(Aviat-Modified Super
Stinker)
As I turned off the runway
on to a taxiway, my mind
hardly heard me as I
automatically spoke to
ground control. Most of my
brain was doing arithmetic
of an entirely unrelated
nature.
A voice
inside my head was saying,
"Okay, so I can probably
build up an IO-540 for
around $15,000. It doesn't
have to be a 300 hp
version. And all the
tubing won't cost $1,000.
The wing wood may go close
to $2,000. Cover costs
might..." By the time I
pulled up in front of the
fuel pits and Aviat's Lou
Meyer and VP of
Engineering and Special
Projects, Ed Saurenman met
me, I already had an
approximate total of what
it would cost to build one
of their unbelievable
S-1-11B/Super Stinkers
from scratch. This
airplane is the Super
Stinker on steroids, a
Super-Super Stinker, and I
wanted one badly.
It's no
secret I have a thing for
Pitts Specials. It's also
no secret that at
different times I have
professional ties to Aviat.
Yes, I have predisposed
opinions, but I dare
anyone to step out of that
airplane and not have
similar thoughts to mine:
This is one very serious
airplane. Kirby Chambliss
summed it up after flying
it when he reportedly
said, it flew as if it was
a monoplane with an extra
wing. Coming from a
confirmed monoplane pilot
and National Champion,
that's saying a lot.
But,
let's not get too far into
the aerobatic accolades
before recognizing several
other aspects of the
airplane that may well be
more important than the
fact that it is of
unlimited competition
calibre. First of all, the
airplane is the only
unlimited type airplane we
know of that can be
scratch-built from a set
of plans. What this means
to the homebuilder is that
costs can be kept to an
absolute minimum while the
final result is of world
class quality. By
utilizing Aviat-built
components, the project
can be moved a long a lot
faster, but that's not
necessary for the
budget-minded builder.
Also, the builder doesn't
have to be an acro-nut. He
can just want a simple,
great flying airplane that
he can say he built
himself.
In the
cost control department we
find big variables like
the engine itself. The
version I flew and which
lit my gotta-have-it wick
was powered by a high end,
Monte Barrett custom
IO-540 with 10.5:1
compression and a bunch of
other custom do-dads that
pumped it up to more than
305 hp on the dyno. And it
felt like it. Talk about a
stump-puller! But with an
airplane this light (1090
pounds empty), you don't
need that much engine. In
fact, when I flew the
Super Stinker in 1994,
when it first came out, it
was powered with an stock
0-540 reportedly putting
out around 230-240 hp and
it was still a killer
machine.
In some ways, building up
a six-cylinder Lycoming
these days, is no more
expensive than building a
four-cylinder. Ask anyone
who's building an RV-6 how
hard it is to come up with
a low-cost rebuildable
core for a four-cylinder
Lycoming versus the cost
for a low-end six
cylinder. Cores for the
low-compression 235 hp
0-540 go for a comparative
song with the 250 hp
version only slightly
more. Don't want to burn
so much fuel? Bring the
go-fast lever back a notch
or two.
A lot
of costs can be cut right
at the power-plant.
The
prop is another area where
costs can be cut. The
factory's S-1-11B had the
top dog of aerobatic
propellers bolted up
front, the Hartzell
composite aerobatic
series. This is a very
expensive propeller. Very
expensive! The prototype
Super Stinker, however,
had a garden variety,
two-blade, aluminium
Hartzell on board and,
other than the stresses it
puts on the crank in
aerobatics, is still a
good choice. Between the
two would be the
three-blade composites
from either MT or Hoffman
(available from Steen
Aerolab).
By
doing a little shopping,
this airplane could be
scratch-built for less
than $30-35,000 in Sunday
hell-raising form. The
airframe alone shouldn't
top $10,000 leaving the
final cost question being
one of engine and prop.
Using the
professionally-built
components from Aviat
raises the price but cuts
the building time by an
estimated 60-70%. Almost
every builder would have
to purchase the heavy,
spring aluminum gear from
Aviat as it is beyond the
backyard builder's shop
capabilities
But,
not everyone wants an
unlimited aerobatic
airplane. What about those
of us who don't care about
aerobatic competition? I'm
going to make a flat
statement here: This
airplane is so much fun to
take off and land that if
you do nothing more than
dropping the hammer on
takeoff to get your
adrenaline pumping, the
project would be worth the
effort.
On my
first takeoff out of
Scottsdale, I can honestly
say I wasn't prepared for
the effect of smoothly
moving the noise lever to
the stop. As the Monte
Barrett Lycoming began
pumping out the ponies, I
had the illusion I was
desperately hanging onto
the controls just to keep
from being left behind. I
had to concentrate to keep
the throttle forward so
inertia wouldn't bring my
hand back unintentionally.
But, we're getting ahead
of ourselves.
There have been a lot of
changes in the airplane
since Aviat bought the
rights for the airplane.
Since we flew the airplane
in Homestead, Florida
right after Curtis Pitts
finished it (see Sport
Aviation, May, 1994) the
design has gone through
several ownership changes
before landing at Aviat.
During the in-between
stages, Ed Saurenman, who
then was a partner in
Certification Specialists
in Wichita, put his
CAD-CAM expertise to work
and produced a complete
set of very thorough
drawings for the Super
Stinker. Those are the
plans Aviat is now
selling.
When
Stuart Horn took over
Aviat in January of 1996,
one of his goals was to
return the name Pitts
Special to the glory it
had enjoyed in years past.
His first step was to
purchase the rights to the
Super Stinker. His second
step was to spend a lot of
time with competition
oriented people, both
inside and outside of his
company, to revise the
lines of the airplane to
make them more easily
judged in international
competition. These changes
were primarily cosmetic
and straighten out the
lines of the airplane by
flattening the belly and
squaring off the lower
rudder surfaces. At the
same time they went to a
rakish, flat-wrap
windshield and laid the
seat back 20°. The end
result is a long, really
snarky looking airplane
that, if you put your hand
up to visually block the
top wing while looking at
its side view, it could
easily be a monoplane. The
plans they offer have
Super Stinker outlines
while the finished
components have S-1-11B
cosmetics. Aerodynamically
and structurally, they are
the same airplane.
The
second I stepped down into
the airplane to fly it,
the laid back seat was an
obvious change. In fact, I
could have used another
cushion under me for
visibility but it was
close enough. Lou pulled
the prop through a few
times and we cranked it.
The high compression was
obvious even at idle.
The
Haigh, locking tailwheel
of the Super Stinker has
been replaced by a tiny
steerable unit on a Doug
Dodge tapered rod spring
which makes ground
handling much more
convenient although I knew
I'd have to pay more
attention on landing.
The
inverted "J" control
stick, with its reverse
curve and dangling stick
grip proved to be a
fatigue problem from the
start. Lou said it was
left over from early test
programs and was on its
the way out. Configured
the way it is, even on
taxi there's no way to
slide your hand down the
stick and rest your arm on
a knee. It sounds like a
minor point but I was
surprised how tired my arm
and hand were after I
returned from the flight.
Rolled out onto centreline
with the throttle coming
up, I was treated to the
most amazing acceleration
I've ever felt in an
airplane. Actually, it may
have been the most
acceleration I've felt in
anything which includes
some fairly serious drag
cars. I would have
grinned, but was a little
nervous because it was
obvious the airplane was
getting ahead of me. The
tail blew itself off the
ground as soon as I
relaxed back pressure and
the airplane was off the
ground and screaming
upward before I had time
to think about it. This
was one takeoff where I
was definitely behind the
curve.
Later I
did the math: At that
weight and power, the
power loading was under
4.5 pounds/horsepower. No
wonder it was a rocket
ship!
I
glanced at the airspeed
almost as soon as we left
the runway and the needle
was racing through 100
mph. I guessed the best
rate to somewhere around
90 mph, but the deck angle
was already ridiculous so
I settled on 110 mph as a
climb. There was no VSI,
but I had nearly 3,000
feet between me and the
ground by the time we hit
the other end of the 7,000
ft runway. Aviat claims
4,000 fpm and later timed
climbs showed the rate of
climb may actually be
higher than that. Now I
was definitely grinning!
This
was truly astounding
performance. More
important, other than
feeling I was behind the
airplane, the skill
required during takeoff
had actually been minimal.
The airplane had tracked
straight ahead and my
primary duty had been to
simply grit my teeth and
hang on.
As soon
as it was off the ground,
the quick ailerons made
themselves known.
Break-out pressures around
neutral are low and,
because I couldn't rest my
arm on a leg, turbulence
made the weight of my hand
on the funny shaped stick
a factor. The wings jinked
a few degrees left and
right before I got the
message: be gentle. I'm
glad they're changing the
stick.
The
S-1-11B includes what has
become known as "Super
Stinker Wing Technology."
When designing the wings,
Curtis incorporated his
patented method of using a
thicker airfoil section on
the bottom wing so the top
one would always stall
first. This is the way all
symettrical-wing Pitts are
designed. However, when
doing this for the Super
Stinker, he came up with a
unique aileron design that
gives light, quick
pressures and phenomenal
roll rates without
resorting to shovels which
would hang below the
ailerons. Basically what
he did is hinge the
symmetrical ailerons well
back on their chord to get
the pressure down and then
profiled the nose of the
aileron in such a way that
the sizeable
aileron-to-wing gap
decreases to zero as the
aileron is deflected. This
gives a slightly lower
roll rate near neutral but
seals the ailerons for max
effectiveness as full
deflection is neared. It's
like having on-demand
power steering.
Curtis
also used Super Stinker
technology on the new
wings he designed for
Aviat's newly certified
follow-on to the S-2B, the
S-2C, and the difference
really shows in that
airplane. The new wings
and Ed Saurenman-designed
tail give the S-2C
completely different, and
much better, handling than
the earlier airplane.
Out in
the practice area with the
-11B, the first thing I
did was play with the
ailerons, which is another
way of saying I played
with tumbling my own
gyros, it goes around so
fast. Aviat says the roll
rate is somewhere around
400°/sec, give or take a
little. From my
perspective, as the
horizon was ripping
around, all I can say is
that at max deflection it
is at the upper limits of
my own ability to see
what's happening. The
horizon seemed to be
coming around to level
just about the time I
thought I'd actually
gotten the aileron against
the stop.
The
airplane is dead neutral
on every axis, so you
don't leave it unattended
for long periods of time.
Duck your head to study a
chart for too long and
you'll find yourself
pointed somewhere else
when you bring your head
back up.
The airplane's aerobatic
capabilities are so far
beyond my own that it made
my feeble efforts
seem...well...effortless.
The inside-outside
pressures aren't perfectly
balanced, but are so close
that when doing rolling
360° turns, hitting the
points was no sweat and I
wasn't conscious of having
to fight pressures while
pushing the stick forward.
Outside loops, from either
top or bottom seemed to
happen almost
automatically because it
clawed its way up the
backside so easily. Its
vertical maneuvers seemed
especially easy. Doing
vertical rolls has never
been one of my strong
suites, but it seemed to
settle into an up line and
give me all day to get it
right before going for the
ailerons. I'm always
amazed when I get two
vertical rolls out of
anything, but here it was
child's play. Three was
just as easy and I was
going in at only a little
over 200 mph and could
easily fly away at the
top.
The
snaps took a little while
to figure out because it
has so much aileron. It
rolls so fast, its hard to
tell which is snap and
which is aileron in the
roll. I was going to try
some without aileron, but
got side tracked.
The most impressive part
of the airplane (other
than its willingness to
keep going up hill) was
the absolute lack of any
kind of rolling inertia.
It starts and stops rolls
instantly. Instantly!
Point rolls in any
direction, up, down or
anywhere in-between, are
so easy they should be
illegal.
I found
the semi-supine seating to
be interesting but I
didn't know how
interesting until I got
back on the ground. The
airplane has one of those
new fangled digital,
electronic "G" meters and
I couldn't tell how much
"G" I was actually pulling
because the meter was in
recording mode or
something. I was using
pulls and pushes that felt
more or less normal to me
and was absolutely no more
aggressive than usual
because I have a bad habit
of making myself sick. So,
I was just flying to my
usual limit. Later, when
Lou checked the "G" meter,
I had put 8 positive and
5.1 negative on it. That
really surprised me. At no
time did I feel as if I
was working the airplane
that hard because my body
wasn't feeling it.
Coming
back into the pattern, I
initially had to work to
get the speed down to an
acceptable pattern speed.
This meant pulling back to
about 14" of manifold
pressure which was still
about 130-140 mph. It
wasn't until the throttle
was practically closed
that speeds came down to
110-120 mph where I wanted
them.
On my
initial landing, even
though I was in as close
as I would be for a normal
Pitts, power-off landing,
it became immediately
apparent, power-off with
that big prop out there
wasn't going to work. The
second the power was
against the stop, the
airplane decelerated and
pushed me forward in the
seat and the ground
started up immediately.
With
just a touch of power, the
airplane rode through a
turning approach as though
it was on rails. I used
110 mph initially with 100
mph over the fence. As I
intersected centreline and
rolled wings level, I
slowly killed the power.
The airplane settled into
a three point position for
a few seconds then
dribbled onto the ground
with a firm series of
clunks and a slight scream
from the tiny tailwheel
bearing.
Out of
three or four tries, all
but one saw me kissing
gently off the mains and
getting a little
hippity-hop. Fortunately,
the spring gear is nice
and stiff so I had no
problem telling what the
airplane was trying to do.
The airplane was amazingly
well behaved, especially
considering I was working
with an 8 knot, quartering
tailwind which always
makes tailwheel airplanes
do quirky things on
landing. Naturally, as
soon as I quit, the tower
changed runways.
The
first touch and go was
really a hoot and will
stick in my mind for a
long time. I was working
on ironing out the hippity
hop and, without thinking,
briskly moved the throttle
to the stop for the go
part of a touch and go.
Instantly the airplane
slapped me on the back
side and was in the air.
Instantly! I knew a 152
was somewhere ahead of me,
also in a touch and go, so
I slid to the right where
I could see him. I was
trying to keep the nose up
so I wouldn't catch him,
but I'd forgotten the
throttle was still against
the stop and all of Monte
Barrett's pumped up ponies
were still roaring at full
bore. I caught sight of
the 152 quickly growing
bigger to the left of my
nose and I was already
well above him. I
hurriedly asked the tower
for an early crosswind and
ripped into a tight turn
across behind the 152 as
soon as they rogered. I
glanced at the altimeter
as I came behind the
Cessna: Pattern altitude
is 1,000 feet and I was
already at 1,500 feet
barely half way down the
runway. Rock and Roll!!
At the
Aviat Fly-in at the
factory in Afton, Wyoming
in October of last year
(this year it's the second
weekend in September),
several pilots evaluated
the 11B and all were
impressed. That however
was at 6,000 MSL altitude.
They ought to try it down
here. At 1,500 ft MSL it
is an amazing airplane.
Even
though most of the talk
about the airplane centres
on its aerobatic
capabilities, I keep
coming back to its
possibilities for the
average sport pilot.
Especially those on a
budget. It would cost
little more to build this
airplane than any other
single place biplane and
less than almost any
composite kit. Although a
two-blade Hartzell prop
would raise the costs over
other projects with fixed
pitch props, that would be
partially offset by the
lower cost of the
six-cylinder core.
For
those builders in a hurry,
the components offered by
Aviat Aircraft are all in
finished form. The
fuselage is finish-welded,
epoxy coated and ready for
installing systems. The
same is true of all other
welded components. The
wings are assembled and
ready for cover. Aviat
Aircraft, however, wants
to make it clear, they are
only making these specific
components, not kits.
As
homebuilt airplanes go,
the S-1-11B/Super Stinker
is low-demand in the
building department and,
once the thrill factor is
overcome, only slightly
more demanding than a
Citabria to takeoff and
land. However, it would be
absolutely imperative for
those who have no time in
something with a lot of
power and light controls
to get some dual
instruction in a two-place
Pitts before attempting a
first flight. All the
Champ or Cub time in the
world isn't going to help.
The
S-1-11B is a comfortable
airplane and cruises at
anything you want
depending on the amount of
fuel you want to burn.
It's hard to get it much
below 150-160 mph in
cruise at any logical
power setting and Lou
Meyer says he flight plans
190 mph (165 knots) at
21-22" which is down
around 55% power. It holds
35 gallons, so, with a
"normal" 250 hp, O-540
burning 13 gph, or less,
at normal, not reduced,
power settings, you've got
a solid 2.7 hours of fuel.
Aviat
Aircraft is still offering
plans for the old Pitts
standard, the S-1S, which
is a huge amount of
airplane for those wanting
performance on four
cylinders. However, for
those wanting the absolute
ultimate in homebuilt
amazement, the S-1-11B is
going to be hard to beat.
Of course, it's a Pitts.
So what else did you
expect?
SPECIFICATIONS
Seats 1
Empty Weight 1090 lbs
Maximum Weight 1500
Competition Weight
1350
Wing Span 18 ft
Length 18 ft. 2 inch.
Height 6 ft. 2 inch.
Wing Area 110.3 Sq. Ft
Engine IO-540 Lycoming
Propeller Hartzell
HC-C3YR-1A/7690
Max Fuel 35 Gal
Oil 12 qt.
Landing Gear Spring
Aluminium
Tailwheel Steerable
Wing Loading 12.2
lbs/sq. ft.
Power Loading 4.5
lbs/hp
Performance
At competition weight
(1350lb.)IAS @ sea
level w/300 hp
Never Exceed Speed 199
kts (229 mph)
Stall Speed 56 kts (64
mph)
Max Speed 181 kts (208
mph)
Rate of Climb 4,000
fpm
Roll Rate 400°/sec