4 ms·

> "[...] When I fly a roll and hold a glass of water in my hand, not a drop falls out.” I assumed this was hyperbole, but it seems possible [0], [1] - although

by wumms 2y ago

> "[...] When I fly a roll and hold a glass of water in my hand, not a drop falls out.” I assumed this was hyperbole, but it seems possible [0], [1] - although they both seem to fly a barrel roll [2]. Would this be possible with just a roll in a fighter jet? [0] "Airplane Drink Trick-Pouring a Beverage While Rolling the Plane" https://www.youtube.com/watch?v=DjHD1U-QWv4 https://www.youtube.com/watch?v=DjHD1U-QWv4 [1] "Pilot successfully performs barrel roll without spilling water" https://www.youtube.com/watch?v=4LP-YXfmgGM https://www.youtube.com/watch?v=4LP-YXfmgGM [2] https://en.wikipedia.org/wiki/Barrel_roll https://en.wikipedia.org/wiki/Barrel_roll

Y_Y 2y ago
Even Newton knew that party trick. The centrifugal force has to at least equal gravity when the glass is upside down, so F/m=w^2r=g. If r (the distance from the axis of revolution is about a metre, then w (the angular velocity) is roughly sqrt(10)/second. In more familiar terms that's about 30 rpm. Anything rotating that fast will be able to keep all its water in the glass.
- wumms 2y ago
  Thanks! It seems to be possible: some roll rates I found (not very good sources, though): F/A-18E Super Hornet 120 deg/s [0], F-16 240 deg/s [0], Eurofighter 250 deg/s [0]. For the Starfighter I found up to 720 deg/s in some discussions, though I go with 360 deg/s [1]. Min. distance (r) from the glass of water to the roll axis to achieve 1g: 120 deg/s (20rpm): 245cm (you'd have to put that glass on the landing gear) 180 deg/s (30rpm): 100cm 240 deg/s (40rpm): 55cm 250 deg/s (42rpm): 51cm 360 deg/s (60rpm): 25cm 720 deg/s (120rpm): 6cm [0] https://theaviationist.com/2015/05/01/aileron-roll-in-t-346a/ https://theaviationist.com/2015/05/01/aileron-roll-in-t-346a... [1] https://www.key.aero/forum/modern-military-aviation/106866-roll-rate-data-of-jets https://www.key.aero/forum/modern-military-aviation/106866-r...
satiated_grue 2y ago
The classic example of this was Bob Hoover, who poured iced tea in his Rockwell Shrike Commander twin-engine propeller airplane while completing a barrel roll with both engines shut down (gliding). https://www.youtube.com/watch?v=PT1kVmqmvHU https://www.youtube.com/watch?v=PT1kVmqmvHU

by wumms 2y ago

Y_Y 2y ago

Even Newton knew that party trick. The centrifugal force has to at least equal gravity when the glass is upside down, so F/m=w^2r=g. If r (the distance from the axis of revolution is about a metre, then w (the angular velocity) is roughly sqrt(10)/second. In more familiar terms that's about 30 rpm. Anything rotating that fast will be able to keep all its water in the glass.

wumms 2y ago
Thanks! It seems to be possible: some roll rates I found (not very good sources, though): F/A-18E Super Hornet 120 deg/s [0], F-16 240 deg/s [0], Eurofighter 250 deg/s [0]. For the Starfighter I found up to 720 deg/s in some discussions, though I go with 360 deg/s [1]. Min. distance (r) from the glass of water to the roll axis to achieve 1g: 120 deg/s (20rpm): 245cm (you'd have to put that glass on the landing gear) 180 deg/s (30rpm): 100cm 240 deg/s (40rpm): 55cm 250 deg/s (42rpm): 51cm 360 deg/s (60rpm): 25cm 720 deg/s (120rpm): 6cm [0] https://theaviationist.com/2015/05/01/aileron-roll-in-t-346a/ https://theaviationist.com/2015/05/01/aileron-roll-in-t-346a... [1] https://www.key.aero/forum/modern-military-aviation/106866-roll-rate-data-of-jets https://www.key.aero/forum/modern-military-aviation/106866-r...

satiated_grue 2y ago

The classic example of this was Bob Hoover, who poured iced tea in his Rockwell Shrike Commander twin-engine propeller airplane while completing a barrel roll with both engines shut down (gliding). https://www.youtube.com/watch?v=PT1kVmqmvHU https://www.youtube.com/watch?v=PT1kVmqmvHU