|
Some random thoughts on spin
recoveries:
My up front disclaimer is that I am not a IV/IV-P
flyer, have no significant level of expertise in the plane and my comments are
generic in nature to hopefully give some food for thought. As a former
military pilot, I have a fair amount of experience spinning airplanes, both
props and jets. While I've been surprised by some of the spin entries and
exits, the ratio of the two is 1:1 for me, so in that regard I have been
successful in dealing with them.
I'd also like to note that I've never entered
a spin unintentionally and that I've also never attempted one where I wasn't
either wearing a parachute in a plane designed for easy egress or sitting on an
ejection seat. I have no intention of ever exploring that part of the
flight envelope in my ES regardless of my experience.
In the case of the IV-P, there are a few
knowns from my own observations and what I've learned from about five years
reading the LML:
1. When Dave Allen, acting as a
professional test pilot for an ES builder, entered an unintentional spin at
a mid CG location, he observed that he didn't believe the ES has enough elevator
or rudder to recover from a spin at an aft CG. The IV's have a much
smaller horizontal stab and elevator than the ES, which would make recovery even
more problematic.
2. The ES's typically have an empty CG that's
near or right at the forward limit and they're nearly impossible to load
such that the aft CG limit is exceeded. The IV's have a more aft
CG to start with, which moves even further aft when the gear is raised.
Has anyone ever measured the CG shift with the gear up? My guess is that
some aft limit loaded planes may actually go out of limits when they raise
the gear.
3. It's a fact of life that the further aft
the CG is in just about any plane I can think of, the more difficult it it
becomes to recover from a spin. It occurs to me that anything you
could do to move the CG forward would somewhat enhance your chances of recovery
from a spin if you have sufficient altitude to attempt a recovery, as it appears
that the IV-P over the Grand Canyon had. With that in mind, have any of
the experienced IV flyers/instructors ever suggested dropping the gear to
help move the CG forward in the event of a spin?
4. On the aerodynamic side, a further aft
center of lift on the wing will help get the nose lower. Lowering
flaps moves the center of lift aft. Has there ever been any suggestion to
partially lower the flaps on the IV's in the event of a spin to help lower the
nose (and angle of attack)? Worrying about a possible flap overstress
seems to be a moot point when lives are at stake.
5. We all know that the p factor from our
props gives a push to the left side of the vertical stab, necessitating varying
degrees of right rudder to counter it. If you happen to enter a spin
that's turning to the RIGHT, using power would seem to me to offer some
additional aerodynamic help in stopping the rotation. CAUTION: There's the
very real possibility that a recovery of this nature could rapidly develop into
a spin in the opposite direction if the controls aren't neutralized and
power pulled to idle at the first sign of recovery, so a pilot would have to be
spring loaded to recognize a recovery.
There's no substitute for training and you can't
train for spins an any Lancair. There's a huge difference between a
reasoned, experienced reaction to a stall, post stall gyration, departure
or a fully developed spin and a reaction of stark terror and panic because you
find yourself in a situation you've never seen before. We can talk all we
want about proper training in Lancairs, but unless you've had military
experience with all of this stuff, proper high performance training for us as
pilots should include spin training at an established aerobatic
school. It's a small investmment that will increase not only our awareness
of the elements of a spin, but avoidance of them and the proper recovery from
them. While that won't guarantee that you'll be able to recover an aft
loaded IV-P or any other plane for that matter (altitude most often being the
limiting factor for recovery), it will certainly offer us the best chance at
it.
I welcome the comments of our experienced IV
drivers and teachers out there.
Skip Slater
N540ES
|