare poorly in mach 0.85 headwinds). The airplane will need a very fast winch, but it should be possible to reel in a Chicago pizza before the plane lands at JFK.

The Rüppell's vulture mentioned was lofted by very strong African thermals. Normally such thermals do not occur over the temperate northern US. However, with the aid of a descendant of Mrs. O'Leary's cow, we should be able to create a very hot thermal over Chicago, and as a bonus, keep the pizza hot during flight.

Edit: To clarify, the thin filament (liftable by the birds) is to pull up heavier filament to the winch drum, which in turns pulls up heavier filament really fast. Hence, "carbon nanotubes", the magic handwaving phrase in 2016 for "unobtanium". If 100 vultures stacked at 100 meter intervals can lift 100 grams each to 10 km altitude, that is an initial filament weighing 10 kg, or 1 gram per meter. At 1.4 g/cm³, that initial filament would be close to 1 mm diameter, and have a theoretical tensile strength (at 100GPa) of about 70 kN, capable of lifting 100 kg of larger filament at 7 gees, though reduced because of air drag. A 1 square meter pizza box face-on to a 1kg/m³, 260 m/s wind stream encounters around 70 kN of drag; that (plus acceleration and air drag) might require a 10x heavier CNT filament, lifted to the airplane winch by the thinner "leader" filament. Thin lines lifting thicker lines lifting a succession of thicker lines past a winch pulley is how a fishing line can be used to lift (eventually) a fat cable.

Of course all this is ridiculously impossible, but when has that ever mattered for a what-if question? Or the fate of vultures, Chicago, or even the planet? Let's remember to be unreal and impractical here!

### Re: What-If 0149: "Pizza Bird"

Posted: Mon Apr 25, 2016 6:07 pm UTC
You're proposing pressing a frame against "a string of diameter 1nm and mass 100mg/m" as a means of lifting something?

Does anyone have access to a wind tunnel? We need the drag force on a pizza box at 1100 kt for the calculations of just how much pressure that thread is exerting on the frame that snagged it.

### Re: What-If 0149: "Pizza Bird"

Posted: Tue Apr 26, 2016 2:30 am UTC
Bar headed geese might be a good canidate for the carrier bird. They migrate over the Himalayas at altitudes of greater than 20,000 feet, so that's in reach if the plane dives down a bit to receive the pizza. Having multiple birds carrying the line would be important. You'd want some sort of breakaway line attaching to the birds so they'd get loose when the plane hooked the line, since I suspect that being dragged along at 600 MPH is hard on birds. The actual Skyhook had this so that the balloon would break free upon capture.

One concern would be what happenes when the airplane hooks the very thin line at 600 MPH. The phrase "like a knife through butter" comes to mind. I guess you'd have some sort of thick padded section for it to hook.

### Re: What-If 0149: "Pizza Bird"

Posted: Tue Apr 26, 2016 11:17 am UTC
keldor wrote:One concern would be what happenes when the airplane hooks the very thin line at 600 MPH. The phrase "like a knife through butter" comes to mind. I guess you'd have some sort of thick padded section for it to hook.

... because it totally makes a diference that the knife cuts through its own padding first before slicing the butter?

### Re: What-If 0149: "Pizza Bird"

Posted: Fri May 13, 2016 7:38 am UTC
Durandal_1707 wrote:I feel like there'd be a risk of the bird adding... extra toppings to the pizza if it carried it in the fashion illustrated above.

Then you'd have to let me keep it. Free pizza.