Governor question

[Ivan]

I have just installed a CSM revlock 10 on my sceadu.

The engine is an OS 50 with the same carb as the Hyper, but otherwise standard.

With the governor, I can't get the heli to keep from "burbling" where it comes in and out of a too rich to just about right. it is pouring loads of smoke out, and it seems to run ok, the throttle response is nice etc. If I do a hard climb out, the engine sounds just a tad lean on the top end, and if I adjust the low end to try and lean the midrange, it gets too lean to idle.

How do I handle this?

how do I know where the throttle is in a hover, since it is no longer linked to the throttle curve?

ANy help would be very appreciated.

Ivan

[z11355]

actually, the revlock DOES link to the throttle curve. it uses it to 'predict' where it has to move
the throttle and then uses actual engine RPM feedback to finetune.

have you adjusted the sensitivity control on the revlock?

in general, governors (and the revlock in particular), like a leaner engine than what your
ears would tell you is 'it runs great w/o a governor'.

[Ivan]

So I should inhibit the governor and re tune the throttle curves to fly without the governor?

Also is there any need for the cyclic to throttle mixes with a governor?

Lastly, am I understanding you right meaning that you should run a touch leaner tha you would without a governor?

Thanks again.

[BarracudaHockey]

The revlock does not like an overly rich engine. Thats not to say you need to burn it up, just that cold to the touch back plate isn't going to cut it.

Cyclic to throttle mixes, like proper throttle curves help the revlock as they minimize the difference between what is happening and what is required so the governor has less work to do.

Do your engine tuning with the governor bypassed, so that the backplate is warm but not hot and try it again.

[DavidH]

Cyclic to throttle mixes, like proper throttle curves help the revlock as they minimize the difference between what is happening and what is required so the governor has less work to do.

If proper throttle curves and cyclic to throttle mixes have to be set up. What is the point behind using the Rev Loc? I am not saying anything bad about the Rev Loc. I just thought the point of getting a governor was so that it could control the throttle without having to set up throttle curves or mixes. The other governors I have seen on the market really do not require
setting up throttle curves or mixes that I have aware.


David

[Ivan]

David,

I have asked the same question about governors in general for a long time. Why would a governor be needed if you can set up your heli properly?

At this point, I am becoming frustrated, since it took a pretty sweetly flying heli, and made it need to be re tuned, re setup and the engine is not following my general set of tuning guidelines.

That being said, the contrl the revlock has over the RPM is absoultely amazing. Other governors I have seen used seem to faulter on hard and fast collective movements, like "pumps" or hard and fast tic tocs. While I am not the greatest at tic tocs, I can say that using hard collective pumps the governor seems to keep the rotor locked to an RPM, and I can not audibly discern any RPM sags. It seems to be an edge over a well set up heli.

My biggest problem is getting the engine to settle down into a nice smooth note, instead of burbling, which is making the tail kick constantly, and it sounds terrible. This only occurs in a hover, and on climb out or loading the engine a touch more, it smooths out and flies like a champ.

Thanks to all who have replied, I may call upon your wisdom again :mrgreen:

[BarracudaHockey]

None of them "require" mixes or throttle curves to be set up. For idle up I just use a simple 100, 75, 50, 75, 100 and a 20 percent cyclic mix.

The governor just has more work to do if the signal the transmitter is putting out is farther away from whats needed than if its not.

You are correct, you watch a heli with a GV1 flying around through a skytach and the blades are moving under load and unload. With a Revlock they are locked in, even sitting at 0 pitch on the ground and slamming the stick to full will, with a well tuned engine, result in maybe a quarter turn or so, watch it with a gv1 and they swing all the way around till they lock in.

[DavidH]

The governor just has more work to do if the signal the transmitter is putting out is farther away from whats needed than if its not.

Why?

I would think once the governor is engaged. The only signal it needs from the transmitter is the one that tells it to turn off. That is how a governor is suppose to operate. Once it is activated, it goes to the set rpm and should stay at the rpm or close till the transmitter signal is sent to disengage or turn it off.

David

[WillJames]

from what I have seen of the Revlock, if you have it to sensitive it pulses the throttle.

[Ivan]

I think the ability to read the throttle curve allows the governor to "anticipate" the needs of the throttle, the curve will move quicker than the RPM will, and this would allow the governor to maintain a much finer controll over the RPM.

It is not unlike automotive engine managemnt,although on a much simpler scale. If the ECM were to use only the O2S (Oxygen sensor) for mixture control, the engine woudl almost become un drivable. The ECM uses several other sensors to help the mixture. The TPS, the MAP/MAF, CPS etc. the TPS gives the ECM a way to compensate for quick throttle moves (like the accellerator pump on a carb) the MAP/MAF gives updates on how much air is going into the engine, the crank position sensor gives RPM, and the O2S only provides fine tuning of the mixture, over long periods of time.

I suspect the magnet and sensor are like the O2S in the governor's programming, making fine tuning adjustments over a time. The throttle curve would be equivalent to the TPS, letting the governor give a command much sooner, based on a seperate parameter, in a sense being "procative" to some extent, rather than purely "reactive".

Clear as mud?

Ivan

[Ivan]

I guess Will nailed it, I moved the sensitivity down ever so slightly and the engine now hums along nicely in a hover.

It sounded exactly like an engine that is just slightly over rich, and burbles all the time.

Thanks for the suggestions guys. I learn something new on here everyday.

Ivan