NEW TO HELIS. A BASIC SET-UP QUESTION.......

[ChemicalAli]

I have two helis, both of which are 120-degree CCPM. According to my Futaba radio manual, the swash plate arrangement is SR-3, however, both of my helis have swash plates that are reversed from the picture shown in the manual (in other words, both helis have one control arm on the front of the swash and two control arms toward the back).

For one of the helis, I'm using a 9-channel receiver. For the other, I'm using a 6-channel receiver.

The "9-channel" heli controls its blade holders from the leading edge (i.e. swash must move up in order to increase pitch)

The "6-channel" heli controls its blade holders from the trailing edge.

Can someone tell me which channel each servo needs to be inserted into, and which servos need to be reversed for these two helis?

I'm using a Futabe 9CHPS radio. Any additional information you could give me would be very helpful.

Unfortunately, the Futaba manual doesn't describe it thoroughly enough for newbies like me!

[jrohland]

It is not quite that easy because we can't workout your normal/reverse requirements without knowing how the servos are mounted and which side of the horn the ball is on.

However, the front servo goes on the elevator (#3) channel. The port side servo (left if looking from the tail to the nose) goes in the aux1 (#6) channel and the starboard servo goes in the aileron (#2) channel.

The normal/reverse is easy to work out. Push the left (throttle) stick up (disconnect the motor if electric). If all servos push the swash up, the normal/reverse selector is correct. If any move the swash down, change the normal/reverse for that/those channel(s).

jrohland

[ErichF]

Jrohland is speaking JReese....Futaba servo pinouts are different.

Channel 2 is elevator and channel 1 is aileron on Futaba gear.

Having the swash "backwards" doesn't change anything in the servo channel asignments.

The best way to know if you have to reverse a channel is to raise collective up and down. All three servos have to work in unison to raise the swash. If one is backwards, and pulls it's side down, reverse that channel. After that, cycle the cyclic stick to all four corners, making sure the swash is tilting in the respective directions. At this point, the swash my tilt side to side (aileron) backwards. If this is the case, swap the chan 1 and 6 servo leads at the RX. Repeat the collective check, and set channel reversals as needed. You should now be done.

Erich

[ChemicalAli]

Jrohland is speaking JReese....Futaba servo pinouts are different.

Channel 2 is elevator and channel 1 is aileron on Futaba gear.

Having the swash "backwards" doesn't change anything in the servo channel asignments.

The best way to know if you have to reverse a channel is to raise collective up and down. All three servos have to work in unison to raise the swash. If one is backwards, and pulls it's side down, reverse that channel. After that, cycle the cyclic stick to all four corners, making sure the swash is tilting in the respective directions. At this point, the swash my tilt side to side (aileron) backwards. If this is the case, swap the chan 1 and 6 servo leads at the RX. Repeat the collective check, and set channel reversals as needed. You should now be done.

Erich

Ok, channel 2 is elevator, channel 1 is aileron. Which aileron servo goes into channel 1? And, where does the other aileron servo go?

[ErichF]

look at the book, it should point that out. One of the "aileron" servos is technically the pitch, or collective, servo plugged into ch 6. I think the ch6 one is the left side, but if you do as I say above, it doesn't matter where they end up plugged into.


Erich

[BarracudaHockey]

It doesnt matter, plug the single servo into the elevator, the others into the aileron and channel 6.

Then get all of them moving the right direction for collective pitch by reversing the servos. If they are ALL going the wrong direction goto the Swash AFR menu and invert the number there, if its +50 turn the wheel to 0 then it will start counting up in negative numbers.

Same with aileron and elevator, if the FUNCTION is going the wrong way reverse it in the AFR menu, if a SERVO is going the wrong way reverse it in the servo reverse menu.

[ChemicalAli]

It doesnt matter, plug the single servo into the elevator, the others into the aileron and channel 6.

Then get all of them moving the right direction for collective pitch by reversing the servos. If they are ALL going the wrong direction goto the Swash AFR menu and invert the number there, if its +50 turn the wheel to 0 then it will start counting up in negative numbers.

Same with aileron and elevator, if the FUNCTION is going the wrong way reverse it in the AFR menu, if a SERVO is going the wrong way reverse it in the servo reverse menu.

What's the difference between Swash AFR and servo reversing?

[Skiddz]

Lemme see if I can clarify. (This is much easier to show than to explain)

Servo reversing changes the direction of the servo based on stick movement only. Swash AFR changes the direction of a specific function. Don't confuse the name of a servo with an AFR function. The "pitch" servo does not act by itself to change collective pitch. All 3 servos, working in unison via the PITCH function change collective pitch. The "aileron" servo does not act by itself to change cyclic pitch for roll control. Both the "pitch" and "aileron" servos act in unison via the AILERON function to input cyclic pitch for roll control. The ELEVATOR function does control just the "elevator" servo, but the servo is not the same as the function.

Let's try a "visual"... The numbers and actions are just tossed out there. Your actual channel directions and AFR settings will be different.

Let's say the swash AFR value for PITCH is +50%. The swashplate moves up and tilts backwards when you push the left stick (assuming mode 2) forward. This means the elevator servo's direction is backwards. Reversing the elevator channel now gets all three servos moving in the same direction at the same time. (The PITCH function only moves all servos the same distance at the same time. It doesn't care which way each servo rotates, only that all three move in unison.)

If you change the swash AFR for PITCH to -50%, when you push the left stick forward, the swashplate will then move down. You haven't changed the servo reversing at all, just the direction in which the AFR PITCH function operates.

OK, now you've got the swashplate moving the correct direction with the PITCH function and the proper servo reversing. ELEVATOR AFR is set to +50%. This function moves only the "elevator" servo and leaves the other two servos alone. You pull the right stick all the way back and the swash tilts forward, which is opposite of the desired direction.

Thinking the elevator channel is moving the wrong way, you change the servo reversing for the elevator channel. So now, you pull back on the right stick, the swash tilts back. Cool.

Letting the right stick pop back to center, push the left stick full forward. What the hell? Now the swash tilts backwards when a second ago, it went up level.. What gives??

What happened is you reversed the direction of the "elevator" servo, not the ELEVATOR function. The correct fix would have been to reverse the direction of the function with the ELEVATOR AFR setting by changing it from +50% to -50%.

Changing the value of an AFR function from positive to negative (and vice versa) changes the direction of that particular function. Note that AFR values will also set the travel limits for that function (Which is a topic for another discussion)

On Futaba, the servos on channels 1 and 6 (pitch and aileron) can be reversed. It doesn't matter which one goes where because you'll get 'em working properly with the AFR functions for pitch and aileron.

Like everyone else has said, get the servos all moving the right direction, THEN worry about getting the functions all moving the right direction.

Hope this helps.