> This brings to mind the thought I've recently had about using the
> sickle claw as a sort-of launch device, a possible 'nother reason for
> the switchblade action the enlarged pedal claw apparently portays...
Dromaeosaur sickle claws would have been poor climbing or launching
devices. They were too thin and blade-like, built more for penetration
than holding. Most climbing claws tend to be circular or ovoid in
cross-section.
If a dromaeosaur tried to push off with its sickle claws, there was a
greater chance of it sinking its claws deeper into a substrate than
pushing the animal up and away.