Landing Technique Refresher Needed?

[Jim Lee]

No?  Well sorry here it is anyway.  Here comes another flying season.  Fly safe!

PHOENIX LANDING TECHNIQUES

OVERVIEW

The Phoenix motorglider is a taildragger with a twist.  The tailwheel is controlled by the rudder pedals via cables to the rudder and steel rods connecting the rudder to the wheel.  The tailwheel never “breaks free” or castors.  Also, the main wheel disc brakes are controlled by a lever on the left control stick, which operates both main wheel brakes equally when used.  There is no differential braking.  The steerable tailwheel and lever operated brakes provide the ability to fly the Phoenix in crosswinds that ground most other taildraggers, with little worry of groundloops when certain techniques are mastered.

The Phoenix can be landed using the 3 point or wheel landing.  Wheel landings (landing on the mains and then holding the tailwheel off until speed is reduced) are easier and can be made with more precision than 3 point landings.  But the 3 point landing is critical when there is a crosswind blowing (because the tailwheel is on the ground and tracking can be controlled with the rudder pedals), so that is the first and primary technique to master.

The 15 meter tips give the Phoenix a 29/1 glide ratio which means that there will be a lot of float or ground effect within 10 feet of the ground.  The glide ratio with the 11 meter wingtips is 20/1 which reduces the ground effect and also the amount of patience required by the learning pilot.  Also, when the spoilers are fully deployed after touchdown with the short tips, the plane remains planted on the ground with less chance of a bounce even if the plane touches down with extra energy.   Therefore the short tips can reduce the amount of training required and are normally used first when landing training commences.

The stall angle of attack is the same as you view the Phoenix in the 3 point stance on the ground or from the cockpit.  No special angle of attack should be sought  during the landing, the only job is to hold the plane 1 foot off the ground, and keep it flying with slow back stick motion as required, until the stall is reached and the plane touches down.

The round panel with the left side seating position produces a sight picture that makes everyone think they are lined up straight when in fact the plane is pointed left.  Think about the sight picture as you taxi down the taxiway.  And remember the four forces resulting in left turning tendencies?  They don’t help either.

Landings involve the same techniques with long or short tips with one major difference.  With the long tips and fully deployed spoilers, there is still enough wing producing lift to be able to enter ground effect and make a normal landing.  However, there is not enough lift produced with the short tips with full spoilers, so we never enter ground effect with full spoilers with the short tips.  Otherwise, on attempted rotation to the landing pitch attitude, the plane could stall and hit the runway hard.  Consequently we initially teach the half-spoiler landing technique for both 15m and 11m spans.

PATTERN AND LANDING – 11 METER SPAN

Once pattern altitude is reached, reduce power to 4000rpm and fly 70kts.  Perform the landing checklist (GPSFUSTALL).  Turn base and reduce power to idle.  Use the spoilers for glide path control.  Fly 60kts on final, maintaining a little extra height and then hold the spoilers at half  for the remaining segments of the landing.  Have enough height that reducing spoilers on short final is not necessary to make the runway, which involves added complications.  Do not adjust the spoilers in ground effect!  This is an advanced maneuver only.  Glance at the ASI as you cross the runway threshold so that you have an idea about how far down the runway the touchdown will take place.

Finish the round out within 5 feet of the runway.  Slowly descend to the runway until the wheels are 1 foot above the runway, on the right side where you can see the centerline.  Look ahead to the left at the centerline about 100 feet where you can see detail in the runway and the centerline.  Track the centerline back towards you and then jump ahead 100 feet again.  Keep doing that with your eyes.  Glancing across at the edge of the runway also helps judge your height above the runway.   Use the laser beam focus of your central vision down the runway to judge your height.  Staring straight ahead at the panel and trying to use your peripheral vision to judge the height above the ground does not work!

Hold the plane off the runway.  Don’t let it land.  Keep pulling back on the stick as necessary to maintain 1 foot height.  Try to touch down tailwheel first.  You can’t.  But if you try hard enough, you will continue to pull back on the stick until the stall is reached and the plane lands.  Anticipate the landing, and when it happens, pull the spoiler handle full aft to full open position to reduce the stall speed even further and keep the plane planted on the ground.  Keep the stick right where it was for the touch down.  Don’t pull it further back (the elevator still has enough power to pry the plane back off the runway especially in gusty winds) and certainly don’t ease it forward.  If the stick goes forward, the tailwheel will come back off the ground and you will lose directional stability.  Don’t move the stick!

If you lack patience and touch down early, keep the stick in the touch down position, don’t push or pull.  This will reduce the height of the bounce, and you can smoothly pull again as the plane descends to the second, and hopefully, final touchdown.  If it is a high bounce (more than 1 foot) or more than one bounce, go around.  Close the spoilers and add full power.  Know ahead of time what you are going to do.  Your hand is on the spoilers, so close them first, then add power.  Don’t fumble around!  The Phoenix climbs fast and gets you out of the danger zone in a hurry.  You will not be struggling down the runway at minimum speed as in most other small single engine planes.  A balked landing and go-around is a tool every pilot should have and be ready to use.  A prompt go-around is the sign of a good pilot, not a failed landing.

Once on the ground, keep about 1 pound of force on each rudder pedal to keep them aligned in the neutral position.  Apply very light pressure to one side or the other for directional control.  Don’t reduce the pressure on the other rudder pedal or you will fishtail.  It only takes very small adjustments on the rudder pedals when the plane is rolling at 40kts.

Keep the spoilers full open until clear of the runway.  When doing touch and go’s, don’t be too quick to close the spoilers on the go or you may get airborne unexpectedly or lose control directionally as the tailwheel comes back off the ground.  Slow way down to 20kts or so before closing the spoilers and adding power for another take-off.

The key to a successful landing is reciting a mantra during the deceleration in ground effect.  Think to yourself “don’t let it touch, don’t let it touch, don’t let it touch” or “keep it flying, keep it flying, keep it flying” all the way to the touch down.  Then slam open the spoilers, don’t move the stick, and make very small corrections with the rudder and you’ve got it made in the shade.

Flap Settings

Normal Phoenix landings are made with the zero flap setting with the flaperons in the neutral position.  Flap 1 is 5 degrees and flap 2 is 10 degrees.  Flap 1 has no appreciable effect and are not used.  Flap 2 at 10 degrees is helpful for thermalling as the stall speed decreases by 4 kts, and you can fly slower in a tighter circle.

(By the way, flap -1 is a -4 degree setting.  This increases the stall speed by 4 kts.  Still a very small change.  So when I allow a student to “forget” to move the flaps from cruise at -1 setting to zero for landing, guess what happens.  Nothing!  The student doesn’t even realize that anything was different).

But 10 degrees of flap increases lift without much increase in drag.  For landing, we want to increase drag, not lift, so flap 2 is not helpful in a normal landing.  But primarily, flap 2 setting increases adverse yaw.  So if it is windy or gusty and the stick is moved side to side, the nose of the plane tracks back and forth in the opposite direction which is very unsettling.  It is almost a roll reversal (which would be very bad!) but not quite.  Try flying slow at altitude with flap 2 and move the stick back and forth and you will see this.  Plus, the controls get stiffer due to the extreme down angle of the one downward flaperon and the air resistance against it.

To see this on the ground, place the stick in the center and then put the flaps to 2.  Now move the stick all the way to the right as if you are trying to drop that wing lower.  Note the extreme downward deflection on the left wing flaperon, which will add tons of drag and try to slow that wing down and turn the plane to the left.  If you stand at the fuselage right behind the wings and compare the two deflections it will become more clear what is happening.

Again, for these reasons, flap 2 is not recommended for normal landings.  And the same thing applies to take offs.  You don’t want to increase the adverse yaw low to the ground on take off.  Plus, it is just one more thing to remember and mess with after the climb.  And if you forget them as you reach cruise speed you may overspeed the flaps.

Flap 2 only decreases stall speed by 4 kts.  That is only meaningful for thermalling.  On all paved runways of at least 3000’, using flap 2 to decrease the landing or take off roll by 100’ is not meaningful.  It is more trouble than it’s worth.

For a comparison, my Jonker JS1 glider lands with a flap 5 setting in windy conditions which is 17 degrees of flap.  In light or no wind, landing flap is used which is 20 degrees.  At these flap settings we really are increasing drag for the landing.  The thermal flap setting is 13 degrees.  You can begin to see that a 10 degree flap setting is not a landing flap setting.

Is there ever a time to use flap 2?  Well, yes, maybe, if you are landing in an extremely short cow pasture after an engine failure.  We’re talking less than 1000’ of pasture.  An experienced Phoenix pilot can land short with no obstacle in 400’ with flap 2, and 500’ with no flap on pavement (lots of friction for hard braking).   Landing over a 10’ fence onto dirt (with less braking power), the numbers both come out to about 1000’.  I practice flap 2 landings in light winds just for emergency use.  But I never use flaps in normal operations on paved runways.

At least one Phoenix pilot thought that slamming the spoilers to full open to practice short field landings was the right call.  He broke the landing gear.

Approach short field landings just like regular landings.  The only thing to change is the aim point.  Instead of the aim point being the end of the runway (which results in a touchdown some 200’ beyond that point), move the aim point 100-200’ before the end of the runway to achieve a touchdown at the end of the runway and then use hard braking to stop short.  CAUTION!  The wheel brakes are very effective and you can pitch the plane onto the nose if you brake too hard!  You must develop a feel for just how hard you can brake before the nose starts to drop and then back off.  And you better make sure that your brakes, wheels, and tires are all in perfect shape because if your brakes lock up while you are practicing short field landings, you will regret it!  Only when you have perfected normal landings to a T and you are bored out of your mind and ready for a new challenge should you even think about short field landings with full flaps.  And you should know about the runway transition from dirt or grass to pavement.  If there is a big lip onto the runway, don’t come up short!  It is best to try for the numbers as your touchdown point, not the end of the runway.