vertical grimmace

My Feedback: (1)

Yah, explain to me why the servos need to be reversed?

gravityking

My Feedback: (19)

If you put 2 servos opposite each other when the same signal is served they will spin in opposite directions of each other. One surface will go up and one down. You can reverse by means of the radio or in my case with Hitec's servo programming program for thei digital servos. However that's not an option when I use Savox servos.
Also a pain when setting up flaps. Yes both servos are the same orientation to each other as soon as you put push rods both either inside or outside the servos you get the same problem. In the old days we ran one pushrod to the inside of the servo and one to the outside. Same with the elevator, one push rod on top, one on the bottom. Digital radios are great!

vertical grimmace

My Feedback: (1)

So they don't need to be reversed. Put the pushrod on the opposite side.

Then, if you mix through the radio, and you can't swap the servo horn to the other side (which we do not know this from not seeing the application) you give one servo -100% and the other +100%.

I am of the opinion that you do not add additional items unless absolutely necessary. More expense and failure points.

BarracudaHockey

My Feedback: (11)

On some planes you can get away with running the pushrod off the top of one and the bottom of another. On 3D planes the servos are usually in the tail which would throw your geometry way off

cloudancer03

My Feedback: (22)

The point Abu is there are multiple solutions some don't cost anything like my 8ch fg super futaba or reserving a servo or you can get expensive with match box it's your plane and your choice just have fun and fly.no is going to agree do what makes you feel good.i know dual elevators early on drove me nuts.but I never enjoyed installing electronics

JollyPopper

My Feedback: (6)

The simplest way I have ever found to reverse one servo in the tail is to use two different brands of servo with roughly the same specs. For instance, Futaba and Hitec servos spin in opposite directions with the same input, and will do exactly what you want. Since you said yourself that you are only going to be putting around the sky with this airplane, you won't even detect the difference in total throw or speed of two different brands. Bringing linkages from different sides of the servos will produce much greater differences in throw and speed than two different brands will. I have done this in both dual elevator and flap applications to keep the control rods on the same side of the servo(s), more because it looks better that way than anything else.

vertical grimmace

My Feedback: (1)

Or you could turn the servo around and have a longer and shorter pushrod. Problem is, for all we know, the servos are in the cabin and not mounted in the tail on the side of the plane.

abufletcher

I'll do a preliminary radio set up today and see how it all works out.

TFF

I set my airplane default to two ailerons and two elevator for all my planes. I may or may not use the second servo, but it is always a plug away.

pkoury

My Feedback: (7)

Turning a servo around does not change its rotation.

stegl

I had the RDS8000 and no dual elevator mixing with servo reverse..... Fixed that real quick the the SD-10g transmitter and never looked back.

another way to reverse a servo ,if handy with small solder jobs ,is changing internal wiring.

gravityking

My Feedback: (19)

You should have posted to radio support yourself. I have and have used 2 RDS8000's for years and they do have dual elevator mixing and reversing. I now use them for training and use the SD10G primarily.

stegl

So what you are saying is that you can plug each split elevator servo into a separate channel and reverse one of them ? Interesting as I
had asked Airtronics support at the time (5 years ago) and they said it couldn't be done. Guess I was talking to the wrong specialist ..... Good to know and thanks for the correction.

abufletcher

That's exactly what I've just done (as explained on p.62 of the RDS8000 manual). No problem at all. The first step (as explained by gravityking above) is to go to the ETC. menu, then down to D-EL ("dual elevator"), which is by default set at INH ("inhibited"), then using the "yes" button change this to ACT ("activated"). Then press the END button to get back to the main menu. That's it. The radio is now set up to use channels 1 and 7 for the two elevator servos.

The lead for the left elevator servo goes into channel 1 (the usual elevator channel) and the lead for the right elevator lead plugs into channel 7. You can then reverse the left side on the usual elevator channel menu and reverse the right side under the channel 7 menu. You have the full set of adjustment controls under each of these two channels.

*****

I just completed the preliminary steps in any radio setup:

1. Connect all the wires. (I also labeled the ends of all leads since I'll be detaching the tail for transport.)
2. Remove all the servo arms (which were just temporarily in place).
3. Turn on the Tx then Rx to allow the servos to move to their base positions.
4. Re-attached the servo arms, focusing on the best possible position (usually but not always 90 degrees).
5. Check that the servos are moving all the flight surfaces in the right direction.
6. Finally, adjust the push-rods for the closest possible mechanical fit.

Once all of that is done, I can move on to setting and fine tuning everything else on the Tx.

abufletcher

Here she is so far.

abufletcher

#@%@! Two unpleasant discoveries: 1) I'm getting some twitching on the servos at rest and 2) while I was under the wing I found that on the right aileron three of the seven hinges hadn't slipped into their slots while doing the epoxying. If we number them 1, 2, 3, 4, 5, 6, 7 starting inboard, then hinges 1, 2, and 4 aren't attached to the wing (only to the aileron). I don't know how I allowed this to happen. I was so cautious otherwise, even went to the effort to put dabs of grease around the actually hinge area to prevent epoxy from getting in there. It probably looked fine from the other side and I didn't check it. #@%@#. Not sure what to do about that. Cut off all the other hinges? Drill out the old hinge bits? Start all over?

Also don't know what to think or do about the twitching.

gravityking

My Feedback: (19)

Bummer, she's a beauty. The hinge issue, I'm afraid, is going to be the hard road. Cut out and start over is the only way I know. As for the twitching try rebinding the receiver. You don't have a velcro strap or anything wrapped so tight the bind button gets pressed do you? No carbon fiber near the antennas? That's terrible. You really expect that service with your spent money and get steered wrong. Not right. Next time remember your buds on the forums!

abufletcher

I'll also try a different battery. In the past I've sometimes gotten twitching with a low Rx battery. As for those hinges, well, as the Brits say: "There's nothing for it." The nice thing about having done some scratch building is that you learn that anything that can be built can be unbuilt...and then built again.

stoneenforcer

My Feedback: (23)

Speaking with decades of experience.... ABSOLUTLEY DO NOT USE A SERVO REVERSER. They are not very reliable and often the causes of crashes. Simply plug the servo into another rx channel and do a mix with the radio. If you don't know how, pick up the manual and read it. If you value your pricey build and want it to last a long time, do not use a servo reverser.

Didn't read all the posts, but if you used a reverser, it can cause twitching. If you didn't use a reverser, then you most likely have a bad servo ( servo with a bad potentiometer ) which causes other servos to twitch by giving unwanted feedback into your RX. Find it and replace it!

stoneenforcer

My Feedback: (23)

I have an extra he can have. just pay the $5 for shipping... as worst case if his radio doesn't support dual ele

stegl

The dual elevator issue has been resolved as the RDS8000 does have the ability to work split elevators with separate servos. as well as they can be reversed.... See old dogs ( me ) can still learn something new. After some research I found how to do it.

Regarding the servo twitch , try swapping out the twitchy one with a known good one that does not and see what happens. If the twitchy one is a used servo
; it could be a dirty pot, would be my first guess. I agree that the servo reversing harness is not a good way to go . Seems to have issues with certain brands of radios more than others

gravityking

My Feedback: (19)

Yeeaaahhhh!

stegl

OK, Ok... don't rub it in eh ! LOL....... The SD-10G is still 10 X easier in programming .... one heck of a radio.

abufletcher

I've used Airtronics from the very beginning. But I keep wondering whether for my next radio I should move to Futaba. By the way, do I love the RDS8000 and have had 3 of them...I especially like that the screen is at the top rather than the bottom...but a couple of years ago I had a model crash (completely destroyed) due to a faulty wire on a Tx gimbal. After the crash, I removed all the radio gear, re-connected everything, and it all worked fine except for one servo. So I figured that was a bad or damaged servo. I replaced that will a brand new one and it also didn't work. So that sent me into the forums where I found that this was apparently a QC issue with early productions of the RDS8000: Very small gauge wire and questionable soldering.

So I opened up the Tx and sure enough, a wire on the gimbal was loose. Here in Japan, virtually no one flies with a Sanwa radio (the actual maker of Airtronics). In fact, I've never seen one here. It's either Futaba or JR.

rcguy59

My Feedback: (8)

Airtronics radios are rare here, too. Poor marketing I suspect, as I've never heard anything bad about them in the last 15 years or so. Our field is 80% Futaba with a few JR's and some Recktums on the foamies.