In-flight adjustable propeller - bush pilot skills

 Adjustable propeller in flight - a good servant but a bad master.


The function and use of the adjustable propeller can be found in every pilot's textbook. What you won't read in any textbook is what can happen if it fails and what you can do about it to survive.

What you won't learn at all is what kind of in-flight adjustable propeller to get for your particular engine and what to consider, what to look out for, what diameter, and what adjustments you can make to make the transfer of torque and power to the surrounding air as efficient as possible and to significantly improve the performance of the aircraft.

The wonderful benefits of in-flight adjustable propellers:
Controllable pitch -  in-flight adjustable propeller will increase the power transferred to the air during take-off, roll, take-off and climb. An in-flight adjustable propeller allows for a greater angle of climb, so we can efficiently and safely climb over nearby obstacles beyond a plane or airfield. In-flight adjustable propeller will also save you a lot of fuel if you have it properly set for economical flight at maximum engine torque.

You will appreciate the huge benefit of an in-flight adjustable propeller during an emergency landing when you set it to the maximum rough angle, or into the flag regime and then glide much, much further and you can enjoy the emergency landing more as you have more time and more surfaces to glide to and therefore more suitable surfaces to choose from.
With an in-flight adjustable propeller, you can significantly change the flight performance of your aircraft otherwise originally equipped with a fixed wooden propeller or a ground adjustable propeller.
With an controllable pitch propeller and other modifications, you can more easily fly any other surfaces outside of the airport.


WARNING:

In-flight adjustable propellers can be dangerous for some forgetful pilots!
However, an in-flight adjustable propeller can also be the cause of many accidents and damage to the airplane and injury to the pilot compared to a fixed or ground adjustable propeller. The most common pilot error is improper propeller adjustment or forgetting to operate the propeller! This is especially true during landing and takeoff when the pilot fails to set the propeller to maximum takeoff power in time.

Unfortunately, I myself am sometimes one of those forgetful pilots, so I had the privilege of experiencing what to do with a fully cranked propeller when I had to repeat it while grazing a doe and her fawns in the middle of a 236m area at 2000ft altitude, in 30degC.

Thus, many times in continuing bush training I have had pilots feel the helplessness of aborted landings when they have primarily forgotten to set the propeller to fine and attempted to take off on the propeller's cruise mode. For the first tenth of a second it was quite amusing to watch them get very frustrated when their engine didn't come up to the expected full speed, it's such a tiny bit of gloating satisfaction,that I am not the only one who sometimes forgets to adjust the propeller and, moreover, does not notice the increased glide during the descent because I was thinking about other things, not related to flying.


An engine with a coursed in-flight adjustable propeller on a repeat take-off has a different than expected sound and the plane doesn't pull at all, much less climb as the pilot would like! And after those few tenths of a second, the realization I am already fully available to help them address this - for them - unusual and dangerous condition.

You wouldn't believe how many pilots panic at that first opportunity, low to the ground, with a visible, close, and rapidly approaching obstacle. They commit another secondary error when they keep pulling in an attempt to climb over that obstacle!

This only puts the aircraft at a higher angle of attack and slows it down. Then the airspeed will decrease to stall speed, or near stall speed. Another factor that will reliably send your airplane crashing to the ground when stretched out like this can be turbulence in the drift behind a nearby obstacle or forest edge, when the airplane suddenly loses lift. We don't need to talk about downburst or microburst, everyone who has a pilot's license understands that in detail...

At low altitudes above the ground, without timely and intensive intervention of an instructor trained for these situations, a crash and subsequent crash becomes inevitable, because at that altitude the pilot would probably not be able to effectively select the crash correctly and in time.

At the same time, if the pilot had already made the primary and crucial mistake of not setting the propeller for maximum fine, take-off power, it would have been sufficient not to make another secondary mistake and not to climb, but to follow the ground surface in ground effect until he had rented the propeller!

And, as I have already described, he could have prevented all this by realising how much glide his aircraft had and how different it was from what he knew and had read from the past.

The other option in a forced re-takeoff with a roughened propeller for cruise flight is in avoiding the approaching obstacle laterally with the maximum acceleration of the airplane that will be possible to achieve sufficient airspeed needed to make the turn and simultaneously soften the propeller without climbing!

Everything must always be done with immediate consideration of the ambient conditions of temperature, altitude and wind direction and most importantly the gyroscopic effect. If I know that my aircraft is more willing to go into a left turn and descend there, it is more advantageous for me to use the left turn and watch the descent. A right turn would have too large a radius, plus a tendency to bring the plane back to a higher angle of attack - unless you have it in hand.

Unfortunately, most untrained pilots no longer have the capacity for these realizations described above and are overwhelmed just keeping the airplane in the air at low power. This is also the reason to suddenly create and practice such situations... 

Flight school training in basic training is always built to be as safe as possible, and that's a good thing.
That's the only way to train maximum pilots. This is because some elements of piloting could be very difficult for novice pilots and could - if insisted on being safely mastered by the instructor - prolong the training disproportionately or frustrate the pilot so much that he/she would stop flying.And no one wants that, neither the student, nor the instructor, and certainly not the flight school.

However, it is clear that many manoeuvres and contexts cannot be known by such a fresh pilot and certainly not experienced. Even pilots with thousands of hours of flight time are often unsure...
"I am an instructor, I have 30 years and 2000 hours, but I have never needed such things as you describe Mr. Zejda and it rather shows your incompetence, incompetence and poorly managed budgets".
Well, yes, of course. From his point of view. If such a pilot flies from Frankfurt to Ruzyně, or from Jihlava to Dresden, he probably never needed anything like that...

He who flies almost daily in any reasonable flying weather at any time of the year on short any other area located perpendicular to the prevailing wind direction along the forest, where occasionally some of the animals run out, knows his...


Continued next time ...


LETECKÁ ŠKOLA ROKU

V roce 2014 jsme se umístili na skvělém druhém místě v anketě "Letecká škola roku" ve kategorii škol věnujících se výcviku pilotů ultralehkých letadel.

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