Speaking of Hitec servo testers...

[jgunpilot]

I've got the Hitec servo tester/progreammer. Let's say I have a cyclic servo that isn't perfectly at 90 degrees. So i take my programmer and go to +4 to get a good 90 degrees on the output arm. Now, I have to reset the endpoints. Should I set +100 and -100 (or 125 or whatever), or should I take the +4 for the center into account and go -96, +104?

The instructions with the unit are pretty fuzzy on this point. Thanks.

[Finless]

The Hitech box allows you to program the center position (as well as other things). So if you internally adjust the servo using the programmer then in your radio use NO subtrim or trim. That is the purpose so you can get the servo centered without having to use subtrim in the radio.

Now you can also adjust total throw (or end points internally in the servo). Thus you would MATCH all 3 cyclic servos and thus you would not need to change the servo end points in your radio (you would leave them 100/100) to remove full positive and full negative pitch interactions.

Bob

[jgunpilot]

Bob, I'm talking about programming the end point on the programmer, not the radio. If my new centerpoint is +4, when I use the programmer to set end point sI'm wondering if I should go -96, +104 or just go +/- 100.

[Finless]

No I don't think you have to do that... the amount of end point is a percentage. I don't think changing the center will reduce total throw in one direction. I am not 100% sure though. You should be able to see it if so...
But neither here nor there. You want to get all the servo for cyclic moving the same distance from center and match them all so whatever you do with endpoints your doing it for that reason. Get them on the heli and use a swash leveler and check full + and - pitch and change each servos end point so the swash is level.

Another way to match them is to put a protractor on top of the servo arm and measure the total throw both ways and adjust each servo so they are the same. Then put them in the heli and if all your link are right the swash should be level.

Bob

[Pinecone]

Setting center on the servo should not change end points.

The servo receives a given pulse from the Rx, it interpets this as Center. But different Txs send a slightly different pulse length. And different servos will expect a certain pulse length as Center, so if the two don't match, you will not be what you think is center.

When you program the servo, you are just telling the servo that THIS is Center, not what it thought.

The pulse length will still vary +/- for each end point, and if the end points on the Tx the same, the servo will see the smae change in each direction, leading to the same throw each way.

[jgunpilot]

OK, thanks for the replies. I'll throw a protractor on it just to make sure. I sure love being able to recenter Hitec servos and reset the endpoints for more cyclic. I think my Raptor will be a bit peppier this rebuild.