500 km Triangle at 306 km/hr in Argentina

Greg Arnold wrote:

When you are cruising at 20,000' to 30,000', doesn't the effect of
altitude cause IAS to be substantially less than ground speed?

That is indeed true. However, there are aeroelastic concerns (such as
flutter) which may result in a lower indicated vne at high altitude.

Charles

"Charles Crosby" wrote in message
...
Greg Arnold wrote:

When you are cruising at 20,000' to 30,000', doesn't the effect of
altitude cause IAS to be substantially less than ground speed?

That is indeed true. However, there are aeroelastic concerns (such as
flutter) which may result in a lower indicated vne at high altitude.

Charles



http://home.comcast.net/~johan.larso...ride-home.html

The Long Ride Home
Harold Peterson


This article originally appeared in the August 1, 1966 issue of Sports
Illustrated. David Stevenson provided the issue of SI for scanning.


' "We're plagued with people who want to emphasize the danger," George said.
"Just flying a sailplane around is safer than power flying. One fundamental
safety factor is the soft landing. You have marvelous control-anywhere
between a 40 degree approach with full dive breaks to 3 degrees with none.
In contest or record flight, of course, you're definitely stretching a
little. On a glide you may easily reach 150 mph where the placard speed is
listed at 86." Placard speed is that beyond which the manufacturer makes no
guarantee that things will not start coming off. '

[Quoting George Moffat. G.T.]


--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.

Soarin Again wrote:
At 05:42 23 December 2006, Js wrote:
306 km/hr = 190 mph = 165 knots

That is an amazing feat!

Yes, it is.
Anyone trying to beat that record should be certain
their parachute is
in good shape, as the number of wings will likely total
zero.
Jim

Does anyone know if his Nimbus 4DM has had special
modifications to increase the vne at altitude, or does
he just not care about operating limitations?

306 km/hr true airspeed is 200 to 220 km/hr IAS at the 20000+ foot
altitudes used for these wave flights. Some gliders do require a
reduction in Vne at higher altitudes, but it isn't necessarily the case
that the limitation was exceeded.

Marc

Marc Ramsey wrote:
Soarin Again wrote:
At 05:42 23 December 2006, Js wrote:
306 km/hr = 190 mph = 165 knots

That is an amazing feat!

Yes, it is.
Anyone trying to beat that record should be certain
their parachute is
in good shape, as the number of wings will likely total
zero.
Jim

Does anyone know if his Nimbus 4DM has had special
modifications to increase the vne at altitude, or does
he just not care about operating limitations?

306 km/hr true airspeed is 200 to 220 km/hr IAS at the 20000+ foot
altitudes used for these wave flights. Some gliders do require a
reduction in Vne at higher altitudes, but it isn't necessarily the case
that the limitation was exceeded.

If the 4DM follows the protocol used by the Duo (for which I have a
manual), Vne is IAS up to approximately 2500M altitude, then the
equivalent TAS from there up. If Vne for the 4DM is 275 km/hr, the TAS
limitation would be around 310 km/hr.

Marc Ramsey wrote:
Marc Ramsey wrote:
Soarin Again wrote:
At 05:42 23 December 2006, Js wrote:
306 km/hr = 190 mph = 165 knots

That is an amazing feat!

Yes, it is.
Anyone trying to beat that record should be certain
their parachute is
in good shape, as the number of wings will likely total
zero.
Jim

Does anyone know if his Nimbus 4DM has had special
modifications to increase the vne at altitude, or does
he just not care about operating limitations?

306 km/hr true airspeed is 200 to 220 km/hr IAS at the 20000+ foot
altitudes used for these wave flights. Some gliders do require a
reduction in Vne at higher altitudes, but it isn't necessarily the case
that the limitation was exceeded.

If the 4DM follows the protocol used by the Duo (for which I have a
manual), Vne is IAS up to approximately 2500M altitude, then the
equivalent TAS from there up. If Vne for the 4DM is 275 km/hr, the TAS
limitation would be around 310 km/hr.

The Vne for the Nimbus 4DM is 285km/h (154 kt). Flutter speeds do not
follow TAS, but actually follow approximately 3/4 the way between IAS
and TAS. So it is possible to fly safely past 300km/h at altitude.

I do remember reading something a little while back on the SH website
about them having modifed a Nimbus 4 for high altitude record flights
in Argentina. If I recall correctly they did modifications (probably
some mass balancing) to counter the onset of flutter as a result of
high TAS at altitude.

Markus

Marc Ramsey wrote:
Soarin Again wrote:
At 05:42 23 December 2006, Js wrote:
306 km/hr = 190 mph = 165 knots

That is an amazing feat!

Yes, it is.
Anyone trying to beat that record should be certain
their parachute is
in good shape, as the number of wings will likely total
zero.
Jim

Does anyone know if his Nimbus 4DM has had special
modifications to increase the vne at altitude, or does
he just not care about operating limitations?

306 km/hr true airspeed is 200 to 220 km/hr IAS at the 20000+ foot
altitudes used for these wave flights. Some gliders do require a
reduction in Vne at higher altitudes, but it isn't necessarily the case
that the limitation was exceeded.

I find these sorts of discussions amusing. Do F1 drivers religiously
follow redline engine speeds or anticipated braking limits for
conditions when they're out to beat the next guy?
Breaking records in aircraft is not analogous to driving the family SUV
to the mall, or the 1-26 around a silver distance triangle. Speed
limits and safe and reasonable don't apply. If it wasn't pushing the
envelope, we'd all be doing it.
My $ 0.02.


Shawn

Shawn schreef:

Marc Ramsey wrote:
Soarin Again wrote:
At 05:42 23 December 2006, Js wrote:
306 km/hr = 190 mph = 165 knots

That is an amazing feat!

Yes, it is.
Anyone trying to beat that record should be certain
their parachute is
in good shape, as the number of wings will likely total
zero.
Jim

Does anyone know if his Nimbus 4DM has had special
modifications to increase the vne at altitude, or does
he just not care about operating limitations?

306 km/hr true airspeed is 200 to 220 km/hr IAS at the 20000+ foot
altitudes used for these wave flights. Some gliders do require a
reduction in Vne at higher altitudes, but it isn't necessarily the case
that the limitation was exceeded.

I find these sorts of discussions amusing. Do F1 drivers religiously
follow redline engine speeds or anticipated braking limits for
conditions when they're out to beat the next guy?
Breaking records in aircraft is not analogous to driving the family SUV
to the mall, or the 1-26 around a silver distance triangle. Speed
limits and safe and reasonable don't apply. If it wasn't pushing the
envelope, we'd all be doing it.
My $ 0.02.


Shawn

When not flying in an airworthiness glider you're simply not allowed to
fly at all, so no records either. That does give Americans (of which
most have an experimental registrated glider) in fact an unfair
advantage, but up to now no one cared. Maybe that's gonna change...

Shawn wrote:
Marc Ramsey wrote:

306 km/hr true airspeed is 200 to 220 km/hr IAS at the 20000+ foot
altitudes used for these wave flights. Some gliders do require a
reduction in Vne at higher altitudes, but it isn't necessarily the
case that the limitation was exceeded.

I find these sorts of discussions amusing. Do F1 drivers religiously
follow redline engine speeds or anticipated braking limits for
conditions when they're out to beat the next guy?
Breaking records in aircraft is not analogous to driving the family SUV
to the mall, or the 1-26 around a silver distance triangle. Speed
limits and safe and reasonable don't apply. If it wasn't pushing the
envelope, we'd all be doing it.

And that's why I think these discussions are interesting instead of
amusing. What risks are they taking, and how did they determine these
risks? Klaus does not seem a like a crazy man, so I suspect his risk
analysis would be very enlightening. And now we know it's a modified
Nimbus, so perhaps he is not taking any extra risk at all - even more
interesting! I hope we hear more about the modifications and how they
tested their effect.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly
* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

To average 306 he certainly exceeded that speed for much of the flight.
I too would like to understand the mods and the risk analysis for this
flight.

"Marc Ramsey" wrote in message
m...
Soarin Again wrote:
At 05:42 23 December 2006, Js wrote:
306 km/hr = 190 mph = 165 knots

That is an amazing feat!

Yes, it is.
Anyone trying to beat that record should be certain
their parachute is
in good shape, as the number of wings will likely total
zero.
Jim

Does anyone know if his Nimbus 4DM has had special
modifications to increase the vne at altitude, or does
he just not care about operating limitations?

306 km/hr true airspeed is 200 to 220 km/hr IAS at the 20000+ foot
altitudes used for these wave flights. Some gliders do require a
reduction in Vne at higher altitudes, but it isn't necessarily the case
that the limitation was exceeded.

Marc