Barrows Bearhawk 260
A Case Study in Refinement
by Budd
Davisson, courtesy of
www.airbum.com
Nasty!
That's the only to describe the wind,
as I lined up on Winter Haven's long
runway. Nasty! It had to be gusting
15-25 knots and snapped from slightly
in front of the right wing to behind
it. Yeah, this was a great kind of day
to fly a new airplane for the first
time. NOT!
On the one hand, it
was a shame the day was so bad,
because I'd been looking forward to
this flight for a long, long
time....for five years, to be exact,
since I last flew the 180 hp version
of the same airplane, the Barrows
Bearhawk. This was a new prototype
with lots of subtle refinements and,
more importantly, 260 hp driving
through a three-blade prop. The up
side to this kind of day was that the
nasty conditions would let me see the
airplane at it's worse. There's no
tougher condition than a
sometimes-quartering tailwind to find
out how evil a tailwheel airplane can
be.
First,
some background. The first time I flew
the airplane was for a pirep in EAA's
Sport Aviation. At the time, editor
Jack Cox and I agreed that the
four-place, straight forward airplane
made a huge amount of sense. 1200
pounds of useful load, good cruise
speed, even better good looks and it
could be scratch built, which would
allow a builder to get into the
finances of the project at a rate he
could afford. That's one of the
downsides of the kit approach: bigger
chunks of change are required to make
it happen. With a scratch built
airplane, such as the Bearhawk, you
can squirrel away a couple hundred
bucks, spend it on tubing and have
enough to build the tail surfaces at
your own speed. Of course, now that
AviPro Aircraft, Ltd. has introduced
complete kits for the airplane, a
builder has the option of building
fast or building cheap.
At the time the
first report came out in October of
1995, the designer, Bob Barrows (for
more of his background, go back and
read the first report), had sold
exactly 12 sets of plans. Once the
word went out on the airplane, it
appeared that many others felt the
same way Jack Cox and I had; the
airplane scratched enough aeronautical
itches that plans sales really took
off. As of this writing, May, 2000,
Bob reports they are closing in on 500
sets of plans sold.
The
airplane is fervently supported by the
several hundred builders who are
convinced they are building the most
practical airplane in the homebuilt
catalogue, and they may be right.
If there is a
frustrating aspect to scratch building
any airplane, rather than kit-building
(a situation that may change for the
Bearhawk in the near future, more on
that later) it is that it takes a
longer time for the first airplanes to
start showing up at fly-ins so very
few builder/pilots have had a chance
to fly the Bearhawk. They are building
it on faith. In fact, many report they
are building it based on what we said
in that first pilot report. That's a
pretty heady responsibility and it was
lurking in the back of my mind as I
sat at the end of the runway watching
the windsock whip back and forth.
Would this new version of the airplane
live up to my memory of the first one
and would it justify the enthusiasm of
the rapidly growing group of Bearhawk
builders?
Since Bob had only one set of brakes
in the airplane and a centre throttle,
I opted for the right seat, when we
saddled up. When taxiing out, I was
pleased to see the tailwheel ratios
(he even built the tailwheel itself)
was dead on the money and the airplane
reacted "just right" to rudder input.
Not too slow not too quick. And the
visibility over the nose was great. If
I'd had a one inch cushion, the entire
taxiway would have been in view.
Without brakes, however the residual
thrust of the smoothly idling 0-540
driving through a Hoffman hub with
Bob's homebuilt composite blades, was
enough that I had to ask Bob to poke
the brakes from time to time to slow
us down. Oddly enough, even with the
hard wind, I didn't need brakes while
taxiing crosswind. At the time, I
didn't think much about it, but now,
after the flight, I realize the
airplane was telling me that it had
plenty of rudder even when slow.
Time to go flying!
I smoothly started the power in being
mindful of what the wind was likely to
do to me. I had purposely hunkered
down a little so the side of the
runway cut the edge of the cowling
which gave me a definite reference so
I'd catch the nose if it tried to move
even a little. The instant the
throttle started in however, I nearly
forgot about the runway reference
because the acceleration was
absolutely amazing! It really was a
rush and almost instantly I felt the
tail getting light. Amid the clamour
of an airplane that was obviously
gathering momentum much faster than I
was thinking, I unloaded the stick
intending to gently lift the tail off
the ground. Then, just as the
tailwheel started to leave the ground,
the airplane lunged into the air
clawing upwards at a truly ridiculous
angle. The takeoff actually surprised
me by happening long before I expected
it. Bear in mind, I make an average of
five takeoffs a day in my Pitts, seven
days a week, yet this airplane
surprised me, which is saying a bunch.
I glanced over at
the airspeed and we were already
blasting through 90 mph with the nose
pointed up at an almost scary angle.
Bob has said rate of climb is 1700
feet per minute, but that must be with
a full load, because we were well over
2,000 fpm with two guys and full fuel.
On top of that, I doubt seriously if
we rolled much over 250 feet. Maybe
much less. This is where the nasty day
worked against us: I would have loved
to have played with short field
techniques on a more normal day. I'd
be willing to bet the ranch that using
a three-point takeoff and half flaps,
that thing would leap off the ground
in some unbelievably short distance,
especially with the wind down the nose
instead of coming down the wing tip.
I'm certain that as the throttle went
forward, I could feel the prop blast
"blowing" the mid section of the wing
and that most of the wing came up to
flying speed as soon as full power was
in. The rest of the takeoff roll was
just waiting for the rest of the wing
to catch up.
The instant the airplane launched
itself and we were rocketing upwards,
I threw a thumbs-up signal over at Bob
and yelled, "Fantastic! Absolutely
fantastic!" To say I was loving it was
an understatement. Now, THIS is the
way airplanes are supposed to takeoff
During the takeoff
roll, I wasn't conscious of making any
rudder movements. This might have been
because the right crosswind was
cancelling out any torque induced turn.
In a straight wind situation, I would
expect the right foot to be keeping
the airplane straight with a slight,
constant pressure.
We hit 3,000 feet
in nothing flat and, as I pushed over
and reached overhead to roll in the
trim, I yelled at Bob (he doesn't
believe in intercoms, or electricity
or any of the other "luxuries" most of
us do, which is why his airplanes are
so light) that I was going to set up a
23 square cruise. He shouted back
(it's really noisy in the cockpit and
ear plugs are a must) that he'd like
me to see his normal cruise first.
Before we get into
the "normal cruise" thing, you have to
understand Bob Barrows. Bob doesn't
think speed is worth anything, which
considering how little effect it has
on time actually spent enroute, he's
probably correct. He does, however,
think money IS worth something, so he
doesn't think a pilot should spend any
more than is absolutely necessary.
This includes keeping the airframe
cost down by eliminating anything
costly (he makes his own tail wires
out of turned down and threaded 1/4"
4130 rod and eliminates the clevis
forks by threading thick wall tubing.
See the detail shot. Very effective!).
He also eliminates cost by eliminating
anything that uses electricity and by
keeping the fuel burn down. Simplicity
and low cost are his commandments in
everything he does.
When he set up the
"Bob Barrows Low Buck Cruise
Configuration" he had to fiddle with
the prop a little as it didn't want to
immediately adjust itself. This later
proved to be a couple of blocks inside
the hub that were dragging. His final
setting was 19" manifold pressure and
1900 rpm. This is somewhere well under
50% power, which, as a by product,
brings the noise level way down
because it feels as if the engine is
at idle. The speed stabilized at about
117 mph indicated for about 125 mph
TAS. This isn't exactly lightening
fast, but, Bob grins his
characteristic grin and defends it by
saying, "Yeah, but I'm only burning
7.5 gallons an hour."
Considering that a 180 Lycoming in
cruise burns about 9 gallons/hour this
is something worth thinking about. I
later measured its 23 square cruise
(approx. 60%) at about 155 mph TAS, at
which point it's burning about 13
gallons/hr. Over a 300 mile trip, the
speed difference would save about 25
minutes but the fuel burn would be 8.6
gallons more. At $2.30/gallon that's
$19.78 more. In other words, it cost
$1.32 for each minute saved.
Translated into hours saved, that's
$79/hour saved. Put in those terms,
it's hard to fight Bob's logic. Using
the big 0-540 gives him unreal takeoff
and climb capabilities but lets him
run the engine so far back on the
power curve while still putting out
plenty of thrust that he's doing as
well as, or better than, a smaller
engine in fuel economy. At high
altitude, where the drag comes down
but the engine still has power, the
differences would be even more
dramatic. Like we used to say back in
my drag racing days, "The only
substitute for cubic inches is more
cubic inches."
As I brought the
power up to a more real world power
setting of 23 square, a couple of
things happened. For one thing, the
noise built up considerably. The other
is that as the airplane went through
about 135 mph indicated (145 mph TAS),
the airplane began assuming a nose
down attitude until at a stabilized
145 IAS (155 TAS) the wing was easily
2° nose down, which means, with the 2°
angle of incidence added in, the
fuselage was 4° tail high.
There's been a lot
of conversation about this and it's an
excellent example of how airplanes are
nothing more than one compromise
layered on another. If you want short
takeoff and landing capabilities, the
cruise speed is going to be
compromised and vice versa. Obviously
to take advantage of the Bearhawk's
power at cruise, the angle of
incidence needs to be reduced, this
would bring the tail down 2° which
would result in much less drag and a
higher cruise. At the same time,
however, it would hurt the visibility
in short approach because the nose
would be higher and, when landing on a
short, short runway, the ability to
see and hit the spot is more important
than the actual speed. It would also
hurt the takeoff performance unless
the deck angle was also increased.
Changing the angle of incidence would
have no effect on the wing's nose down
cruising attitude. That is a factor of
coefficient of lift which is a
function of the airfoil section. Going
to a lower lift airfoil (less camber)
would flatten the wing out and give
the airplane much higher cruise
numbers but it would raise the stall
speed and lengthen the takeoff and
landing roll, which is also
undesirable. Clipping the wing a foot
or so would have the same pros and
cons.
After a lot of
bantering on the e-group, it looks as
if the best Band-Aid would be to
reflex the flaps slightly, as Maule
does. With the huge flaps on the
Bearhawk, stowing them at a negative
3-4° would probably do the trick as it
would have the effect of reducing the
camber on a huge section of the wing
during cruise, but would still have
its high lift available on takeoff and
landing. I'd suggest a method of
adjusting the amount of reflex a
degree at a time to match the load and
power available. It could be nothing
more than a sliding ring on the flap
handle that bears on a slightly
tapered ramp on the floor. The entire
reflex mechanism could be very, very
simple. Quite recently a builder in
New Zealand reflexed his flaps 5° and
is claiming a ten knot increase. This
seems high, but five knots seems quite
obtainable.
I wanted to play
with the stalls, so the throttle came
back and the nose went up. Clean,
somewhere down around 50 mph, the
controls went soft and the nose nodded
slightly down. I kept the stick back
to see what would happen and nothing
did. It let me use both aileron and
rudder to control it. With full flaps,
the number came down closer to 40 mph
with only a slightly sharper edge to
the stall itself. This time, just for
the heck of it, I added a little power
and played with slow flight. It took
very little power to hold altitude and
keep the needle nipping at about 45
with nothing in the controls loosening
up or indicating the airplane was
about to do anything stupid.
One of the most
noticeable refinements from the first
airplane was in the control harmony
and feel. The ailerons, which had been
a little stodgy, had been lightened up
by moving the hinge point back. The
result is a nice, responsive,
Beechcraft-like feel with a little
higher roll rate. I'm an aileron freak
and I've got to say that I wouldn't
change a single thing in that area.
They are perfect. Ditto the rudder and
elevator.
It's
overall stability profile is very much
in the middle of the envelope,
meaning, if displaced on any axis it
returns to neutral. It isn't quite as
positive as some airplanes, but it is
much better than most homebuilts and
compares favourably with most factory
Spamcans.
In level cruise,
you're looking down over the nose with
terrific visibility. In turns,
however, you're a fair amount behind
the leading edge and it's really not
convenient to lean forward to clear
for traffic. However, because your
eyes are so far below the wings, you
only have to pick up the inside wing a
little bit to clear for a turn. If
(actually, when) I build a Bearhawk,
it'll have a tinted sky light with a
shade that pulls forward. With no
headliner, you could actually sit
higher for short field work and you'd
be able to see over the down wing in
turns.
The cockpit area,
for those who don't know, was sized to
be slightly bigger than a 172.
However, the panel is quite a bit
lower and you sit higher so all around
room and visibility feels much better
than a Skyhawk. Also, with the cargo
door option in the right side of the
airplane, you can put a huge amount of
stuff in or, roll out an air mattress
in the back and you have your own
three-dimensional camper.
Again, keeping to
his goal of simplicity, the airplane
has no boarding steps. Bob has a
method of boarding in which he puts
his right leg in the airplane past the
control stick, then sits on the seat
edge and brings the other leg in. Bob
is also tall and all legs. Those of us
who are crotch-challenged would
appreciate a step. I think it could be
nothing more than a simple peg or
wedge on the back side of the gear leg
which would allow you to grab the
tubing overhead inside, put your left
foot on the peg and pick yourself up
to put your leg and butt inside. That
might not work, but it needs
something, as I refuse to wear high
heels just to board an airplane.
At some point, we
both knew we were going to have to go
back land the airplane. I wasn't too
worried, but then it wasn't my
airplane.
As I turned final
at 70 mph to cover the gust spread
with only half flaps, we could see the
wind had gotten worse. I could also
see that Bob was getting nervous and I
didn't blame him. The turbulence and
gusts were beating the crap out of us
but it wasn't until we were on short
final and we could see how serious the
wind really was that Bob, using the
most tactful voice he could muster,
shouted, "Do you want me to land it?"
By that time I was
zeroed in on the edge of the runway
and I shouted back without turning my
head, "What ever you think you want to
do, Bob." Inwardly I was grinning
because I could see both of his hands
nervously hovering around both the
stick and the throttle. He wasn't
enjoying this. But, I was. And it was
too late for him to interrupt the
process safely and still land.
There comes a time
in transitioning into any new
airplane, especially in a condition
like this, that you suddenly sense the
airplane's complete character and it
either does or doesn't work for you.
In this case, while Bob was
vacillating about whether to knock me
off the controls and go around or not,
I was looking the Bearhawk right in
the face and I was loving what I saw.
The wind was the
kind that is absolutely dangerous in a
taildragger; hard, sharp gusts and
quartering from the rear. But at no
time did I feel as if the situation
was coming even close to the edge of
the airplane's envelope. I was having
absolutely no trouble flying the line
I wanted; going for a three point
(don't ever wheel land in a tailwind
and I almost never wheel land anyway),
cancelling out the drift, keeping the
tail behind the nose. The airplane let
me do it effortlessly (depending on
your definition of effortless).
As the speed bled
off, it took only a little more wing
down to keep us centred and straight.
Then the airplane painted itself onto
the runway in a single, flowing
motion, right main and tailwheel
first, and stayed there. The airplane
squatted over on all three and it
wasn't until we had slowed way down
that I had to call for some left brake
because the wind had overpowered the
rudder and we were slowly turning
right.
Absolutely no
sweat! I'll take luck over skill any
day!
A note here: very
few airplanes would have given me the
control authority or response to
handle that kind of wind as easily as
we did. If we would have had a better
day, I would have never seen that
corner of its character and wouldn't
have learned as much about it as I
did. I would have liked to have done
some sneaking-over-the-trees short
fields, but I have no doubt it excels
in that, because I did those in the
other airplane. It's very comforting
to know the airplane can handle bad
environmental situations as well as it
can.
I'm more convinced
now than ever that the Bearhawk, with
any engine, is the airplane more
people should be building. It offers
tremendous utility and comfort in an
excellent handling package. Lots of
airplanes are faster, but how many of
them are carrying four people and lots
of stuff? And how many can be built as
inexpensively? If you scratch build,
the steel and aluminium will cost
about $3,500 and that will give you a
complete airframe ready to start
bolting the expensive stuff on. Also,
you can buy that material at the rate
your money comes in. And then there is
the kit route: the quick build is
$25,500 which whacks about three years
off your building time for an
estimated 1000 hour build time.
Do I think the
airplane is worth building? I would
think that should be obvious by now.
Bearhawk Kits
An obvious question has to do with kit
availability. AviPro Aircrarft, Ltd.
is now in full production of kits for
the airplane ranging from complete,
quick-build airframes to complete
wings, wing components, etc. Go to
www.bearhawkaircraft.com for more
information.
Bearhawk
Structure
The Bearhawk is a steel tube fuselage
and welded tail with aluminium, single
strut wings.
The fuselage has
doors on both sides with fold up
windows and a cargo/back door on the
right side. The structure is such that
you tack weld the top and bottom
trusses first, jig it up and put the
side pieces in, rather than doing the
sides first as with most tubing
fuselages.
The tail uses bent
up sheet ribs with tubing spars. The
landing gear has a uniquely simple oil
shock assembly for each leg that
minimizes the amount of machine work,
but works really well.
The plans have no
specifications for seats, but the most
popular seems to be the Tripacer seat
for the front with a variety of
possibilities for the rear. In truth,
almost any kind of seat could be
adapted because the tubing structure
would let you mount any kind of track.
The wings use
folded up "C" shaped spars with
multiple-strap spar caps on the main
spar. Almost all of the skin rivets
are flush and the struts are shortened
C-182 units, although a custom
extrusion is available from Bob
Barrows.
The ailerons and
flaps are fabric covered aluminium and
are actuated through a combination of
cables and push rods, with a minimum
of push rods. There are a number of
steel tubing parts in the wings
including the aileron mounts and
pulley mounts.
The tail wires can
be either streamlined stainless steel
with clevis forks or, a much less
expensive alternative, is to turn down
steel rod as shown in the accompanying
detail photos. Bob is big on building
everything, including the tailwheel
illustrated.
The engine can be
nearly anything, but Bob likes
Lycomings. In fact, building Lycomings
is part of his main business. A
Continental would work just as well
but would require building a bed mount
for it. A number of builders are using
automotive conversions including the
Ford V-6 and Mazda units. It is
entirely practical to build the
airplane with something as small as a
160 hp Lycoming, although the aircraft
would have to be kept light. Flown as
a two place airplane, 160 hp
performance would be surprisingly
good. That would put the airplane at
less than 2000 pounds with full fuel
(55 gallons), for a power loading of
12.5 pounds per horsepower which is
significantly better than a C-172 at
gross (15 pounds/horsepower). The 260
hp airplane at the same weight is 7.7
pounds per horsepower which is right
up there with Pitts Specials. Yeehah!
A note about the
airplane's useful load: Bob's 260 hp
airplane came in at a little over 1100
pounds and he's certain an airplane
with full electrics would come in
under 1200 pounds. This gives it a
useful load of 1200 pounds. Four FAA
sized people weigh in at 680 pounds.
55 gallons of fuel is about 350
pounds. So your baggage/cargo
allowable with full tanks and seats is
50 pounds. You should know one thing
right up front; no one builds an
airplane as light as Bob Barrows. His
finish is thin, his upholstery is
painted Ceconite and he has no radios.
It would be very easy to add 100
pounds with upholstery and radios
which will cut down your useful load.
You didn't hear it
from me, but I wouldn't worry too much
about that. The airplane will carry
anything, but, as long as you stay
somewhere in the neighborhood of
2400-2500 pounds gross, you'll be okay
as the airframe is strong enough to
handle an extra few pounds. Just don't
abuse that margin.
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