Wheel
landings
There are
two common techniques used to land tailwheel aircraft: three-point and wheel landings.
Three-point
refers to the landing attitude – typically around 5 degrees nose up – which
allows all three tires of the tailwheel aircraft to contact the runway at the
same time.
Wheel
landing refers to a near-level (or slightly tail low) landing attitude, where
the two main tires touch first, and after a while, the tailwheel is gently lowered
to the ground.
Almost all
tailwheel instructors, including myself, start students with the three-point
landings, and only after they have developed some proficiency with the rudder,
is the wheel landing introduced.
Many pilots
of light tailwheel aircraft never master the wheel landing, and that’s ok. Other pilots prefer wheel landings all the
time. Whatever works for you, in that
particular airframe, in that particular situation.
The way I
teach tailwheel landings is for the student, just as he would in a nosewheel
aircraft, to establish himself on the runway centerline – let’s forget about
crosswinds for now, so no crab required on final. I like to turn the VASI/PAPI lights on, so
that the student can clearly see if he is too high (all white lights) or too
low (all red lights). Too high, push the
nose down. Too low, pull the nose up.
Once the
student is established on the runway centerline and correct glidepath, then the
desired airspeed is attained with the use of power. Too slow, add power (and typically push the
nose down). Too fast, reduce power (and
pull the nose up). If power reduction
won’t cure excessive airspeed, a forward slip is a good idea. I try to use the same amount of flaps every
time, for the sake of consistency in the flare.
The amount of flaps I like to use is the amount of flaps specified for
takeoff – often zero degrees, to reduce pilot workload during a touch & go
landing.
However you
get there, it’s important for the student to precisely maintain the desired
airspeed until passing over the runway threshold, and then the power is reduced
to idle, and the student can now entirely focus on flaring the aircraft to the
three-point attitude and establishing it at a height of ideally less than one
foot above the ground. With the power
off, airspeed will be decreasing and the pilot does his very best to try to
stop the aircraft from touching down with progressive back elevator. Eventually the aircraft runs out of speed and
lift, and settles down on the runway.
Hopefully
the pilot has kept the aircraft perfectly aligned with the direction of
travel. Any crab will now launch him to
the side of the runway as discussed before.
Once the
aircraft sits down on the runway, the stick is steadily pulled all the way
back, to put weight on the tailwheel to improve directional control, and to get
rid of any porpoising in pitch.
At this
point, the student can now totally concentrate on using his feet to stay
straight – that’s the only thing he has to do at this point. The power is off, the stick is all the way
back, and the ground speed should be decreasing during the rollout. As required, the student will perform the
Three Step as described before to control the aircraft directionally. Eventually the speed will decrease during the
rollout to a taxi speed. The slower the
aircraft is moving, the easier it will be for the student to control it.
Below 20
mph, you’re really taxiing. A light
tailwheel aircraft might touch down around 50 mph, but it won’t have much
weight on the tires at that speed – the wings are still developing significant
lift, and if you try to use the brakes, all you will do is flat-spot the
tires. Between 40 mph and 20 mph is what
I call the “expensive speed”. You won’t
kill yourself - or likely even get hurt
badly – if something goes horribly wrong, but you can sure spend a lot of money
if you lose control of the aircraft between 40 mph and 20 mph, because you
can’t fly, but you are careening down the runway with a lot of speed on.
Keep in
mind that aircraft – even nosewheel aircraft – are lousy ground vehicles. They are about as graceful as an enormous
pregnant duck, and the faster they go, the crappier they are. Tailwheel aircraft are horrible ground vehicles,
and the faster you go on the ground, the worse they get.
Anways,
first the student masters the three point landing, which allows him to
concentrate solely on keeping the aircraft straight with his feet after
touchdown, with the stick all the way back.
Once the student masters the three point landing, they can work on the
wheel landing.
Wheel
landings can be awfully frustrating. The
reason why is that if you don’t get a greaser touchdown, after the mains touch
down, the center of mass behind the mains has momentum and it pulls the tail
down. This increases the angle of attack
of the wing, and hence lift, shooting the aircraft up and converting what
little airspeed it had into height with near-zero airspeed (and lift). A hard second touchdown usually follows, and
this porpoising can get worse with each successive bounce. As always, when something goes wrong with a
tailwheel landing, apply FULL POWER, stabilize and accelerate with a couple
feet of height, get some airspeed and get up and get the hell out of Dodge. Calm the nerves, go around the pattern, and
get set up again.
The secret
to a good wheel landing is to sideslip, as if there was a crosswind – even if
there is no crosswind! This allows one
main to touch first, and if you don’t get a greaser touchdown, the other main
comes down – not just the tailwheel – so the angle of attack (and hence lift)
doesn’t increase, shooting you back up into the sky. A little forward stick to decrease the AOA
and stick the mains on the ground and you’re rolling down the runway, now with
two chores – stay straight with your feet, and control pitch with the stick via
the elevator.
This is why
I recommend teaching wheel landings after three point landings, because the
touchdown is trickier and the workload is higher during the rollout.
--
acboyd@gmail.com Sept 2011