More modellers/pilots/flyers have been installing electronic stabilizors into their model airplanes. These are small units plugged in between the receiver and the servos, which electronically senses movements in a flying model that doesn't correspond to transmitter input (example: the wind, not your transmitter control, makes the model plane roll), and then automatically corrects the flight path faster than human perception/input.
Some model airplane distributers, specifically E-Fliite, sell planes with these electronics already programmed into their receivers. Some receivers can be purchased with this technology already installed as well. A stand alone unit, such as the one I will be discussing here, can be used with receivers lacking this technology.
Previously, I have shunned the use of such components. After flying model airplanes for 40 years, I assumed that I would have little need for any type of flight-enhancing circuitry (that's called ego!).
Well, as it turns out, I have tried one, and I am really impressed. Especially with smaller, lighter and low wing-loaded model airplanes, the unit has really contributed to much nicer and smoother flying. Also, the unit in no way limits nor stifles extreme aerobatic maneuvers.
So here I go, sharing with you the installation of one of these units into a model airplane.
I will be installing a TL-70 3-axis gyro purchased from Banggood for under $30.
https://nz.banggood.com/3-Axis-A-AUX-Control-System-Gyro-Flight-Controller-Stabilizer-For-FPV-Flying-Wing-EDF-RC-Airplane-p-1333737.html?cur_warehouse=CN&rmmds=buy
Here is the online user manual for the unit.
https://imgaz.staticbg.com/images/upload/2014/04-1/3Axis%20Manual.pdf
I will be installing it in a Flite Test Widgeon. This is a small/medium twin motor semi-scale model that can be flown from land or water. In my opinion, the model is an excellent flyer, capable of steady slow flight, and extreme aerobatics. The motors spin in opposite directions (clockwise and counter clockwise), which contribute to its inherent stability. However, the plane does get bounced around a bit in the wind. The TL-70 should make the plane fly better in windy conditions.
First step is to fully build and fly the model without the gyro. Shown here is the model airplane, the gyro unit, 4 extension wires, and one square inch of thick and high-quality double-sided tape. Note: the tape is extremely important.
The information I am posting here is specific to the TL-70 gyro, and to the Flite Test Widgeon. While it may be similar to other units and model airplanes, there may also be differences. Always proceed with caution, and always keep safety in mind.
The TL-70 3-axis gyro.
Shown here are the gain pots, input and output ports, and the reversing switches.
The gain pots are adjustable dials for the quantity of stabilizing control for yaw (rudder), pitch (elevator) and roll (ailerons).
The input and output ports are for wires in from the receiver and out to the servos.
The reversing switches reverse the direction of how the unit corrects the flight pattern. I will explain more later. They do not reverse the direction of rudder/elevator/aileron deflection; your transmitter will still do that.
As you can see in the immediate above photo, the unit can handle setups for separate aileron control, delta wings and V-tails.
I am not covering that in this thread.
With a small flat-head screw driver, turn each gain-pot (dial) fully clockwise, to the maximum, until the dial stops. This will be for installation and testing, and will be dialed down later.
Put the 4 included servo extension wires into the IN ports. Note the wire polarity order (white, red, black) in the photos.
We will only be using the first (lower) wires in this installation: AIL, ELE, RUD.
The installation and testing only takes a few minutes, but taking and finishing/altering photos, and making these texts/posts, takes more time.
I'm taking a break, and will do more later.
Input wires are plugged into the appropriate ports in the receiver. Note the wire polarity.
This gyro is not used on the throttle nor any other channels. Those wires into the receiver are not changed in any way.
The 4th wire is not plugged in anywhere. I leave it loose.
Wire extensions to the ailerons, elevator and rudder servos (already installed in the model) are plugged into the appropriate OUT-ports in the gyro.
The included double-sided tape is applied very securely to the bottom of the TL-70.
The TL-70 is pressed down firmly, with the double-sided tape, near the C-of-G (balance) location, the length (longer dimension of the unit) parallel with the fuselage length.
It is extremely important that the unit is secured properly; if it comes loose during flight, the plane will likely crash due to loss of control. When this installation is complete, I will further secure the unit with a plastic zip-tie.
The model is re-assembled for testing. Access to the unit (gain-pots and reversing switches) will be needed once testing is finished.
***
I'm taking a break, and will finish this thread tomorrow morning.
Next step is to test the direction of the gyro corrections.
Essentially, if the plane noses down, then the gyro should automatically move the elevator up, or if it noses up, the gyro should automatically move the elevator down.
It will wiggle up and down, but the initial movement should be opposite to how the plane moves initially.
If the plane rolls left, then the gyro should automatically move the left aileron down, or if it rolls right, the gyro should automatically move the right elevator down.
It will wiggle both ways, but the initial movement should be to correct the roll. In other words, the ailerons must move in the direction to roll the plane back to level.
If the plane turns left, then the gyro should automatically move the rudder right, or if it turns right, the gyro should automatically move the rudder to the left.
It will wiggle both ways, but the initial movement should be to correct the turn.
Your transmitter and model airplane need to be powered on (either use throttle to cut to make sure the propeller won't start, or even better, disconnect the motor or remove the propeller for safety.
Make sure the transmitter moves the controls in the proper directions. Then, without touching the transmitter, hold the plane in your hands, and roll the plane left and right, and observe the aileron movements.
Gently and slowly rock the plane nose up and nose down, and observe the elevator movement.
Hold the plane level and turn the plane left and right and observe the rudder.
See if the gyro is moving the control surfaces (initial movement) in the needed directions. Different planes will react differently, depending on servos, placement of the gyro, and other factors.
Take note of which surfaces are moving the wrong way.
In my case, the rudder and ailerons were moving in the wrong directions. The elevator was moving in the right direction.
Using a small flat-head screw driver, I moved (reversed) the switch directions of the aileron and rudder switches on the TL-70.
Once I tested that all surfaces moved in the proper directions, I dialed the 3 gain-pots counter-clockwise all the way, and then dialed them clockwise about 20% or 25%. This is what I used on initial flight testing.
If the plane flies straight and smooth in windy conditions, the setting are good. If it is blown around in the wind, then the gain-pots need to be dialed clockwise some more. If the plane wiggles and waggles, then you need to dial the gain-pots counter-clockwise.
The marvels of modern technology!
Just to think that just a few years ago, this was only a dream.
How things have progressed quickly.
I have heard of people describing uncontrollable flying and/or crashes while using units such as these, but after investigation, the problem was that the unit became unstuck and moved to an unknown position/direction. In such a circumstance, the gyro would continue to "correct" the plane's flying in the wrong or unpredictable directions.
It shouldn't become loose, but it could. A very rough flight, rough landing, extreme cold or extreme hot conditions, could loosen the double-sided tape.
Just in case, I was able to to secure the unit to the plane with a plastic zip-tie.
Anyway, that's it. That's the installation and set-up of the TL-70 3-axis gyro.
If anyone has any questions, or wants to add more content, feel free to do so.
If I made any mistakes, please point them out.
Remember that this unit is simply used to make flight more stable and smooth in windy conditions. It will not correct pilot errors, and it will not save your plane from a crash or bad landing. You still need to fly the model as before.
I have since used one of these gyros in a plane (without retracts) with additional channel ports in the receiver.
I plugged the 4th wire into the (retract) gear port, and now the retract switch can turn the gyro on and off anytime.
Any unused receiver port will do, as long as you can assign a an on/off switch to it (flaps?).
Caution ...
It seemed that this gyro-stabilizer does not work with mixes (ailerons in different ports, rudder on differential steering, etc.), or maybe I don't know how to use it in those circumstances. Either way, be careful.
The unit continues to function exceptionally well in standard radio wiring situations.
Dave recently commented that my gyro-equipped PT17 was the most stable biplane he'd ever seen fly!
Quote from: Michael on May 26, 2021, 09:59:00 PM
Dave recently commented that my gyro-equipped PT17 was the most stable biplane he'd ever seen fly!
I think that's just the pilot! ;D
That's kind SIMON, but we both know that I'm not stable.