General Technics Ridgefield, CT (203) 431-9056

General Technics – Ridgefield, CT (203) 431-9056

Check Your Angle CYA-100

Installation and Operation Manual

1.0 General

1.1 Angle of Attack

Angle of attack (alpha,a) is the angle between the chord of an airfoil and the relative wind. An airfoil will stall, and stop providing lift, at a fixed angle of attack, unique to each airfoil shape. That angle does not change appreciably over changes of airspeed, bank angle, g load, or aircraft weight.

Many fixed wing aircraft have some kind of stall warning system, which illuminates a light or makes a warning sound (or both) at, or shortly before, stall. The problem is that most of these systems do not actually measure angle of attack, but just warn when there is an abnormal pressure difference between the top and bottom of the wing. This is not at all the same as angle of attack. Stall can occur at ANY airspeed and is dependant on g-load, bank angle, and center of gravity location. ONLY angle of attack can predict when the wing will stall regardless of these factors.

While a stall warning system is better than nothing, it’s a bit like getting a warning shout AFTER stepping off the cliff. And in a fixed wing airplane, the edge of the cliff keeps moving!

The General Technics CYA-100 constantly keeps track of the “edge of the cliff”, and lets you know just how far away you are!

1.2 Why Use a Vane

There are several methods of measuring angle of attack. One is to measure the pressure difference between the top and bottom of the wing (DP), and divide the result by total ram air pressure (Q). The equation DP/Q can be a very good measure of angle of attack, but at General Technics we don’t like the idea of a measurement that is “one step removed” from what we want to display. And we didn’t want little holes for the required pressure sensors. We know that mud daubers and other critters just love little holes (like static ports and pitot tubes).

We wanted to make our CYA-100 system as affordable, small, light weight, and reliable as possible. Using

a vane is simply the most direct method of measuring a wing’s true angle of attack.

1.2.1 Part Number CYA-100 Installation Kit

The CYA-100 angle of attack system is supplied as an installation kit consisting of:

1) P/N TAOA-100-1 Display Processor with connector and mounting screws

1) P/N TAOA-100-2 Vane Probe with mounting screws

1) Interconnect cable

2) Heat shrink tubing

1) 63/37 RMA flux core solder

1) Programming switch

1) Installation and Operation Manual

Works for the Heavy Iron

1.3 TAOA-100-1 Display Processor

The TAOA-100-1 display processor is a single circuit board built to aerospace standards using Surface Mount Technology. The entire unit is potted in tinted, optical urethane for protection from the environment and for visual contrast enhancement.

A 12 pin Molex™ Picoblade™ connector is used to interface the TAOA-100-1 to the aircraft and to the TAOA-100-2 vane probe.

Ten high brightness color coded Light Emitting Diodes (LEDs) are used to indicate angle of attack, to a resolution of 0.35 degree over a user programmable range of 0-360 degrees. The LEDs dim automatically for night flight, and at full brightness are easily viewable in direct sun light. Programming of the display angle range is done by simply pushing a button.

1.4 TAOA-100-2 Vane Probe

The vane on the TAOA-100-2 vane probe assembly is made of ultra-violet resistant acrylic and anodized aluminum. Inside the vane is a rare earth magnet, and the magnetic field signals an Integrated Circuit Hall Effect device at what angle the vane is “flying”. The entire TAOA-100-2 vane probe is hermetically sealed, requires no lubrication, and can be safely washed down with the rest of the aircraft. There is no place for critters to build nests, or plug with mud, and the vane probe is permanently fixed in place. Calibration of the CYA-100 angle of attack system does not require adjustment of the vane probe in any way.

1.5 Bells and Whistles

The TAOA-100-1 display processor has one audio output which is active when the last RED LED is

illuminated. Capable of driving loads down to 32 ohms, it can be connected either directly to the pilot’s headset, or to the aircraft audio panel. The audio is a unique, VERY loud, high pitched warbling tone. Studies have shown that trained pilots can react almost instinctively to a unique tone, while voice commands need to be “heard” and “interpreted” before the pilot can take action. If needed, a 1/4 watt resistor of any selected value may be placed in series with this output to reduce the volume.

2.0 Installation

The CYA-100 angle of attack system is fully compliant with Federal Aviation Administration (FAA) Memorandum No. AIR100-14-110-PM01 dated February 5, 2014 and its latest referenced ASTM International Standard F3011.

2.1 TAOA-100-1 Display Processor

2.1.1 Mechanical

The TAOA-100-1 display processor is very small (2 x 1.25 x 0.375 inch) and very light (28 grams, or one ounce), and can be mounted almost anywhere, and in any position. But, we designed the display to be a “command instrument”, like a glideslope display or a VOR needle. We think it is more natural for the pilot to follow the display indications with control inputs (display down, nose down):

A) Mount the TAOA-100-1 display with the RED LEDs DOWN, and the GREEN LEDs UP. As the airplane approaches stall, the LEDs will descend from green, through yellow, to red. The pilot should push the stick or yoke to allow the aircraft nose to follow, and prevent stall. To assist with orientation of the display during installation, the mounting screw hole for the RED end of the display is color coded RED. Additionally, the label on the display is clearly marked “THIS END UP”.

B) The TAOA-100-1 display should be within direct view of the pilot, but not so as to obstruct or distract from the normal view of the pilot, including the primary flight instruments. Many pilots find that a position just under the glareshield and between the top “6 pack” instruments is ideal. The small size of the TAOA-100-1 helps with mounting in this position. Just don’t place the unit where it can’t “see” the cockpit environment, so that the automatic dimmer function will do its job.

C) The TAOA-100-1 display is mounted with two, 3/8 inch long, 4-40 thread, 100 degree flat-head Phillips stainless steel machine screws. Use a 1:1 copy of Figure 1 as a template to locate and drill seven (7) 0.113 inch diameter (#33 drill) holes in the aircraft instrument panel or other suitable surface. Countersink the top and bottom holes with a 100 degree countersink so that the mounting screws will be flush with the panel. Preferably using a step drill, expand the inner five holes to 0.250 inch diameter, and file or route between the holes to fit the TAOA-100-1 display face when it is mounted from behind the panel or mounting surface.

NEVER use any kind of thread locker, like Loctite™, on the mounting screws! A drop of waxy preservative, like LPS-3™, or a dab of paraffin or beeswax on the screw threads is more than enough to keep the screws from loosening.

2.1.2 Electrical

The TAOA-100-1 display processor J1 connector is a 12 pin Molex™ Picoblade™. The pin-out orientation is noted on the display label. Because the crimp terminals are so small, and most installers will not have the special (and expensive) tool to apply them, 7 pre-crimped, color coded 28 gauge leads are supplied. These seven leads are already inserted into the mating connector for the required V+ (white), Airframe Ground (black), Programming Switch (blue), and (optional) Audio Output (orange) connections, and the three probe wires (red, green, and yellow).

Refer to Figure 2 for required wiring. FAA AC43.13-1B, Section 11 should be used as guidance for the wiring installation. Note that the CYA-100, as a stand-alone system, MUST have its own dedicated power switch to enable isolating it from the aircraft power bus.

The system will operate over any input voltage from 7-30 volts DC, and will withstand reverse connection and alternator load dump. The maximum current consumption is 0.075 amperes.

2.1.3 Audio

The optional audio output at connector J1, Pin 7 is a ground referenced 5 volt peak-to-peak, AC coupled signal. It is capable of driving a 32 ohm load at a level of 750 milliwatts. This level is painfully loud, and a series resistor of 1/4 watt rating should be placed in series with this output to limit the volume. The value of the resistor will depend upon the intended load, which may be directly to the pilot’s headset jack or the input to an audio panel. Values of 150 to 100,000 ohms are commonly used, but must be selected based upon the installation.

2.1.4 Programming Switch

An SPST pushbutton switch is provided to program the display unit by momentarily shorting connector J1, Pin 10 to airframe ground. The switch is only used for the programming operation, and should be removed after programming the CYA-100 installation. Alternatively, the wire from J1-Pin 10 can be manually shorted to a clean point anywhere on airframe ground to program the unit. However, using the switch provides a cleaner, more “bounce free”, and repeatable connection during the programming process.

2.2 TAOA-1001-2 Vane Probe

2.2.1 Mechanical

The 56 gram (two ounce) TAOA-100-2 vane probe is a streamlined aluminum extrusion. At an airspeed of 250 knots, the TAOA-100-2 has a drag of less than 0.7 pound. The vane probe must be mounted in undisturbed air, at least 18 inches outside of the propeller arc, and preferably at least 4 inches from the wing tip. The vane probe must be mounted as far forward under the wing as possible (no more than 4 inches aft of the wing leading edge). The vane assembly is mass balanced to very close tolerances, and must never be painted.

The vane probe is mounted, blunt edge of the streamlined extrusion forward, using the two 3/8 inch long 10-32 stainless steel fillister head screws provided. A fabricated aluminum backing plate is recommended. Use a 1:1 copy of Figure 1 as a template to locate and drill the three required holes in the inspection plate. Mark the interior surface of the plate “FWD” so that it will be correctly oriented during future aircraft maintenance and inspections.

Many aircraft have inspection panels under the wing which meet these location criteria; otherwise, refer to FAA AC43.13-1B, FAA AC43.13-2B, and the aircraft structural repair manual for guidance and acceptable practices.

The vane probe will withstand normal wash-down, and is impervious to all normally encountered aviation fluids, including de-ice glycol, alcohol, skydrol, and 5606 hydraulic fluid.

2.2.2 Electrical

The vane probe has three wires. The RED STRIPED wire receives +5 VDC from J1/Pin 5 (red) of the TAOA-100-1 display processor. The wire NEXT to the red striped wire is signal ground, and must be connected to J1/Pin 6 (green) of the TAOA-100-1 display processor. The remaining wire is the vane probe output signal, and must be connected to J1/Pin 4 (yellow) of the TAOA-100-1 display processor.

Refer to Figure 2 for wiring. Once the cable is routed and securely fastened per FAA AC43.13-1B, Section 11, the interconnect cable should be stagger spliced to the probe and connector wires, with each wire being insulated with the included small heat shrink tubing, and the entire splice area also covered with the length of larger heat shrink tubing. Use ONLY the provided RMA 63/37 flux solder for these splices. More active fluxes and different solder alloys are NOT recommended!

Pay careful attention to the wire and terminal orientation! Thirty (30) feet of interconnect cable is supplied. If longer runs are needed, use readily available 4 conductor, 26 gauge stranded telephone cable, such as ICC P/N IC1000S4SV. This cable is commonly used for the installation of Emergency Locator Transmitter (ELT) remote actuation switches, and has demonstrated excellent service in that application.

2.3 Power On Self Test (POST)

2.3.1 General

At this point, the vane probe will be wired to the display processor, and the display processor will be wired to the aircraft bus through a fuse or circuit breaker, and to airframe ground. The temporary programming push-button switch will also be wired between the display processor and airframe ground. There may or may not be a connection from the display processor to the pilot’s headset or aircraft audio panel.

2.3.2 Power Up

After the conditions in 2.3.1 above are met, turn ON the ship’s power to the General Technics CYA-100. During POST, the display will repetitively “strobe” from red, through yellow, to green while gradually increasing to maximum brightness.

At the end of POST, the display will show one of three possible LED patterns:

A) Two GREEN LEDs at maximum brightness – No +5VDC at vane probe, or no signal from vane probe (check wiring and probe)

B) One or Two RED LEDs at maximum brightness - No GROUND at vane probe (check wiring, and ground resistance at display)

C) One LED, any color, brightness dependant on ambient lighting – System good, proceed to programming. If the bottom RED LED is on, the stall warning tone (if installed) will also be on. Move the vane on the probe to stop the warning tone.

3.0 Programming

3.1 General

The General Technics CYA-100 contains a microprocessor which must be programmed to correctly show the angle of attack for each particular aircraft installation. Programming is a simple, two step process using the previously installed push-button switch. Once programming has been completed, the switch may be permanently removed.

During the programming process, many aircraft owners discover that their airspeed indicator is not accurate. If that is the case, it is strongly recommended that the airspeed be calibrated before proceeding further. An accurate airspeed is the only way to ensure that the aircraft V speeds are in agreement with the aircraft Pilot’s Operating Handbook (POH).