Thermal right, land left

In article ,
Eric Greenwell wrote:
Mark James Boyd wrote:

Where's the stall warning horn? I'm still utterly baffled why there
isn't a stall warning device on each wingtip? Is this really that
much extra drag? Is it more drag than that caused by having
to make a wing design that buffets before a full stall?

It might be useful to look at small airplane accidents, since they DO
have stall warning horns. I'm under the impression that stall/spin
accidents are a big cause of fatal accidents also. Do you have any numbers?

I looked up the last ten years of gliders (49 fatalities)
and then I looked up a three month window of airplane fatalities
from 3/94 to 6/94 (102 fatalities). I got lazy and didn't want
to look through more than 100, but I wanted to see final reports, so...

Gliders: 21 stalls of 49 fatalities = 43%

If you eliminate midairs and disconnected controls, 21 of 42 = 50%

Airplanes: 9 stalls of 102 fatalities = 9%

If you eliminate midairs and disconnected controls, 9 of 91 = 10%

A bunch of the airplane ones were also night and/or IFR (less than
half). But it seemed real clear that more of the glider fatalities
could have been stalls. Anyway, I concluded that airplane guys
don't stall very much close to the ground...

I was also VERY surprised to find a lot of medical problems
with airplenes, and I don't think even one fatal glider accident
due to a medical condition. This is really surprising...I'll
need to look at all 250 fatal glider reports at some point to
see if there are ANY medical fatalities...

Anyway, yes glider pilots die from stalls as a real big
factor. I think it's because they don't have warning devices.
Hells bells, just hook 'em to the gear down and spoiler cracked
switches, so they're off the rest of the time (thermalling).

Or maybe somebody has a better idea. I dunno, I'm just real
surprised we don't have any stall horns at all on any gliders...



--

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

In article ,
Jack wrote:
On 3/12/04 2:05 PM, in article 40521816$1@darkstar, "Mark James Boyd"
wrote:

Where's the stall warning horn?

On the Cessna, where it belongs. Don't even think about putting one in a
sailplane.

Soaring ought to be about flying the aircraft, not just monitoring the
government-mandated distractions. The thing would either be activated during
most thermaling, or have such a close tolerance as to give no useful warning
to those who would most need it -- and they are expensive. Would you
recommend flashing lights on the panel, a speaker tone to compete with the
vario, or both? Perhaps you would also like to incorporate a stick-shaker?

Who said anything about the gubmint? And what would I want
with a vario during the landing phase, off-field or not?
If I've got the gear down and the spoilers out, I'd be
playing the fool to try using the vario for anything...

Have the vario shut itself off and let the stall warning
buzzer on...

Expensive? I couldn't comment on that...And are the fatal accidents
so rare as to make this idea pointless? Perhaps...

As far as spoilers and flaps changing the stall speed, I suppose that's
glider dependent on how much. And as far as bugs, again I
don't know how far off the normal stall speed you'd see...
Maybe it's negligible, maybe not. Dunno...


--

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

In article ,
Eric Greenwell wrote:
Andreas Maurer wrote:
On 12 Mar 2004 12:05:42 -0800, (Mark James Boyd)
wrote:



Where's the stall warning horn? I'm still utterly baffled why there
isn't a stall warning device on each wingtip? Is this really that
much extra drag? Is it more drag than that caused by having
to make a wing design that buffets before a full stall?


There are gliders that are equipped with stall audio warnings. Most of
these stall warnings have been switched off permanently because they
were yelling all the time while thermalling.

THe difficulty is getting a true stall warning, rather than an airpeed
alert (even if it is adjusted to G loading). Other difficulties with the
type Andreas mentions is it doesn't know when the spoilers are out, the
flap position, or the bugs on the leading edge.

Well, on Cezznas and others, it's just a dorky cheap little tab
which is at the right angle to flip up and close
a circuit when the AOA is pretty close to stall. The Beech
Duchess has 2, one for not so much flaps (on one wing),
one for lotsa flaps (on the other wing).

I guess I'm not even that surprised they aren't on nost
sailplanes, I'm interested to know of the folks who've built
their own, have you guys thought of trying it? Man
I'd love to know what them wingtips are doing...
--

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

Mark James Boyd wrote:
It might be useful to look at small airplane accidents, since they DO
have stall warning horns. I'm under the impression that stall/spin
accidents are a big cause of fatal accidents also. Do you have any numbers?


I looked up the last ten years of gliders (49 fatalities)
and then I looked up a three month window of airplane fatalities
from 3/94 to 6/94 (102 fatalities). I got lazy and didn't want
to look through more than 100, but I wanted to see final reports, so...

Gliders: 21 stalls of 49 fatalities = 43%

If you eliminate midairs and disconnected controls, 21 of 42 = 50%

Airplanes: 9 stalls of 102 fatalities = 9%

If you eliminate midairs and disconnected controls, 9 of 91 = 10%

A bunch of the airplane ones were also night and/or IFR (less than
half). But it seemed real clear that more of the glider fatalities
could have been stalls. Anyway, I concluded that airplane guys
don't stall very much close to the ground...

I was also VERY surprised to find a lot of medical problems
with airplenes, and I don't think even one fatal glider accident
due to a medical condition. This is really surprising...I'll
need to look at all 250 fatal glider reports at some point to
see if there are ANY medical fatalities...

Anyway, yes glider pilots die from stalls as a real big
factor. I think it's because they don't have warning devices.
Hells bells, just hook 'em to the gear down and spoiler cracked
switches, so they're off the rest of the time (thermalling).

Or maybe somebody has a better idea. I dunno, I'm just real
surprised we don't have any stall horns at all on any gliders...

I'm not suggesting this isn't a good idea, but I do wonder...

Why do airplanes have ANY stall/spins during landing? Typically, they
have full control of their pattern (altitude, entry point), while the
glider accidents most often occur when the pilot can't do the desired
pattern because he returns too low.

Maybe we don't need a stall warning for gliders: perhaps a simple
airspeed alert would do everything that is needed, as long as it was
enabled by the gear being extended. I think it should alert regardless
of the spoiler position, since a low, slow pilot isn't likely to open
the spoilers.

DG sailplanes makes such a device, called the DSI. Take a look he

http://www.dg-flugzeugbau.de/dsi-e.html
DG Flugzeugbau GmbH / DSI - Digital Soaring Indicator

Is anyone using one of these? Maybe we already have what we need, but
not enough people are using it.

--
-----
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Eric Greenwell
Washington State
USA

Mark James Boyd wrote:
Soaring ought to be about flying the aircraft, not just monitoring the
government-mandated distractions. The thing would either be activated during
most thermaling, or have such a close tolerance as to give no useful warning
to those who would most need it -- and they are expensive. Would you
recommend flashing lights on the panel, a speaker tone to compete with the
vario, or both? Perhaps you would also like to incorporate a stick-shaker?


Who said anything about the gubmint? And what would I want
with a vario during the landing phase, off-field or not?
If I've got the gear down and the spoilers out, I'd be
playing the fool to try using the vario for anything...

Have the vario shut itself off and let the stall warning
buzzer on...

Expensive? I couldn't comment on that...And are the fatal accidents
so rare as to make this idea pointless? Perhaps...

As far as spoilers and flaps changing the stall speed, I suppose that's
glider dependent on how much. And as far as bugs, again I
don't know how far off the normal stall speed you'd see...
Maybe it's negligible, maybe not. Dunno...

Some varios, like the Cambridge 302, already have gear warning, spoiler
unlocked on takeoff warning, and airspeed alert built into them. It even
adjusts for G loading. I suspect it would be a simple change to it's
software to have two airspeed alerts, based on gear position:

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).

--
-----
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Eric Greenwell
Washington State
USA

"Eric Greenwell" wrote in message
...

DG sailplanes makes such a device, called the DSI. Take a look he

http://www.dg-flugzeugbau.de/dsi-e.html
DG Flugzeugbau GmbH / DSI - Digital Soaring Indicator

Is anyone using one of these? Maybe we already have what we need, but
not enough people are using it.

--
-----
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Eric Greenwell
Washington State
USA


Interesting device but maybe a little too much feature bloat.

It wasn't clear to me that different minimum airspeed warnings could be set
for various glider configurations such as, say, 55Kts with the gear down but
42 knots with the gear up. doesn't really matter - I'd settle for just a
differential pressure switch that is set once and interlocked with the gear.

The "Dolly Warning" is interesting. Just place a magnetic reed switch
inside the tail boom where the dolly fits and bolt a strong magnet on the
dolly.

900 Euro is probably cheap compared to the mayhem it is intended to prevent
but I'd bet that an equivalent device could soldered up for a lot less by an
electronics hobbyist.

Bill Daniels

In article ,
Eric Greenwell wrote:
Mark James Boyd wrote:
It might be useful to look at small airplane accidents, since they DO
have stall warning horns. I'm under the impression that stall/spin
accidents are a big cause of fatal accidents also. Do you have any numbers?


I looked up the last ten years of gliders (49 fatalities)
and then I looked up a three month window of airplane fatalities
from 3/94 to 6/94 (102 fatalities). I got lazy and didn't want
to look through more than 100, but I wanted to see final reports, so...

Gliders: 21 stalls of 49 fatalities = 43%

If you eliminate midairs and disconnected controls, 21 of 42 = 50%

Airplanes: 9 stalls of 102 fatalities = 9%

If you eliminate midairs and disconnected controls, 9 of 91 = 10%

A bunch of the airplane ones were also night and/or IFR (less than
half). But it seemed real clear that more of the glider fatalities
could have been stalls. Anyway, I concluded that airplane guys
don't stall very much close to the ground...

I was also VERY surprised to find a lot of medical problems
with airplenes, and I don't think even one fatal glider accident
due to a medical condition. This is really surprising...I'll
need to look at all 250 fatal glider reports at some point to
see if there are ANY medical fatalities...

Anyway, yes glider pilots die from stalls as a real big
factor. I think it's because they don't have warning devices.
Hells bells, just hook 'em to the gear down and spoiler cracked
switches, so they're off the rest of the time (thermalling).

Or maybe somebody has a better idea. I dunno, I'm just real
surprised we don't have any stall horns at all on any gliders...

I'm not suggesting this isn't a good idea, but I do wonder...

Why do airplanes have ANY stall/spins during landing? Typically, they
have full control of their pattern (altitude, entry point), while the
glider accidents most often occur when the pilot can't do the desired
pattern because he returns too low.

Maybe we don't need a stall warning for gliders: perhaps a simple
airspeed alert would do everything that is needed, as long as it was
enabled by the gear being extended. I think it should alert regardless
of the spoiler position, since a low, slow pilot isn't likely to open
the spoilers.

DG sailplanes makes such a device, called the DSI. Take a look he

http://www.dg-flugzeugbau.de/dsi-e.html
DG Flugzeugbau GmbH / DSI - Digital Soaring Indicator

Is anyone using one of these? Maybe we already have what we need, but
not enough people are using it.

Well, some of the power accidents are just newer pilots that
weren't trained to properly react to the horn. In some
I suspect the horn wasn't even working (I've been surprised by
failed horn a few times).

The airspeed idea is good (better than nothing) but doesn't
tell the AOA at both wingtips, and doesn't seem to account for the
G loading in a tight turn. Also, as another poster pointed out,
the horn detects gusts, which is pretty useful IMHO.

In any case, I'd just love to have a glider with an AOA tab
(each with a different tone) on each wingtip, and teach some spins in it.
I'd also love to see how well it does when thermalling. Maybe
Andreas is right and one can't tell horn vs. vario, but it would be
a kick to try...

Anyway, just another fun idea...now let's cut out this
nonsense and get back to implementing the turbine powered sparrowhawk ;P

--

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

Mark James Boyd wrote:
Well, some of the power accidents are just newer pilots that
weren't trained to properly react to the horn. In some
I suspect the horn wasn't even working (I've been surprised by
failed horn a few times).

The airspeed idea is good (better than nothing) but doesn't
tell the AOA at both wingtips,

This probably won't be useful for landing, since the selected airspeed
should be high enough to make the AOA at the tips irrelevant.

and doesn't seem to account for the
G loading in a tight turn.

Take another look: both the DSI and the 302 have accelerometers that let
them account for G loading. Anyway, the stall/spins typically aren't
from tight turns, but shallow ones.

Also, as another poster pointed out,
the horn detects gusts, which is pretty useful IMHO.

I think any gusts that affect your landing will be readily apparent as
the glider twitches and bobs in response to them. Certainly they are
noted by the pilot while thermalling.

Maybe it's time to give airspeed alerts in the pattern a chance.


--
-----
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Eric Greenwell
Washington State
USA

Looks to me that having AOA indicators in the IP for both wingtips to
optimize climbing performance and avoid the onset of spin would be great .

Karel, NL


"Mark James Boyd" schreef in bericht
news:4053a369$1@darkstar...
In article ,
Eric Greenwell wrote:
Mark James Boyd wrote:
It might be useful to look at small airplane accidents, since they DO
have stall warning horns. I'm under the impression that stall/spin
accidents are a big cause of fatal accidents also. Do you have any
numbers?


I looked up the last ten years of gliders (49 fatalities)
and then I looked up a three month window of airplane fatalities
from 3/94 to 6/94 (102 fatalities). I got lazy and didn't want
to look through more than 100, but I wanted to see final reports, so...

Gliders: 21 stalls of 49 fatalities = 43%

If you eliminate midairs and disconnected controls, 21 of 42 = 50%

Airplanes: 9 stalls of 102 fatalities = 9%

If you eliminate midairs and disconnected controls, 9 of 91 = 10%

A bunch of the airplane ones were also night and/or IFR (less than
half). But it seemed real clear that more of the glider fatalities
could have been stalls. Anyway, I concluded that airplane guys
don't stall very much close to the ground...

I was also VERY surprised to find a lot of medical problems
with airplenes, and I don't think even one fatal glider accident
due to a medical condition. This is really surprising...I'll
need to look at all 250 fatal glider reports at some point to
see if there are ANY medical fatalities...

Anyway, yes glider pilots die from stalls as a real big
factor. I think it's because they don't have warning devices.
Hells bells, just hook 'em to the gear down and spoiler cracked
switches, so they're off the rest of the time (thermalling).

Or maybe somebody has a better idea. I dunno, I'm just real
surprised we don't have any stall horns at all on any gliders...

I'm not suggesting this isn't a good idea, but I do wonder...

Why do airplanes have ANY stall/spins during landing? Typically, they
have full control of their pattern (altitude, entry point), while the
glider accidents most often occur when the pilot can't do the desired
pattern because he returns too low.

Maybe we don't need a stall warning for gliders: perhaps a simple
airspeed alert would do everything that is needed, as long as it was
enabled by the gear being extended. I think it should alert regardless
of the spoiler position, since a low, slow pilot isn't likely to open
the spoilers.

DG sailplanes makes such a device, called the DSI. Take a look he

http://www.dg-flugzeugbau.de/dsi-e.html
DG Flugzeugbau GmbH / DSI - Digital Soaring Indicator

Is anyone using one of these? Maybe we already have what we need, but
not enough people are using it.

Well, some of the power accidents are just newer pilots that
weren't trained to properly react to the horn. In some
I suspect the horn wasn't even working (I've been surprised by
failed horn a few times).

The airspeed idea is good (better than nothing) but doesn't
tell the AOA at both wingtips, and doesn't seem to account for the
G loading in a tight turn. Also, as another poster pointed out,
the horn detects gusts, which is pretty useful IMHO.

In any case, I'd just love to have a glider with an AOA tab
(each with a different tone) on each wingtip, and teach some spins in it.
I'd also love to see how well it does when thermalling. Maybe
Andreas is right and one can't tell horn vs. vario, but it would be
a kick to try...

Anyway, just another fun idea...now let's cut out this
nonsense and get back to implementing the turbine powered sparrowhawk ;P

--

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

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