Alltrikes

For all pilots who want to go above and beyond basic sport, private and CFI certificates to new levels of skill, precision and safety.

Getting your trike license is a “license to learn”. What about after that. What can you do to keep learning? How can you make your flight review productive rather than another bureaucratic/regulatory hassle? How can you develop greater bar and throttle (stick and rudder) skills to become One with your trike?

Here are three maneuvers that help accomplish this which is a new chapter I just added in the WSC Pilot’s Handbook of Aeronautical knowledge. Any other techniques, maneuvers, tips and tricks for advanced trike flying is welcomed here.

Introduction

This chapter focuses on Advanced Flight Maneuvers not covered in the FAA Weight-Shift Control Aircraft Flying Handbook.

These maneuvers are not required in the Practical Test Standards but are included here for the purpose of increasing safety and building additional piloting skills.

Reading and understanding the FAA Weight-Shift Control Aircraft Flying Handbook Chapters “2 Aerodynamics”, 

“5 Flight Maneuvers” plus this book Chapter “4 Aerodynamics  of Flight” are prerequisites to  read and understood before reading this chapter.

About Advanced Flight Maneuvers

Advanced maneuvers are used to develop an enhanced degree of pilot skill. These aid all pilots in understanding the proper coordination and timing for maneuvering trikes in intentional and unintentional adverse flying situations and conditions.

These  maneuvers are termed “advanced” because the degree of skill required for proper execution is normally not acquired until a pilot has obtained a sense of orientation and control feel in “normal” Practical Test Standards (PTS) maneuvers for the basic sport and private pilot certificate.

An important benefit of advanced maneuvers is the sharpening of fundamental skills to the degree that the pilot can cope with unusual or unforeseen circumstances occasionally encountered in normal flight.

Advanced maneuvers are variations and/or combinations of the basic maneuvers previously learned. They embody the same principles and techniques as the basic maneuvers, but require a higher degree of skill for proper execution.

The pilot should first master the normal flight maneuvers, ground reference maneuvers and especially the performance maneuver (high banked turn) with confidence and in bumpy air before attempting any of these advanced maneuvers in calm air.

Flight instructor’s should first start with the components of the basic PTS maneuvers by breaking the maneuver components down into their basic  elements  in an attempt to identify and correct any deficiency before continuing with these advanced maneuvers.

Advanced maneuvers can be used for experienced pilots for flight reviews and/or additional training.

With the new low drag small wing high power  trikes available now, airspeed can increase quickly so proper precise techniques must be developed to deal with these new advancements.

It is important to understand that improper control inputs in the performance and/or recovery of advanced maneuvers may result in over stressing the trike beyond the limitations which can result in serious injury or death.

For WSC, advanced maneuvers have not been covered so some new terms and definitions will help define specific areas in this chapter.

Overall, there is a large variation between the handling characteristics of different trike wings, undercarriages and combinations of wings and undercarriages. Especially with the more recent new breed of smaller wings and higher horsepower engines creating faster speeds, more precise piloting techniques are required to handle these greater speed ranges.

It must be clearly understood that the information provided in this chapter is generic and will have a large variation for different makes/models. Therefore, it is very important to follow the specific recommendations of the manufacturer for the make/model when attempting any maneuver and use this as a general guideline to understand the fundamental concepts and generic techniques.  

Terms and definitions

For the purpose of this chapter, the following definitions are provided:

High banked turn – a 45 degree to 60 degree banked turn in a climb, level flight or descent.

Very high banked turn – greater than 60 degree banked turn in a climb, level flight or descent.

Steep spiral – Maneuver that results in a high to very high banked turn stabilized as a climb, level flight or descent. There is no acceleration or any increase or decrease in speed during a stabilized steep spiral.

Spiral dive-  Steep to very steep turn that becomes a progressively tighter turn and/or increasing airspeed and/or increasing bank angles over time. In comparison to a steep spiral, a spiral dive is not a steady state maneuver and must be stabilized and/or corrected before aircraft limitations are exceeded.

Advanced Maneuver Aerodynamics

Forces in High Banked Turns

As covered in the previous Chapter 4 of this book, load factor, or G force, increases dramatically during steep turns. Flying straight, in steady state unaccelerated level flight the load factor is 1. In steady state coordinated flight, load factor increases to 1.4 in a 45 degree bank, load factor is 2 in a 60 degree bank, and load factor is 4 in a 75 degree bank. A load factor of 4 is the structural limits for an ASTM certificated trike.

It should be noted that in a 45 degree banked turn (Figure 5-1), horizontal and vertical components of lift are equal. Increasing the total lift through increasing the angle of attack or increasing speed will provide an equal increase in vertical lift and horizontal components of lift. Thus, increasing the angle of attack by pushing the bar forward creates an equal vertical component slowing the aircraft and horizontal force increasing the turn rate thus increasing horizontal speed/turn rate.

Above 45 degrees bank angle, increased lift creates a greater horizontal component of lift than vertical component of lift as shown in Figure 5-2. This additional sideways force  increases the horizontal speed and thus the overall airspeed. This is counter initiative to what has been previously learned – “pushing the control bar forward slows the aircraft”.

Thus, at medium bank angles, below 45 degrees, increasing the angle of attack (pushing the control bar forward), slows the trike. But in very high banked turns the opposite is true. Pushing out on the control bar increases the horizontal speed, thus the overall airspeed. Pushing out will also increase the load factor. Similarly, pulling the bar in will decrease the speed and reduce load factors.

Therefore, a different understanding must be understood and learned to control speed and load factor in high and very high banked turns.

Since the aerodynamic control of the trike is with physical weight-shift, and a direct connection to the wing, increased loading will often create greater side to side effort required to roll the trike. This is why it is important to understand that pulling the bar in during very high banked turns may be required to reduce the control forces to roll the wing as needed back to level flight.

In high banked turns, the outside wing is going faster than the inside wing. This additional speed   creates more lift on the outside wing verses the inside wing, wanting to roll it further (Figure 5-3).

This over banking tendency or “spiral instability” is one of the design challenges for aircraft designers to minimize pilot input to stabilize bank angles with minimum pilot input.  

Throttle Effects

Nose down pitch attitudes may result in any advanced maneuver. At nose down pitch attitudes, increased thrust has vertical and horizontal components as shown in figure 5-4. At nose down pitch attitudes, increased thrust increases airspeed and vertical descent. Therefore, throttle settings must be reduced with nose down pitch attitude where airspeed must be maintained or reduced to stay within aircraft speed limits and/or the pilot needs to minimize altitude loss.                                                                   

Unique Design Characteristics of Trikes

The design of the weight-shift control aircraft is significantly different than an airplane which has a third axis vertical stabilizer plus a movable rudder to maintain yaw/side to side coordinated flight.

Generally, during the start of a turn, most trikes have a tendency to initially slip in the direction of the turn.  This tendency can also be looked at as the nose initially going in the opposite direction of the turn and commonly known as “adverse yaw” for airplanes.

For weight-shift control aircraft, after the turn is initiated, the swept wing design and the area behind the CG of the undercarriage tend to correct adverse yaw tendencies and automatically coordinate the trike straight into the airflow for a coordinated turn. Each design of the trike wing and undercarriage in combination is different, but some correct adverse yaw/slip more than others, This yaw stabilization varies greatly from make/model and combination of wing and trike undercarriage.

Generally the higher performance faster wings with less sweep and twist tend to slip more and may take additional pilot skill to coordinate.

Again, this is another design challenge for the manufacturers to design an easy to handle high performance wing for varied speed ranges.

This adverse yaw in trikes, especially high banked  turns may create unusual handling characteristics and surprising losses in altitude with recovery techniques unique to each individual design.

 Overall as pilots, understanding the aerodynamics and practicing advanced maneuvers are important for flight safety and precision flying for each make/model.

The effects of throttle at nose down pitch angles and adverse yaw tendencies with altitude loss in different situations with different recovery procedures is an important safety concept in practicing advanced maneuvers. With the different trike designs, follow manufacturer’s recommendations for specific make/model’s.

Students, pilots and instructors should approach advanced maneuvers with extreme caution and slowly build up to the advanced maneuvers gradually in calm air and never perform or continue maneuvers below 1500 feet minimum AGL.  

Very High Bank Turn Recovery

Let’s look at a scenario where a trike is in a 45 degree high banked turn as shown in figure 5-5. Note the control bar is in the side to side neutral position, centered in the middle of undercarriage. The control bar fore/aft is in a neutral position holding a coordinated turn. There might be a slight forward pressure to coordinate speed and bank angle.

A strong gust hits the aircraft and the trike rolls up to a 75 degree very high bank angle as shown in figure 5-6. Typically in this situation the trike would start to pitch down and increase speed. The natural reaction would be to push out to decrease speed and give it throttle. However, at the high bank angles and low pitch angle this would increase the speed and increase loads, neither of which is desirable in this situation.

As shown in Figure 5-6, he proper recovery control input is to simultaneously

• move the control bar to the side to level the wing,
• pull in to reduce the angle of attack and
• reduce throttle.

It is important to note that pulling the bar in and reducing the angle of attack unloads the wing and assists in the necessary roll correction. 

In a critical situation such as this, it is important to understand that proper control inputs must be applied to correct this situation.

It should be noted that in a 75 degree turn and a load factor or 4, the stall speed about doubles. Pushing the bar out would aggravate the situation. At the high load factors in this situation, the control forces may increase where it is hard to bring the bar sideways as needed.

Therefore, pulling the bar in to reduce the angle of attack while simultaneously rolling the wings to level is the correct procedure as shown in Figure 5-6 to recover from a very high banked turn, intentional or unintentional  

Advanced Maneuvers

Steep Spirals

The objective is to improve pilot techniques for airspeed control, wind drift control, planning, orientation, and division of attention. The steep spiral is not only a valuable flight training maneuver, but it has practical application in providing a procedure for dissipating altitude while remaining over a selected spot in preparation for landing, especially for emergency forced landings.

A steep spiral is a constant turn, during which a constant radius around a point on the ground is maintained similar to the maneuver, turns around a point only at a much greater bank angle. The steep spiral can be done with power on for level flight/minimum descent or done with minimum/power off for a steep spiral descent. The bank angle is at least 45 degrees and should not exceed 60 degrees or the manufacturer’s maximum bank angle limitation.

Sufficient altitude must be obtained before starting this maneuver so that the spiral may be continued through a series of at least three 360° turns alternating right and left. [Figure 5-7] The maneuver should not be performed or continued below 1,000 feet AGL unless performing an emergency landing in conjunction with the spiral descent. In this case bank angle must be decreased as required when getting near the ground for safety.

A speed is established that is well above stall speed for the desired bank angle. A turn is initiated with an increasing bank angle maintaining speed which usually requires some forward pressure on the control bar as the bank angle increases.

The steep spiral should first be done maintaining a constant bank angle in calm wind but can also be practiced in wind with a turn of constant radius maintained around the selected spot on the ground. This will require correction for wind drift by steepening the bank on downwind headings and shallowing the bank on upwind headings, just as in the turns around a point maneuver.

During a descending spiral, the pilot must judge the direction and speed of the wind at different altitudes and make appropriate changes in the angle of bank to maintain a uniform radius. A constant airspeed should also be maintained throughout the maneuver.         

During practice of the maneuver, the pilot should execute three turns and roll out toward a definite object or on a specific heading. During the rollout, smoothness is essential, and the use of controls must be so coordinated that no increase or decrease of speed results when the straight path is resumed.

Common errors in the performance of steep spirals are:

• Failure to adequately clear the area.

• Failure to maintain constant airspeed.

• Inadequate wind drift correction.

• Failure to coordinate the controls so that no    increase/decrease in speed results when

    straight flight is resumed.

• Failure to scan for other traffic.

• Failure to maintain orientation.

Chandelle

The objective of this maneuver is to develop the pilot’s coordination, orientation, planning, and accuracy of control during maximum performance flight.

A chandelle is a maximum performance climbing turn beginning from approximately straight-and-level high speed flight, a constant turning and slowing and ending at the completion of a precise 180° of turn in a wings-level, nose-high attitude at the minimum controllable airspeed. [Figure 5-8]

The maneuver demands that the maximum flight performance of the aircraft be obtained to gain the most altitude possible for a given degree of bank and power setting without stalling.

Since numerous atmospheric variables beyond control of the pilot will affect the specific amount of altitude gained, the quality of the performance of the maneuver is not judged solely on the altitude gain, but by the pilot’s overall proficiency as it pertains to climb performance for the power/bank combination used, and to the elements of piloting skill demonstrated.

Prior to starting a chandelle, the power is set to some high speed cruise condition, and the airspace behind and above clear of other air traffic. The maneuver should be entered from straight-and-level flight (or a shallow dive) and at a speed no greater than the aircraft’s design maneuvering speed (VA).

After the appropriate airspeed and power setting have been established, the chandelle is started by smoothly entering a coordinated turn with an angle of bank appropriate for the aircraft being flown. Normally, this angle of bank should be around 30°, but greater bank angle’s can also be used.

After the appropriate bank is established, a climbing turn should be started by smoothly applying forward control bar pressure to increase the pitch attitude at a constant rate and to attain the highest pitch attitude as 90° of turn is completed. Full throttle may be applied during the climbing turn but this is not necessary for the basic maneuver.

Once the bank has been established, the angle of bank should remain constant until 90° of turn is completed.

When the turn has progressed 90° from the original heading, the pilot should begin rolling out of the bank at a constant rate while maintaining a constant-pitch attitude. Since the angle of bank will be decreasing during the rollout, the vertical component of lift will increase slightly. For this reason, it may be necessary to release a slight amount of forward control bar pressure  in order to keep the nose of the aircraft from rising higher.

As the wings are being leveled at the completion of 180° of turn, the pitch attitude should be noted by checking the outside references. This pitch attitude should be held momentarily while the airplane is at the minimum controllable airspeed. Then the pitch attitude may be gently reduced to return to straight-and-level cruise flight.

Common errors in the performance of chandelles are:

• Failure to adequately clear the area.

• Too shallow an initial bank.

• Too steep an initial bank, resulting in failure to gain maximum performance.

• Allowing the actual bank to increase after  establishing initial bank angle.

• Failure to start the recovery at the 90° point in the turn.

• Allowing the pitch attitude to increase as the  bank is rolled out during the second 90° of turn.

• Removing all of the bank before the 180° point  is reached.

• Nose low on recovery, resulting in too much  airspeed.

• Control roughness.

• Stalling at any point during the maneuver.

• Execution of a steep turn instead of a climbing  maneuver.

• Failure to scan for other aircraft.

Lazy Eight

The lazy eight is a maneuver designed to develop perfect coordination of controls through a wide range of airspeeds and altitudes so that certain accuracy points are reached with planned attitude and airspeed.

In its execution, the dive, climb, and turn are all combined, the combinations are varied and applied throughout the performance range. It is the only standard flight training maneuver during which at no time do the forces on the controls remain constant.

The lazy eight as a training maneuver has great value since constantly varying forces and attitudes are required. The maneuver helps develop subconscious feel, planning, orientation, coordination, and speed sense.

 This maneuver derives its name from the manner in which the extended longitudinal axis of the aircraft is made to trace a flight pattern in the form of a figure 8 lying on its side (a lazy 8). [Figure 5-9]

A lazy eight consists of two 180° turns, in opposite directions, while making a climb and a descent in a

symmetrical pattern during each of the turns. [Figure 5-10]

 At no time throughout the lazy eight is the aircraft flown straight and level; instead, it is rolled directly from one bank to the other with the wings level only at the moment the turn is reversed at the completion of each 180° change in heading at the bottom of the maneuver.

 As an aid to making symmetrical loops of the 8 during each turn, prominent reference points should be selected on the horizon. The reference points selected should be 45°, 90°, and 135° from the direction in which the maneuver is begun.

Prior to performing a lazy eight, the airspace behind and above should be clear of other air traffic. The maneuver should be entered from straight-and-level flight at normal cruise power and at the airspeed recommended by the manufacturer or at the aircraft’s design maneuvering speed.

The maneuver is started from level flight with a gradual climbing turn in the direction of the 45° reference point. The climbing turn should be planned and controlled so that the maximum pitch-up attitude is reached at the 45° point. The rate of rolling into the bank must be such as to prevent the rate of turn from becoming too rapid. As the pitch attitude is raised, the airspeed decreases, causing the rate of turn to increase.

Since the bank also is being increased, it too causes the rate of turn to increase. Unless the maneuver is begun with a slow rate of roll, the combination of increasing pitch and increasing bank will cause the rate of turn to be so rapid that the 45° reference point will be reached before the highest pitch attitude is attained.

At the 45° point, the pitch attitude should be at maximum and the angle of bank continuing to increase. Also, at the 45° point, the pitch attitude should start to decrease slowly toward the horizon and the 90° reference point.

As the aircraft’s nose is being lowered toward the 90° reference point, the bank should continue to increase.

When the airplane completes 90° of the turn, the bank should be at the maximum angle (approximately 30°), the airspeed should be at its minimum (5 to 10 knots above stall speed), and the aircraft pitch attitude should be passing through level flight. It is at this time that an imaginary line, extending from the pilot’s eye and parallel to the longitudinal axis of the aircraft, passes through the 90° reference point.

Lazy eights normally should be performed with no more than approximately a 30° bank. Steeper  banks may be used, but control touch and technique must be developed to a much higher degree than when the maneuver is performed with a shallower bank.

The pilot should not hesitate at this point but should continue to fly the aircraft into a descending turn so that the aircraft’s nose describes the same size loop below the horizon as it did above. As the pilot’s reference line passes through the 90° point, the bank should be decreased gradually, and the aircraft’s nose allowed too continue lowering.

When the aircraft has turned 135°, the nose should be in its lowest pitch attitude. The airspeed will be increasing during this descending turn, so it will be necessary to gradually relax control pressure and to simultaneously raise the nose and roll the wings level.

As this is being accomplished, the pilot should note the amount of turn remaining and adjust the rate of rollout and pitch change so that the wings become level and the original airspeed is attained in level flight just as the 180° point is reached.

Upon returning to the starting altitude and the 180° point, a climbing turn should be started immediately in the opposite direction toward the selected reference points to complete the second half of the eight in the same manner as the first half.

The correct power setting for the lazy eight is that which will maintain the altitude for the maximum and minimum airspeeds used during the climbs and descents of the eight. Obviously, if excess power were used, the airplane would have gained altitude when the maneuver is completed; if insufficient power were used, altitude would have been lost.

Common errors in performance of lazy eights are:

• Failure to adequately clear the area.

• Watching the aircraft or instruments  instead of    the reference points.

• Peaks of the loops both above and below the  horizon not coming in the proper place.

• Control roughness.

• Persistent gain or loss of altitude with the completion of each eight.

• Allowing the aircraft to “fall” out of the tops of  the loops rather than flying the aircraft through

    the maneuver.

• Failure to scan for other traffic.

Chapter Summary

Advanced maneuvers provide additional pilot tools for safely dealing with expected and unexpected unusual attitudes. Additionally, advanced maneuvers provide additional pilot skill above and beyond the minimum practical test standards similar to those required for commercial pilot airplane.

Understanding trike aerodynamics of high banked turns plus throttle effects are fundamental concepts to understanding in the performance of advanced maneuvers.