I am in an unpowered glider somewhere over Oxfordshire, with Bruce, my pilot and instructor,
behind me. Bruce, thank you very much.
And I have a bottle of water with me.
Now we're in level flight at the moment, so as you'd expect, the water in the bottle is about level.
But watch what happens when we start to turn.
Bruce, give us a -- there we go. Bit of a turn to the left.
Oh, that's a heck of a view! Now, look at that.
Have a look at the horizon line. According to the camera, it's massively away from horizontal.
But look at this bottle: the water level here is still flat. If you can't see the horizon,
then as far as you're concerned: you're not in a turn.
And look how fast we're going round!
Now, that's very strange, isn't it? But if you've ever been in a jetliner, an actual
commercial aircraft, you'll know that: a commercial aircraft can do this kind of turn without
slopping your in-flight meal or your drink all over the place.
Thank you, Bruce, let's go back to level.
So what would happen if we couldn't see the horizon?
'Cos there's some really weird sensory illusions that come into effect there.
If you lose sight of the horizon, and you've been turning for about 15-20 seconds, your
ears, the balance centres of your brain, get used to it. The only difference you feel is
a little bit of G-force, but that's really difficult to detect.
And if all you've got to go on is what you think is down: well, the forces are adding
up so down is always going to be towards your feet even if you're turning.
And even a bottle of water or something isn't going to clue you in.
So again, as we turn to the right: still straight here.
So if we were a little bit higher, if we were under those quite scary clouds above us, and
we couldn't see:
we wouldn't know if we were turning. And that's worrying.
Because if you turn, you start to lose a little bit of altitude. And if you're starting to
descend, if your altimeter says you're going down: and you think you're flying le vel?
Then you're going to pull up, to try and keep your height together. In a turn, that just
makes it worse. That just tightens the turn and tightens the turn, and you go into something
that is a called the graveyard spiral, for obvious reasons.
That is also the reason that we are not flying in cloud or at night.
BRUCE: I'm going to accelerate to 100 knots, pull up level, and then gradually pull up...
TOM: Oh boy. Yep, yep, yep.
BRUCE: Here we go.
TOM: Oh boy. Oh boy. Don't freak out.
Don't freak out. Don't freak out. Don't freak out.
[SHOUTING]
BRUCE: Look up.
TOM: Oh my. Oh wow. [INCOHERENT]
BRUCE: Yee-ha!
TOM: Bruce. Thank you so much.
BRUCE: That was awesome.
TOM: Bruce is from the Edinburgh University Gliding Club, I also need to thank the Loughborough
University Gliding Club and Alistair who brought me up here.
Let's get safely down on the ground. Thank you so much.
That was astonishing.