Mike Schumann wrote:
The NOAH system looks like a kludge to me that does not address
survivability for accidents that happen at low altitudes.
It's a good design, intended to address exiting the glider quickly. This
is a very important at low altitudes. We all agree a glider rescue
system that *actually works* would be better in that situation.
Here is a link showing the specs and prices for typical BRS chutes:
http://www.brsparachutes.com/ViewDoc...?DocumentID=84
I suspect that the concerns about impact survivability in a glider are
overblown.
Technical Soaring, and probably other publications, has had articles on
the design and operation issues for glider rescue systems. You might
find your suspiscions are modified after you have read these articles.
If it were easy, all the manufacturers would offer one in all their gliders.
You might want to contact BRS directly to discuss this issue.
I have talked to a designer working on glider rescue systems. BRS is not
not as eager as you might think to have their products incorporated
into our gliders.
One way you could reduce the impact forces is to have the glider descend
under the chute so that the tail impacts the ground first and dissipates
part of the energy before the cockpit contacts the ground.
This requires the parachute to descend without oscillating while holding
the fuselage in the tail down position, basically flying backward;
further, the tail must be designed to absorb energy during impact, which
is not a normal design parameter. How can we know the installation will
do this without flight testing? Without careful design of the tail
structure, it seems likely to me that when the tail hits first, the
fuselage will slam down at the cockpit end, increasing the forces on it
and the pilot. And what protects the pilot if the tail is missing after
the collision?
--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly
* "Transponders in Sailplanes"
http://tinyurl.com/y739x4
* "A Guide to Self-launching Sailplane Operation" at
www.motorglider.org