GY501 fr

R/C helicopter web site and local Abitibi R/C Clubs

	With the advancements in piezo gyro design technology, various manufacturers have been working overtime to out do each other with that extra feature which makes their product more preferable. The "Heading Hold" technique implemented first on CSM gyro was probably the best thing that has happened since the introduction of digital proportional radios to the R/C industry. And it sets off other manufacturers scrambling to come up with units with similar capabilities.
The old meets the new. Note the difference in size.	The latest gyro from Futaba, GY-501, is their attempt to regain the gyro market with their version of heading hold called Active Velocity Control System (AVCS). This little gem has enough bells and whistles to make it one of the most flexible gyro on the market. Since it is not intended for beginners, setting it up may be a bit tricky. But before we go into that, let's check out some of its features.
	Physical Appearance: The gyro is housed in metallic anodized plastic casing, a bit heavier than its G501 predecessor. There are 4 screws holding the gyro casing together, one of them covered with silicon for possible anti-tempering purpose. The wire that comes out of the gyro is the standard Futaba black/red/white wire with normal servo lead, not the black insulated wires in their previous gyros. Some type of quartz technology was used in the gyro unit instead of piezo element to combat the temperature drift problem. Apparently the gyro's internal contains 3 piece of circuit boards surrounded by silicon. This was confirmed by a fellow heli flier Sid Epstein, who was also kind enough to send me a link which describes the internal of this gyro. UpdateHere is a link a picture of the gyro internals without the silicon.
	To an untrained eye, the gyro amplifier looks exactly like the Futaba GV1 governor. Similar to GV1, there are 4 push buttons, two of which for function select, and two for data settings in each function. The menu accessing logic is similar to that of Futaba 7/8UHP radios. The input/output jack layout is identical to previous Futaba gyros, two leads goes into rudder and gyro gain channel on receiver, two jacks to accept a servo and the gyro itself. The most noticeable feature on the amplifier is the 8 character dot-matrix alphanumeric display which provides a good feedback of adjustments being done. There is also a small dial for adjusting the contrast of the LCD display. There is no power switch on this gyro. Upon powering up the gyro, the screen displays some funny characters and the RX's voltage. It was not until today that I was pointed out about the "funny characters" was in fact picture of a helicopter spinning its blades. Cute!
	Included with the gyro is Futaba’s new 9205 servo specifically designed for GY501. The spec lists its speed at 0.11sec/60 degrees with 4.8 volts, but it seems to be faster than other servos I had. I can’t tell much physical difference between it and 9203 though. This servo operates at the standard frequency similar to all other Futaba servos. Therefore the "framing rate" setting on the gyro should be set to normal. Setting to "half framing" rate would fry the 9205, as it is reserved for servo specifically designed to operate in faster framing rates (such as JR's 2700G or Futaba's brand new S9250 digital servo). I also noticed my 9205 was buzzing constantly. This was confirmed to be normal.

Functions:

User are able to access 9 function layers from the push buttons, each of which contains adjustment to certain feature of the gyro. I have not had the chance to experiment with all these features, but here are brief explanations of what each one does:

V/voltage	This is the default display showing the current RX voltage. When the voltage drops below 3.8v, LOW BAT is displayed.
G: 1A 99% (1B,2A,2B)	Gain adjustment. 1A indicates gyro gain setting 1, in AVCS mode. 1N indicates gain 1 normal mode. There are 2 gain settings.
GDir NOR (REV)	Output polarity setting. This is used to reverse the gyro.
ACGA100% (NCGA,ACGB,NCGB)	Rudder servo gain. A and B indicates left or right side. Normal and AVCS settings are adjustable independently.
CD1A0% (CD1B)	Servo delay adjustment. This is a feature (similar to 9Z's servo delay) where you can delay the servo for smoother or faster pirouette. If your tail overshoots and then bounce back after a pirouette, increase this setting.
Trk +0%	Tracking adjustment. Another new feature where the "breaking power" of pirouette can be adjusted for smooth or harsh stops.
Frm NOR (HIGH)	Servo framing setting. This function is to set the frame rate of the servo control signal. Set to ’high’ to use half of the transmitter’s frame rate. The 9205 utilizes NOR rate, with HIGH being reserved for JR's 2700G or Futaba's new S9250 digital servo.
Mode CMT (AVC,NOR)	Operating mode setting. Setting to NOR will force the gyro to act like a regular gyro. AVC will force it to function in AVCS mode(heading hold). CMT will allow switching between normal and AVCS mode.
LmtA100%	Servo travel limiter. Limits the end point of rudder servo travel to prevent possible binding.

In addition, the LCD also displays these status messages:

**IDLE** This is displayed when RX is switched on with the TX being off.
**INIT** The gyro is performing power on initializing (5 seconds).
**** Gyro is updating neutral point.

Setups

gy501 amp on Reza Fatemi's XL-Pro

gy501 gyro on the back of XL-Pro

gv-1 on the other size of XL-Pro

GV-1 and GY-501 allows hands off hovering!

The instruction booklet I received wasn’t very helpful since it was in Japanese. The English manual is now available on top of this page. It does show some diagram of example setups for both 9Z and 8UHP TX. I opt to set mine similar to CSM to avoid complications. Basically the gain channel is used to adjust gyro gain and switch between AVCS and normal gyro modes. The gyro is in normal mode when the gain channel output is between 0% and 50%. 50% to 100% will switch the gyro into AVCS mode. The amount of output in each mode’s range is interpreted as the amount of gain on the gyro. No suprise here. What is very interesting is the way it centers the rudder trim. The way to trim this gyro is this: First the mounting point on the servo horn needs to be 13.5mm from the center, with the horn EXACTLY 90 degrees perpendicular to the sides of servo case. Up on powering up in the CMT mode, switch to normal mode and trim the rudder with rudder trim tabs. When satisfied, land the helicopter and then switch the gyro mode 3 times in one second between AVCS/Normal mode. This will force the gyro to memorize the center point for AVCS mode. There is no need to trim anything electronically or mechanically in AVCS mode. The LCD display will indicate the updating process through different codes. Should the gyro become off center for whatever reason (hasn't happen to me yet), repeat the above procedure will cause the gyro to re-memorize the centering point.

Another feature worth mentioning is that the actual gain as result of gain adjustment on TX and on gyro is displayed on the gyro’s LCD screen. In another words, the gain percentage display on the LCD is the actual gain calculated from the TX setting and the gyro setting.

Latest Update (12/14)

It has been a couple of months, and I have been trying to learn all the features on the gyro to fine tune its parameters and to explore its capabilities. Between busy work schedule and other commitments, I didn't have enough time to experiment much. I have since fitted my Baron30 with a carbon/titanium pushrod from Central Hobbies and a K&S tailboom servo mount. This combination was able to remove 90% of the slop in the system, which allowed the gyro gain to be increased a bit. The engine in the Baron seems to have broken in which is indicated by smoother transitions between needles.

My current gain in AVCS mode is at 47% in normal, and 30% in idle-ups, still well below the 70+% indicated in the manual. I thought it was due to the belt driven tail, but the tail still locks in perfectly. I had to play around with the channel delay and tracking to remove the bouncing effect after pirouette. Absolutely no drifting was observed, and the tail just stay pointed at where you left it! I have never tried my CSM in this Baron, but compared it to my Concept where the CSM used to reside, the GY501 is more precise with a crispier feeling to it. When I get the chance to move the CSM into the Baron, I will be able to make comparison and report any differences then.

The overall quality of the unit is superb, as expected from Futaba. With all these features incorporate in such a small unit, it should be a serious contender to the gyro market.

Update!
The new Futaba digital servos, S9250 and S9450 are now being tested by Futaba pilots. Apparently these servos utilizes the higher frame rates (I.E. JR's 2700G), but achieved differently with new digital servo amp circutry. The specifics are not clear, but it's supposed to make this super gyro even more superb. The specs of 9250 are listed at the end of this page. Expect these servos to be available in March/April of 1999.

Here are my final settings on a Futaba 9ZHP radio:

.	ATV	AFR
RUD	100%A-100%B	80%A-80%B
GYR	34%A-40%B	100%A-100%B

Channel Delay on rudder set to 60%. This has the same effect as CD feature on the gyro itself. The purpose of this setting is to slightly delay the signal sent to the rudder servo to reduce hunting caused by sudden rudder inputs.
GYR: Disabled
P->R: Disabled

On the gyro itself:

	Lim: 86% - 90%
	Trk: 12%
	CD1A: 0%, CD1B: 5%
	G1A: 30%, G2A: 47%

YS's new 61ST2 engine

The other side

Close up of the 3-needle carb

YS 61ST-2 Engine

As my luck would have it, Reza fatemi was running the new YS 61ST-2 engine on the XL-Pro where the pictures of GY501 were taken. The heli was screaming doing fast forward flight using Hatori muffler and 30% PowerMaster synthetic. According to Reza, this engine puts out noticably higher power than the previous 61ST. The new 3 needle carb allows fine tuning of the throttle curve. Expect this engine to be available in the near future.

Specifications

GY501

Operating voltage Range: 3.8-6.0V DC
Current Consumption: 60mA
Operating Temperature: -10C ~ +50C
Operating Humidity: 10%RH ~ 90%RH
Dimension: 56.5x30.5x16mm
Weight: 34g (amplifier) 55g (gyro)

S9205

Speed: 0.11sec / 60 degrees
Torque: 5.5kg-cm
Dimension: 40.5 x 20 x 37.5mm
Weight: 53g

S9250
[Image 1] [Image2]

Speed: 0.11 sec/60 degrees (4.8v)
Torque: 5.5kg-cm (4.8v)
Dimension: 40.5 x 20 x 37.5mm
Weight: 54g

This from stephen's web page ->http://stephen.eni.net/heli/gyro/

I promised to put in some disclaimers on this page, so here it goes:

All above content are the opinion of the author. Futaba does not guarantee any comments or claims made on this page. Any comments or feedback are greatly appreciated.

Futaba, AVCS, and all pictures are copyright by Futaba Corporation of America.

Thanks to Reza Fatemi for helping me set up the AVCS mode and patiently answer all my questions.

Thanks to DA and Ranger for their help and translation of user’s guide.

Physical Appearance:

Functions:

Setups

Latest Update (12/14)

YS 61ST-2 Engine

Specifications