Jeff Findley wrote:

In article ,
says...
You fart a lot when you go from 14.7 PSI to 5 PSI. They don't tell
you this.


I when to a talk by a U2 pilot once. As a data point, they did open the mask up at 70,000 feet as necessary. The aircraft was put on autopilot allowing sleeping time. Drinking and eating and nose scratching/puking were allowed.


Obviously you misunderstood what was said, as usual, Dougie. There is
no 'mask' on a U-2 suit. It's a hard helmet. They eat paste that is
squirted in through a lock in the helmet. The original aircraft were
pressurized to around 30,000 feet altitude equivalent, which means if
you aren't in a sealed suit you die.


U-2 started out as unpressurized
http://www.lockheedmartin.com/us/new...U260Years.html

But later, cockpit pressure was increased to the equivalent of about 14k
feet, which is pretty thin.
http://aviationweek.com/blog/what-do...ane-pilots-eat

Still, the above article does confirm that flight at altitude is done
with a sealed helmet and that pilots must remain alert, so I don't see
how "sleeping" would ever be allowed. That plane is a bitch to fly.
It's very unforgiving at altitude.


Actually the original aircraft pressurized to 50,000 feet. If they
were totally unpressurized the pilots would have been unable to
manipulate the controls at high altitude due to the pressure in the
suit. As you note, there was a later program to reinforce the
airframes so that they could hold more pressure. This was undertaken
because several pilots exhibited symptoms of the bends because of the
low cockpit and suit pressure. By increasing the pressure in the
cockpit they could increase the pressure in the suit and still have
the pilot able to fly.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw