I had the opportunity to fly a Yak-55M recently. For those of you not
familiar with this kind of aircraft, it is a large Russian-built
monoplane with a supercharged 360HP radial engine - a 9 (!) cylinder
M14P Vendenyev - swinging the prop to the left instead of the right.
It's a taildragger (most aerobatic aircraft are), it's big, it's crude,
and it's one tough and reliable airplane. (Actually, it's also for sale
- you can see a picture of it here.)
One other thing. It's also a single-seater, so you get to learn how to
fly it by, well, flying it. No dual checkout, unless the instructor
wants to hang onto the wing for the flight.
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"There are a few interesting factoids - 1) there is no mixture control,
2) there is no trim control, and 3) it starts with a pneumatic air
system which is not electric. Oh, and the gauges are in Russian, there
are leather straps to keep your feet attached to the rudder pedals, and
it's about as unergonomic a seating position as you can imagine." |
I flew this airplane quite unexpectedly - I had finished my aerobatic
practice for the day and went over to hang out with some other pilots
when the offer to fly the plane came. Of course, I took it!
Getting to know the Yak
The pre-flight includes draining the oil from the bottom cylinders to
prevent hydraulic lock when starting. Crawling up into the thing is an
interesting feat to begin with - you've got to sort of climb backwards
up the tall landing gear struts to sit on the wing, then you can walk
over to the cockpit. You get the feeling of sitting very high up in the
thing.
There are a few interesting factoids - 1) there is no mixture control,
2) there is no trim control, and 3) it starts with a pneumatic air
system which is not electric. Oh, and the gauges are in Russian, there
are leather straps to keep your feet attached to the rudder pedals, and
it's about as unergonomic a seating position as you can imagine. I'm a
middle-sized guy, about 185 lbs. and 5'9", and my knees were poking up
towards my chest - slightly uncomfortable, but it didn't impede my
ability to get to all the controls. I'm sure that if I flew the plane a few times I'd get used to it quickly.
I had a "5 minute checkout" on the ground with the owner. We covered
the gauges - prop is in percentage of power instead of RPM, ASI is in
klicks, MAP is in some other type of unit (but the 30" hg. setting was
straight up at 7.5 with the engine off, and the owner explained that
with supercharger full power would be at about 8.5.) Downwind and
approach were to be flown at about 200 klicks, and short final at 150.
I fretted about this a bit during the ground checkout but it later
turned out to be unnecessary, as it was very easy to 'feel' the proper
airspeeds. Of course, we discussed emergency procedures, how to cut off
the fuel, and jettison the canopy. It's all straightforward. I did a
few sweeps of the strange panel with my eyes to start memorizing where
everything was. (All russian placards except for MAP, oil press/temp,
and altimeter! The CHT was, thankfully, color coded by some thoughtful
individual so I could keep an eye on the temps.)
Starting procedure
So, here's how you start a 360hp supercharged Yak-55M.
5 shots to prime the engine. Rotate the primer to the left and pump it 5 more
times - that's for the pump itself. Switch on the battery switch to
'on'. Switch on the mags to "1+2". Prop full forward and throttle to
1/4" open. Now all you do is mash the little starter button until the
engine fires. Easy! No 3-handed juggling act like most of us are used
to doing. Generator, instruments, radios, and compressor are now
brought online. The idea behind the compressor is to re-accumulate
enough air pressure for your next air start. However, this builds
slowly so you need to watch a small air pressure gauge installed for
this purpose as you taxi. Prior to 'red-line' on the gauge, you shut
the compressor down. Piece 'o cake.
Taxiing was no big deal. I'm used to a Pitts, and the forward
visibility in the Yak was far greater than in my little rocket ship.
The tailwheel only swivels 30 degrees in either direction, but other
than that, very straightforward. I made small S-turns out to the
runway. I noticed that one gets a lot of attention when taxiing around
in this strange-looking bird.
I memorized the 'sight picture' out to the left and right of the plane
as I taxied into position on the runway - I would use this to gauge my
flare height for the landing later on. I applied full power - there's a
little lag there at low power settings - and boy was this baby roaring!
It's a pretty rough and loud ride. I immediately sensed the need for
left rudder (boy, that felt strange) and eased off the rudder just a bit
to account for gyroscopic precession as I raised the tail. I had been
warned not to pop the tail up smartly as is customary with the Pitts -
the 'tail arm' is quite long in this airplane and the empennage is also
heavier. Also, even with the extended landing gear struts there's less
prop clearance than in most taildraggers. It was no big deal, though -
some gentle forward pressure brought the tail up nicely. The controls
which felt heavy on the ground were already extraordinarily light. (I
should note that the control surfaces are HUGE. The ailerons, for
example, span nearly the entire wing. The rudder is nearly as thick as
the leading edge of a C-172's airfoil. Etc.!)
"I decided to
try a loop, entering at 300 klicks ('30' on the ASI.) This time I
passed the vertical without any problems (although I was much more
careful with the rudder.) Right at the 3/8 mark of the loop as I was
nearing inverted flight, it did it again, although this time the snap
was a good 3/4 of a roll ending with the nose pointing downward and the
telltale start of a power-on spin setting in."
Cleared for takeoff
I had a pretty decent crosswind from the northeast (taking off runway 9L
at SFB [Sanford, Florida], winds from 050 at 14 knots gusting to 19.)
The big rudder made it easy to track the centerline on the takeoff
roll. A slight aft pressure on the stick, and... whoosh! Airborne.
Time to have some fun with this thing. The airplane climbs like a
tractor - I'm not sure if it would outclimb my Pitts, but it was close
nevertheless. I got out from under the class bravo shelf around MCO
[Orlando International] and headed for my practice area northeast of the
airport. I made a few turns and immediately noted the significant
adverse yaw caused by the huge ailerons. It was harder to 'feel' the
uncoordinated turn as I was sitting directly above the main wing spar,
but after a few turns I sensed about how much I needed. In short order
I worked up to 6G turns and was able to nail the altitude without so
much as a burp from the altimeter. Time for some rolls and inverted
flight.
Takes a lot more top rudder on the slow rolls, I noted. Probably due to
the radial shape of the fuselage - my little Pitts' fuselage acts more
like an airfoil on knife-edge. I rolled the plane inverted and did some
shallow and steep banked inverted turns. Still very stable, and I noted
that I didn't need nearly as much forward stick pressure as I did in my
Pitts. (Not to say I need a lot in the Pitts either, but this thing
would practically fly inverted hands-off.)
I mentioned earlier that the Yak has no trim or mixture controls. How,
you ask? Well, the airplane is always automatically in trim. Russian
simplicity - they built it into the very design of the aircraft. It was
slick - the controls never felt heavy. Mixture was handled by a device
which automatically compensated for altitude. This airplane was built
for the harsh environment of the former Soviet Union, and it shows.
Everything is rugged and built as simple as possible. I think I'll look
further into how this system works - I don't really understand it.
Getting intimate with the Yak
Time for some vertical maneuvers. The plane had been pretty gentle
(although still 'rough' in feel) to me so far. Now it was about to show
me some quirks in its behavior. I made a 3.5G pullup to the vertical
with the intention of a hammerhead turn to the right (left-swinging
prop, hammerhead to the right - opposite my usual routine.) As I pulled
up I had the immediate sensation of flying a spinning gyroscope - which
I quite literally was. The effects of gyroscopic precession, p-factor,
torque, and whatnot are nothing new to student pilots, but boy did I
feel it in the this plane! I used right rudder to compensate for the
fastest rate of pitch change and started easing into left rudder as I
drew my vertical upline. The plane started rolling in the vertical and
I felt unable to stop it! I did a pretty ugly hammerhead (I hesitate to
even call it a hammerhead) and tried to draw a nice vertical
downline. Same thing on the pullout - right as I reached the 45 degree
point the plane started wobbling again and then threw me somewhat
violently into a quarter snaproll to the right. Heh! Cute. I called
Larry on the radio to confirm the entry speeds - he told me anything
over 250 klicks. I noted the '25' mark on the altimeter and decided to
try a loop, entering at 300 klicks ('30' on the ASI.) This time I
passed the vertical without any problems (although I was much more
careful with the rudder.) Right at the 3/8 mark of the loop as I was
nearing inverted flight, it did it again, although this time the snap
was a good 3/4 of a roll ending with the nose pointing downward and the
telltale start of a power-on spin setting in. I simply reduced power
and the plane flew right out of it with no recovery needed. I tried the
loop three more times, finally getting it right the last time. In the
Pitts the required rudder input is very easy to sense, probably because
the pilot sits so far behind the wing spar. In this plane, I really had
to fine-tune my senses. I imagine it would be pretty easy to fly an
'avalanche' (loop with a snap roll at the top) in the Yak! This plane
is truly a flying gyro. Every pitch change requires the pilot to be
cognizant of precession and torque. I imagine that's due to the immense
power generated by the powerplant.
Round and round she goes, where she stops, nobody knows...
Finally, it was time to try a tumble. This is a maneuver which should
only be attempted in an aircraft approved for such a manuever, which the
Yak is. My Pitts is very tumble resistant - probably due to the bi-wing
and draggy flying wires and such - so I was really looking forward to
giving it a try. I made sure I had plenty of altitude and slowed down
to 220 klicks, the recommended entry speed. Mashed the right rudder
pedal to the floor, followed instantly by full forward elevator and full
right stick deflection. Wooooohooooo! Better than Mr. Toad's wild
ride. I probably did some combination of somersault and cartwheel. I
have no idea how it looked from the ground, but that's how it felt in
the air. Recovery was simply neutralizing the controls. VERY easy
airplane to fly in that sense - get in trouble? Just let the plane fly
itself out.
I came back for landing and wouldn't you know it, the tower asked me to
provide my airspeed on downwind. I was following (and catching up to) a
Seminole in the pattern. I guesstimated my speed at about 100-105kts
and told the tower so, and was told to make a short approach inside of
the Seminole and a 727 on final. Okay, no time like the present, and no
pressure to make a nice landing on the first try - ha!
I slowed down to 185 on base, 175 for final, and pretty near 150 for
very short final, which the airplane seemed to like. It was an
extremely easy airplane to land (but just remember how high you are off
the ground for the flare!) I am convinced that anyone with a little
tailwheel experience could easily land this airplane. The crosswind was
still present but I simply needed to dip those big wings into the wind a
bit and apply a skosh of rudder pressure to track the centerline. I
came down on the tailwheel just an instant before the mains gently
touched down and didn't bounce - woohoo, a squeaker to boot! I taxied
back and shut down. (The astute of you will remember that this aircraft
has no mixture control - you shut down by simply turning off the mags.)
One for the logbook
All in all, a very worthwhile and satisfying experience. I hope
everyone gets a chance to try something like this - it is very
exhilarating to be challenged by a new aircraft and have the confidence
to fly it and learn it simultaneously! I feel like it was a very
memorable event in my 'career' as a pilot.
-Ryan
