Dual elevator servos?

[cyoung450]

I am using a Futaba 9c radio and Hitec 5945 servos for my elevators on my 30% YAK. I am using one of the new Hangar 9 digital throw/incidence meter to set up. My question is how do you guys normally do your elevator servos?

I have both servos going into separate channels on my RX (Fut 9ch PCM) and I am mixing them with my radio. but they don't seem to throw evenly. Also how do you check to see if when they are centered that both halves are even? Would these be a situation where you would use a match box?

Anyway I would like to know your technique for setting up elevator servos any help would be greatly appreciated!

Thanks,
CY

[SleepyC]

Meters and such are great... but you can't beat 2 sticks of basla taped to each eleavator,
and comming together behind the rudder.
That way you can see that each surface is matched to each other, and that the throw is the same.

Old skool trick.. on big planes welding rods work great as well!

[Downhumpty]

SleepyC,
Are you using channels 2 and 8 with the preprogrammed
alivator<-(spelling?) mix?

Kent

[Dennis C]

I believe on a 9-C you have a deticated mix for dual elevators.

Anyways when i set up mine i use the counter balance on the elevator's to center them. as far as throw i adjust that with my atv & a throw meter. if you set it up to 45 deg's of throw up & dwn you will have equal throw though out your stick movement.

I see your local also if you want to call me on the phone i can help you out the best i can.

[Mike East]

I use the long stick method too. I like to use carbon fiber tubes about 18-24" long, like the ones that are used for foamies.

1. 1st thing is make sure that your endpoints for the elevator halves are both set at 140 and leave them there, do not move them. This will give you max resolution and you get better linearity if you make your corrections mechanically. The only way I would reduce on EP or the other would be if you have gotten the mechanical setup to the point that 1/2 turn of a control horn or pushrod either way is too much. Thats why I use the Hangar 9 pro-link titanium turnbuckles for pushrods. You can make tiny corrections AND you do not have to break the linkage apart to make adjustments.

2. Make sure that your subtrims are set to zero.

3. Make sure that your control horns are in the EXACT same place on the elevator halves relative to the hingeline and the same distance away from the fuselage, so that they are in the same spot relative to the hingeline. Ideally the hole where your ball joint or clevis connects the pushrod to the control horn should be over the center of the hingeline or as close as you can possibly get it. If they are not you will have differential in the amount of up and down travel you get.

4. The ball joint/clevis should the exact same distance away from the surface of the elevator half. 1/2 of a turn on a Rocket City Control Horn can make all the difference in the world.

5. The pushrods should be the same length, exactly the same length if possible.

6. Do your setup on high rates. If you get the high rate perfect, the low rate should follow.

7. Make sure that the servo arms are oriented the exact same way on the servo spline shaft. Being off 1 spline can make a huge difference.


Once you get to that starting point, move the controls and see what happens and adjust mechanically accordingly.

Or you can switch to Hitec Programmables and make it quick and PERFECT.

[LawnJockey]

I have one the H-9 Throwmeters also. DON"T Use IT. Two sticks are more accurate. Nothing against H-9, Just the digi meter. I use Hitec servos and a Programmer. Fast and easy.

Bruce

[JoeAirPort]

I like to mechanically match the two sides by lengthening or shortening the control rods. Also I raise or lower the adjustable height control horn. I use paper protractors on the servos and elevator halves to measure each side. Then I'll always end up with some offset on both sides. If I have a Hitec programmable servo, I then program the centers and end points to match what my mechanical setup is (I set the tx endpoints to max, center the trims, and zero the subtrim before programming the servos). If I don't have Hitec programmables I have successfully used the tx subtrim and end points to make the servos match my mechanical setup perfectly. Many people don't think/agree that this works but trust me it's dead nuts perfect on my 50cc gasser (50 degree deflections, no lag in speed, and positions are a dead perfect match). I did have to go back and forth a few times as the subtrims affect the end points but it did work really well in the end.

I usually just site the halves by eye from the rear of the plane. Some times the elevators are warped a little and the counter balances do not reflect the position of the rest of the surface. It's not a perfect world but you can get aweful close from my experience.

[jumah]

Your did right way to put elevator servos I have a JR 9x radio; I put one servo in elev. cont and one in aux2, you should be do some triming for both servos and go to fly