Re: pteros have lift-off

[Michael Habib <mhabib5@jhmi.edu>]

That's pretty darn close.  On the power available side of things, it's 
probably worth noting that I have been using 390 W/kg as the max 
anaerobic power capacity in my pterosaur models for the quad launch 
calculations.  However, based on potential phylogenetic position and 
morphology, it is quite possible that the big guys did substantially 
better than this, so that value is a conservative estimate.  I chose 
390 because it is the high end for birds, and makes for a nice minimum 
marker for the expected burst performance in pterosaurs.  It is, 
however, likely to be a minimum.

Cheers,

--Mike


On Thursday, January 22, 2009, at 10:45  PM, jrc wrote:

> Looking back over some of my old notes, I noticed that on March 7, 
> 1999, in a letter to Paul MacCready I wrote, "Combined with phasing of 
> the foreleg and back leg stroke production that should allow the leap 
> to take the shoulder velocity to the vicinity of best L/D without 
> exceeding a load factor of about four".   I'm still messing about with 
> the quad leap, and currently I'm getting a launch to Vminsink with an 
> acceleration of about 3.78 g's with the terrestrial part of the launch 
> about 0.31 seconds in duration.  Vminsink is slower than Vbg, but 3.78 
> vs. 4 does seem to me to be in the vicinity for guvm'nt work.  
> Launching to Vminsink ameliorates the work required during the 
> terrestrial launch by loading the wings more heavily once they do 
> start to flap.  My hunch is that now further work on optimization can 
> get the launch acceleration down toward the vicinity of 3 to perhaps 
> 3.25.
> JimC