Perlan High Altitude Tow Plane

[Frank Whiteley]

http://www.reporterherald.com/lifestyles/neighbors/ci_32061333/loveland-family-soaring-new-heights-study-earths-stratosphere Arne is an SSA member and member of Colorado Soaring Association.

[[email protected]]

On Monday, August 13, 2018 at 9:18:01 PM UTC-6, Frank Whiteley wrote:
> http://www.reporterherald.com/lifestyles/neighbors/ci_32061333/loveland-family-soaring-new-heights-study-earths-stratosphere Arne is an SSA member and member of Colorado Soaring Association.

The article mentions "weight turbulence" I think that should read "wake turbulence. Shouldn't be an issue unless Perlan plans on boxing the wake.

[Bruce Hoult]

On Monday, August 13, 2018 at 9:59:35 PM UTC-7, wrote:
> On Monday, August 13, 2018 at 9:18:01 PM UTC-6, Frank Whiteley wrote:
> > http://www.reporterherald.com/lifestyles/neighbors/ci_32061333/loveland-family-soaring-new-heights-study-earths-stratosphere Arne is an SSA member and member of Colorado Soaring Association.
>
> The article mentions "weight turbulence" I think that should read "wake turbulence. Shouldn't be an issue unless Perlan plans on boxing the wake.

Journalists never know what they're writing about. They mishear and don't understand anyway. They also never show their article to anyone with any knowledge of the subject matter before publishing. You see the very common result.

[Tango Eight]

Wake news.

T8

[Steve Leonard[_2_]]

On Monday, August 13, 2018 at 11:59:35 PM UTC-5, wrote:
> On Monday, August 13, 2018 at 9:18:01 PM UTC-6, Frank Whiteley wrote:
>
> The article mentions "weight turbulence" I think that should read "wake turbulence. Shouldn't be an issue unless Perlan plans on boxing the wake.

Sometimes, you do things you hadn't initially planned to do!

Steve Leonard

[Eric Greenwell[_4_]]

Bruce Hoult wrote on 8/14/2018 12:17 AM:
> On Monday, August 13, 2018 at 9:59:35 PM UTC-7, wrote:
>> On Monday, August 13, 2018 at 9:18:01 PM UTC-6, Frank Whiteley wrote:
>>> http://www.reporterherald.com/lifestyles/neighbors/ci_32061333/loveland-family-soaring-new-heights-study-earths-stratosphere Arne is an SSA member and member of Colorado Soaring Association.
>>
>> The article mentions "weight turbulence" I think that should read "wake turbulence. Shouldn't be an issue unless Perlan plans on boxing the wake.
>
> Journalists never know what they're writing about. They mishear and don't understand anyway. They also never show their article to anyone with any knowledge of the subject matter before publishing. You see the very common result.

Too broad and too harsh, in part because the article may have been edited, or fell
victim to spell-checking. Most journalists do have areas of significant
competence, It is a bit ironic one would complain about a misspelling in a forum
where people complain about the errors in the forum ...

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf

[[email protected]]

On Tuesday, August 14, 2018 at 11:28:13 AM UTC-4, Eric Greenwell wrote:
> Bruce Hoult wrote on 8/14/2018 12:17 AM:
> > On Monday, August 13, 2018 at 9:59:35 PM UTC-7, wrote:
> >> On Monday, August 13, 2018 at 9:18:01 PM UTC-6, Frank Whiteley wrote:
> >>> http://www.reporterherald.com/lifestyles/neighbors/ci_32061333/loveland-family-soaring-new-heights-study-earths-stratosphere Arne is an SSA member and member of Colorado Soaring Association.
> >>
> >> The article mentions "weight turbulence" I think that should read "wake turbulence. Shouldn't be an issue unless Perlan plans on boxing the wake.
> >
> > Journalists never know what they're writing about. They mishear and don't understand anyway. They also never show their article to anyone with any knowledge of the subject matter before publishing. You see the very common result.
>
> Too broad and too harsh, in part because the article may have been edited, or fell
> victim to spell-checking. Most journalists do have areas of significant
> competence, It is a bit ironic one would complain about a misspelling in a forum
> where people complain about the errors in the forum ...
>
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> - "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm
>
> http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf

I found the article interesting and had no trouble with one glitch.
UH

[[email protected]]

Not perfect, but a better effort than many articles I've read.

What a thrilling, once-in-a-lifetime adventure this must be for their entire family!

Chip Bearden

[kinsell]

On 08/14/2018 09:35 AM, wrote:
> On Tuesday, August 14, 2018 at 11:28:13 AM UTC-4, Eric Greenwell wrote:
>> Bruce Hoult wrote on 8/14/2018 12:17 AM:
>>> On Monday, August 13, 2018 at 9:59:35 PM UTC-7, wrote:
>>>> On Monday, August 13, 2018 at 9:18:01 PM UTC-6, Frank Whiteley wrote:
>>>>> http://www.reporterherald.com/lifestyles/neighbors/ci_32061333/loveland-family-soaring-new-heights-study-earths-stratosphere Arne is an SSA member and member of Colorado Soaring Association.
>>>>
>>>> The article mentions "weight turbulence" I think that should read "wake turbulence. Shouldn't be an issue unless Perlan plans on boxing the wake.
>>>
>>> Journalists never know what they're writing about. They mishear and don't understand anyway. They also never show their article to anyone with any knowledge of the subject matter before publishing. You see the very common result.
>>
>> Too broad and too harsh, in part because the article may have been edited, or fell
>> victim to spell-checking. Most journalists do have areas of significant
>> competence, It is a bit ironic one would complain about a misspelling in a forum
>> where people complain about the errors in the forum ...
>>
>> --
>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
>> - "A Guide to Self-Launching Sailplane Operation"
>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>> - "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm
>>
>> http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf
>
> I found the article interesting and had no trouble with one glitch.
> UH
>

The one incorrect word was hardly an issue. The explanation of why they
needed such a high altitude tow unfortunately got a bit garbled, of
course they want to go above the area of no lift, not just to it. That
would be confusing to non-pilots.

"The goal is to pull them to a place in the atmosphere where there is no
lift, so they don't have to waste their battery, which limits flight
time," Roberta said about the glider's battery power of eight hours.

-Dave

[AS]

On Monday, August 13, 2018 at 11:18:01 PM UTC-4, Frank Whiteley wrote:
> http://www.reporterherald.com/lifestyles/neighbors/ci_32061333/loveland-family-soaring-new-heights-study-earths-stratosphere Arne is an SSA member and member of Colorado Soaring Association.

Here is a video of the first tow by the Grob G520 towing a G103.
https://youtu.be/q-1qBOUMfwo
There is no N-# visible on the Egrett in the video. Does anyone know what category it is registered?

Uli
'AS'

[kinsell]

On 08/15/2018 07:32 PM, AS wrote:
> On Monday, August 13, 2018 at 11:18:01 PM UTC-4, Frank Whiteley wrote:
>> http://www.reporterherald.com/lifestyles/neighbors/ci_32061333/loveland-family-soaring-new-heights-study-earths-stratosphere Arne is an SSA member and member of Colorado Soaring Association.
>
> Here is a video of the first tow by the Grob G520 towing a G103.
> https://youtu.be/q-1qBOUMfwo
> There is no N-# visible on the Egrett in the video. Does anyone know what category it is registered?
>
> Uli
> 'AS'
>
It would be the one registered in Delaware in this list:

https://registry.faa.gov/aircraftinquiry/AcftRef_Results.aspx?Mfrtxt=&Modeltxt=EGRETT&PageNo=1

[Ramy[_2_]]

Typo aside, am I the only one somewhat disappointed to learn that the plan is to tow the Perlan to 50,000 feet, or I missread the article? I was kind of hoping the Perlan is capable of climbing to 90K from a reasonable tow altitude.

Ramy

[Eric Greenwell[_4_]]

Ramy wrote on 8/15/2018 8:13 PM:
> Typo aside, am I the only one somewhat disappointed to learn that the plan is to tow the Perlan to 50,000 feet, or I missread the article? I was kind of hoping the Perlan is capable of climbing to 90K from a reasonable tow altitude.
>
> Ramy

My understanding is the Egret has that capability, but they don't plan to use it
routinely.


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf

[kinsell]

On 08/15/2018 09:13 PM, Ramy wrote:
> Typo aside, am I the only one somewhat disappointed to learn that the plan is to tow the Perlan to 50,000 feet, or I missread the article? I was kind of hoping the Perlan is capable of climbing to 90K from a reasonable tow altitude.
>
> Ramy
>

Arnie told me that Perlan was having a lot of trouble climbing through a
certain altitude band (30K?). With an unheated cabin and limited
electrical power, that made if difficult to have successful missions.

I don't think they're planning on going to 50K, but yes, high fast tows
is why the Egrett was brought in. First high tow went to 40K.

-Dave

[Bob Gibbons[_2_]]

On Mon, 13 Aug 2018 20:17:58 -0700 (PDT), Frank Whiteley
> wrote:

>http://www.reporterherald.com/lifestyles/neighbors/ci_32061333/loveland-family-soaring-new-heights-study-earths-stratosphere Arne is an SSA member and member of Colorado Soaring Association.

Perhaps an interesting side note. The late A.C. Williams was heavily
involved as a key consultant to Grob during the development of the
Egrett.

At one point the aircraft was housed in one half of Southwest
Soaring's hangar, with a large hanging curtain cutting off view from
the other half of the hangar.

[kinsell]

On 08/15/2018 10:43 PM, Bob Gibbons wrote:
> On Mon, 13 Aug 2018 20:17:58 -0700 (PDT), Frank Whiteley
> > wrote:
>
>> http://www.reporterherald.com/lifestyles/neighbors/ci_32061333/loveland-family-soaring-new-heights-study-earths-stratosphere Arne is an SSA member and member of Colorado Soaring Association.
>
> Perhaps an interesting side note. The late A.C. Williams was heavily
> involved as a key consultant to Grob during the development of the
> Egrett.
>
> At one point the aircraft was housed in one half of Southwest
> Soaring's hangar, with a large hanging curtain cutting off view from
> the other half of the hangar.
>

It was to be Germany's answer to the U-2, if Wikipedia is to be believed.

[Dan Marotta]

Was that Gary Powers climbing into the Egrett?Â* Nah...Â* Couldn't have been.

On 8/15/2018 7:32 PM, AS wrote:
> On Monday, August 13, 2018 at 11:18:01 PM UTC-4, Frank Whiteley wrote:
>> http://www.reporterherald.com/lifestyles/neighbors/ci_32061333/loveland-family-soaring-new-heights-study-earths-stratosphere Arne is an SSA member and member of Colorado Soaring Association.
> Here is a video of the first tow by the Grob G520 towing a G103.
> https://youtu.be/q-1qBOUMfwo
> There is no N-# visible on the Egrett in the video. Does anyone know what category it is registered?
>
> Uli
> 'AS'

--
Dan, 5J

[Ernst]

>
> It was to be Germany's answer to the U-2, if Wikipedia is to be believed.

Yes, that's why they are registered as gliders.

Ernst

[[email protected]]

Maybe it was something I ate, but I had a strange thought last night on towing really high.

What if you put a cg tow position on the tow plane and payed out cable from the tow plane winch launch style?

3/16 spectra is 100feet per pound, or 500 pounds for 50k feet. This weight would sometimes be carried by the tow plane's wings and sometimes by the glider's. The line on the tow reel would never be under tension, so you would not need an impossibly strong reel.

Logistics would be interesting to say the least, perhaps:

Launch like a normal aerotow with a tail connection point on the tow and a cg hook on the glider. Use 200 feet of tow rope.

Climb normally to something safer like at least 10kfeet. Perhaps to the tow plane's limit.

Transition the front end of the rope from tow plane tail to tow plane upper CG. Certainly use windows in the bottom of the glider and some computer help. Fouling the tail on the tow is a concern. Perhaps position the glider high and to the side or use a vtail. Definitely a trickey maneuver.

Pay out the other 49,800 feet of tow rope as the glider climbs.

Release both ends and pick up the rope in the ocean.


Definitely something I ate, but fun to think about.

[AS]

On Friday, August 17, 2018 at 9:08:11 AM UTC-4, wrote:
> Maybe it was something I ate, but I had a strange thought last night on towing really high.
>
> What if you put a cg tow position on the tow plane and payed out cable from the tow plane winch launch style?
>
> 3/16 spectra is 100feet per pound, or 500 pounds for 50k feet. This weight would sometimes be carried by the tow plane's wings and sometimes by the glider's. The line on the tow reel would never be under tension, so you would not need an impossibly strong reel.
>
> Logistics would be interesting to say the least, perhaps:
>
> Launch like a normal aerotow with a tail connection point on the tow and a cg hook on the glider. Use 200 feet of tow rope.
>
> Climb normally to something safer like at least 10kfeet. Perhaps to the tow plane's limit.
>
> Transition the front end of the rope from tow plane tail to tow plane upper CG. Certainly use windows in the bottom of the glider and some computer help. Fouling the tail on the tow is a concern. Perhaps position the glider high and to the side or use a vtail. Definitely a trickey maneuver.
>
> Pay out the other 49,800 feet of tow rope as the glider climbs.
>
> Release both ends and pick up the rope in the ocean.
>
>
> Definitely something I ate, but fun to think about.

Stu,
I think that has actually been done already in Russia a while back. I put a reference to an article describing that process in our 'winchdesign' forum but since Yahoo got hacked, most of the links to those references are lost..
The glider was towed up like a normal aero-tow. Then, the line was paid out and the tow plane started a descent which allowed the glider to climb like it would in a winch launch.

Uli
'AS'

[Ventus_a]

On Monday, August 13, 2018 at 9:59:35 PM UTC-7, wrote:
On Monday, August 13, 2018 at 9:18:01 PM UTC-6, Frank Whiteley wrote:
http://www.reporterherald.com/lifestyles/neighbors/ci_32061333/loveland-family-soaring-new-heights-study-earths-stratosphere Arne is an SSA member and member of Colorado Soaring Association.

The article mentions "weight turbulence" I think that should read "wake turbulence. Shouldn't be an issue unless Perlan plans on boxing the wake.

Journalists never know what they're writing about. They mishear and don't understand anyway. They also never show their article to anyone with any knowledge of the subject matter before publishing. You see the very common result.

Maybe so Bruce but the amount of wake turbulence is a function of the weight being lifted so it's not too out of whack lol :D

[[email protected]]

On Wednesday, August 15, 2018 at 10:13:37 PM UTC-5, Ramy wrote:
> Typo aside, am I the only one somewhat disappointed to learn that the plan is to tow the Perlan to 50,000 feet, or I missread the article? I was kind of hoping the Perlan is capable of climbing to 90K from a reasonable tow altitude.
>
> Ramy

What, Real Men scratch around for hours just to prove ...what?...
The fact is that Perlan was designed to fly in and study *stratospheric* wave, not tropospheric wave. These waves are rarely stacked and connected. Perlan I found such linked wave once in two years, and then set a record over 50,000 ft. Perlan II found such linked wave once in two years, and then set a record over 50,000 ft.

The hope is to do aerodynamic and atmospheric research in the stratosphere. In the winter, the tropopause (the boundary between tropo- and strato-sphere) generally descends to about 30,000 msl. It happens to be about 40,000 msl in the southern hemisphere at the moment.

The Egrett, used as a towplane, is able to reliably bring Perlan II into the lower reaches of the stratosphere in about an hour. Only in this way will the glider be a reliable research vehicle.

And such research is important: the polar night jets are poorly understood, yet are known to drive climate in some ways. It is not know what triggers stratospheric wave, and one of the hindrances to Perlan "success" is that predictive models are inaccurate simply because of human ignorance.

While it's spectacular to set altitude records, the real importance of this project is making steps toward stratospheric research in a vehicle that will not contaminate the nearby atmosphere with noise: chemical, mechanical, aerodynamic.

This is not a toy and its mission is not play.
DrDan Johnson

[[email protected]]

"This is not a toy and its mission is not play."

Yeah, maybe so, but it still looks like fun and an amazing, challenging project. Best of luck to all your endeavors. Say Hi to Jim, Jackie, Morgan, Sandra, Stewart, Liz, Tim, Tago and all of the other team members I will remember about two seconds after I hit "Post Entry."

[Peter Purdie[_3_]]

Do I recall correctly that Einar Enevoldson descibed the Egrett as the
worst plane he ever flew (and considering some of the candidates at
NASA Dryden, that would be an amazing distiction).

At 02:01 24 August 2018, wrote:
>"This is not a toy and its mission is not play."
>
>Yeah, maybe so, but it still looks like fun and an amazing, challenging
>pro=
>ject. Best of luck to all your endeavors. Say Hi to Jim, Jackie, Morgan,
>Sa=
>ndra, Stewart, Liz, Tim, Tago and all of the other team members I will
>reme=
>mber about two seconds after I hit "Post Entry."
>

[Steve Leonard[_2_]]

On Friday, August 17, 2018 at 8:55:12 AM UTC-5, AS wrote:

> Stu,
> I think that has actually been done already in Russia a while back. I put a reference to an article describing that process in our 'winchdesign' forum but since Yahoo got hacked, most of the links to those references are lost.
> The glider was towed up like a normal aero-tow. Then, the line was paid out and the tow plane started a descent which allowed the glider to climb like it would in a winch launch.
>
> Uli
> 'AS'

Described in the book "Without Visible Means of Support" by Richard Miller. A very good read.

Oh, and the Russians also did testing where they towed a glider up and intentionally jettisoned parts of it in flight to determine controlability.

Steve Leonard

[Bob Kuykendall]

On Thursday, August 23, 2018 at 5:55:25 PM UTC-7, wrote:

> While it's spectacular to set altitude records, the real importance of this project is making steps toward stratospheric research in a vehicle that will not contaminate the nearby atmosphere with noise: chemical, mechanical, aerodynamic.
>
> This is not a toy and its mission is not play.

On that basis, wouldn't you be much better off doing your oh-so-serious research with a UAV?

--Bob K.

[Martin Gregorie[_6_]]

On Fri, 24 Aug 2018 12:21:03 -0700, Bob Kuykendall wrote:

> On Thursday, August 23, 2018 at 5:55:25 PM UTC-7,
> wrote:
>
>> While it's spectacular to set altitude records, the real importance of
>> this project is making steps toward stratospheric research in a vehicle
>> that will not contaminate the nearby atmosphere with noise: chemical,
>> mechanical, aerodynamic.
>>
>> This is not a toy and its mission is not play.
>
> On that basis, wouldn't you be much better off doing your oh-so-serious
> research with a UAV?
>
Possible/probable reasons why Perlan 2 is the best choice:

- Perlan 2 already exists.

- There are no electric UAVs with a similar flight envelope.

- Any powered replacement has to be electric to avoid atmospheric
exhaust contamination.

- Even an electric UAV will add unwanted disturbances with its prop wake.


--
Martin | martin at
Gregorie | gregorie dot org

[Bob Kuykendall]

> Possible/probable reasons why Perlan 2 is the best choice:
>
> - Perlan 2 already exists.

And, hey, the made production-quality wing and fuselage tooling for it, so they can make more if they want!

> - There are no electric UAVs with a similar flight envelope.
>
> - Any powered replacement has to be electric to avoid atmospheric
> exhaust contamination.
>
> - Even an electric UAV will add unwanted disturbances with its prop wake.

This isn't about electric versus unpowered. It's about the necessity of doing this with a crewed vehicle. There is nothing in any of those arguments that supports carting two humans and several hundred pounds of life-support infrastructure around the sky.

I'm sure that there are valid arguments for having humans aboard so they can respond adaptively and innovatively to any flight or scientific situation that might arise. I simply don't buy the idea that doing so is best or even lowest-cost option. I think that a UAV, or a cooperative swarm of UAVs, or even a series of balloon-dropped UAVs, could do the planned research with a risk/reward ratio about an order of magnitude better.

--Bob K.

[[email protected]]

Perlan is cool as hell. And I'm glad they are doing it manned, but I have to chuckle at the 'serious science stuff.' All the great explorers from years back used to admit the science part was just to get funding so they could go off adventuring. And there is nothing wrong with that, matter of fact it is awesome.

[Martin Gregorie[_6_]]

On Fri, 24 Aug 2018 14:00:59 -0700, Bob Kuykendall wrote:

> This isn't about electric versus unpowered. It's about the necessity of
> doing this with a crewed vehicle. There is nothing in any of those
> arguments that supports carting two humans and several hundred pounds of
> life-support infrastructure around the sky.
>
Sure, but would you be happy to tow an autonomous glider above the lower
stratospheric boundary?

> I'm sure that there are valid arguments for having humans aboard so they
> can respond adaptively and innovatively to any flight or scientific
> situation that might arise. I simply don't buy the idea that doing so is
> best or even lowest-cost option. I think that a UAV, or a cooperative
> swarm of UAVs, or even a series of balloon-dropped UAVs, could do the
> planned research with a risk/reward ratio about an order of magnitude
> better.
>
Isn't there a fairly radical bit of mission redesign going on? IIRC
Fossett and Einevold were set up the Perlan because they could and to
push the record up as high as they could, with a bit of science thrown in
as well, but now DrDan Johnson (and Airbus) are saying that was all very
well then but NOW the project is all grown up and concentrating on
Serious Meteorological Science.

You may well be right than an unmanned vehicle can do it cheaper if the
mission was designed that way from the start. All I'm really saying is
that wasn't how it happened.

Judging by an article by Jean-Marie Clement in Sailplane & Gliding (Dec/
Jan 18 p40) the Perlan Project may have missed the boat for setting a
properly high record. M. Clement says that climate change has stretched
the Andean wavelength by causing and increase in wind speed, so it is no
longer in phase with the mountain topography. This weakens wave lift
while the increased wind speed has also reduced the duration of weather
cycles. He talks about having to accept 2-3 m/s wave climbs in 2017 where
a decade ago they'd have had 5-8 m/s, but adds that the vertical velocity
in hydraulic jumps wasn't affected though the jumps may have become more
frequent.


--
Martin | martin at
Gregorie | gregorie dot org

[kinsell]

On 08/24/2018 06:55 PM, Martin Gregorie wrote:

> Judging by an article by Jean-Marie Clement in Sailplane & Gliding (Dec/
> Jan 18 p40) the Perlan Project may have missed the boat for setting a
> properly high record. M. Clement says that climate change has stretched
> the Andean wavelength by causing and increase in wind speed, so it is no
> longer in phase with the mountain topography. This weakens wave lift
> while the increased wind speed has also reduced the duration of weather
> cycles. He talks about having to accept 2-3 m/s wave climbs in 2017 where
> a decade ago they'd have had 5-8 m/s, but adds that the vertical velocity
> in hydraulic jumps wasn't affected though the jumps may have become more
> frequent.
>
>

https://www.youtube.com/watch?v=I-cZzVA0Gcc

[Eric Greenwell[_4_]]

kinsell wrote on 8/24/2018 6:18 PM:
> On 08/24/2018 06:55 PM, Martin Gregorie wrote:
>
>> Judging by an article by Jean-Marie Clement in Sailplane & Gliding (Dec/
>> Jan 18 p40) the Perlan Project may have missed the boat for setting a
>> properly high record. M. Clement says that climate change has stretched
>> the Andean wavelength by causing and increase in wind speed, so it is no
>> longer in phase with the mountain topography. This weakens wave lift
>> while the increased wind speed has also reduced the duration of weather
>> cycles. He talks about having to accept 2-3 m/s wave climbs in 2017 where
>> a decade ago they'd have had 5-8 m/s, but adds that the vertical velocity
>> in hydraulic jumps wasn't affected though the jumps may have become more
>> frequent.
>>
>>
>
> https://www.youtube.com/watch?v=I-cZzVA0Gcc

I don't remember the joke, just the punch line: "Talking to him is like explaining
off-street parking to a cranberry".

Now I'm wondering what other "-ologies" are confusing.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf

[[email protected]]

"He has not so much brain as earwax."

William Shakespeare, Troilus and Cressida Act V, Scene 1