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-   -   Programming crow with X Bus recievers (https://www.rcuniverse.com/forum/jr-radio-spektrum-radios-116/11632791-programming-crow-x-bus-recievers.html)

Ricko1 09-22-2016 08:56 PM

Programming crow with X Bus recievers

I want to programme some crow into one of my planes with my XG 14 and RG731BX receiver. The manual mentions crow but does not explain how to achieve it with powered planes, it only mentions it in reference to gliders. I have tried numerous times but can't seem to get it right.

Any advice would be most welcome.



AWorrest 09-22-2016 11:16 PM

What kind of aircraft do you have? Is it a biplane with four ailerons? Quique Somenzini used an unconventional way of hooking up the servos for his Beast that gave crow action.
If you have a monoplane with dual ailerons and dual flaps there is another way of doing it. Crow is accomplished through the transmitter programming without considering whether the wing servos are connected conventionally or through the XBus.

Ricko1 09-23-2016 03:37 AM

Hi Allan,

I have an Xcalibur jet that I think would benefit from having crow. At the moment it comes in for landings and glides on forever.

My set up consists of RX : RG731BX with a XB1- CV4 PMW converter ( 4 ports).

Channel allocations are:

1- throttle
2- aileron (right)
3- elevator
4- nose wheel
5- gear
6- aux1 flap
7- aux2 brakes
8 - XBus 02 - 01 aileron left
04 - 02 rudder left
04 - 03 rudder right
08 - 04 aux3 engine cut

With this set up if I check the servo movements with the radio "monitor" screen both the ailerons only operate on the one channel. Therefore I can not access the mix program to separate the two ailerons.

AWorrest 09-23-2016 12:19 PM

Looking at your channel assignments, you have only one aileron channel with both the right and left aileron tied to it. The right aileron is by the PWM port and the left aileron is on the XBus port. Similarly there is only one rudder channel for your dual rudders and brake. The XBus doesn’t create dual channels. It redirects the PWM channels to the serial bus and allows you the gang multiple servos onto one channel. This is different from having dual channels. You should first program your transmitter as if the XBus doesn’t exist and then use it to redirect the channels to the serial bus connector.
To get crow which is just having the ailerons act as spoilerons when the flaps go down. Start with a NORMAL wing type and dual/mate a channel to the AILERON channel. Then using the FLAP SYSTEM in the Function list. In that menu, you can set the flaps to go in one direction and the ailerons in the other.
If you want your rudders to act as air brakes, you’ll have to dual/mate a channel to the RUDDER and then use a program mix of FLAP -> RDVT.
I was going to recommend an alternative channel assignments but too many questions popped up, such as is the nose gear steering disengaged when the wheels are retracted. Is the steering travel less than the rudder? And do you have brakes on the nose gear?

Ricko1 09-24-2016 01:06 AM

Thanks Allan,

I think I understand now, When you said that Xbus allows you to gang multiple servos onto the one channel makes sense. That was where I went wrong. Will take your advice and try again.



AWorrest 09-24-2016 12:40 PM

I got a little carried away with offering a solution to your question. To have crow requires that the ailerons have the flaperon attribute. To have the flaperon attribute the wing type must have more than one aileron channel. In your situation, the FLAPERON wing type can’t be used as it doesn’t allow for an actual flap. So you have to use the NORMAL wing type with another channel mated to the aileron channel.
Once you have dual ailerons, if the output of the FLAP is set to SYS (its default setting) in the DEVICE SEL menu, the FLAP SYS menu in Function list will add a FPRN (flaperon) setting column on page 2 of the menu. Using this menu, you can set up a crow configuration for one of the flap switch position. Or you could do it the hard way and set up a FLAP -> FPRN program mix.

In the XBus when you used 02-01(or any other subchannel of channel 2) for the left aileron, you were using the same signal as is on the receiver’s channel 2 PWM port. While this signal allows you to actuate the left aileron servo for rolls, it won’t allow for more complex actions such as differential or flaperons. The transmitter has only one channel programmed for the aileron.
Sent you a PM on another subject.

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