BRS for emergencies

"Bob Kuykendall" wrote in message
ups.com...
Earlier, George Young wrote:

Jim......You are misinformed about the Owl project. The BRS was
never deployed by the pilot.

He never said it was deployed by the pilot.

The glider literally disintegrated with the pilot
being ejected through the canopy still strapped
into the seat pan.

Somehow I don't think that's a good thing.

the wreckage descended safely to the ground.

All safety is relative. Every sense of security is at least partly
false.

Thanks, Bob K.


I think what this is down to is that BRS that would work in the majority of
imaginable situations would be too heavy, too complicated, and too expensive
for wide acceptance.

Which brings us back to the alternative, pilot egress aids. The DG NOAH
system is but one possible approach. I think that just an inflatable seat
cushion that would raise the pilot's butt to the level of the cockpit sides
while pulling his legs from under the panel would work.

Bill Daniels

On Sep 13, 12:38 pm, Bob Kuykendall wrote:
One major challenge for sailplane BRS systems is water ballast.

If you size the BRS system to the ballasted gross weight, you end up
needing a rather large system that costs a lot and takes up a lot of
internal volume.

On the other hand, if you size the BRS to the dry gross weight you
have a system that is overmatched under many flight regimes, including
many in which BRS capability is most desirable - such as climbing away
from a start at a crowded contest site.

You could placard the system into compliance with a sticker that says
"Dump ballast before deploying BRS" or "Do not deploy BRS while
ballasted." But that doesn't address an important issue: most ballast
dump systems can't empty the water out in less than about a minute,
and some take as much as three or five minutes.

I suppose the savvy glider developer could also embed a steel cable
into the wing skin, and tie it into the BRS harness so that deployment
unzips the wing and liberates the water. That'd be a sight to see.

Bob K.

How about the pilot dumps the water after activating the BRS ?
If the BRS held the aircraft in a level attitude, the water would
dump.

Todd Smith
3S

Earlier, "Bill Daniels" bildan@comcast-dot-net wrote:

I think what this is down to is that BRS that would work in the majority of
imaginable situations would be too heavy, too complicated, and too
expensive for wide acceptance.

I think that might be a bit on the pessimistic side. There's excellent
coverage for light sailplanes from light, simple, and affordable BRS
systems currently available. The problem comes when you try to scale
it up and cover large gliders, racers, 2-seaters, and massive stuff
like that. For example, my old HP-11 would be a pervect candidate:
Fairly light yet robust, with a nice big chunk of empty volume right
behind the wing spar.

One good thing that came out of the Owl incident was that it points
the way towards an interesting alternative: Instead of protecting the
whole aircraft and pilot, how about protecting just the seat pan and
pilot? The seat pan could be mounted on a rail, with the pilot belted
to the seat pan. The BRS deployment could mechanically unlatch the
canopy and seat pan, and extract the pilot and seat pan from the
forward fuselage. Heck, you could even take your expensive instruments
with you!

I recall that one of the Akafliegs was working on a system like that
called (I think) SOTIERA or something like that. But that was a long
time ago, before BRS systems were as common as they are now. It was
comprised of a lot of expensive custom components. These days such a
system might be built or customized from commercially-available BRS
elements.

Thanks, Bob K.

On Sep 13, 3:53 pm, "Bill Daniels" bildan@comcast-dot-net wrote:

I think what this is down to is that BRS that would work in the majority of
imaginable situations would be too heavy, too complicated, and too expensive
for wide acceptance.

Bill Daniels


No, what I think this shows is that we can think up situations that
the BRS won't work for.

Parachute use seems to be associated with mid-airs or jammed
controls. The BRS seems capable of either of those situations.
Extreme conditions are not my biggest concern, since I am not doing
flight test.


Todd Smith
3S

Eric Greenwell wrote:
shawn wrote:
Bob Kuykendall wrote:
One major challenge for sailplane BRS systems is water ballast.

snip

I suppose the savvy glider developer could also embed a steel cable
into the wing skin, and tie it into the BRS harness so that deployment
unzips the wing and liberates the water. That'd be a sight to see.

How about embedding det cord around each wing, connected to go off
with the BRS rocket? Zip the wings off, along with the water
ballast. With just the fuselage to lower, the 'chute can be smaller
too ;-)

Might as well remove the tail boom, too. This would reduce the glider to
just the cockpit with the pilot. Having a known weight, shape, and size
to control would make it substantially easier for the rescue system
designer. It would speed the certification process, because only one
shape would need to be tested, instead of configurations with all
surfaces attached, one or both wings missing, tail missing, etc.

It would be a very safe glider, as most pilots would never get in it!


Just put in an ejection seat and you can eliminate the BRS altogether!

On 12 Sep, 16:12, "Bryan" wrote:

However, I would appreciate
any information or thoughts concerning the effectiveness of BRS deployment
and if the current ground-impact energy absorption systems are proving
effective for pilot protection.

The main disadvantage I see about ballistic recovery systems is that
they absolutely guarantee you an uncontrollable crash landing.
Electrical substation below you? Railway line? Motorway? There is
nothing you can do about it - that's where you're going to land.

The slower descent rate and controlled attitude does mean, of course,
that in any of the above cases it's better than an uncontrolled
plummet in a fuselage. The Big Midair Question is therefore "How much
control do I have?" If the answer is "None" then the answer is obvious
- press the button. If the answer is "Plenty" then the answer is
obvious - land as near normally as possible.

The difficulty comes with an answer of "Some" - because you then need
to assess how much that is, and what choice is likely to lead to the
best landing.

I have an additional doubt about the whole idea. The most obvious case
for using a BRS is when the glider is completely uncontrollable.
However, the most likely reason for the glider being completely
uncontrollable is major structural damage following a midair collision
- and how much use is a BRS going to be for a glider which has
suffered major structural damage. Someone elsewhere in the thread
suggests configuring things to land tail first for energy absorption.
That's an excellent idea ... unless the BR is being deployed because
the tail boom has been broken off in midair ...

Overall in gliding as in sailing I am sceptical about technological
post crash "solutions." I think it's much better simply to avoid
having the crash in the first place ...

Ian

I suppose the savvy glider developer could also embed a steel cable
into the wing skin, and tie it into the BRS harness so that deployment
unzips the wing and liberates the water. That'd be a sight to see.

From the ground, preferably :-).

Tony V
http://home.comcast.net/~verhulst/SOARING

On Sep 13, 1:54 am, "Michael Huber" wrote:
Streifender developed a BRS system for gliders, his website (sorry, in
german) ishttp://www.streifly.de/Preise9-00.htm
That´s the system you can buy with some of the newer Schempp - Hirth and
Schleicher gliders.

Oh, good! I see from it's location that I have a choice of keeping my
self-launching engine or putting in a recovery parachute.

On Sep 13, 2:13 am, bikensoar wrote:
On Sep 12, 11:54 pm, "Michael Huber" wrote:

Streifender developed a BRS system for gliders, his website (sorry, in
german) ishttp://www.streifly.de/Preise9-00.htm
That´s the system you can buy with some of the newer Schempp - Hirth and
Schleicher gliders.

Michael

I am suprised no one has mentioned the Sparrowhawk Glider. Everyone
of the 20
or so sparrowhawks except one has a BRS parachute. The decision was
to go
with a large parachute to REDUCE opening shock. The one is use in
rated for a
900 lb. aircraft. The Sparrowhawk fully loaded with the heaviest
possible pilot would
not even be 500 lbs. I suspect it will come down quite slowly.

Greg Cole fired off the ballistic parachute while it was attached to
the Sparrowhawk.
It was a ground test. He has it on video and it deployed perfectly
with no problems.
The cost is somewhere around $3000.00.

George Young, Sparrowhawk owner # 6

Raspet Labs was using a modified Lighthawk sailplane for testing last
fall, which crashed. http://www.msstate.edu/web/media/detail.php?id=3621
It had a BRS chute which was triggered by the scissoring main spar
when the wings folded, and the pilot was ejected through the cockpit
by the deceleration, I think because the ring that causes slow chute
deployment did not function properly..

Point: the aircraft must be engineered to take the stresses of chute
deployment and the chute must deploy properly. (Nothing is 100% sure
and safe.)

Dan Johnson

danlj wrote:

Greg Cole fired off the ballistic parachute while it was attached to
the Sparrowhawk.
It was a ground test. He has it on video and it deployed perfectly
with no problems.
The cost is somewhere around $3000.00.

George Young, Sparrowhawk owner # 6

Raspet Labs was using a modified Lighthawk sailplane for testing last
fall, which crashed. http://www.msstate.edu/web/media/detail.php?id=3621

The LightHawk is a very different glider than the SparrowHawk, much
larger and slower, with a lighter wingloading. As the other posters have
mentioned, it was a modified SparrowHawk, which Raspet Labs call the
OWL. I was at Windward Performance last week, where I learned they
delivered an OWL earlier this year, and are preparing another one.

It had a BRS chute which was triggered by the scissoring main spar
when the wings folded, and the pilot was ejected through the cockpit
by the deceleration, I think because the ring that causes slow chute
deployment did not function properly..

When I spoke with Greg Cole at the convention this year, he said the
problem was more excessive speed (50 knots above the 123 knot Vne) than
the parachute operation.


Point: the aircraft must be engineered to take the stresses of chute
deployment and the chute must deploy properly. (Nothing is 100% sure
and safe.)

Of course, but should the rescue system be expected to work properly at
speeds 40% beyond red line? In my glider, that would be 206 knots!

--
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