Butterfly vario side-by-side with ClearNav vario

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

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

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.

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

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

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

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

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