Thermal right, land left

Robertmudd1u wrote:

Gear up (soaring): set it a little below normal thermalling speed (about
46 knot setting works on my glider with my 302).

Gear down (landing): set it a little below the typical pattern speed
(about 50 knots would work on my glider).



Some may think this a cheap shot, but what the heck.

Believe it or not some pilots fly gliders with fixed gear. They even fly them
X-C and make land outs. They even stall/spin them.

I was trying to keep the discussion simple and focused on the air speed
alert idea. It'd also failin a retractable gear glider if the pilot
forgot to put the gear down.

Fixed gear gliders could use a switch for "landing mode". Perhaps one
switched on by opening the spoilers during the pattern checks that stays
switched on even when the spoilers are closed after the checks would be
better. The pilot would manually reset it after landing, or after using
the spoilers while soaring.

Too many people in this sport think you need ALL the bells and whistles and a
$100,000+ glider to be a "real" glider pilot. That attitude is hurting us.

Agreed, but the discussion isn't about being a "real" glider pilot, but
how to help the pilot when his piloting fails. People spinning in are
definitely hurting us. If the airspeed alert idea is useful, it can be
cheaply implemented by pilots using the Cambridge 302 and similar high
end varios. That's got to be good.

Extending the protection (if it is protection) to pilots that won't buy
an expensive vario, or the $1100 DSI from DG, would be the next
challenge. If proven to be of value (and having people using the idea
via 302/DSI route would be one way), I think you'd see it popping up in
cheaper systems. A special unit that did only the airspeed alert for
landing would be a lot cheaper than the DSI. The DSI itself might get a
lot cheaper if these kinds of things began selling, and competitors
appeared.

--
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change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

Robertmudd1u wrote:

Some may think this a cheap shot, but what the heck.

Believe it or not some pilots fly gliders with fixed gear. They even fly them
X-C and make land outs. They even stall/spin them.

Too many people in this sport think you need ALL the bells and whistles and a
$100,000+ glider to be a "real" glider pilot. That attitude is hurting us.

Robert Mudd

I certainly would not use the word "need" with respect to a
glider AOA indicator.

And yes, cheap and simple is important. Perhaps the cheapest idea
is simply the ol' harmonica style Cezzna AOA indicators, one
mounted on each wingtip of a 1-26 (easier to install on a metal wing,
and the 1-26 is a glider with more than it's share of stalls
leading to fatalities).

Then, if added complexity is warranted, a small switch on the
spoilers which deactivates the audio vario when the spoilers are out,
so one can now just barely hear the stall horns.

Ideally, it would be nice to have removable wingtips, so
one could experiment without modifying a whole wing...

Perhaps there are other types that would have this feature
to allow inexpensive experimentation. Then maybe try the electric
AOA tabs too...

--

------------+
Mark Boyd
Avenal, California, USA

SAILPLANE STALL WARNING SYSTEMS - Recent History

Because of concern about sailplane stall accidents, during early 1987
OSTIV announced that they would sponsor a "Competition for Development
of a Special Flight Instrument for Stall Warning of Sailplanes". We of
the Dallas Gliding Association decided that entering that competition
was certainly a worthwhile project. The offered prize for 1st place
was 2,550 DM, and 1,000 DM for 2nd place. Those prizes were awarded
after flight-testing judging and during the 1989 OSTIV Congress at
Weiner Neustadt in Austria.
Over a 2-year period we studied various candidate configurations, and
performed developmental flight-testing with 5 or 6 different
experimental stall warning systems. While most of the flight-testing
was performed with my Ventus A, several other sailplanes ranging from
a Schweizer 1-26 to a Nimbus 3 were included. Flight testing included
flying into moderate rain showers, and flying with many natural bugs
along the wing leading edges.
We judged our best overall stall-warning configuration to be a small
floating vane mounted well aft on the top surface of the wing, and
entered that configuration into the 1998 OSTIV Competition fly-offs at
Weiner Neustadt. The Polish entry was judged to be the winner there,
but our configuration placed 2nd. The weakness in our design was that
its external mounting was subject to damage during club use.
The Polish design used the differential pressure measured between the
fuselage nose pitot tube and a small flush orifice located on the
bottom of the nose several inches aft of the pitot. It is essentially
an angle-of-attack indicator, and I believe that it is still marketed
today.
Although its external mounting makes it subject to handling damage,
the DGA design performs well in my opinion, even in rain and with bugs
and various flap settings. I have used it on my sailplanes
continuously since its development, and feel my flying is safer for
that. Its design is shown in the 7/90 issue of Soaring, and I believe
it was also published Sailplane & Gliding about that time.
Dick Johnson

"Mark James Boyd" wrote in message
news:4054b43e$1@darkstar...
Robertmudd1u wrote:

Some may think this a cheap shot, but what the heck.

Believe it or not some pilots fly gliders with fixed gear. They even fly
them
X-C and make land outs. They even stall/spin them.

Too many people in this sport think you need ALL the bells and whistles
and a
$100,000+ glider to be a "real" glider pilot. That attitude is hurting
us.

Robert Mudd

I certainly would not use the word "need" with respect to a
glider AOA indicator.

And yes, cheap and simple is important. Perhaps the cheapest idea
is simply the ol' harmonica style Cezzna AOA indicators, one
mounted on each wingtip of a 1-26 (easier to install on a metal wing,
and the 1-26 is a glider with more than it's share of stalls
leading to fatalities).

Then, if added complexity is warranted, a small switch on the
spoilers which deactivates the audio vario when the spoilers are out,
so one can now just barely hear the stall horns.

Ideally, it would be nice to have removable wingtips, so
one could experiment without modifying a whole wing...

Perhaps there are other types that would have this feature
to allow inexpensive experimentation. Then maybe try the electric
AOA tabs too...

--

------------+
Mark Boyd
Avenal, California, USA

Tape two yaw strings (which then become pitch strings) on each side of the
canopy at the lowest and most forward part you can still see. Fly once with
a grease pencil to mark the inside of the canopy at the string positions for
best L/D, minimum sink, and stall. By using a string on each side of the
canopy, the error introduced by inadvertent yaw is obvious and can be
eliminated with rudder.

The string position for best L/D, min sink, and stall will always be the
same whether the glider is ballasted, empty or in a steep turn - although
the airspeeds will be very different.

The string angle difference between minimum sink and stall is large so the
bright red, wiggling strings angled up steeply are a good visual stall
warning.

Bill Daniels

Hi Robert,

Read the story at http://home.wxs.nl/~kpt9/gear.htm and you may have second
thoughts.

Karel, NL

"Robertmudd1u" schreef in bericht
...
Gear up (soaring): set it a little below normal thermalling speed (about
46 knot setting works on my glider with my 302).

Gear down (landing): set it a little below the typical pattern speed
(about 50 knots would work on my glider).


Some may think this a cheap shot, but what the heck.

Believe it or not some pilots fly gliders with fixed gear. They even fly
them
X-C and make land outs. They even stall/spin them.

Too many people in this sport think you need ALL the bells and whistles
and a
$100,000+ glider to be a "real" glider pilot. That attitude is hurting us.

Robert Mudd

Speaking of simple warning devices:
How about a simple hookup to a horn which is activated when the
airbrakes are opened while the towhook is engaged (i.e. open spoilers
during tow)?
A microswitch on the airbrake levers would be the no-brainer part.
What about the towhook? Magnetic sensor? where? How? Other ideas?
Uri

(Mark James Boyd) wrote in message news:4054b43e$1@darkstar...
Robertmudd1u wrote:

Some may think this a cheap shot, but what the heck.

Believe it or not some pilots fly gliders with fixed gear. They even fly them
X-C and make land outs. They even stall/spin them.

Too many people in this sport think you need ALL the bells and whistles and a
$100,000+ glider to be a "real" glider pilot. That attitude is hurting us.

Robert Mudd

I certainly would not use the word "need" with respect to a
glider AOA indicator.

And yes, cheap and simple is important. Perhaps the cheapest idea
is simply the ol' harmonica style Cezzna AOA indicators, one
mounted on each wingtip of a 1-26 (easier to install on a metal wing,
and the 1-26 is a glider with more than it's share of stalls
leading to fatalities).

Then, if added complexity is warranted, a small switch on the
spoilers which deactivates the audio vario when the spoilers are out,
so one can now just barely hear the stall horns.

Ideally, it would be nice to have removable wingtips, so
one could experiment without modifying a whole wing...

Perhaps there are other types that would have this feature
to allow inexpensive experimentation. Then maybe try the electric
AOA tabs too...

Hi Robert,

Read the story at http://home.wxs.nl/~kpt9/gear.htm and you may have second
thoughts.

Karel, NL


Sorry Karel, I am missing your point. I did not say such systems were not a
good idea just that they need to be designed for fixed gear glider too, and not
be expensive. On my retractable gear glider I do have a warning horn for
airbrake and landing gear.

The information in your link is interesting, Ia m sure some will find the
schematic valuable. I sure saved it.

Robert Mudd

Speaking of simple warning devices:
How about a simple hookup to a horn which is activated when the
airbrakes are opened while the towhook is engaged

David Noyes had such a system on his Ventus CM. There was a micro switch
mounted so that the trigger blade was moved by the oval Tost ring as it was
inserted into the tow hook.

Robert Mudd

We judged our best overall stall-warning configuration to be a small
floating vane mounted well aft on the top surface of the wing,

Beechcraft used this system on the early models of the Bonanza.

Robert Mudd

"Bill Daniels" wrote:

Tape two yaw strings (which then become pitch strings) on each side of the
canopy at the lowest and most forward part you can still see.

The string angle difference between minimum sink and stall is large so the
bright red, wiggling strings angled up steeply are a good visual stall
warning.

That must be true only for unflapped gliders, or it's valid only for
one specific flap setting in a flapped glider. Or you have to make
different coloured markings for each and every flap setting.

Aldo Cernezzi