Re: More Bat uh Stuff

From: Jane Williams <janewilliams20_at_...>
Date: Sat, 3 Apr 2004 19:11:17 +0100 (BST)

> Hi all. I just joined this list.

Hi! Take a few minutes to read through the archives (erm, make that a spare weekend...) and don't forget to visit the Wiki.

I'm not quite sure what point you were tryng to make with the quotes, but one thing hit me:

> heavily flew into sight and clumsily swooped
> Later, the Bat is described as having "lifted slowly

Heavily. Clumsily. Slowly. Oh dear :(

However, when I tried to visualise this, a Thought occured. A normal bat flaps its wings so fast you can't see them. So how slow is "slow"? I tried visualising it, I tried flapping in time, I reckoned say two seconds from top of stroke to bottom of stroke is "slow". That's four seconds for each complete stroke.

We've looked at various sizes for the Bat. Let's be conservative and say its wings are each 300m long: total wingspan a bit over 600m

I seem to remember the flap angle is quite big: the wings don't quite meet above and below, but they come pretty close to it. Again, let's be conservative and say each flap covers 1/3 of the possible angle, not the full 1/2.

In each 2 sec up to down, the wing tip covers around 620m. Average speed of 310m/sec. That's *average* - it has to stop at each end and reverse direction.

The speed of sound is 340m/sec. At this scaled down and slowed down size, you're getting sonic booms off the wingtips with every flap. Yes, I know, physics and Glorantha do not mix, but does this give some idea of what we mean by "slow"?



Jane Williams                                   

Powered by hypermail