Like the title says. I know Falcons and raptors can dive at 200+ mph. So when they spread their wings to slow down how do they handle the insane force that they would be experiencing?
In: 160
Falcons are yoked, like most wild animals. To top it off, they’re hunters. They’re really strong for their size and are really light for their size, with hollow bones and muscle being 99% of their mass. It’s like taking a corner in a sports car compared to a Corolla. Yeah, the Corolla can take a corner, but not as well as a Porsche.
Like most trained physicists they disregard air resistance as trivial.
Kidding. But the truth is the forces are either dealt with thru structure (strong wings/shoulders/feathers) or mitigation (shallow pullout of dive vs steep) depending on the bird and the situation.
They can control their speed and angle through the dive with their tail feathers. They typically begin slowing down a few seconds before they “open the parachutes.”
When they dive like that, they aren’t hunting land animals. They’re hunting airborne animals.
So they blast past the prey bird at 200mph, barely tap a wing (to not injury itself) and break it. And then snag the meal after it falls to the ground.
They have plenty of time to gradually pull up and avoid crazy stress from air resistance.
Gradually. But also 200mph isn’t really enough to rip a mammal apart from air resistance. F1 drivers have their helmets in the air at 230+, MotoGP riders their whole bodies in the air at 220+ – they actually use their torsos and dangle legs as an air brake of sorts.
They’re adapted to the forces they’re experiencing. For one thing, they’re much, much smaller and less dense. A peregrine falcon, the fastest animal in the world, can withstand up to 25Gs of acceleration. A trained human fighter pilot can withstand up to 9Gs, for a short period of time. They are lighter, they have a very high systolic pressure, and have very strong chest muscles.
Scaling laws are relevant here.
The strength of a muscle is proportional to its cross-section area (length ^ 2). But its mass is proportional to its volume (length ^ 3). So the ratio of strength to mass scales as (L ^ 2) / (L ^ 3) = 1 / L. Which means that, for a similarly shaped animals, the small ones (low L) are strong AF relative to their mass, while big ones (high L), are really strong on an absolute scale, but weak relative to their mass. Which is why elephants can’t jump, ants seem super strong, and falcons can handle higher g forces than Maverick.
Kind of worth mentioning that the forces in a dive at steady state balance out. The maximum force on the wings/body is the weight of the bird. When the bird is pulling out of a dive it’s not just throwing it’s wings out recklessly, it’s progressively pulling from 1g to 2g to 3g etc. The aerodynamic forces to pull a xg dive are just x*(weight of the bird). There’s no sharp transition here that the bird hasn’t carefully studied.
Birds are not very heavy, so it takes very little force to stop that fall the moment they open their wings – instead of breaking their wings, they “bend” to where the air current takes them. (open wings, flapping, that direction would be up)
If they tried to stop a free fall and the bird was the size of a brontosaur or giraffe, no doubt the force required with be greater and the chance of breaking a limb would go up.
I think what I’m saying is: its not the air that breaks the wing, its the animal’s own momentum (mass*velocity), that wants to continue to fall.
They’re aerodynamic to get to those speeds in the first place, their wings are made to allow air past them.
Even “stopping”, where they deliberately introduce friction by adjusting their wings, there’s almost no friction in force terms, just enough to stop a small bird falling quite so fast.
More interesting are the birds who power-dive direct into water to catch fish many meters down.
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