How Low to Spin??

(Mark James Boyd) wrote in message news:412eb379$1@darkstar...

You have a BBQ and beer cooler in the nose? How inventive...
I suppose your landouts are quite a party...

You bet!

In an aileron roll, the head is moved. In max dutch rolls
45 to 45, the head is moved. So again, I guess you are agreeing with
me that high roll rates and steep banks can induce vertigo.
If you don't agree. Take a pax at night cover all instruments.
Head perfectly straight ahead. Close eyes. Then max roll rate
left 45 bank, then 90 degrees of turn, slow roll right,
and tell them to open eyes while level and recover. Fun, huh?

No, I do not agree with you that high roll rates and steep banks
induce vertigo. It's the disconnect between what you see, and what
the inner ear feels, that causes vertigo. If you can see the horizon,
then as long as you don't make a sudden movement of your head in a
"wrong" direction (which depends on which way the plane is moving"),
you should not experience vertigo. But close your eyes, or fly into a
cloud, and even a small roll or pitch rate can induce vertigo. Unless
you are thermalling with your eyes closed (reminds me of some pilots I
know!) or in a cloud (not common in the US), vertigo should not be a
problem in a glider, no matter how fast you roll or steep you turn.
Now, I will caveat that statement with the observation that it is
possible to trigger vertigo in some individuals by a sudden (and I
mean unusually rapid) head movement at the same time as the plane is
rolling - and that should be taught to pilots, just like IFR pilots
are shown how lack of outside references can lead to vertigo. But you
shouldn't be jerking your head around while flying!

And yes, lack of coherent outside reference is important too.
Pretty easy to get when looking at clouds and fog and mountainsides...
And sometimes tough to correct without...
wait for it...moving your head

You don't need a lot of outside references to maintain your attitude -
but yes (as I say above), when you lose outside references, you are
vulnerable to vertigo. But to get a glider into a situation where
there are no useful outside references is a bad thing.

The only disadvantages I can find of very effective spoilers a

1) If they ain't locked for takeoff, a gnarly pio
2) If they don't have very fine controls, hard to be precise
about glide slope.
3) If at max out, landing flare is VERY fast, and stall speed
increased

1. Use a checklist. Oh, and why is the tow pilot fanning his rudder
at me?
2. G-103s are horrible in this respect. Most gliders are fine.
3. You don't have to land with them all the way out, but it's nice to
have the option.

Kirk