How to: 8FG Gov menu and Revlock - three headspeeds
by, 22-04-2012 at 11:59 PM (254 Views)
I spent a while racking my brain trying to get this to work, and I'm sure there's probably a dozen how tos already out there, but I thought I'd write this small guide.
The Revlock Governor
As those who have used it will know, the Revlock governor has it's own built in dual headspeed feature. Typically, the user adjusts the end points to gain two speeds via a switch. A negative amount of travel (switch up for example) will select mode A, and a positive amount of travel (switch down) will select mode B. The purpose of this is to adjust these EPA values and watch the lights to choose your desired range and speed. More detail can be seen of this from the Revlock manual: http://www.rcmodels.org/csm/RevlockManual.pdf
This is great if you just want two headspeeds for normal and idle up 1 for example. But what if you want three speeds? There is no 'C' mode so you can't do this just via the Revlock itself. But there is a way...
8FG Governor Menu
Without going into too much detail, the governor menu is a simple way that allows the use to quickly control headspeeds without having to fiddle with EPAs directly. Like the GYRO menu, it can be configured to a standard switch, or tied to the COND (condition) menu. When using it with Futaba's CGY750 it is fantastic, as you just tell it via the menu what headspeed (2000 for example) you want and it takes care of it for you. The Revlock isn't quite as fancy and relies on the 'old fashioned' EPA value. The 8FG's governor menu has two methods of use controlled via the mode option: % and RPM Ranges (1000-2000 etc). We will be using the % method.
So how do you use this menu to tell the Revlock what headspeed to run? How do we use the governor menu with this?
First of all, make sure the EPA for the governor channel (7 typically, I have mine set to 2 as I'm using SBUS) is -100 to +100 so it's giving a full range.
Program the Revlock RPM range (by lowering the throttle channel to idle and using the button to choose one of the four ranges); I chose the 11k+ range. Now because we're using the % mode in the governor menu, 0% translates as -100EPA, with 100% being +100% EPA. As said earlier 0 to -100 EPA on the governor channel is one mode on the Revlock, and 0 to +100 EPA is the second mode. The Revlock only accepts values +/-5% from neutral, so that means we can only use 0-45% and 55-100% in the governor menu. 45%-55% is a deadband (governor off).
So, what we're doing is tricking the Revlock to see three different EPA readings. You don't even have to use both modes A and B on the Revlock, but I chose to as to have another reference to check everything is working. As you can see, in both Modes A and B, I have the range in 14k+. Now what we need to do is move the throttle stick above the threshold so the governor arms (shown by the ARMED LED).
Usually, we would just go into the End Point menu and adjust the values for governor and watch the LEDs on the Revlock. Instead what we need to do is flick into normal mode (mode A) and change the % value whilst keeping it between 0 and 45% to ensure we stay in Mode A. I have mine set on exactly 45% which gives me no range lights on the Revlock. In the 14k range, this gives me 14000RPM which, on an 8.5:1 ratio, gives me a headspeed of ~1650.
Now, flick into Idle 1, and make sure you set a % of at least 55%; it doesn't matter exactly what for now. The mode LED on the Revlock will jump to B. Again, looking at our RPM selector chart (Revlock manual) choose the light combination for the engine RPM you want - I chose 15250 giving me a headspeed of ~1800. This is 68% in the governor screen.
Finally flick into Idle up 2 and, again, make sure the % on the governor screen is above 55%. You will see the mode LED still says B. This does not matter. All you need to do now is choose a % on the governor screen to give you the LEDs you need. I chose a RPM of 17250 giving me a head speed of ~2000, which is 82%.
So, now you're all done. Most will read this and think "well, I already knew this so what's the point?". I didn't, and there are others out there who won't know this either, so I wrote this quick guide.
Things to remember:
- 0% in the Governor menu is full travel of the channel one way, with 100% being full travel the other.
- You can easily change it from the COND switch to any other.
- If you still want to use the A and B mode, the gov % has to be 45% or under for A, and 55% or above for B.
- Use Logic switches to set up more than 3 headspeeds using combinations of several switches.