FPV-Community Reviews

There are already various flight stabilization systems for model airplanes on the market. Now, because of their small size, weight and handling, they are more suitable and affordable for FPV. The new FY-20A (basic) and the FY-21AP (with Return Home feature) are excellent examples of such systems. These systems have no sensors outside the model and perform in every weather condition as well as in complete darkness.
The FPV shop www.fpvflying.com has provided us with the basic version, the FY-20A.

Technical data (manufacture data)

Type: basic version FY-20A gyro 3- axes stabilization

Input voltage: 4.0 to 6.0V
Current draw: 5 mA (5V)
Size: 55× 33 x 20mm
Weight: 20g
Temperature range: -25°C – +70°C
Maximum rate of rotation: < 1200 °/s

Application: normal plane with or without aileron, with v-tail or standard rudders, and planes with delta mix

Compatible remote control systems: Robbe-Futaba PPM / PCM 1024 / PCM G3 Mode Graupner JR PPM 8, PPM 12, SPCM Mode Multiplex PPM 8, PPM 12 with UNI Mode 1,5ms

Packaging and content

The package arrived well packed in an air cushion bag delivered by DHL. The accessories were extensive. The module itself is in a light blue transparent housing. Its size is 55mm x 33mm x 20mm and weighing only 19g. Contrary to many similar products this module is not covered with simple heat shrink. The housing is robust and can be unscrewed.
If you want to save weight, you can take out the circuit board; it’s only 9,5g.
In addition the unit comes with four JR- servo connectors with 18,5cm length cord, one plastic shock mount, two Velcro tapes and an illustrated English manual.

Functional principle and installation

The FY-20A offers stabilization on three axes (elevator, rudder, aileron). It’s even possible to control models with v-tail or delta mix. The model type is selected via plug contact. The stabilization is provided by three gyro sensors and processor controlled electronics.

Schematic picture of the function:

Unfortunately the system needs a y-cable for the second aileron. So it’s not possible to set an aileron differential via the transmitter. If the servos are running in the same direction, it’s possible to buy an electrical y-cable with switch able inverting. In the test we tried to misuse the rudder axes for the second aileron, but failed.

The installation is done in a few steps. You should install it in a position with good airflow, to have a constant temperature. Otherwise the gyros will drift too much. The manufacturer suggests resetting the module before the flight, if the temperature fluctuates more than 30 °C. The same should be done after a longer break. Possible problems with the gyro drift are explained in the flight test chapter.

The FY-20A calibrates itself after powering up. Once adjusted, there are no additional steps necessary before flying.
The module is mounted with Velcro tape onto the shock mount. The printed arrow on the module must point in the flight direction.
The FY-20A must be connected with the following channels from the receiver: aileron, elevator, rudder and a free switch channel. Here we use the four servo cables provided. The switch channel is a user defined switch of the transmitter, like a three position switch. It’s used to toggle the three different modes:

• Mode 1: Deactivated – normal RC control – no stabilization
• Mode 2: 3D-Mode – stabilization with automatically recognizing the latest position of the aircraft – control deflection is unlimited
• Mode 3: Auto balance mode – aircraft will enter horizontal level flight, when the transmitter’s control sticks are centred. Deflections are limited and the FY20-A will not allow any acrobatic flights.

The modes can be switched in flight if desired. You will need a 3 position switch on your transmitter. If you have only a 2 position switch, you can only choose between mode 1 and 2 or between mode 1 and 3.

The ailerons are connected through a y-cable to the unit. Rudder and elevator are also directly connected to the module. We had no problems with the connections during our test. All plug connections were stable and the connections were secure.
During the first start-up you have to check for the correct rotation directions of the servos and the rudder effect in the stabilization mode. With the help of the three rotation potentiometers you can set the maximum deflections and the correct rotating direction. We suggest using as little deflection as possible to get the right feeling during flying. Too much deflection can cause a crash, if you are not fast enough to deactivate the stabilization during the flight.
Ultimate Attention is required and the maxim “Less is more” is valid here.

Flight tests

For the maiden flight we chose the Bormatec MAJA. We did a test flight with and without the shock absorber during low wind conditions. We flew the MAJA without stabilization to a secure flying level and switched to mode 3. At this point the FY-20A fully controlled the plane. We were amazed how stable the MAJA was, even with its weight of around 3kg. Even stronger gusts of wind had no negative effects. This is one of the main advantages of this system. We couldn’t control the MAJA as well as the FY-20A in those wind conditions. There was no flight path deviation noticeable. The MAJA flew stable and smooth.
Controlling while on mode 3 took some getting used to. It is like having 100% expo on all channels, we adjusted quickly. The model was responded very well and the flight felt very secure.  You should watch the flying speed during an autonomous gliding flight, especially with non self stable models, because of the risk of stalling.
In mode 2 (3D-mode) the control effects are neutral and you can fly as normal. The FY-20A in mode 2 worked like a head holding controller. The FY-20A tried to maintain the plane’s position every time we released the control sticks. Our aircraft and settings were certainly not the set up for 3D flight. To do this would require fine-tuning of the deflection values. Basically the 3D-mode works as it should and is perfectly suited to the ambitious 3D flyer.

The FY-20A does not like vibrations. That’s why the shock absorber is very important. We made several test flights without this absorber and the FY-20A reacts irraticly. For this reason the FY-20A would not work well in a gas driven aircraft, though due to missing models we were unable to confirm this.  During tests was the weather quite hot, and we noticed a little drift because of the temperature fluctuation. We could fix that really fast and easy with a manual calibration.

For better exemplification we show you a flight video:

Conclusion

Compared to its competitors, the FY-20A is a small and lightweight device with well thought out engineering. The price of about 110 Dollar makes it affordable and attractive. The only thing missing was the second aileron connection. The stabilization system works very well and does make flying safer. The shaking so common in video and photographs is reduced and approaches for landing are easier. Flying in higher wind and even complicated 3D flying figures is easy, even for the untrained pilot. The system is not suited for the absolute beginner. An experienced pilot should help during assembling and configuration to avoid crashes.

Scoring

Pro
+++ reliable operation
+++ very lightweight
+++ small size
+++ uncomplicated and easy assembling
+++ modes switch able during flight
++ extensive accessories inclusive

Con
- – - no second aileron connection
- - little gyro drift in the case of intense temperature fluctuation
- manual only in English and sometimes mistakable

Further information about this product

• FY20A discussion thread – English
  
• FY20A discussion thread – German
  
• FY20A Review – German
  
• FY20A manual (last updated 29th July 2010)

Tags: autopilot, FPV, FY20A, FYETECH, RC, return to home, RTH, UAV

This entry was posted on Monday, August 9th, 2010 at 11:06 pm and is filed under Reviews. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.