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New Butterfly Vario



 
 
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  #231  
Old February 18th 12, 05:35 PM posted to rec.aviation.soaring
Dan Marotta
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Posts: 3,345
Default New Butterfly Vario

I have an old J-8 gyro attitude indicator and a static inverter to feed it
400 cps AC (yup, it was cycles per second before they bestowed the honor on
Prof. Hertz). I'd mount it in my panel but it takes a large hole (80 mm?)
and the weight would probably put my CG past the forward limit or, as a
minimum, break my carbon panel. It's also a totally black sphere except for
the yellow "targets" at the plus and minus 90 degree pitch attitude points,
and there's a yellow horizon line which moves independently of the sphere,
and a yellow airplane symbol. It's probably radio active with radium paint
and, therefore, probably illegal even to own (do I hear black helicopters?).

Somebody make me an offer. It works, but I don't know how much current it
draws... Also, it's so old that most people wouldn't even think that it
works and, therefore, wouldn't think to protest its presence in the panel.
This is a full-fledged mil-spec attitude indicator, not a wimpy turn
indicator...


"Eric Greenwell" wrote in message
...
On 2/17/2012 8:07 PM, Sean Fidler wrote:
Tom,

Why do any gliders have gyro's at all?


40 years ago, almost nobody did, because they were expensive ($1000 for an
AH when gliders cost $20,000), drew an amp, and were big and heavy, and
most people didn't have a real use for it.

Now, they they are cheap ($500 when gliders cost $100,000), use very
little current, and are small and light, so even though people don't have
any greater use for it than 40 years ago, they like the look of it and
think it might help some day. Some power pilots seem to feel naked without
them, having had one for hundreds or thousands of hours in their
airplanes.

I used to have a gyro T&B in my panel, because I got it dirt cheap, and it
looked prettier than the empty hole in the panel. I thought, maybe some
day I'll get stupid or have some really bad luck, and maybe it would help
me descend through a wave cloud that closed in. I never worried about
being sucked into a cloud, though.

And some people use them to cloud fly, illegally and legally.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email
me)


Ads
  #232  
Old February 18th 12, 07:04 PM posted to rec.aviation.soaring
Jim White[_3_]
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Posts: 258
Default New Butterfly Vario

At 16:15 18 February 2012, Dan Marotta wrote:
Chris, I'm going to try to analyze the height trace using the graphical
functions in Microsoft Excel. I'll look for a sudden increase in rate of


climb and make a guess from there. I might say in advance that I'm not
hopeful, but this should be a fun exercise.

Dan

Dan, I do quite a lot of cloud flying mostly to keep current as cloud
flying is allowed in UK competition and sometimes it is necessary to fly in
cloud to stay up.

However....it rarely is faster. I usually find that my climb rate drops as
I enter cloud because the artificial horizon although good is not anything
like as good as the real thing. In my experience if cloud base allows it is
much faster to fly the energy below cloud.

BTW I also find cloud flying fun which is after all the reason I go
flying.

J1M

  #233  
Old February 18th 12, 07:07 PM posted to rec.aviation.soaring
Dan Marotta
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Posts: 3,345
Default New Butterfly Vario

Well, just going on a look-see, it looks like cloud base in one of the
traces was around 17,200 MSL with a top of climb of 24,740 MSL and, in the
other, around 16,000 MSL with a top of climb of 34,480.

So... How'd I do? I'm also thinking that your altitudes might be in meters
and if that's the case, then it might be...

Cloud Base: 1,720 meters, Top of climb: 2,447 meters for the first flight,
and, for the second,

Cloud Base: 1,600 meters, Top of climb: 3448 meters.

Since I can't paste a picture in here, I sent you the Excel file with the
traces included on Sheet 3. Please let us know if such a quick look came
close.

"Dan Marotta" wrote in message
...
Chris, I'm going to try to analyze the height trace using the graphical
functions in Microsoft Excel. I'll look for a sudden increase in rate of
climb and make a guess from there. I might say in advance that I'm not
hopeful, but this should be a fun exercise.

Dan

BTW, I received your IGC files.


"Chris Nicholas" wrote in message
...
Dan, see your emails. Regards - Chris



  #234  
Old February 18th 12, 08:49 PM posted to rec.aviation.soaring
Chris Nicholas[_2_]
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Posts: 198
Default New Butterfly Vario

Dan was about right. Using metres is more like right – the plots Dan
sent me showed way too many feet on the left hand scale. My
recollection is that cloudbase was a bit over 4000 feet and I climbed
to about 11000 feet that day.

By the way, to repeat part of what I sent Dan privately - I do not
claim to be a very good IMC pilot. I had a bit of instruction at
first, then a lot of self-learning in a Ka6E which is strong, draggy,
has speed-limiting brakes/spoilers, and is fairly forgiving when
things go wrong – which they often did when I was slowly acquiring the
skill, using only a glider Turn and Slip (stronger spring, less
sensitive than a Power T&S so it does not go onto the stop in a
thermalling turn). I also advise other people not to cloud fly. Modern
gliders are too slippery to self-teach safely, IMHO. I do it because I
like it and accept the risk (which I think is minimal having learned
the slow way).

I also agree with Jim's comments.

Chris N.
  #235  
Old February 19th 12, 05:21 PM posted to rec.aviation.soaring
Dan Marotta
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Posts: 3,345
Default New Butterfly Vario

Thanks to Chris who took the time to look up the IGC specification for the
log file. From his analysis, I was able to determine that the cloud base on
one of the flights was around 5,200 ft (lower than my airport!). The trace
looked the same, just the altitude scale was changed.

And it's interesting what Jim said about reduced lift inside the cloud. I
would have expected higher lift due to the heat release. Maybe that's all
expended right at cloud base...

It was a fun exercise!


"Dan Marotta" wrote in message
...
Well, just going on a look-see, it looks like cloud base in one of the
traces was around 17,200 MSL with a top of climb of 24,740 MSL and, in the
other, around 16,000 MSL with a top of climb of 34,480.

So... How'd I do? I'm also thinking that your altitudes might be in
meters and if that's the case, then it might be...

Cloud Base: 1,720 meters, Top of climb: 2,447 meters for the first
flight, and, for the second,

Cloud Base: 1,600 meters, Top of climb: 3448 meters.

Since I can't paste a picture in here, I sent you the Excel file with the
traces included on Sheet 3. Please let us know if such a quick look came
close.

"Dan Marotta" wrote in message
...
Chris, I'm going to try to analyze the height trace using the graphical
functions in Microsoft Excel. I'll look for a sudden increase in rate of
climb and make a guess from there. I might say in advance that I'm not
hopeful, but this should be a fun exercise.

Dan

BTW, I received your IGC files.


"Chris Nicholas" wrote in message
...
Dan, see your emails. Regards - Chris




  #236  
Old February 19th 12, 06:12 PM posted to rec.aviation.soaring
Chris Nicholas[_2_]
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Posts: 198
Default New Butterfly Vario

In my experience lift in cloud is stronger only if the cloud has a lot
of vertical development – say several thousand feet, which of course
developing CBs do have, and provided you can stay centred in the lift,
which as Jim points out is harder if you can’t see the real horizon. I
have found that expanding the GPS scale helps a lot in keeping in good
lift, in VMC or in IMC. (I still do not advocate people teaching
themselves to do the latter these days – if it goes wrong in a
slippery glider, it can do so very quickly and very badly.)

In the more usual “good” conditions in the UK when we get them, an
inversion stops vertical cu development and they are often only a few
hundred or 1-2000 feet deep. Then, as Jim says, it is usually faster
to keep in the energy where you can see it, in VMC. With very shallow
clouds, it is not even worth going up to cloud base – the lift weakens
before getting there. Even if it does strengthen briefly at and into
cloud, I usually lose more in the fumble of coming out on the wrong
heading, or on the right one but into another cloud and in its sink,
than staying below, if achieved speed is what you are after.


Chris N


  #237  
Old February 19th 12, 08:50 PM posted to rec.aviation.soaring
Mike the Strike
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Posts: 905
Default New Butterfly Vario

On Feb 19, 10:12*am, Chris Nicholas wrote:
In my experience lift in cloud is stronger only if the cloud has a lot
of vertical development – say several thousand feet, which of course
developing CBs do have, and provided you can stay centred in the lift,
which as Jim points out is harder if you can’t see the real horizon. I
have found that expanding the GPS scale helps a lot in keeping in good
lift, in VMC or in IMC. (I still do not advocate people teaching
themselves to do the latter these days – if it goes wrong in a
slippery glider, it can do so very quickly and very badly.)

In the more usual “good” conditions in the UK when we get them, an
inversion stops vertical cu development and they are often only a few
hundred or 1-2000 feet deep. Then, as Jim says, it is usually faster
to keep in the energy where you can see it, in VMC. With very shallow
clouds, it is not even worth going up to cloud base – the lift weakens
before getting there. Even if it does strengthen briefly at and into
cloud, I usually lose more in the fumble of coming out on the wrong
heading, or on the right one but into another cloud and in its sink,
than staying below, if achieved speed is what you are after.

Chris N


It is very common in Arizona to have at least a slight inversion at or
below cloud base. What happens in these cases is that the rising
airmass in a strong thermal continues going up under its own
momentum. It's not uncommon in these circumstance to find the lift
cutting off a thousand feet below the clouds and very nice looking
clouds have no lift under them. I sometimes refer to these clouds as
resulting from the last dying gasp of a rising thermal!

With instability of the atmosphere rising above cloud base, thermals
will often increase with strength as you approach the cloud and this
increase continues into the cloud. These are the circumstances when
you might get too close to the cloud - it's not uncommon here to find
a ten-knot thermal strengthening to 12 to 15 knots! At these vertical
speeds, you can go from a safe distance below into cloud in about half
a turn. It's very easy to do and a not uncommon experience out west.

Mike
  #238  
Old February 19th 12, 11:50 PM posted to rec.aviation.soaring
John Firth
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Posts: 10
Default New Butterfly Vario

VG post by Andy Gough.
This debate has been going on since the '60s!
AH s and T and S had to be removed for constests outside
the UK ( and Yugoslavia etc) but then the Bohli compass appeared
which confused the issue.

I personally proved to myself that I could manage for a while
using a COOK compass, predecessor of the Bohli.
Cloud climb with only ASI and vario! Wow.
I would not try that in a modern ship.

The GPS record should take care of transgressions, but
wave either lee o thermal ,poses a problem.

John Firth



  #239  
Old February 20th 12, 05:05 AM posted to rec.aviation.soaring
Sean Fidler
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Posts: 1,003
Default New Butterfly Vario

Whatever. Time to go flying. Moving on.
 




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