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A few hours after hooking up with Byron we were
somewhere out in the eastern Oregon wilderness which looks
surprisingly like a desert, but after drenching rains, it was all
mud. We were sitting on top a small mesa with the engine idling and
out in front of me, maybe 250 feet away, was a distinct semi-ditch
where an old stock road had eroded into sharp edges. Half way to the
ditch was a narrow swale I'd have to ride through. The entire
undulating surface was low sage brush and mud. Lots of mud.
Byron was sitting in the back seat with no control
stick and no throttle. He had no way to correct if I screwed up. The
best he could do was scream into the intercom. I was going to have
to get off on what was in front of me and then come back around and
land on what was behind me. The 150 feet or so behind me started at
a sheer cliff, went up hill for 30 or 40 feet, and then plateaued
with the ditch at the far end. We had about 400-500 feet of runway,
mud for a braking surface, and very little wind on the nose to
help.
Was I nervous? Surprisingly, no, I wasn't. I'd seen
Byron make three approaches and landings and for some reason, the
airplane gave me so much confidence I wasn't worried. Byron must
have felt the same way because I was the first person outside his
company to occupy the sole pilot seat and he was turning me loose in
what I thought was a marginal situation. Later I was to find that
wasn't the case. 500 feet wasn't even close to being marginal.
Byron's voice was somewhere in the back of the Bose
headsets (which are an absolute necessity!) but I wasn't hearing it.
As the throttle went in, I was listening to my own voice inside my
head coaching me as if I was a student. With 400 horses streaming
out of the IO-720 Lycoming and over the tail, I just held on and
tried to hold the tail wheel just barely out of the mud.
There is no way you can imagine what it feels like
to be bounding over rocks and sage brush and down into a swale,
while hanging on to a raging bull. My mind was speaking to my right
hand, asking it to keep gently applying back pressure, while willing
the airplane off the ground and away from the awful beating we were
taking.
The big tires soaked up an amazing amount of what I
knew were airplane destroying impacts, then we bounced once and were
airborne. I held that attitude for a second, letting the airplane
accelerate until it felt as solid as it had at cruise, before
banking steeply around as we came out over the yawning edge of a
small canyon. As I banked I glanced at the airspeed for the first
time. 55 knots! I thumbed the electric trim on the stick forward for
a second and grinned. At that speed the airplane felt absolutely
stone solid.
The confidence the Sherpa gave in that situation
was truly awe-inspiring. I don't ever remember an airplane that felt
that good that slow or that early in a flight It just seemed so
right that I immediately felt comfortable, which is not the way I
usually feel before even making the first landing. I'm not one of
those super pilots who are good in every airplane and this airplane
couldn't have been further removed from my usual mount, a Pitts
Special, if it tried. Here I was, 55 knots, 100 feet over a desolate
wilderness in a 30 degree bank in a machine that weighed nearly two
and a half times what my Pitts does and I felt good about it. Really
good. That says something for the airplane.
I stayed low and bent it around in a tight pattern
heading for the other end of our so-called runway, which was nothing
more than a piece of raw wilderness. I punched the rest of the flaps
out (40°, slotted-Fowlers) and trimmed for 50 knots as I turned
final.
The vertical edge of the mesa and the short,
up-hill ramp which was my intended touch down spot was well up in
the windshield. It was as if the airplane had no nose the visibility
was so good. Also, the airplane was so speed stable, I found cross
checking the airspeed was a waste of time. As long as I didn't move
the nose, the needle stayed stuck in one place. I trimmed it back to
45 knots, licked my lips and visually fixated on my landing
stop.
Not once in my entire life have I ever been in that
type of situation, one which demanded the airplane hit exactly where
I wanted and for which the consequences of failure were so great.
Land short and we'd be a jumbled pile of junk on the edge of the
mesa (or so I thought at the time) and the multi-million dollar
investment of Byron Root and his partner Glen Gordon would be gone.
Land long and I'd go slithering through the mud into the road/ditch
unable to stop (or so I thought at the time).
I flew an abbreviated final but it took only a few
seconds to realize the airplane absolutely followed the throttle,
what little I was using of it. We weren't grinding along nose high,
with the power screaming to keep us in the air. Rather, we were
simply in what would have been a steep glide but we were using just
a little power to flatten it out and overcome the drag.
At 45 knots everything is happening in slow motion
and it seemed as if I had all day to gently move the power in and
out to draw a straight line to my landing spot. Then, suddenly we
were there and the spot loomed large in the windshield. I gently
brought the nose up and eased the power off (Byron had demonstrated
it needed just a bit of power to flair). We flopped into the mud
with me sucking the stick into my gut and the airplane had nearly
stopped rolling before it dawned on me to get on the brakes.
I let out the breath I had taken on downwind and
grinned about as wide as I believe I have ever grinned. What an
absolute, positive, unqualified blast! I looked ahead at the
road/ditch I was worried about and realized I had more distance left
to takeoff than I had the first time. We hadn't used much over 150
feet on landing and I didn't know what I was doing! That says a lot
for the airplane.
I made a bunch more take-offs and landings on top
that mesa before trading places with Byron so he could show me how
the airplane really flew.
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I was feeling like a bush pilot until we
dropped down into a canyon and started buzzing along right
over a serpentine river 1,000 feet below the rim. We did our
eagle routine and twisted and turned right along with the
river. As we did, Byron was pointing out gravel bars and small
spaces along the bank they used as landing spots while
fishing. That's when I knew I was no bush pilot and why Byron
was so willing to let me flop around in the mud on top the
mesa...the spots he was pointing out weren't large enough or
smooth enough to orchestrate a crash, much less a landing. At
least that's what I thought.
Just to prove a point, Byron pointed out a
small speck of gravel sticking out of the water and said that
was a good spot for steelhead fishing. He ran out all the
flaps, pulled up over a rock ledge sticking out of the side of
the canyon, floated around in a tight turn and dropped down
close to the surface of the water. From the back seat, I never
saw the gravel bar until our big baloney tires crunched onto
it at the edge of the water. We bounded along over the
incredibly rough surface for less than half the length of the
gravel bar. I paced off our landing roll as 110 feet. We were
two people, 85 gallons of gas, 65° F and 3,500 ft MSL. I had
trouble pacing off the distance because the surface was
comprised entirely of water-worn rocks the size of cantaloupes
and I was afraid I was going to break an ankle!
This was the kind of surface that, according
to Byron, eats stock Super Cub structure and it was easy to
see why. Even with fat tires, the Cub's structure just wasn't
designed for those kinds of loads, especially around the tail
post.
Byron also says fully loaded to 4,750 pounds
(2,200 pounds usable) the airplane will still get into or out
of anywhere you'd dream of putting a Super Cub and loaded to
lower weights can go places you wouldn't dare take a stock
Super Cub. In most situations it will even out fly his big
engine Cub.
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Undoubtedly the most impressive part about
the airplane is the ease with which a pilot could learn to
handle it in the bush environment. The controls are very
normal feeling, meaning neither light nor heavy and the
airplane responds surprisingly quickly for an airplane that
size. They have a number of aerodynamic changes in the works
to be completed before certification which include a longer
tail moment to take care of the reduced tail efficiency at
full flap extension and a larger wing with more flap. Their
aerodynamicist says they will trim another 6 knots off the
stall speed with the new wing. Considering they have radared
the airplane as flying 34 mph (power-on), a 6 knot speed
reduction would make the airplane even easier to get in and
out. In fact it would be the next best thing to a helicopter,
which it is already. Byron says their goal is an airplane that
can get off in less than 100 feet, zero wind with 500 pounds
on board. As it is, with a ten mph wind they can do that in 72
feet!
It's this last point, the comparing of the
airplane's utility with that of a helicopter, that continually
bounced through my mind during the day. With the possible
exception of landing on roof tops and tennis courts, the
Sherpa could do probably 80% of what a helicopter does with a
fraction of the purchase and maintenance cost and with much
less chance of equipment breakage in the field.
When we were enroute back to home base I
noticed a curious change had taken place in my mind. I found
myself thinking like I used to when flying a Super Cub on skis
after a major snow storm. In that situation, with skis and
lots of snow, everything flat is a runway. You can land
everywhere. On the way back with the Sherpa, I'd look down and
see a small flat spot and think, "...we can land in that
easy..." It was a very comforting feeling.
And when I saw a small remote town without a
runway, I realized it didn't need a runway for emergency
medivac situations. There were a dozen flat spots within city
limits where the Sherpa could land with no sweat. A football
field becomes an airport...literally!
The Sherpa is also faster than all but the
most exotic choppers. We were showing 120 knots, which at that
altitude and temperature was a shade over 140 knots true.
Incidentally, while we were cruising along at altitude, the
visibility in all directions was amazing. The nose is way, way
down and the glass doors let you look straight down. Byron
said the fish and wild life boys who were evaluating the
airplane would go for the standard 29 x 11 x 10 tires because
they wouldn't block as much of their view. He also said they
were working on a curtain/shade for over the pilot's head
because he is out in the Plexiglas and gets pretty hot.
Ignoring the airplane's ability to work in
the bush, I'd be very surprised if government agencies, both
ours and other country's, didn't jump on this bird as one
which could replace helicopters and other fixed wing airplanes
for a lot of use where ultra-short runways aren't even a
factor. At 45 knots it is slow enough to do bird counts,
pipeline patrol, border surveillance and on and on. It is also
an airplane almost anyone can fly easily since its ground
handling is so benign.
I think these guys are really onto
something!
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Sherpa Tech
Specs
Structurally the Sherpa is a rag and
tube fuselage and metal wings (airfoil 43015A Modified)
with 120 gallon (to be increased to 180 gallon!) fuel
tanks. But this is a serious tube fuselage...the
longerons, for instance, top and bottom are 1 1/4 "x
.058". Everything about the airplane is built tough to
take a beating.
The landing gear, besides being massive,
utilizes a shock absorber along with the bungee's
to dampen rebound. This shock is not an air/oil
oleo because that wouldn't let the gear come
back to rest quickly enough after hitting
a rock. The gear might still be partial extended
when it hit the next one. The Sherpa shock
uses urethane washers which have a more immediate
response.
The elevator trim is electric utilizing
dual screw jacks and the flap motor looks big enough to
move a house. It takes about 9 seconds for extension and
ten to retract them.
The Lycoming IO-720 engine is an enigma
to most of us because most of our knowledge
of it comes from its use in the Comanche 400.
There it had a less than enviable reputation
largely because it was tightly cowled and
prone to over heating. The Sherpa team has
utilized the experience of numerous Piper
Brave ag operators in the area which swear
by the engine. They say they go to 2,000 hr
TBO will few problems. While we were flying
the airplane, in ten hot-starts, it never
hesitated.
They have gone through a number of
propellers and have yet to finalize the selection. The
four-blade they had on the airplane during our
evaluation wasn't putting out as much thrust as their
earlier Hartzell three-blade had.
Some foreign governments have expressed
an interest in a turbine installation, but no one at
Sherpa is wild about the idea. Besides doubling the cost
of the airplane, they say its not going to improve its
performance enough to justify the cost except possibly
on floats.
The tires can be either the standard 29
inch, aircraft versions or the baloney skin tundra tires
like we flew. Those are actually four-wheel truck tires
with the tread ground off mounted on 15 inch aluminum,
one-ton Chevy truck rims. They say they have been flying
that type of tire for nearly 15 years with little or no
problems. The brakes are two, three-spot calipers on
each wheel.
The tail wheel is a standard
500 x 5 main gear unit and the tail wheel
assembly is something that is undergoing continual
revision. Because of the airplane's weight
and the surfaces they intend to work off of,
nothing commercial has stood up so they've
left a lot of tail wheels up in the canyons.
Presently they are testing their own assembly
which utilizes a CNC'd 7075 pivot with a 4130
weldment fork.
The airplane is currently configured
for a 1-2-2 seating arrangement but the seats are
actually wide enough for three across in a tight
squeeze. The single front seat will be changed to a side
by side arrangement for those who want it along with a
sliding, side opening door in the rear of the fuselage
for passengers, cargo or litter cases. Knowing what
little I know about bush flying at this point, I'd
rather have the single pilot seat so both sides of the
nose are visible on landing.
The floors are a honeycomb sandwich and
production airplanes will have a multi-use track system
which would allow easy removal or repositioning of seats
as well as cargo tie down. The cargo space aft of the
pilot's seat will accept the equivalent of five 55
gallon drums. Useful load is just short of 2,200
pounds!
It's some kind of hoss!
Budd Davisson. EAA/Sport
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Sherpa Aircraft Manufacturing, Inc
34100 Sky Way Dr.
Scappoose, Or 97056
Phone 503-543-4004
Fax 503-543-4005
E-mail: sherpaworldwide@att.net
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