slider46
rrProfessor
Location: Gloversville, NY
| Here is a post from the trex forum that I was reading last nite from Dkshema It will explain the entire setup and programing for a ccpm head...
GENERIC CCPM SETUP:
It's based on a JR radio (DX7 is the same) -- as far as channel assignments, but for whatever brand radio -- the receiver plugs are labeled Aileron, Elevator, and collective pitch is usually the AUX 1 channel.
Typical 120 degree CCPM Setup:
Plug your servos into the correct channel on the RX. You have three servos controlling the swashplate. One connects to either the front or the rear of the swash, the other two are 120 degrees apart, on either side of the heli's centerline.
The servo connected to the ball that is in-line with the heli centerline (either fore, or aft of the MR shaft) is the "Elevator" servo, and plugs into the ELEVATOR channel of your RX (in a JR/DX7 system the servo plugs into RX channel 3).
One of the remaining servos that controls one "side" of the swashplate (it doesn't really matter at this point) plugs into the Aileron channel of the RX (RX Channel 2 for a JR/DX7 system).
The third servo which drives the other "side" of the swashplate plugs into the PITCH channel of the RX, generally the AUX 1 channel (channel 6 in a JR/DX7 system).
Select the 120 degree swash CCPM mix in your TX. Set all trim settings to zero, no trim in any direction. Go to the SWASH mix menu, and set ELEVATOR, AILERON, and PITCH numbers to +65. This is only a starting point, we'll fix the SIGN of the number (+/-), and the SIZE of the number (bigger/smaller) later on down the page.
Ignore the direction of the servos for now. We're about to fix that:
Two servos in CCPM mix tilt the swash left and right. All three servos tilt the swashplate fore and aft.
Go to your servo reversing menu.
The two servos that tilt the swashplate for left and right will be the servos plugged into the aileron and pitch (auxiliary 1, probably) channel.
Using the servo reversing function, make these two servos move such that if you command a left turn, one moves up, the other moves down. Don't worry if they don't seem to move the correct direction, just make sure that they go in opposite directions when you move the stick left and right.
Now, move the stick for fore/aft cyclic. The servo connected to the elevator channel on the RX needs to have its direction set so that when the pitch and aileron servo move UP together, the elevator servo moves down (and when the elevator servo moves up, the other two move down). Use the elevator reversing function to make this happen.
Now you have the aileron and pitch servo moving in opposite directions for left and right stick, and you have the aileron and pitch servo moving in the same direction as each other, but in opposite direction of the elevator servo for the fore/aft function.
Don't touch the reversing switches again. Leave them where they are. We'll now fix the function direction so the swash moves in the right direction with regard to the sticks.
Go to the swash mix menu -- the one that lets you set the aileron, pitch, and elevator mix percentages.
Move the aileron stick left and right. If the swashplate moves in the correct direction, the aileron mix is OK. If the swash tilts left when you command right (backwards from the stick), then reverse the "polarity" of your aileron mix number. If you have +65 selected, change it to -65 (and if you have -65 selected, change it to + 65). Changing from "+" to "-" (or "-" to "+" reverses the aileron direction in a CCPM setup. The actual VALUE of the number increases (bigger number) or decreases (smaller number) the amount of travel you get from the associated function.
Move the elevator stick forward. If the swash tilts in the correct direction, fine. If the swash tilts the wrong direction (back when you command forward, for example), change the "polarity" of the elevator function -- if you have "-65" set, change it to "+65" ( and vice versa). This reverses the fore/aft cyclic function in a CCPM setup.
Move the throttle stick full open. You should get more positive pitch (leading edges of the blades tilt up). If the collective pitch is backwards (you get negative pitch when you command full positive) then reverse the "polarity" of the pitch mix -- if you have it set to "-65", set it to "+65" (and vice versa). This is how you reverse the pitch function in a CCPM setup.
Playing musical chairs with the servo reversing function at the same time you mess around with the swash mix will drive you nuts.
With a linear 0 to 100% pitch curve, set your collective stick to its midway setting (middle). The three servo arms controlling the swash should be in the middle of their travel range. Due to the way the splines on the servo shafts are designed, you'll have to try different positions of the servo arms on the shaft to achieve this. In addition, you may also need to mess with sub trim to get the servo centered with the collective at its midpoint. The arms are either going to be horizontal or vertical, depending upon servo arrangement.
The swash should be horizontal, and perpendicular to the MR shaft. Adjust the pushrods supporting the swashplate to make this happen.
At this setting, your blades should have ZERO pitch, the washout arms and the pitch mixing levers should be horizontal. Adjust pushrods to achieve this setting. The pushrods up on the head generally go in pairs. Make each pushrod in a pair the same length -- follow the helicopter build instructions to get the proper length of each pair of pushrods.
The swash should be in the middle of its up and down travel distance at this setting. Adjust the pushrods supporting the swashplate to achieve this setting.
So, with a linear pitch curve, at mid collective, the swash is level, the servo arms are in the middle of their travel range, the washout and pitch mixing levers are horizontal, the swash is in the middle of its travel range and the blade pitch is zero degrees (check both blades and adjust as necessary).
At this point you can select the various flight modes you are going to use and customize your pitch curve settings to match the flight mode.
If you need more overall COLLECTIVE pitch travel, increase the value of the number in the PITCH mix menu for the CCPM swash setting. If you need less overall pitch travel, decrease the value of the number in the PITCH mix menu for the CCPM swash setting.
If you need more Aileron CYCLIC pitch, increase the size of the AILERON number in the swash mix menu. If you need less Aileron CYCLIC pitch, then make the AILERON number in the swash mix menu smaller.
If you need more Elevator CYCLIC pitch, increase the size of the ELEVATOR number in the swash mix menu. If you need less ELEVATOR CYCLIC pitch, then make the ELEVATOR number in the swash mix menu smaller.
Tom..... No "D" flying.... |
