> did not land, did not eat, did not drink and did not stop flapping
My understanding is that these incredible distances are achievable less by "flapping" and more by leveraging small adjustments to harness the incredibly powerful forces found among and between air currents and waves as they traverse across the ocean.
For example, here is an unpowered remote control glider achieving measured speeds of 548+! mph using nothing but natural energy harnessed from wind and gravity.
> My understanding is that these incredible distances are achievable less by "flapping" and more by leveraging small adjustments to harness the incredibly powerful forces
That is not correct. This particular bird (Bar-tailed Godwit) has never been observed to "dynamically soar" nor does it have the proper wing shape for that type of flight. If you ever seen Godwits in the wild, you will know why, it's a flapping only bird, they have no other mode of flight.
Albatrosses on the other hand do employ dynamic soaring and fly even greater distances than Godwit does (they can circumnavigate the Southern Ocean several times) although albatrosses have additional advantage of being able to use water for rest (Godwits cannot).
This is interesting. Let’s say 600g Bar-tailed Godwit goes on 13500 km flight and spends very optimistic 200g of fat. Theoretically, if fat is only used for going up, it can climb to 170km (i.e. potential energy). This means that to get to destination in needs to glide by dropping 12.5m per km, or have glide ratio of 80.
Best human gliders have glide ratio of 60. So Godwit still needs to be very efficient glider, or, what is more likely also knows how to use winds and updrafts.
What this calculation shows is what glide ratio Godwit must have if it spends 1/3 of its body weight very efficiently to gain altitude and reaches destination in completely calm air. By the looks of it it doesn’t have this glide ratio, and I doubt it spends 1/3 of its weight only gaining altitude.
So it means that it must gain altitude and, perhaps, travel speed by alternative means, most likely using updrafts and riding winds.
Your calculation is interesting, but I beg you to go outside and look at how Godwits actually fly. Godwits fly in a straight line using rapid powerful nonstop flaps. They are relatively heavy birds with high "wing loading ratio" and their entire body plan is hyper-optimized for this type of flight and no other. This is especially true during migration when they accumulate lots of fat and their wing loading ratio is particularly unfavorable for soaring. Godwits are among the fastest-flying birds in a straight line, and they have never been observed to engage in any other mode of flight, nor can they. They cannot use regular soaring. They cannot use dynamic soaring. They do not fly like seagulls. Their wing area is simply too small to allow any other type of flight. They also typically do not wait for favorable wind to fly. They just take off and go.
I agree with your points. What this calculation shows that godwits must rely on favorable winds and updrafts (which benefit any flying object, including birds, since motion is relative); if this is not the case, they just not going to reach claimed distances given their weight and how much fat they are carrying.
You see this even more in the ocean. There are sharks who, being cold-blooded, have the ability to slow their metabolism to very near zero and simply ride a current for thousands of kilometers to entirely different parts of the globe where feeding is better without expending any energy to do it. It's probably why sharks have been around so long. They can be extremely resistant to famine conditions.
I met that guy at a glider meetup a few months after that record. That Transonic plane is huge. He managed to fit the 3m wingspan into a regular car, lengthwise.
I never got out to Parker Mountain but those guys had great stories. 100G will find the weak point on your model, often explosively.
But they’re also a masterpiece of weight reduction - the less mass, the less of a problem the Gs are. No big IC engine to deal with. The electronics are tiny and the fuselage walls are also super thin. It’s a stressed surface carbon fibre/kevlar frame to spread the force.
What I like is the common idea that only powered flight is fast. A propeller would only slow this model down. They’re so sleek.
My gliders are very casual — this one is a serious machine!
My understanding is that these incredible distances are achievable less by "flapping" and more by leveraging small adjustments to harness the incredibly powerful forces found among and between air currents and waves as they traverse across the ocean.
For example, here is an unpowered remote control glider achieving measured speeds of 548+! mph using nothing but natural energy harnessed from wind and gravity.
https://www.youtube.com/watch?v=4eFD_Wj6dhk
https://en.wikipedia.org/wiki/Dynamic_soaring