faisalk

I wanted to buy the Paggy wagstaff extra 300 from Great Planes. It says that you need atleast a 7 channel computer radio. I have a Jr XP662(6 channel computer radio) I was wondering if I can use this radio or it is imperative that I have a 7 channel radio atleast.

shenion

Minnimum:

1 for throttle
1 rudder
1 elevator
1 ailerons

There are 2 elevator servos and one needs to be reversed. Easiest to use another channel slaved to the elevator.

2 aileron servos can by 'Y'ed together. I used two channels so i can trim each one on the radio. Most radios have a flaperon option,; just set it up with no flap mix.

I actually used 8 channels on my Patty:

1 left aileron
2 left elevator

3 throttle
4 rudder
5 Smoke pump
6 Right aileron
7 Right elevator
8 engine kill switch

You can get away with 4 channels, but adjusting may be a problem.

If you use a reverser on one of the elevators, you might get a different thow on one side. I have rewired servos internally to reverse them when using a 'Y-ed elevator.

One thing that is important. If you use two channels for either the elevator or the ailerons. The radio must have an option to mix the trims. I tried a 2-channel elevator on a 6XA and when you adjusted the elevator trim only one side moved. Useless.

You will want dual-rates or exponential.

I think one reason they said a 7 channel radio is you need to get to 7 channels before it provides the right mixing for dual-elevators. Since GP sells the Futaba 6XA and 6Y radios that don't provide the right trim mixing for split elevators, they probably say 7 channel.

My ainchient JR Max 6 would work (I think.) I have use it with mixing channels and I remember it working with the trims. I bet your XP662 has the capability. Try it, plug an extra servo in one of your planes and try setting up the channel to be reversed elevator and see if the trims work.

faisalk

I am sorry but all this is so confusing. Ok so If there are 2 aileron servos i can just put them on one channel using y-harness right? for elevator and rudder also can i use y-harness? My radio has 3 mixing optons available. If im not wrong what I can do is plug one elevator servo in channel 2(this is the channel where i would normally put my elevator servos if i were just using one) and the other elevator servo in channel 6. Then I can make my channel 2 as master channel and channel 6 as slave channel. What this will do is that when i pull the elevator stick down one servo will push the elevator up and one will pull it down. But will they move in exact proportion. Please correct me if ive said something wrong.

shenion

For ailerons you can just Y them.

For the elevator mix. You need to reverse one channel. The travels should be the same. But some servos have variances in the travel. On mine, I changed the travel on one by a few % to get them exact.

The issue is when you use a second elevator channel slaved, does the tx mix the trim to the second channel. Try it and move the elevator trim. Both elevator servos should move. My 6XA will not do this as the trim only effects the main channel, not the slaved channel.

If your TX does not mix the trims correctly, you will have to use an external reversing-Y module. I doubt your 622 is that stupid.

To get gual elevators on my 8U I have to do the following:

mix 2 --> 7 100%, trim mix= Yes
mix 7 --> 7 -100% (disables knob on tx.)
Then set channel 7 reversed.

For the rudder, I used a single digital servo. This prevented the need to exactly match the two servos on the rudder. The servo has about 120 oz of torque and is plenty for this plane unless you do serious 3D.