Variometer installation

Chris Reed wrote:
Without TE, you pull back on the stick and the vario cries "lift". Push,
and you hear "sink". Even local soaring, this will have you confused
enough to be back on the ground faster than you intend.

Having once flown a club glider with defective TE, so that in practice
it was completely uncompensated, the only way I could soar it was to
turn off the audio and fly by the seat of my pants, looking at the
needle only when established in a circle at a steady airspeed.

Just to offer a different perspective on this, I've been doing a lot of
flying this year in a friend's borrowed 1-26 with no audio vario at all.
This so disturbed me that I bought one of Mallettec's Mini Varios, the
kind that's about the size of a box of matches and just clips on to
something. (For me, the hat, because I can't hear it if it's any farther
away in a noisy cockpit.)

This vario is obviously uncompensated. Worse, I'm pretty sure it's
actually negatively compensated. The vent effectively provides pitot-like
pressure to the cockpit and, I believe, will cause it to indicate *more*
than the true rate of climb in a stick thermal. With a constant airspeed
it is surprisingly good; I had thought that cockpit leakage would cause a
lot of inconsistency, but unless I do something like open the spoilers it
does great.

To get to the point of all this, I've done pretty well with this vario.
I'm sure I'd do better with a compensated one and it certainly took some
getting used to at first. When I first hit a thermal I hold speed to see
how big it is, and when I turn in I ignore the beeping until I slow to
thermalling speed. Once I've established speed, I can start listening to
the beeps again to figure out the structure of the thermal. I really just
have to remember that the frantic beeping it gives me when I pull up is
not because I'm in a boomer, but just because the vario is
temporarily delusional.

I'd certainly recommend a compensated vario given the choice, and it may
matter a great deal more in higher performance gliders, but at least for
me it hasn't been the end of the world.

--
Michael Ash
Rogue Amoeba Software

wrote in message
...
On Nov 27, 2:11 pm, Chris Reed wrote:
wrote:
Shall
I infer from your comments that a ****ty TE probe is better than none
at all?

Yes, definitely.

I have a fuselage mounted TE on my glider, and I'm pretty sure I have a
slight leak (to be fixed this winter). Even so, it's far, far better
than none at all.

Without TE, you pull back on the stick and the vario cries "lift". Push,
and you hear "sink". Even local soaring, this will have you confused
enough to be back on the ground faster than you intend.

Having once flown a club glider with defective TE, so that in practice
it was completely uncompensated, the only way I could soar it was to
turn off the audio and fly by the seat of my pants, looking at the
needle only when established in a circle at a steady airspeed.

heh the funny thing is that my longest flight was without TE or
audio. of course i guess i have a seat of the pants glider. and
flying at a steady speed is important.

I sent you a couple personal emails. Please check the email account in your
ras return address.

Wayne
HP-14 "6F"
http://www.soaridaho.com/

On Nov 26, 6:21 pm, Bob Kuykendall wrote:
Earlier, wrote:
...So I guess my choice is either a fuselage mounted probe, or
no probe at all.

I recommend the fuselage probe. Ten dollars worth of parts and you're
good to go.

See Nicks and Johnson for the original idea and its refinement. This
article is pretty clear about it:

http://wcsa.org/docs/TEprobe.pdf

Also, see Sebald for an alternative installation that combines TE
probe and radio antenna:

http://www.soaridaho.com/Schreder/Co...E_ANTENNA.html

Thanks, Bob K.

Hi Guys - The quality of the TE probe you need is related to
the square of your speeds of interest. A floater and/or low
L/D glider is going to be fine with a low-performance
probe. The '26 driver that's bothered by the airvent effect
should simply remove the canopy and all will be well...
See ya, Dave "YO"

On Nov 27, 5:00 pm, wrote:
...The quality of the TE probe you need is related to
the square of your speeds of interest...

Ah, that makes sense. Thanks!

Bob K.

On Nov 27, 9:05 pm, Bob Kuykendall wrote:
On Nov 27, 5:00 pm, wrote:

...The quality of the TE probe you need is related to
the square of your speeds of interest...

Ah, that makes sense. Thanks!

Bob K.

No problem ! In my case, I need a good probe,
even though at 100 knots cruise my L/D is
degraded to a mere 35:1...
See ya, Dave "YO"

wrote:
Hi Guys - The quality of the TE probe you need is related to
the square of your speeds of interest. A floater and/or low
L/D glider is going to be fine with a low-performance
probe. The '26 driver that's bothered by the airvent effect
should simply remove the canopy and all will be well...

Speed and drag, it would seem. The need for TE is going to be driven by
how long your stick thermals last, which will be made longer by higher
speeds and less drag.

The vent doesn't bother me exactly, it's just an interesting effect I
thought about. As far as the sport canopy goes, the last time I flew I
almost froze to death right in the air, so I'm going to have to pass on
that idea at least until the weather turns warm again.

--
Michael Ash
Rogue Amoeba Software

On Nov 27, 10:03 pm, Michael Ash wrote:
wrote:
Hi Guys - The quality of the TE probe you need is related to
the square of your speeds of interest. A floater and/or low
L/D glider is going to be fine with a low-performance
probe. The '26 driver that's bothered by the airvent effect
should simply remove the canopy and all will be well...

Speed and drag, it would seem. The need for TE is going to be driven by
how long your stick thermals last, which will be made longer by higher
speeds and less drag.

The vent doesn't bother me exactly, it's just an interesting effect I
thought about. As far as the sport canopy goes, the last time I flew I
almost froze to death right in the air, so I'm going to have to pass on
that idea at least until the weather turns warm again.

--
Michael Ash
Rogue Amoeba Software

freezing is half the fun of the sport canopy. the "im at cloud base
and i cant feel my toes but im not going down cause im higher than my
CFIG" mindset kicks in.

Oh and there goes Nadler, showing off again

I think my L/D at 100 knots is about 3.5:1, practically the same
right??

On Nov 28, 12:55 am, wrote:
On Nov 27, 10:03 pm, Michael Ash wrote:



wrote:
Hi Guys - The quality of the TE probe you need is related to
the square of your speeds of interest. A floater and/or low
L/D glider is going to be fine with a low-performance
probe. The '26 driver that's bothered by the airvent effect
should simply remove the canopy and all will be well...

Speed and drag, it would seem. The need for TE is going to be driven by
how long your stick thermals last, which will be made longer by higher
speeds and less drag.

The vent doesn't bother me exactly, it's just an interesting effect I
thought about. As far as the sport canopy goes, the last time I flew I
almost froze to death right in the air, so I'm going to have to pass on
that idea at least until the weather turns warm again.

--
Michael Ash
Rogue Amoeba Software

freezing is half the fun of the sport canopy. the "im at cloud base
and i cant feel my toes but im not going down cause im higher than my
CFIG" mindset kicks in.

Oh and there goes Nadler, showing off again

I think my L/D at 100 knots is about 3.5:1, practically the same
right??

Please don't try fly that contraption so fast;
life is short enough as it is !

The probe issue was pretty much settled for me when Bob observed that
the fuselage probe works better in practice than in theory. Thanks
for the advice.

I'm curious about the "sport canopy". Do you refer to flying with the
canopy removed? Is this something people talk about? I saw some
video of guys parachuting from a Blanik from which the canopy was
removed. It looked cool for the summer. I've flown with the canopy
of a 2-33 opened and enjoyed the breeze. Will a B4 explode if you fly
it with the canopy removed?

wrote:
On Nov 27, 10:03 pm, Michael Ash wrote:
The vent doesn't bother me exactly, it's just an interesting effect I
thought about. As far as the sport canopy goes, the last time I flew I
almost froze to death right in the air, so I'm going to have to pass on
that idea at least until the weather turns warm again.

freezing is half the fun of the sport canopy. the "im at cloud base
and i cant feel my toes but im not going down cause im higher than my
CFIG" mindset kicks in.

"To death" was only a slight exaggeration there, I was shivering like mad
and could barely get out of the cockpit by the time I landed. It was a
little more than "I can't feel my toes" that time.

--
Michael Ash
Rogue Amoeba Software