On Sun, 5 Oct 2008 13:33:05 -0600, "Bill Daniels" bildan@comcast-dot-net
wrote:


"Ron Wanttaja" wrote in message
...
On Sun, 5 Oct 2008 09:18:21 -0600, "Bill Daniels" bildan@comcast-dot-net
wrote:

I would claim they are directly related. A glider carefully engineered
for great handling and occupant protection will also have a good L/D.

Bill, I don't have a dog in this hunt, but: Unless you're using a
different definition of "occupant protection" than I am, I disagree.
Adding a steel crash cage to a glider cockpit will increase occupant
protection, but has a negative effect on the aircraft weight
without improving the aerodynamic performance.

I think steel tube structures are way overrated for "occupant protection" as
compared to carbon/Kevlar cockpits on modern composite gliders. Race car
builders abandoned steel tube "birdcages" for carbon/kevlar tubs a long time
ago for safety reasons. You'll never look at steel tube structure the same
way after you've seen a folded tube sever a leg artery.

You're missing my point, Bill. Whether steel tube or kevlar, occupant
protection does not contribute to L/D, as you seemed to claim. Wrapping an
eggshell around the pilot will give good aerodynamics, but better occupant
protection will weigh more and hence reduce performance.

Ron Wanttaja