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HomeAircraftHelicopterFlybarless Rotor Head SystemsFutaba CGY › CGY750: Governor setup (nitro engine) with a 12fg Futaba Radio
08-22-2017 08:49 PM  12 months agoPost 1
GHT

rrNovice

Cleveland, OH

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I recently upgraded my CGY750 to version 2.0 that is installed in my Trex 600N and decided to activate the internal governor. My first experience with the CGY750 governor did not go well. Before starting the engine, I set the throttle stick to idle, flight mode switch to normal, governor off (monitor on CGY750 displayed off), and then started the engine. Immediately, it revved to some high rpm. Fortunately, I had a grip on the head and blades and quickly pinched the fuel line to stop the engine. Whew! Not sure what I did wrong. After review, I did notice that when initially powering up the CGY750 a "!" was flashing on the unit, but the Gv value displayed Off. Only after switching the governor on and off, did the exclamation point disappear. When the CGY750 was setup, the rpm values were assigned to each of the flight mode parameters in Governor Basic. What is strange is when the governor switch is turned off, in Governor Basic, the mode and rpm value that display are 2:1500. Why is flight mode 2 displayed with some arbitrary rpm value of 1500? Flight mode 2 is set to 1450. I would appreciate some advice on how to setup this governor so the engine can be started at idle and then react to the rpms assigned to each flight mode. The list of parameter settings for the radio and CGY750 are listed below.

TRANSMITTER:
Make / Model: Futaba / 12fg with 2.4GHz module
Throttle Curve: All flight modes 0 – 100%
Function Settings: CH7 Governor, CH8 RPM (SD switch)
Governor Menu: Act/Inh: ON Unit:RPM Switch:SD (3-position On/Off/Off) Rate:Normal:1080, Idleup1:1450, Idleup2:1750

SWASH BASIC
Opr. Mode: Gyro + Gov

GOVERNOR BASIC
RPMset: 1:1080, 2:1450, 3:1750
Gear.Rt: 8.50 t
Pole.Nmb: 2 p
ServoTyp: DG:1520
Stick.SW: Inhibit
On/OffSW: ON (Note: Assigned to SD switch on radio (On/Off/Off)
LimitSet: Idle/High
Rev.Sens: 22%
SenseTyp: Nitro
Gv.Gain: C1 40%
LLmtLrpm: C1 25%
LLmtHrpm: C1 45%

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08-24-2017 03:39 AM  11 months agoPost 2
Dr.Ben

rrMaster

Richmond, VA, USA

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1,2 and 3 in the governor do not correspond to flight modes. They refer to rpms ranges that your headspeed(s) fall into.

When you did your initial set up, did you calibrate the governor's rpm settings to tbe transmitter's?

Ben Minor

Peak Aircraft/Team Minicopter Team Futaba Team Kontronik USA

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08-24-2017 12:06 PM  11 months agoPost 3
GHT

rrNovice

Cleveland, OH

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Dr. Ben,

If the flight mode switch does not correspond to the three rpm values how are the various head speeds selected?

The three rpm values in the transmitter's governor screen do correspond with the three RPMset values in the Governor Basic map. It did require a few +/- adjustments on the CGY750 to match with the values on the transmitter.

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08-24-2017 09:14 PM  11 months agoPost 4
Dr.Ben

rrMaster

Richmond, VA, USA

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I was unclear. What I meant was that depending on your rpm choices, you might only see 1 and 2 or 1 and 3 or 2 and 3.
Since the numbers on the 750 show what is in the transmitter, let me think on this a bit more.

Ben Minor

Peak Aircraft/Team Minicopter Team Futaba Team Kontronik USA

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08-24-2017 11:05 PM  11 months agoPost 5
helitom

rrApprentice

Pine Grove, Calif, USA

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FWIW - I have several 750's and had a similar problem to what you are describing with all. I found that inhibiting the throttle on/off function and not assigning that function to any switch solved the problem.

I always set throttle curves at Normal - a straight line from idle to full, Idle up 1&2 - generic V Curve. Those settings will give you a safe way to get home should the gov fail due to a broken wire, slung magnet, etc.

I have the gov function at the transmitter default go to off when the throttle curve is toward the idle position (I think its when the throttle stick is somewhere around the 17% position - you can adjust that point - the gov shuts off). That means when the idle up switch is in its normal position and the throttle stick is at/near idle, the gov is off. It also means that when flying in idle up 1or 2, the gov cannot be shut off by the throttle stick moving below the 17% position.

Anyway, it works for me.

Tom

The older I get, the fewer things seem worth waiting in line for.

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08-24-2017 11:32 PM  11 months agoPost 6
PaulBowen

rrKey Veteran

Victoria, Australia.

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I have been through all of this myself with the 18SZ and GY701.

I think it would be great if someone far smarter than myself wrote a definitive Futaba governor setup guide as neither the Tx or gyro/gov instructions are at all adequate or concise.

Futaba T18SZ, JR Propo XG14, Hirobo fanatic!

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08-25-2017 01:02 PM  11 months agoPost 7
GHT

rrNovice

Cleveland, OH

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Tom: I will try your method of activating the governor with the Stick.SW parameter instead of the On/Off SW, removing the governor switch assignment in the transmitter and setting a linear curve for normal and a V curve for Idle1 and Idle2. Do the governor values always override the throttle curves? What throttle curve values did you assign to hold?

Paul: Yes, it would be a tremendous help and time saver if instructions were available that provide detailed examples of setting-up the CGY750 governor with the various parameters. The process of activating the governor should be seamless, especially with all Futaba components (CGY750, 12fg, R6202 S.Bus and BPS-1).

Dr. Ben: The range of RPM values assigned to each of the RPMset values were selected to show each #1, #2 and #3 range. These values will change once I have a better understanding of how these settings interact with the governor and engine.

Should the throttle position of the LimitSet parameter for Idle be at 0 or at the position where the engine idles? With a BPS-1 RPM sensor installed, is it normal for the Rev.Sens parameter to always show 22% even when the engine is rotated with the starter?

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08-25-2017 06:26 PM  11 months agoPost 8
helitom

rrApprentice

Pine Grove, Calif, USA

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BTW - The first time I saw this issue mentioned was when the 750 was at firmware version 1.4. Back then, in RR, there was a long thread about this problem and possible solutions. Someone mentioned they solved the problem by inhibiting the gov on/off switch in the control box. I tried that and the problem went away. I have tried to figure out why this seems to work, but I couldn't.

Responding to one of your questions, when the gov is active and functioning, the RPM values you programmed in the gov over ride the throttle curves set in the transmitter.

All of the below is how I set up my 18MZ transmitter.

Hold - I have the same straight line curve for hold as I do for the normal mode. However, on my 18MZ there is a separate Throttle Hold menu function where I set the switch to activate hold and also set the idle offset when in hold. The function, when activated, does not reference the throttle curve - so whatever curve you have for hold doesn't matter. You should be able to check that the hold function is working on the bench without the engine running. Simply move the throttle stick to a high position then throw the hold switch when in each of the three idle up positions. The throttle servo should move back to the idle position for each idle up condition.

I have also spread my gov rate settings on the transmitter gov menu substantially between normal (15%), idle up 1 (50%), and Idle up 2 (90%). I don't know how much the rate settings need to vary for the gov to recognize a change, but I feel more comfortable with big differences at each idle up position. The Hold switch, in addition to setting the idle offset in Hold menu, is also set to inhibit the gov function in the gov menu.

Hope this helps.

Tom

The older I get, the fewer things seem worth waiting in line for.

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08-26-2017 03:47 AM  11 months agoPost 9
Dr.Ben

rrMaster

Richmond, VA, USA

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Limit for idle should be where the engine idles.

With the backplate sensor, you need to spin the engine with something like your starter to achieve the anticipated reading.

Ben Minor

Peak Aircraft/Team Minicopter Team Futaba Team Kontronik USA

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08-29-2017 01:51 PM  11 months agoPost 10
GHT

rrNovice

Cleveland, OH

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This past weekend I had a chance to test the changes made to the governor parameters suggested by Helitom. The governor is set to activate at 17% throttle stick position with normal, idle1 and idle2 of 1150, 1450 and 1750, respectively. In addition, a throttle curve was assigned to normal 0-100, idle1 70-65-60-65-70 and idle2 80-75-70-75-80. It appeared functional, “GvOn” displayed at 17%, the engine idled and revved fine in normal, then switched to idle1 and the engine ran slower. In idle2 the engine ran faster than normal and idle1. The problem is why is idle1 slower than normal when the governor rpms are incrementally greater? One thought was the transmitter's throttle curves were managing the rpms and not the governor. To confirm, the transmitter's throttle curve for idle1 was changed to match idle2, while the governor rpms remained the same. When switching from normal to idle1, the engine ran as fast as idle2 suggesting the governor is not active. Back to the bench.

Decided to remove the BPS-1 from the back plate to check for any possible oil, dirt or other contaminants that may be affecting the sensor. The sensor was relatively clean, however, two broken wires were revealed. This helped to explain why the sensor constantly displayed 22% and probably some of the ongoing governor issues noted in this topic. Wasn't exactly clear on the acceptable, minimum percentage, specifically for the BPS-1. Really surprised a percentage even displayed with two broken wires.

A new BPS-1 is now installed which displays 83% when cranking the engine. Hopefully, the sensor percentage is within spec to allow the governor to function properly.

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