Perlan High Altitude Tow Plane

On Monday, August 13, 2018 at 11:18:01 PM UTC-4, Frank Whiteley wrote:
http://www.reporterherald.com/lifest...s-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'

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/lifest...s-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/aircraftinq...ETT&PageN o=1

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

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/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf

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

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

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.

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

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.

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/lifest...s-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