For height gain badge and record flights this should not be a
problem because the release height is recorded with "suction on".
For max start height that's a bit of an issue but I would have
thought there would be a noticeable "step" during the ground roll,
both on launch and landing, when the suction effect kicks in and then
drops off again. Similar to "notching the barograph". With a 4 to 5
second recording interval that should be quite visible - unless it's a
winch launch (in which case the landing should still allow gauging the
size of the effect).
Ulrich
On Sat 31/07/10 11:04 , Mike Borgelt [email protected]
sent:
At 10:54 AM 31/07/2010, you wrote:
>Hi Mike
>These guys are doing really well at the Worlds so far, this could be
the new
>glider to beat.
>According to the PDF document linked in your email they say that ..
> "The size and geometry of the extractor lower the pressure level
inside the
>cockpit to ambient levels..."
>I read that as meaning the cockpit pressure is neither higher nor
lower than
>the outside air, so probably no effect therefore on the accuracy of
the
>flight recorder pressure altitude.
>ROSS
>_________________________________________________
However if that is true it won't prevent air leaks out of the canopy
frame as the pressures there will definitely be lower than
ambient(static) pressure.
The article also says the vent"sucks air out of the cockpit" and
"depressurises" the cockpit so I think the article may just be poorly
worded.
DG reckon the Mandl vent reduces the pressure considerably below
static pressure. Several (maybe 5)HectoPascals below static at 100
knots or so. One Hpa is about 27 feet. So you could be reading 135
feet high on your flight recorder pressure altitude. This could cost
you all points for a day. The pilot who lost all points at Benalla
about 18 months ago on one day had had a Mandl type vent installed
not long before. As it is installed under the fuselage near the
trailing edge of the wing the Mandl vent may not be as effective as
the new Jonker vent which may cause even more suction.
Mike
Borgelt Instruments - manufacturers of quality soaring instruments
since 1978
phone Int'l + 61 746 355784
fax Int'l + 61 746 358796
cellphone Int'l + 61 428 355784
email: [email protected]
website: www.borgeltinstruments.com [1]
_______________________________________________
Aus-soaring mailing list
[email protected]
To check or change subscription details, visit:
http://lists.internode.on.net/mailman/listinfo/aus-soaring [2]
Links:
------
[1]
http://webmail.internode.on.net/parse.php?redirect=http://www.borgeltinstruments.com
[2]
http://webmail.internode.on.net/parse.php?redirect=http%3A%2F%2Flists.internode.on.net%2Fmailman%2Flistinfo%2Faus-soaring
_______________________________________________
Aus-soaring mailing list
[email protected]
To check or change subscription details, visit:
http://lists.internode.on.net/mailman/listinfo/aus-soaring
