Originally Posted by
wphamilton
I'm serious, I'm not "arguing" physics with people who haven't studied it. I take this off-topic "why do airplanes flare" as a question. The flare reduces airspeed by increasing the frontal aspect, and produces lift due to the angle. Neither of which have much to do with a bike crash.
I will give you a suggestion though. If you truly want to solve the ballistic motion and get an idea of impact, start with a vector diagram in terms of momentum.
You've seen videos of over-the-handlebars falls surely. Hit a curb at full speed, the bike is impeded but you still have momentum. If you're not clipped in and not holding on deliberately, you'll naturally separate from the bike. And frankly your first instinct should be to push off, not hold on.
The only thing that holding on does for you in over the bars is to help start your body rotating before the roll. You need to turn loose as soon as that happens or the timing is thrown off and you'll land flat, not rolling.
Sorry, but I used to let go of the handlebars in those situations, and all it got me was injured hands. If I "ride" the bike into the ground, I find there's a better than even chance that some part of the bike is going to make the initial contact with the ground and absorb a large portion of the impact. If I let go, generally, my hands hit first, and I'm kind of attached to them.
The other aspect of this, which I think you're ignoring, is that it's often quite difficult to determine exactly when the situation has become unrecoverable. There have been several times where I thought I had lost control of the bike where I was able to pull it back in by holding onto the handlebars. There isn't a lot of conscious decision making going on there as far as how to regain balance, but I'm quite sure if I was focusing on timing a "let go" maneuver, I wouldn't have the mental wherewithal to avoid the ground in the first place.
Yes, airplane flares reduce speed, but they also adjust the attitude so the plan lands on the correct landing gear in as close to horizontal position as possible. And if horizontal speed doesn't matter, why does a plane need to reduce speed in order to land safely? All this "I know physics stuff and you don't" isn't covering for the obvious violations of common sense you're committing. It's quite revealing that you've been asked twice why you can't just step out of a moving car if you're correct, and all you do is tell us we're not qualified to discuss this with you.