varios not using a total energy probe

[Robert]

Hello! Can someone tell me which compensated varios do not need a
total energy probe? (no electronic compensation) Thanks a lot! Robert

[Arnie]

Depends on what u mean by "compensated" varios.

There are three ways to achieve TE compensation, usually :
*Electronic via flight computer (which u ruled out, but also it isn't very
good, it needs VERY accurate pitot-static, among other problems),
*Diaphragm (old solution, and good only for the altitude it was calibrated
for)
*TE Probe (the simplest and most accurate one).

Both an all "mechanical" vario, or a new electronic one (the ones that
"beep") will require a TE probe to achieve the best results.
An old and very good diaphragm compensator used to be manufactured in the
70s by Wil Schueman, but like I said, it would be good only for the altitude
range it was calibrated for.
SZD also used to sell their gliders with cheap diaphragm compensators that
become brittle after a few years.
But I don't think they would be easy to find these days.

There's a reason everybody adopted TE probes : They are simple and the most
effective way to do it.



"Robert" > wrote in message
om...
> Hello! Can someone tell me which compensated varios do not need a
> total energy probe? (no electronic compensation) Thanks a lot! Robert

[Pete Reinhart]

Robert,
Bohli makes a taught band vario with a diaphragm compensator. Once very
popular in Europe, Don't know about now. Still available from Bohli, and
support service is excellent. Very expensive. Reichman's book tells you how
to make one yourself, I think.

Cheers!
"Robert" > wrote in message
om...
> Hello! Can someone tell me which compensated varios do not need a
> total energy probe? (no electronic compensation) Thanks a lot! Robert

[Bert Willing]

If you have a 3-way probe at the fin, electronic compensation will work
perfectly as the positioning of the static is very good and you can adjust
the proper compensation level in-flight.
--
Bert Willing

ASW20 "TW"


"Arnie" > a écrit dans le message de
. com...
> Depends on what u mean by "compensated" varios.
>
> There are three ways to achieve TE compensation, usually :
> *Electronic via flight computer (which u ruled out, but also it isn't very
> good, it needs VERY accurate pitot-static, among other problems),
> *Diaphragm (old solution, and good only for the altitude it was calibrated
> for)
> *TE Probe (the simplest and most accurate one).
>
> Both an all "mechanical" vario, or a new electronic one (the ones that
> "beep") will require a TE probe to achieve the best results.
> An old and very good diaphragm compensator used to be manufactured in the
> 70s by Wil Schueman, but like I said, it would be good only for the
altitude
> range it was calibrated for.
> SZD also used to sell their gliders with cheap diaphragm compensators that
> become brittle after a few years.
> But I don't think they would be easy to find these days.
>
> There's a reason everybody adopted TE probes : They are simple and the
most
> effective way to do it.
>
>
>
> "Robert" > wrote in message
> om...
> > Hello! Can someone tell me which compensated varios do not need a
> > total energy probe? (no electronic compensation) Thanks a lot! Robert
>
>

[Shoulbe]

Bohli is what I was going to mention too. If the preceding message didn't
indicate, it is Swiss made. I think they have a website. I've heard very good
things about them and they're not all that exepensive since you can avoid the
cost of installing a TE probe.

Another item to consider would be an old era Ball vario. Some of them were
also internally compensated.

If you're merely trying to avoid the expense and trouble of fin mounting a TE
probe on an older ship, consider a fuselage mounted upright probe as used on
ASK-21s. They work just fine - especially if this would be for an older ship.

[Tim Mara]

what you're asking is a bit confusing since you say "no TE probe" and also
"no electronic compensation"...
I think you are asking which Variometers will work "with just "Pitot/Static"
which will then be some form of "electronic compensation"...
First, let me say I'm often asked about which TE Probe is best for a
particular variometer, Though there are some probes that do work better
with particular gliders, if you understand that TE is purely a compensated
Static system you'll realize that the brand of variometer has little effect
on which type TE probe is used.....the variometer only "sees" TE compensated
static, or static as good as it is delivered to the variometer itself. This
being said, any variometer can work with normal "uncompensated "static", the
end result will then of course be "Stick thermals" without the TE balancing
act.

There is quite a list of variometers that have do work with electronic
compensation, in fact some going back to very early designs used this, some
not so well, some very well....
RICO VA and VAS were TE compensated while the VACS used Electronic TE
Many early "Richard" Ball variometers used "E" TE.....
Cambridge attempted this with MKIV Variometers
I'm sure there were others
most of the above had mixed results, usually not the best unless the user
had some intimate knowledge of the system and was willing to tinker
IMHO one of the best early "E" TE Vario's came from Westerboer, with the
VW910 then also other good systems from Zander, Peschges and others.
Almost all later "high end" flight computers have "E" TE available or allow
use of TE probes
Borgelt B100 and the SN-10 that came from this system can use "E" TE
Cambridge 302's can use "E" TE
All LX Navigation and Filser systems have excellent "E" TE and are easily
user configured in programming to adjust the compensation, I've used these
both with probe and "E" TE and been equally pleased with either set-up.
I'm sure there are others I have not mentioned
tim


"Robert" > wrote in message
om...
> Hello! Can someone tell me which compensated varios do not need a
> total energy probe? (no electronic compensation) Thanks a lot! Robert

[Bob Kuykendall]

Earlier, (Robert) wrote:

> Hello! Can someone tell me which compensated varios do not need a
> total energy probe? (no electronic compensation) Thanks a lot! Robert

Just FYI, TE probes of the Nicks pattern are pretty easy to make. All
it takes is some brass tubing, a drill, and a plumbing solder rig. I
used to make a kit of parts for a Les Sebald-designed combination TE
probe and VHF radio antenna.

Here's a Web reprint of the 1981 Soaring article by Les. The only
thing I did different was to supply a machined 6061-T6 aluminum base
with a bayonet connector for the antenna cable:

http://www.soaridaho.com/Schreder/Construction/T_E_PROBE_ANTENNA.html

Thanks, and best regards

Bob K.
http://www.hpaircraft.com/hp-24

[Robert]

thanks for the information. to be more precise , I am using a
Schueman box which came with the ASW12 I bought years ago. I connected
the box to a normal winter vario (because I had only the box) and I am
very happy with the result. My other vario, the LX5000 has an
electronic compensation - works good (a bit slower then the Schueman).
I am now thinking about chaning my ASH26E to "NO TE probe"....

[Eric Greenwell]

Robert wrote:
> thanks for the information. to be more precise , I am using a
> Schueman box which came with the ASW12 I bought years ago. I connected
> the box to a normal winter vario (because I had only the box) and I am
> very happy with the result. My other vario, the LX5000 has an
> electronic compensation - works good (a bit slower then the Schueman).
> I am now thinking about chaning my ASH26E to "NO TE probe"....

I changed my ASH 26E to electronic compensation several years ago. It
works just well as the TE probe did with my Cambridge 302. The problem
with the TE probe was the turbulence from the propeller made it
difficult to find and center thermals while self-launching.

You might want to join the ASH 26 owners group, where we discuss things
like this and many others, plus have an extensive archive. Check out

http://mail.serkowski.com/mailman/listinfo/owners

for info on subscribing.

And check out

http://mail.serkowski.com/ash26e/index.html

for a Schleicher ASH-26E Resources web site.

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

Eric Greenwell
Washington State
USA

[Mike Borgelt]

On 16 Apr 2004 03:27:43 -0700, (Robert) wrote:

>Hello! Can someone tell me which compensated varios do not need a
>total energy probe? (no electronic compensation) Thanks a lot! Robert

While some people report good results with pitot/static TE your
results may differ. I wonder if thy've tested two identical varios
capable of being on pitot/static or TE side by side on the same
sources then on the different sources side by side. I've done this
with TE probes mounted in different places on the ship and got
interesting results.The gear doors are a good location for a TE probe.

Generally pitot and static probes/ports are much more sensitive to
sideslip than are good TE probes.(Good TE probe = Irving type two hole
probe )

You may have timing issues due to the distributed flow resistance and
capacitance of the sailplane plumbing.

Remember for pitot/static TE you are measuring two large signals and
subtracting them. Minor timing differences in the signals and small
non linearities in the measurement show up as large unwanted
transients on your vario.

These problems are mitigated somewhat by making the vario response
rather slow.(not what you really want)

I flew an ASW20 at Minden once which had a Schuemann box on a Sage
vario. The TE was OK but the thing was terribly slow compared to a
thermistor electronic vario with TE probe that was also fitted.

The problems of pitot static TE are solvable at some trouble in
installation and tuning but you are still left with the sideslip and
pitch sensitivity of the ports or probes. These can be solved also but
you end up with things like Kiel tubes for pitot and fancy static
probes which you then have to ask - what have you achieved?

The sensitivity of both TE systems to gusts is the same.

Mike Borgelt

Borgelt Instruments

[Bill Daniels]

"Mike Borgelt" > wrote in message
...
> On 16 Apr 2004 03:27:43 -0700, (Robert) wrote:
>
> >Hello! Can someone tell me which compensated varios do not need a
> >total energy probe? (no electronic compensation) Thanks a lot! Robert
>
> While some people report good results with pitot/static TE your
> results may differ. I wonder if thy've tested two identical varios
> capable of being on pitot/static or TE side by side on the same
> sources then on the different sources side by side. I've done this
> with TE probes mounted in different places on the ship and got
> interesting results.The gear doors are a good location for a TE probe.

I have one pitot/static TE vario (With dedicated static ports.) and one TE
probe vario (B40)
>
> Generally pitot and static probes/ports are much more sensitive to
> sideslip than are good TE probes.(Good TE probe = Irving type two hole
> probe )

True, it's easily observed.

>
> You may have timing issues due to the distributed flow resistance and
> capacitance of the sailplane plumbing.

Yep, the TE probe vario is about 0.25-0.5 sec slower than the pitot/static
vario at the onset of lift. Mike, do you think this is due to the long
tubing run to the fin mounted TE probe?

>
> Remember for pitot/static TE you are measuring two large signals and
> subtracting them. Minor timing differences in the signals and small
> non linearities in the measurement show up as large unwanted
> transients on your vario.

Hmm, they seem to track together most of the time but there are differences.
I trust the B40 the more.

Thanks for the comments, Mike.

Bill Daniels

[Martin Gregorie]

On Wed, 21 Apr 2004 10:02:05 +1000, Mike Borgelt
> wrote:

>Generally pitot and static probes/ports are much more sensitive to
>sideslip than are good TE probes.(Good TE probe = Irving type two hole
>probe )
>
Mike, just a quick question:

My ASW-20 is fitted with a fin mounted Irving-type TE probe except
that it only has a single hole in place of the usual two holes. What
advantages would there be to swapping it for a two-hole version?


--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :

[Bob Kuykendall]

Earlier, Martin Gregorie > wrote:

> My ASW-20 is fitted with a fin mounted Irving-type TE probe except
> that it only has a single hole in place of the usual two holes. What
> advantages would there be to swapping it for a two-hole version?

This might be a bit of pedantry, but I believe that the one-hole probe
is generally what you'd call a "Nicks tube," for the late Oran Nicks
who developed the theory and practice of this simple yet relatively
effective TE probe design. And I think that the one with the slot or
two is generally a "Braunschweig tube." I don't know the name for the
two-hole probe design.

Here's an article by Dick Johnson on how he further developed and
validated a Nicks-pattern probe design and location for the PW-5:

http://www.ssa.org/Johnson/89-1998-04.pdf

That article cites Nicks' earlier (1976 and 1977) _Soaring_ articles
on TE probe design.

Elsewhere in this thread I've already posted a link to an article on
thge Les Sebald innovation of using a Nicks TE probe as a radio
antenna.

Thanks, and best regards to all

Bob K.
http://www.hpaircraft.com/hp-24

[Martin Gregorie]

On 21 Apr 2004 13:40:46 -0700, (Bob Kuykendall)
wrote:

>Earlier, Martin Gregorie > wrote:
>
>> My ASW-20 is fitted with a fin mounted Irving-type TE probe except
>> that it only has a single hole in place of the usual two holes. What
>> advantages would there be to swapping it for a two-hole version?
>
>This might be a bit of pedantry, but I believe that the one-hole probe
>is generally what you'd call a "Nicks tube," for the late Oran Nicks
>who developed the theory and practice of this simple yet relatively
>effective TE probe design. And I think that the one with the slot or
>two is generally a "Braunschweig tube." I don't know the name for the
>two-hole probe design.
>
>Here's an article by Dick Johnson on how he further developed and
>validated a Nicks-pattern probe design and location for the PW-5:
>
>http://www.ssa.org/Johnson/89-1998-04.pdf
>
>That article cites Nicks' earlier (1976 and 1977) _Soaring_ articles
>on TE probe design.
>
>Elsewhere in this thread I've already posted a link to an article on
>thge Les Sebald innovation of using a Nicks TE probe as a radio
>antenna.
>
>Thanks, and best regards to all
>
>Bob K.
>http://www.hpaircraft.com/hp-24

Thanks, Bob. That was an interesting read. Bookmarked for future
reference together with the dual use probe you mentioned.
--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :

[Robin Birch]

In message >, Bob
Kuykendall > writes
>Earlier, Martin Gregorie > wrote:
>
>> My ASW-20 is fitted with a fin mounted Irving-type TE probe except
>> that it only has a single hole in place of the usual two holes. What
>> advantages would there be to swapping it for a two-hole version?
>
>This might be a bit of pedantry, but I believe that the one-hole probe
>is generally what you'd call a "Nicks tube," for the late Oran Nicks
>who developed the theory and practice of this simple yet relatively
>effective TE probe design. And I think that the one with the slot or
>two is generally a "Braunschweig tube." I don't know the name for the
>two-hole probe design.
>
>Here's an article by Dick Johnson on how he further developed and
>validated a Nicks-pattern probe design and location for the PW-5:
>
>http://www.ssa.org/Johnson/89-1998-04.pdf
>
Couldn't get this to down load. Can someone who can post it to me?

Regards

Robin
>That article cites Nicks' earlier (1976 and 1977) _Soaring_ articles
>on TE probe design.
>
>Elsewhere in this thread I've already posted a link to an article on
>thge Les Sebald innovation of using a Nicks TE probe as a radio
>antenna.
>
>Thanks, and best regards to all
>
>Bob K.
>http://www.hpaircraft.com/hp-24

--
Robin Birch

[Mike Borgelt]

On Wed, 21 Apr 2004 11:57:40 +0100, Martin Gregorie
> wrote:

>On Wed, 21 Apr 2004 10:02:05 +1000, Mike Borgelt
> wrote:
>
>>Generally pitot and static probes/ports are much more sensitive to
>>sideslip than are good TE probes.(Good TE probe = Irving type two hole
>>probe )
>>
>Mike, just a quick question:
>
>My ASW-20 is fitted with a fin mounted Irving-type TE probe except
>that it only has a single hole in place of the usual two holes. What
>advantages would there be to swapping it for a two-hole version?


Martin,

While I have seen wind tunnel data that suggests that the suction
around the rear 180 deg of the tube is constant there do seem to be
variations and the two hole probe may be less sensitive to sideslip.

Also:

Many years ago now just after the Irving probe design became available
I built one in 1/4" tube and one in 3/16" tube and a Nicks(single hole
type)in 3/16" as per Oran Nicks drawings. I then flew my Mini Nimbus
with a second ASI connected to probe and pitot. I checked the two
instruments against each other and applied static system corrections
to the readings of the normal ASI and reckoned I could get down to an
error band of +/- 4%.

I had had a feeling that the Nicks tube was under compensating and the
test showed it to be short of suction by 20% and a little more at low
speeds.

The Irving probe made per Irving was within my error band and the
3/16" Irving was a little short on suction getting worse at low speeds
leading me to conclude that there may be a Reynolds number effect for
the low airspeeds and smaller diameter tubes.

Interestingly Nicks recommended the hole 2 x tube diameters from the
end and Irving said 1.5

Current Irving type tubes have settled on about 1.67 as the hole
distance from the end and the holes are closer together than on the
original Irving design and 6mm or 1/4" tube is used.

Mike Borgelt

[Mike Borgelt]

On Wed, 21 Apr 2004 00:39:14 GMT, "Bill Daniels" >
wrote:

>
>"Mike Borgelt" > wrote in message
...
>> On 16 Apr 2004 03:27:43 -0700, (Robert) wrote:
>>
>> >Hello! Can someone tell me which compensated varios do not need a
>> >total energy probe? (no electronic compensation) Thanks a lot! Robert
>>
>> While some people report good results with pitot/static TE your
>> results may differ. I wonder if thy've tested two identical varios
>> capable of being on pitot/static or TE side by side on the same
>> sources then on the different sources side by side. I've done this
>> with TE probes mounted in different places on the ship and got
>> interesting results.The gear doors are a good location for a TE probe.
>
>I have one pitot/static TE vario (With dedicated static ports.) and one TE
>probe vario (B40)
>>
>> Generally pitot and static probes/ports are much more sensitive to
>> sideslip than are good TE probes.(Good TE probe = Irving type two hole
>> probe )
>
>True, it's easily observed.
>
>>
>> You may have timing issues due to the distributed flow resistance and
>> capacitance of the sailplane plumbing.
>
>Yep, the TE probe vario is about 0.25-0.5 sec slower than the pitot/static
>vario at the onset of lift. Mike, do you think this is due to the long
>tubing run to the fin mounted TE probe?

May be, particularly the capacity with small holes at the probe.
You may also be seeing the g effect when you enter lift. The probe is
about 1 meter above the instrument. Add g load due to entering lift
and the vertical pressure gradient in the glider plumbing in the fin
increases. As the pressure at the probe holes hasn't increased this
means the B40 sees increased pressure i.e. sink while the G is
increasing which will have to effect of slowing the response to lift.
This is one advantage of pitot static TE when using nose pitot and
fuselage nose statics. Also why a TE probe sticking out of the nose
ahead of the glider is better than a tail mounted probe.
There is also an effect of the rotation of the glider when pitching
with pressure sources a long way from the C of G.



What pitot/static positions are you using? I presume nose and sides
of the nose. Some people run pitot static TE off tail fin mounted
pitot static probes which are no better than a TE probe on the fin and
maybe worse fro the above reasons and the one below.

If you do pitot/static TE you want the pitot to be twice as far from
the C of G as the static port and on the same side. This avoids
pressure transients due to atmospheric pressure gradient during pitch
manouvers. Stig Oye pointed this out to me 20 years ago.

The B40 has electrically adjustable instrument time constant. See the
manual but VERRRY gently on the adjust please! Try about 20 degrees in
the faster direction if you like on the 180 deg trimpot. These are
factory set at the midway position and I haven't seen any reason to
change mine nor have I had people complain about the factory setting.


Mike Borgelt


>
>>
>> Remember for pitot/static TE you are measuring two large signals and
>> subtracting them. Minor timing differences in the signals and small
>> non linearities in the measurement show up as large unwanted
>> transients on your vario.
>
>Hmm, they seem to track together most of the time but there are differences.
>I trust the B40 the more.
>
>Thanks for the comments, Mike.
>
>Bill Daniels

[Bill Daniels]

"Mike Borgelt" > wrote in message
>
> What pitot/static positions are you using? I presume nose and sides
> of the nose. Some people run pitot static TE off tail fin mounted
> pitot static probes which are no better than a TE probe on the fin and
> maybe worse for the above reasons and the one below.

Two static ports on the side of the nose just forward of the instrument
panel. The pitot is in the nose vent.

>
> If you do pitot/static TE you want the pitot to be twice as far from
> the C of G as the static port and on the same side. This avoids
> pressure transients due to atmospheric pressure gradient during pitch
> manouvers. Stig Oye pointed this out to me 20 years ago.

Possibly the static ports are a bit further forward than half the distance
from the CG to the nose pitot.

>
> The B40 has electrically adjustable instrument time constant. See the
> manual but VERRRY gently on the adjust please! Try about 20 degrees in
> the faster direction if you like on the 180 deg trimpot. These are
> factory set at the midway position and I haven't seen any reason to
> change mine nor have I had people complain about the factory setting.

I'll probably take your advice and leave it alone. I often fly in rough air
with the buoyancy/shear ratio in the single digits and 30+ knots of wind
shear in the convective boundary layer. I'd hate to lose the silky smooth
response. The onset of lift is pretty obvious with the stiff carbon wings
on the Nimbus. With softer wings, the vario delay wouldn't be noticeable.

That's interesting what you said about the Nicks TE probe on the nose. Has
anyone tried that?

Bill Daniels

[Mike Borgelt]

On Fri, 23 Apr 2004 01:06:40 GMT, "Bill Daniels" >
wrote:

rs ago.
>
>Possibly the static ports are a bit further forward than half the distance
>from the CG to the nose pitot.

Probably close enough. The maths is simple.

For a TE vario you want pressures so:
static - q
This can be generated as (2 x static) - pitot
pitot = static + q
If you pitch so at the static port you see decrease of delta p then at
the pitot you see 2 x delta p if the pitot is twice as far from the C
of G as the static port, put these in the TE equation and they cancel
hence no transient pressure.
>
>>
>> The B40 has electrically adjustable instrument time constant. See the
>> manual but VERRRY gently on the adjust please! Try about 20 degrees in
>> the faster direction if you like on the 180 deg trimpot. These are
>> factory set at the midway position and I haven't seen any reason to
>> change mine nor have I had people complain about the factory setting.
>
>I'll probably take your advice and leave it alone. I often fly in rough air
>with the buoyancy/shear ratio in the single digits and 30+ knots of wind
>shear in the convective boundary layer. I'd hate to lose the silky smooth
>response. The onset of lift is pretty obvious with the stiff carbon wings
>on the Nimbus. With softer wings, the vario delay wouldn't be noticeable.

The big thing about varios is to get used to the response. That's why
I'm not fan of much user changeable vario response in the cockpit.
Wil Schuemann said this about 30 years ago and was right.
>
>That's interesting what you said about the Nicks TE probe on the nose. Has
>anyone tried that?

I've seen it done and used this on the ASW20B I flew at Uvalde in 1986
at the Nationals.
Worked Ok but the Texans used germ warfare on the Aussies there.

Mike

[Pete Brown]

Watch out for that chile... It catches the unwary.

Mike Borgelt wrote:\
>>That's interesting what you said about the Nicks TE probe on the nose. Has
>>anyone tried that?
>
>
> I've seen it done and used this on the ASW20B I flew at Uvalde in 1986
> at the Nationals.
> Worked Ok but the Texans used germ warfare on the Aussies there.
>
> Mike

--

Pete

[Martin Gregorie]

On Fri, 23 Apr 2004 09:45:33 +1000, Mike Borgelt
> wrote:

>On Wed, 21 Apr 2004 11:57:40 +0100, Martin Gregorie
> wrote:
>
>>On Wed, 21 Apr 2004 10:02:05 +1000, Mike Borgelt
> wrote:
>>
>>>Generally pitot and static probes/ports are much more sensitive to
>>>sideslip than are good TE probes.(Good TE probe = Irving type two hole
>>>probe )
>>>
>>Mike, just a quick question:
>>
>>My ASW-20 is fitted with a fin mounted Irving-type TE probe except
>>that it only has a single hole in place of the usual two holes. What
>>advantages would there be to swapping it for a two-hole version?
>
>
>Martin,
>
>While I have seen wind tunnel data that suggests that the suction
>around the rear 180 deg of the tube is constant there do seem to be
>variations and the two hole probe may be less sensitive to sideslip.
>
>Also:
>
>Many years ago now just after the Irving probe design became available
>I built one in 1/4" tube and one in 3/16" tube and a Nicks(single hole
>type)in 3/16" as per Oran Nicks drawings. I then flew my Mini Nimbus
>with a second ASI connected to probe and pitot. I checked the two
>instruments against each other and applied static system corrections
>to the readings of the normal ASI and reckoned I could get down to an
>error band of +/- 4%.
>
>I had had a feeling that the Nicks tube was under compensating and the
>test showed it to be short of suction by 20% and a little more at low
>speeds.
>
>The Irving probe made per Irving was within my error band and the
>3/16" Irving was a little short on suction getting worse at low speeds
>leading me to conclude that there may be a Reynolds number effect for
>the low airspeeds and smaller diameter tubes.
>
>Interestingly Nicks recommended the hole 2 x tube diameters from the
>end and Irving said 1.5
>
>Current Irving type tubes have settled on about 1.67 as the hole
>distance from the end and the holes are closer together than on the
>original Irving design and 6mm or 1/4" tube is used.
>
>Mike Borgelt

Thanks, Mike. That's exactly what I wanted to know.

--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :