On Sun, 19 Jan 2020 03:42:55 +0000, Michael Opitz wrote:

At 23:58 18 January 2020, Martin Gregorie wrote:
On Sat, 18 Jan 2020 10:50:34 -0800, Tom BravoMike wrote:

Somehow nobody objects to 'ground controlled' world records -
see the
Perlan project. And it is a sort of an ongoing world competition -
with
great expenses involved. Just a thought..

Record setting is a totally different game. No technology is ruled
out
and it can be individual or a group effort.

I was surprised to see how high Perlan 2 was being towed since
they got
use of the Grob towplane, so looked at the rules for the absolute
gliding
altitude record. It turns out you can tow as high as you like and
the
flight counts as a record provided the glider climbs at least another
5000m (16350 ft) after release.


--
Martin | martin at Gregorie | gregorie dot org


Jim Payne has said that on some days where the stratospheric wave is
working to high altitudes, the lower tropospheric waves are not working
so well. To have to use lots of precious battery life and oxygen to
muddle up through the lower wave system detracted from the time that
they could use to focus on the high altitude objectives, so they got a
tow plane that could reliably get them to the bottom of the
stratospheric system without a hassle. The additional 5000 meter gain
turned out not to be an issue with the heights they were able to
achieve. That whole program is way out our normal frame of reference
and comprehension.

I had guessed that battery capacity might be a limiting factor for Perlan
2 high altitude duration, especially when you consider that cabin heat
has to be battery driven, and hence might limit achievable overall
height, so wasn't too surprised when they got hold of the Grob as their
towplane, so thanks for confirmation that battery capacity was the driver.

The one thing that did surprise me was that the absolute glider altitude
record rules take the form they do and allow such high tows when all the
badges (and national height records?) are for height gain above release
height.


--
Martin | martin at
Gregorie | gregorie dot org