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General Category => General Discussion => Topic started by: Gliderjohn on July 17, 2016, 08:01:07 AM

Title: (NGC) - Very interesting Perlan 2 glider attitude record project article
Post by: Gliderjohn on July 17, 2016, 08:01:07 AM
Attempt hoped to be made this summer in a purpose built glider to obtain level flight at 90,000 ft.+. That would be a new record for any kind of aircraft including the SR-71. Current glider record is just over 50K.

http://www.airspacemag.com/flight-today/sailplane-stratosphere-180959154/

GliderJohn
Title: Re: (NGC) - Very interesting Perlan 2 glider attitude record project article
Post by: acogoff on July 17, 2016, 08:35:28 AM
     Yes , interesting. I can't imagine any lift at all available at that altitude except for being over a rare freakish thunderstorm not somewhere I would care to be flying a fragile long winged plane. It better be extra strong. I wish them well.
Title: Re: (NGC) - Very interesting Perlan 2 glider attitude record project article
Post by: Gliderjohn on July 17, 2016, 08:53:14 AM
Actually once they are in the wave lift it is generally a super smooth ride and T-storms really have nothing to do with it. Once back low, flying through the rotor is what will be a rough ride for a bit.
Most glider are quite strong. I have flown a vintage WWII wood and fabric glider into rough enough turbelance that my vision was blurring. The glider didn't mind, just me.
GliderJohn
Title: Re: (NGC) - Very interesting Perlan 2 glider attitude record project article
Post by: oldbike54 on July 17, 2016, 09:55:03 AM
 Interesting concept , using a glider to accomplish extreme altitude . No need for oxygen to power a jet , very light .

 Dusty
Title: Re: (NGC) - Very interesting Perlan 2 glider attitude record project article
Post by: Daniel Kalal on July 17, 2016, 10:26:50 AM
...at 90,000 ft.

wow.  What Mach number will they be at?  You'd think that all the criticacl speeds would be converging.
Title: Re: (NGC) - Very interesting Perlan 2 glider attitude record project article
Post by: Gliderjohn on July 17, 2016, 12:16:59 PM
Daniel, I think the article said at 90K it would still have about a 20 Kt window between stall and overspeed. It's ground speed will be about 400 mph. The U-2 at around 80K only has about a 5Kt window.
GliderJohn
Title: Re: (NGC) - Very interesting Perlan 2 glider attitude record project article
Post by: guzzisteve on July 17, 2016, 02:54:02 PM
How fast would you go being tugged by an AirBus 350?  That would be a real gas on take off!!
Title: Re: (NGC) - Very interesting Perlan 2 glider attitude record project article
Post by: kirby1923 on July 17, 2016, 04:56:06 PM
wow.  What Mach number will they be at?  You'd think that all the criticacl speeds would be converging.

Its about wing loading, span loading and adequate controls and aerodynamic devices , and the biggie  Reynolds numbers, not to mention crew environment.
At 100.000 feet the indicated airspeed would be 88kt (100 mph.) for Mach I. Should be fairly linear at those altitudes. So they will have a an indicated of somewhere in the 45 kt (50 mph,) range to make 400 true.
That would give a stall buffet speed of around 25 kt. Probably got some interesting aerodynamic devices.
Spoilers for roll and maybe a Gurney flap.

My bet is its not that good but if it even comes close, thats pretty fantastic!

A guess but... close.
Very exciting!!
BTW there is enough O2 to operate a internal combustion engine fine...at Mach III.