Variometer installation

[[email protected]]

I have a Pilatus B4 and wish to install an ILEC audio variometer. A
TE probe on the tail is not going to happen, for a number of
reasons. So I guess my choice is either a fuselage mounted probe, or
no probe at all..which I guess would give me an uncompensated
variometer. any advice for me, a rookie? Thanks, Bill

[Bob Kuykendall]

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/Construction/T_E_PROBE_ANTENNA.html

Thanks, Bob K.

[[email protected]]

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/Construction/T_E_PROBE_ANTENNA.html
>
> Thanks, Bob K.

Bob,

I like the idea of incorporating the Radio Antenna and TE Probe. Do
you still have some of the parts, as said in the article?

[Bob Kuykendall]

On Nov 26, 5:32 pm, wrote:

> I like the idea of incorporating the Radio Antenna and TE Probe. Do
> you still have some of the parts, as said in the article?

Yes, I've still got a couple of the antenna-length wands up at the
shop. I think I have a couple of the machined bases as well, but I
hold no particular confidence I could put hand to them, so you're
probably out of luck there. Easy enough to make, though.

Thanks, Bob K.

[Wayne Paul]

> wrote in message
...
> 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/Construction/T_E_PROBE_ANTENNA.html
>>
>> Thanks, Bob K.
>
> Bob,
>
> I like the idea of incorporating the Radio Antenna and TE Probe. Do
> you still have some of the parts, as said in the article?

This system was designed for a metal sailplane. You will need to create a
ground plane inside the fuselage of your Cherokee. Four 22 inch copper wire
radials should do the trick.

Wayne
HP-14 "6F"
http://www.soaridaho.com/
Amateur Radio W7ADK

[[email protected]]

right now i have a homemade ground plane antenna. It is made of
fairly stiff copper wire, which makes it tricky to fit behind the seat
in the glider. would it be equivalent to use some more malleable
copper, run along the inside of the fuselage, curved with the frame,
but still the 22-23 inch length that is important. any thoughts?

[[email protected]]

Thank you. I already have an antenna in place. I've read, over and
over, that fuselage mounted probes (particularly those mounted aft of
the wing - which, of course, is pretty much the only pace I'm going to
be able to put it) really stink compared to those on the tail. Shall
I infer from your comments that a ****ty TE probe is better than none
at all? Let me tell you that the intended purpose is for fun flying
in the vicinity of the airfield. There will be no cross-country to
speak of...mainly climbing back up to play around a bit. Mostly I
want this audio vario so I can generally tell up from down while
looking out of the cockpit.

[Bob Kuykendall]

On Nov 27, 8:09 am, wrote:
> ...I've read, over and over, that fuselage mounted probes
> (particularly those mounted aft of the wing ... really stink
> compared to those on the tail...

I think this is one of those "sure, it works in practice, but does it
work in theory?" topics.

As I've cited earlier in this thread, both Nicks and Johnson agree
that fuselage-mounted probe can be perfectly adequate. My experience
building, installing, and using the Sebald/Nicks antenna/TE probe for
a dozen years correlates what they've written on the topic.

I'm not particularly opposed to tail TEs, and I agree that they can be
more accurate. We plumbed our last three fuselages for them. But
unless a) (preferred) you're working on your fuselage on the half-
shell, b) the ID of your aft fuselage substantially exceeds the OD of
your body, or c) your ferret is trained on AC43.13 plumbing strain
relief, the slight accuracy advantage of the tail TE is likely not
worth the trouble of installing the necessary plumbing.

Thanks, Bob K.

[Chris Reed[_1_]]

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.

[[email protected]]

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.

[Michael Ash]

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

[Wayne Paul]

> 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/

[[email protected]]

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/Construction/T_E_PROBE_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"

[Bob Kuykendall]

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.

[[email protected]]

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"

[Michael Ash]

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

[[email protected]]

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 :D:D

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

[[email protected]]

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 :D:D
>
> 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 !

[[email protected]]

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?

[Michael Ash]

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

[Michael Ash]

wrote:
> I'm curious about the "sport canopy". Do you refer to flying with the
> canopy removed? Is this something people talk about?

Not exactly removed, but replaced with one which only covers the front to
block the incoming wind, leaving the top and sides open. Kind of like a
convertible. I've never used one but I've heard they're fun, although they
cost a fair bit of performance.

--
Michael Ash
Rogue Amoeba Software

[[email protected]]

> Not exactly removed, but replaced with one which only covers the front to
> block the incoming wind, leaving the top and sides open. Kind of like a
> convertible. I've never used one but I've heard they're fun, although they
> cost a fair bit of performance.

not on the 1-26. You cant do anything to them to make them perform
worse
:D

[Wayne Paul]

"Michael Ash" > wrote in message
...
> wrote:
>> I'm curious about the "sport canopy". Do you refer to flying with the
>> canopy removed? Is this something people talk about?
>
> Not exactly removed, but replaced with one which only covers the front to
> block the incoming wind, leaving the top and sides open. Kind of like a
> convertible. I've never used one but I've heard they're fun, although they
> cost a fair bit of performance.

Here are a couple links to pictures of an 1-26 "Sport Canopy:"
http://www.126association.org/graphics/lfsidesport.jpg
http://www.126association.org/graphics/harry-sport2.jpg

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

[309]

> > wrote:
> >> I'm curious about the "sport canopy". Do you refer to flying with the
> >> canopy removed? Is this something people talk about?
>
> > Not exactly removed, but replaced with one which only covers the front to
> > block the incoming wind...
>

Not quite true: both the front AND back (just behind the pilot)
canopy pieces are replaced...to "smooth the airflow".

>
> Here are a couple links to pictures of an 1-26 "Sport Canopy:"http://www.126association.org/graphics/lfsidesport.jpghttp://www.126association.org/graphics/harry-sport2.jpg
>
> Wayne
> HP-14 "6F"http://www.soaridaho.com/

Here are some pix showing "all the pieces," showing a normal canopy
and a sports canopy (front and aft):
http://www.soarelsinore.org/graphics/sprtcomp4.jpg (all four pieces,
in front of the ship)
http://www.soarelsinore.org/graphics/sprtcomp3.jpg (normal canopy,
installed)
http://www.soarelsinore.org/graphics/sprtcomp1.jpg (sport canopy,
installed)
....and a pic of me "freezing" (29 deg F, 12,500 MSL, sucking oxygen
through the hose, because the mask is on the ground...)
http://www.soarelsinore.org/graphics/309sist.jpg

The "performance cost" has not been documented (that I can find). The
rumors of anvil-like glide performance are exaggerated, IMHO. Most of
these reports seem to come from pilots who have the CABIN for the
airspeed static pressure source, rather than hooked up to the external
static ports (normally on the nosecone, sometimes on the aft
fuselage). The normal statics are sometimes "reserved" for the
vario(s).

I installed an alternate static source switch (normal static =
nosecone side statics, alternate = cabin). When switching from normal
to alternate, the airspeed indication jumps +10 mph. This means the
pilots flying with cabin static source were flying 10 mph SLOWER than
they thought, which we know will kill L/D far more than flying faster.

Yes, I'd like to do a flight test to measure L/D with Sports (and
regular) canopies. It's on my list of things to do, but nowhere near
the top.

The glider handles very nicely (including stalls & spins) with either
canopy.

Other than the unexpected mountain wave (which took me to 29F @ 12k),
it's quite fun to fly occasionally with "the top down."

-Pete
#309

[Michael Ash]

wrote:
>> Not exactly removed, but replaced with one which only covers the front to
>> block the incoming wind, leaving the top and sides open. Kind of like a
>> convertible. I've never used one but I've heard they're fun, although they
>> cost a fair bit of performance.
>
> not on the 1-26. You cant do anything to them to make them perform
> worse

I have proven to myself over many flights that opening the spoilers will
make them perform worse.

As for more subtle changes, you might be surprised. My friend who's
letting me fly his keeps talking about moving his oxygen bottle, currently
in the nose, to behind the seat in order to move the CG back and gain a
bit of performance. Personally I'm kind of doubtful about this strategy
but I guess it shows that 1-26ers can worry about performance too. :)

--
Michael Ash
Rogue Amoeba Software

[[email protected]]

> > not on the 1-26. You cant do anything to them to make them perform
> > worse
>
> I have proven to myself over many flights that opening the spoilers will
> make them perform worse.
> --
> Michael Ash
> Rogue Amoeba Software

Clearly Michael is not referring to the "A" model...

[[email protected]]

On Nov 28, 8:56 am, wrote:
> I'm curious about the "sport canopy". Do you refer to flying with the
> canopy removed? Is this something people talk about?

Many years ago, afternoon on a nice summer day at
Sugarbush, one of the pundits spotted my whale, sans
overhead canopy, near the flight line. "Have you forgot
something Dave" asks the pundit ? Nawh, says one
of my buddies, Dave's just decided its too much work
to clean the canopy and decided its unnecessary in
any case, and its easier to see out without the
dirty canopy. So the pundit gives us a long lecture
on how the turbulence from the open area will
cause the thing to be unstable and I'll no doubt
crash and die. And a lot of really big words poor
Dave couldn't pronounce let alone comprehend.
Lecture continued for many minutes.

Had to finally explain that I came down because
I was freezing my ass off in the wave sans canopy,
really guys flies just fine, left it by the flight line
because I'll go back up after I warm up a bit
but this time not up in the wave. And I'll clean
the canopy some other day...

> Will a B4 explode if you fly it with the canopy removed?

Undoubtedly, according to the pundit ;-)

See ya, Dave "YO"

PS: I know, I've got to get the whale back in
the air someday...

PPS: Seriously, not all of our toys are safe
without canopy...

[309]

On Nov 28, 11:25 am, Michael Ash > wrote:
> on the 1-26. You cant do anything to them to make them perform
> > worse
>
> As for more subtle changes, you might be surprised. My friend who's
> letting me fly his keeps talking about moving his oxygen bottle, currently
> in the nose, to behind the seat in order to move the CG back and gain a
> bit of performance. Personally I'm kind of doubtful about this strategy
> but I guess it shows that 1-26ers can worry about performance too. :)
>

It would seem to me that this is a more cost effective solution than
buying the latest logger, glide computer, PDA and versions of
WinPilot, SeeYou Mobile, etc.

Sheesh. Next thing you know, somebody will be blaming (us) 1-26er's
for the demise of the sport (even though we seldom _race_, per se),
blame us for the Hobbs scandals and global warming... After all,
lower L/D means more gas (and hence CO) to tow a glider to a given
height...but then again, 1-26's are LIGHTER than the glass whipper-
snapper (younger) gliders...so maybe it's LESS CO to tow a 1-26 to the
same altitude... Hmm, I wonder if more CO was produced welding the
steel tubing of the 1-26, or in producing the chemicals needed for
gelcoat and it's underlying "structure." Which glider is the
"Hummer????"

Oh, sorry, I'll put away my flamethrower...I've exceeded my carbon
quota (on this thread).

-Pete
SGS 1-26 #309

P.S.: I'm trying to have FUN while soaring -- budget on L/D, skill,
time or any other aspect that constrains our "sport."
P.P.S: My oxygen bottle IS behind the seat (factory mounts!), and I
have two of the three diamonds...so tell your friend that the Oxy tank
in the back works!!! Okay, it's a little harder to reach it to turn
it on when you realize (after tow release) that you forgot to turn it
on pre-flight...but it IS possible, and my previous pic posting is
proof!