Butterfly vario side-by-side with ClearNav vario

[[email protected]]

Anyone used these two varios in the same flight? How do they compare?

[[email protected]]

On Wednesday, May 15, 2013 5:50:37 PM UTC-5, wrote:
> Anyone used these two varios in the same flight? How do they compare?

If you do, get the latest CN vario software. The speed to fly is now working and the filtering has changed a good deal -- for the better imho.
John Cochrane

[Richard[_9_]]

On Wednesday, May 15, 2013 3:50:37 PM UTC-7, wrote:
> Anyone used these two varios in the same flight? How do they compare?

I have compared in Flight the LX Navigation 1606, LXNAV V7, and the ButterFly vario to the CAI 302. Approximatle 10 hours of comparison with the 1606, and about 20 each with the V7 and Butterfly.

The cambridge was sold as a used item immediately after the testing. It is still a nice vario and well worth the $1000 a customer paid for the 302/303 combination but does not perform as well as the newer stuff.


Richard
www.craggyaero.com

[Evan Ludeman[_4_]]

On Wednesday, May 15, 2013 6:50:37 PM UTC-4, wrote:
> Anyone used these two varios in the same flight? How do they compare?

That's going to yield slippery answers. Both instruments are evolving in time. Both have a huge number of user options to set. Given that, it's possible to get any sort of comparison (flattering or otherwise) you desire, so keep that in mind and ask question of the person who makes bold statements of superiority without disclosing a lot of tedious setup info.

We're flying the heck out of CNv at Sports Nats with an internal beta release and expect CNv-Club to be feature complete with a commercial release any day now. We're *extremely* pleased with it, but more about that later.

Good Soaring,

Evan Ludeman / CNi

[Marc - Butterfly Avionics]

I agree with Evan.

We are working very hard since over one year on refining and improving all the features of our vario. Its complex and we are very pleased by the results so far. What we do with our sensors has never been done before and leads to many new things we have to learn. We do not use more than 50% of its potential so far and yet it is really impressing.

Check out our Youtube channel (videos don't really give you the feeling but they at least show how the display looks): http://www.youtube.com/user/ButterflyAvionics

Best wishes
Marc
Butterfly Avionics

[son_of_flubber]

So am I correct that this generation of "Varios" has very similar sensors complements?

And the things that differentiates them is:
1)the software,
2)the display,
3)rate and breadth of access to raw sensor data and internally computed values (for example calculated wind direction) by external applications, and
4)pricing structure and packaging.
5)post-sales support
6)talent of the team and projected trajectory of the company

As the software evolves, the varios will continue to improve. A valid objective benchmark would be rather difficult and expensive to accomplish.

The decision of which to buy though is really very simple because both of them are excellent. Just pick one.

[krasw]

I think the biggest advantge with Butterfly Variometer is that you get actually get several instruments in one package. The "normal" TE-based vario is very good, in my opinion on the level of the best traditional electric varios (Zander etc.). And then you get the netto vario that can be configured to be totally independent of the TE system (though it can be mixed with it), based on inertial sensors. After flying for a while with Butterfly one really sees how important it is to know wheather gust is vertical or horizontal. Traditional TE system can't separate these reliably. Netto variometer and real time wind calculated by the inertial system gives very accurate picture of the airmass around you (and as a side produt most accurate speed-to-fly commands I've seen). In this respect Butterfly Variometer is not comparable with other current systems. I think this fundamental difference is not completely understood here.

krasw

[Mike the Strike]

The advent of varios with inertial probes that enable the compensation or identification of horizontal gusts will be especially useful in hot strongly thermic areas, like Arizona where I mostly fly.

This is especially true on days when the air is stable but still rises strongly because of very strong surface heating. Thermals in these conditions often have a strong horizontal outflow that increases the energy of the ship as you approach the thermal. Since your total energy increases, all conventional varios indicate lift, leading the pilot to turn too soon. Many experienced pilots know this and compensate as best they can, but it would be great to have a reliable vario do this for you.

Mike

[son_of_flubber]

On Friday, May 17, 2013 2:23:21 PM UTC-4, Mike the Strike wrote:
> The advent of varios with inertial probes that enable the compensation or identification of horizontal gusts

So does the ClearNav
1)have an inertial probe and
2)does it have the software (at the moment) to filter out horizontal gusts?

So does an "inertial probe" and an "accelerometer" both provide the same sensor inputs to the software?

[Bill D]

On Friday, May 17, 2013 2:59:18 PM UTC-6, son_of_flubber wrote:
> On Friday, May 17, 2013 2:23:21 PM UTC-4, Mike the Strike wrote:
>
> > The advent of varios with inertial probes that enable the compensation or identification of horizontal gusts
>
>
>
> So does the ClearNav
>
> 1)have an inertial probe and
>
> 2)does it have the software (at the moment) to filter out horizontal gusts?
>
>
>
> So does an "inertial probe" and an "accelerometer" both provide the same sensor inputs to the software?

I'm not sure how it is actually being implemented but I would interpret "inertial probe" as an IMU (Inertial Measurement Unit). IMU's have 3-axis gyros and 3-axis accelerometers. The gyros keep the accelerometers aligned up-down, east-west and north-south. MEMS IMU's these days are nearly chip-size so one could be inside the vario with GPS position data serving as a calibration signal to compensate for drift. This means vertical acceleration can be measured and the integral (velocity) can be displayed as a vario signal. The advantages of an inertial vario include zero lag, gust insensitivity and complete freedom from TE probes and associated plumbing.

The gust/thermal discrimination is done by comparing the inertial-TE with air-data TE. If the air-data shows a gain in total energy but the inertial data doesn't, it's a gust.

The above is the most elegant implementation but partial implementation could also provide an advance over the old air-data only varios.

[Eric Greenwell[_4_]]

krasw wrote, On 5/17/2013 10:33 AM:
> (and as a side produt most accurate speed-to-fly commands I've seen).
> In this respect Butterfly Variometer is not comparable with other
> current systems. I think this fundamental difference is not
> completely understood here.

I really curious about what an "accurate" speed-to-fly command is. What
is the command based on that makes it more accurate than the usual
variometer, like a 302?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl

[[email protected]]

In theory, both the butterfly and the CN have enough innards to really advance variometry, because they have the potential to measure the vertical speed of air around the glider.

If you fly in to a thermal, the g meter increases. If you pull back on the stick the g meter increases. But the gyros can tell that the glider nosed up in the latter case. So, the vario can measure "netto g" if you will, the acceleration of the glider caused by changes in the surrounding air.

This is much faster than a vario. For a vario to work, you have to fly into the rising air, g increases, F = MA does its work, the glider starts rising vertically, then the vario can start to measure it. The system based on g and heading does it instantly, at least giving a second or two earlier lift detection.

Looking at sideways g, correcting for yaw, also can tell the vario if there is a sideways gust. Looking at fore and aft g can tell the vario if the glider has entered a wind shear on the nose rather than vertical thermal.

Eventually, by comparing the GPS track through space with the relative wind, these various could also measure outside air motion directly.

I don't know how much of this is currently programmed in to either one, but the potential seems intriguing.

John Cochrane

[[email protected]]

On Friday, May 17, 2013 6:20:24 PM UTC-7, wrote:
> If you fly in to a thermal, the g meter increases. If you pull back on the stick the g meter increases. But the gyros can tell that the glider nosed up in the latter case. So, the vario can measure "netto g" if you will, the acceleration of the glider caused by changes in the surrounding air.
>

What happens when the flaps go positive?

Marc

[krasw]

On Saturday, 18 May 2013 02:33:22 UTC+3, Eric Greenwell wrote:
> krasw wrote, On 5/17/2013 10:33 AM:
>
> > (and as a side produt most accurate speed-to-fly commands I've seen).
>
> > In this respect Butterfly Variometer is not comparable with other
>
> > current systems. I think this fundamental difference is not
>
> > completely understood here.
>
>
>
> I really curious about what an "accurate" speed-to-fly command is. What
>
> is the command based on that makes it more accurate than the usual
>
> variometer, like a 302?
>
>
>
> --
>
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
>
> email me)
>
> - "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
>
> http://tinyurl.com/yb3xywl

Speed-to-fly is essentially function of vertical airmass movement. When you get inertial-based netto, which is very fast and accurate, your speed-of-command accuracy goes up order of magnitude. With normal TE-based speed-to-fly you normally try to filter out gusts with longer time constant. With inertial netto this gust-induced noise transforms into data that you can use for calculating optimum STF.

With Butterfly I have actually started experimenting with extremely short time constant for inertial netto. It can be set so short that netto becames essentially a quantitative indicator of your seat-of-the-pants feeling. There seems to be no reason to filter or average this data so heavily.

krasw

[kirk.stant]

Watching the Butterfly vario video, it sure looks nice and smooth, with lots of information - then it occurred to me that this is a potential downside that the pilot will have to guard against - "clock watching" while thermalling, trying to make sense of all the changing data, and perhaps relying on Flarm to stay safe!

It's bad enough with all the data available on our glide computers and PNA displays, but that data is usually checked during cruise, and is more static in nature; while thermalling we try to rely on the audio vario and occasionally check inside for the average. Will conventional audio be sufficient to convey the data that the Butterfly (and by extension, CNv and other future varios) will be generating?

Perhaps more synthetic voice data to give trend info would allow the pilot to keep his eyes out of the cockpit and still make use of all the new data. "Gust", "Roll out - Turn in" (for thermal centering), "two six, two six" for the average, etc.

Or a head mounted display - JHMCS anyone? That would need a big battery!

It would be a shame to equip the fleet with Flarm just so we can thermal on instruments!

Kirk

[son_of_flubber]

On Saturday, May 18, 2013 5:14:58 AM UTC-4, kirk.stant wrote:

> Perhaps more synthetic voice data to give trend info would allow the pilot to keep his eyes out of the cockpit and still make use of all the new data. "Gust", "Roll out - Turn in" (for thermal centering), "two six, two six" for the average, etc.

Maybe Themi got it right, ten years ago. Two LEDs in peripheral vision.

[[email protected]]

>
> What happens when the flaps go positive?
>
> Marc

You get a single transient, which you know about because you just moved the flap handle

[Eric Greenwell[_4_]]

krasw wrote, On 5/17/2013 11:30 PM:
> On Saturday, 18 May 2013 02:33:22 UTC+3, Eric Greenwell wrote:
>> krasw wrote, On 5/17/2013 10:33 AM:

>>
>> I really curious about what an "accurate" speed-to-fly command is.
>> What
>>
>> is the command based on that makes it more accurate than the usual
>>
>> variometer, like a 302?

>
> Speed-to-fly is essentially function of vertical airmass movement.
> When you get inertial-based netto, which is very fast and accurate,
> your speed-of-command accuracy goes up order of magnitude. With
> normal TE-based speed-to-fly you normally try to filter out gusts
> with longer time constant. With inertial netto this gust-induced
> noise transforms into data that you can use for calculating optimum
> STF.
>
> With Butterfly I have actually started experimenting with extremely
> short time constant for inertial netto. It can be set so short that
> netto becames essentially a quantitative indicator of your
> seat-of-the-pants feeling. There seems to be no reason to filter or
> average this data so heavily.

Does it give the correct STF for 1 second from now? I can't possibly
change the speed of the glider that fast.

Or does it give me the STF for 10 seconds from now, which I might be
able to achieve with abrupt control movements?

And then, 10 seconds later, when I'm going the speed I was given, but
now I'm in air going down faster/slower, does it give me another STF
that will be wrong by the time I achieve that speed?

I'm trying get an idea of what you mean by "accurate" STF commands. The
top contest pilots I've followed seem to fly pretty steadily - will it
give me the STF that a top contest pilot will cruise at? That's what I
would call "accurate"!


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl

[[email protected]]

Maybe there's a good use for Google Glass here. Much easier than a HUD.

Chris

[krasw]

> I'm trying get an idea of what you mean by "accurate" STF commands. The
>
> top contest pilots I've followed seem to fly pretty steadily - will it
>
> give me the STF that a top contest pilot will cruise at? That's what I
>
> would call "accurate"!
>
>
>
>
>
> --
>
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
>
> email me)
>
> - "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
>
> http://tinyurl.com/yb3xywl

I tried to tell that without accurate info on vertical airmass movement you can't have working STF command. This is where inertial system seems to be very good at. Sorry if I was unclear about this. Without good STF you would probably fly with predetermined still-air mc-speeds. Sure it works also, but it is not optimal. Plus if you know the airmass movement you have a better idea where to fly during glide.

krasw

[Dan Marotta]

Yes, but the vario doesn't "know" that unless you have multiple switches on
the flap detents. Also, how does the vario "know", from increasing "g" that
a pitch up was caused by elevator travel or by the change in angle of attack
due to the vertical component of the thermal? Do we also need stick
movement measuring equipment?

This is all pretty intriguing to me as an engineer because of the
capabilities and the applications we can think up but (just speaking for
myself), I'm less impressed by a 1,000 km flight by a long winged, engine
equipped, highly instrumented glider than I am by a 300 km flight by a rag
and tube machine equipped with a pellet variometer. Still, I like my
LAK-17a!


> wrote in message
...
>>
>> What happens when the flaps go positive?
>>
>> Marc
>
> You get a single transient, which you know about because you just moved
> the flap handle

[Martin Gregorie[_5_]]

On Sat, 18 May 2013 09:08:27 -0700, rudy.letov wrote:

> Maybe there's a good use for Google Glass here. Much easier than a HUD.
>
..... until Google decide its time for an ad break.

It seems that *will* be location-related ads shown ("Coffee time!" as you
pass Starbucks): this is one of the reasons why various states are
talking about banning their use while driving.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Eric Greenwell[_4_]]

Dan Marotta wrote, On 5/18/2013 9:17 AM:
> Yes, but the vario doesn't "know" that unless you have multiple switches
> on the flap detents. Also, how does the vario "know", from increasing
> "g" that a pitch up was caused by elevator travel or by the change in
> angle of attack due to the vertical component of the thermal? Do we
> also need stick movement measuring equipment?

Perhaps it can tell the attitude of the glider didn't change by using
the gyro info, indicating the upward acceleration was caused by a
thermal. If the attitude pitched up - stick thermal.

Using the actual change in attitude may be much better than the stick
movement.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl

[kirk.stant]

On Saturday, May 18, 2013 2:08:58 PM UTC+2, son_of_flubber wrote:
>
> Maybe Themi got it right, ten years ago. Two LEDs in peripheral vision.

I think so, which is why I still have mine installed.

I like the combination of SN10 audio, Themi lights, and Oudie (with SN10 vario data) trail with vario dots for building a picture of the thermal with minimum time inside the cockpit.

Kirk
66

[[email protected]]

Hey Eric, I recently acquired butterfly varios for my ASH25. I immediately liked it better than my SN10's vario, and having flown the 302 a bunch in a Duo Discus I would put Cambridge in third place. I can't comment on the ClearNav . The audio is the most pleasant i've heard and the display is bright and delightful to view. I think it is equal to, if not better, than the high end Sage, and much more visible. I am still trouble shooting the more sophisticated features of the instrument. The artificial horizon is cool even if never used, and it doubles as a nice navigation, and final glide device. As far as the cruise control feature, at this point it seems like too much information to me. I just fly fast if the next thermal looks good, and slow if there might be trouble ahead, making some modest changes to accommodate en route sustained lift or sink. That horizontal gust thing might actually work, as it seems easier to center thermals with the Butterfly, although I might be inclined to say that about any variometer that cost as much as my first glider. As of now I think it might be a better mousetrap, and if you are interested come down and fly with me and check it out.

Dale

[[email protected]]

I am also very interested in the Butterfly vario. I have some questions that the Butterfly people have not answered for me yet.

I fly with a mechanical vario on the T.E. probe and my 302 with electronic compensation. I wanted two independent systems and I was having difficulties with the 302 and mechanical varios on the same T.E. probe line.

How would the Butterfly work with electronic compensation? Any significant loss of functions?

What issues could be anticipated with the Butterfly vario and a mechanical vario (Winter or Sage) sharing the same T.E. probe?

Guy Acheson "DDS"

[Martin Gregorie[_5_]]

On Sun, 19 May 2013 11:19:48 -0700, drguyacheson wrote:

> I am also very interested in the Butterfly vario. I have some questions
> that the Butterfly people have not answered for me yet.
>
> I fly with a mechanical vario on the T.E. probe and my 302 with
> electronic compensation. I wanted two independent systems and I was
> having difficulties with the 302 and mechanical varios on the same T.E.
> probe line.
>
Feeding both a capacity-based vario and a pressure sensing vario from the
same TE probe is known to cause problems if the T-junction is close to
both instruments. Moving the T-junction away from the panel, i.e. using
long connections between the T and the two varios fixes it. There's a
note on Mike Borgelt's website saying that if the T-junction is either
under your seat pan or behind it the problem should disappear.

> What issues could be anticipated with the Butterfly vario and a
> mechanical vario (Winter or Sage) sharing the same T.E. probe?
>
As described above.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[krasw]

On Sunday, 19 May 2013 21:19:48 UTC+3, wrote:
> I am also very interested in the Butterfly vario. I have some questions that the Butterfly people have not answered for me yet.
>
>
>
> I fly with a mechanical vario on the T.E. probe and my 302 with electronic compensation. I wanted two independent systems and I was having difficulties with the 302 and mechanical varios on the same T.E. probe line.
>
>
>
> How would the Butterfly work with electronic compensation? Any significant loss of functions?
>
>
>
> What issues could be anticipated with the Butterfly vario and a mechanical vario (Winter or Sage) sharing the same T.E. probe?
>
>
>
> Guy Acheson "DDS"

I have BF and mechanical vario (0,3l capacity) connected to same TE tube. I haven't witness any problems so far. BF vario requires TE tube, there is no option for electronic compensation.

krasw

[jfitch]

On Wednesday, May 15, 2013 3:50:37 PM UTC-7, wrote:
> Anyone used these two varios in the same flight? How do they compare?

The Butterfly has flap input, analog potentiometer so continuous reading. I don't know if they use it for anything, but the input is there.

[Marc - Butterfly Avionics]

On Sunday, May 19, 2013 11:24:46 PM UTC+2, jfitch wrote:
> On Wednesday, May 15, 2013 3:50:37 PM UTC-7, wrote:
>
> > Anyone used these two varios in the same flight? How do they compare?
>
>
>
> The Butterfly has flap input, analog potentiometer so continuous reading. I don't know if they use it for anything, but the input is there.

yep, we do. We will use it in the future for flap position indication and flap optimization + to help filter flap-induced (dynamic) changes in lift better.

[Marc - Butterfly Avionics]

>BF vario requires TE tube, there is no option for electronic compensation.

Thats right. Discussions about this are old and I guess you all know the arguments. As you may figure we believe that TE compensation is way superior. :)

Cheers
Marc