Geoff Roberts wrote:
> Very. One of the guys I spoke too was literally chalk white when he got
> out of the aircraft.
> After years of flying a docile little Cherokee 140 he'd never
> experienced either a stall related
> snap or seen the effect of aileron on a dropped wing in a Cessna.
When I was a primary student it was standard practice to do stall training
in PA28s at 3000 feet AGL. Then came the Tomahawk, with it's Really Nifty
Wing (literally - it was a technical work of art) That Wasn't Built The
Way The Engineers Designed Nor Like It Was On The Certification Articles
Given To The FAA. Without getting mind-numbingly technical the airfoil
required a stiff wing structure to work well at high angles of attack but
as manufactured it was actually quite soft and would literally deform
at high alpha, with the result that one wing would stall well in advance
of the other in a nondeterministic and quite violent fashion.
We learned that being half-a-ball out was sufficent to make the airplane
perform a perfect, if uncommanded, snap entry into a spin. This discovery
was made by the chief pilot of the FBO (one of these 22,000 hour
Decathalon drivers who had perfected the "I hate talking to ATC" voice and
made one entry a year into his log book based on how much money he made)
with an eight-hour primary student in the left seat. He came boiling in
off the ramp with eyes like saucers:
"The...Tomahawk...IT SPINS!"
Consequently all students had to demonstrate spin proficency before being
allowed to solo in The Tinfoil Pig, which was an experience in itself.
Unlike the 150 which has an empenage of consequence, the Tomahawk's is
attached to the rest of the airframe via a stylish little wasp-waisted
thing which has the structural integrity of cooked pasta. When you spin
a Tomahawk it's like sitting inside a barrel while someone whacks on the
side with a baseball bat; if you sneak a peek through the rear window you'll
se why: the empenage deforms (well, lags behind the spin) until it gets wound
up enough that it snaps back into place with a resounding "bang".
The problem was eventually "fixed" through an AD which required attaching
stall strips, a kludge which causes the wing to stall well in advance of
it's design stall angle of attack and before the wing would start to deform
(think "It's not a bug, it's a feature").
[snip]
> About sums it up. I did a Cherokee endorsement when I moved to Broken
> Hill in the 70's, and all
> they had was Cherokees, I used to fly a Cherokee Arrow
> (PA28-180-Retractable) home on some weekends, it was a nice ride. But
> the short field performance sucked and you can't taxi them through
> gates up to a house. (Both very important in a bush aircraft in this
> country.)
Which version of the 28R? The only version that I found to be a
ground-loving pig was the Arrow IV with that god-awful T-tail that
the marketing guys thought looked so stylish but which moved the
elevator out of both the propwash and ground effect. Both short and soft
field departures suffered (you could hold the yoke in your lap but
the nosewheel wouldn't unweight until, oh, 40 knots) and the famous
short field landing over 100' obstical for the commercial checkride was
more like a carrier landing as you ran out of elevator authority
just about the moment the mains touched.
[snip]
> I first learnt
> how to spin in that, since spins are classed as an aerobatic manouevre
> in this country - and a stock C150 isn't cleared for them - they teach
> you how to recover from an INCIPIENT spin instead. Not sure I'm
> comfortable with that, spins are very disconcerting the first couple of
> times you encounter them, it should be a requirement.
In the US spins aren't required for any certificate. The CFI ride
requires either that you demonstrate spin competency OR have a logbook
endorsement indicating that you've previously demonstrated it. In
practice the only time they'll make you demo one is if you fail to
harp on stall recognition and avoidance during your checkride. If you
take your checkride with an FAA examiner (as opposed to the somewhat
insane DE I used) they'll NEVER ask you to demo one.
Part of the rational (I use the term loosely) for not teaching spins
is that, according to The Commandments Handed Down By The Burning Bush
Of Oklahoma City (the FAA) we are to teach stall recognition and avoidance,
hence people will never see a full stall, hence they won't ever see a spin.
When you ask about the classic problem of someone mashing on the rudder
because they overshot their base-to-final turn you get the "well, they'd
be too low to recover anyway" lecture. I'll teach them to anyone who
asks, but we'll usually do wingovers and cross-control stalls first.
Cheers,
Chris
--
Chris Kennedy
chris_at_mainecoon.com
http://www.mainecoon.com
PGP fingerprint: 4E99 10B6 7253 B048 6685 6CBC 55E1 20A3 108D AB97
Received on Tue Apr 11 2000 - 10:20:42 BST