subtleguru

I have some servos running at close to or just over their maximum torque rating.

I believe I can bring them within tolerance by increasing the servo arm movement. The EPA's are currently at 100%.

So my question is can I increase this to 140% without impacting resolution across the full movement range ? That is, does the granularity of movement increase with a larger movement range ?

Flying freak

The more your servo arm moves the higher your res.

If you got a servo arm moving say 20* but your surface is moving 50* you have much lower resolution compared to :

A servo moving 80* and moving the surface that same 50*

Hope this helps.

Steven

subtleguru

Right got this, but just wonder why the default EPA is 100% and not 140% ?

Perhaps it is a compromise between speed, to max deflection, and resolution.

Thanks

Flying freak

Im not sure now that i think about remeber that the hitec's can be made to be 360* so what would that do to resoluton and torque as far as speed goes that shouldnt change as the gear ratio wont change..

Steven

somegeek

My Feedback: (2)

EPA at 100% gives a 90ΒΊ overall sweep if I recall correctly. There is a significant drop in control rod movement past 45ΒΊ. Someone else could explain it better.

I've been working on that the same situation in my setups to get better resolution out of my control arm movements.

somegeek

da Rock

It is my understanding that EPAs over 100% do exactly what you fear. And the reasoning...............

The radio logic parses the commands into a set number of time slots. It gives each function a fixed number of slots. So each function has just so many slots or ticks to define the information. Any time you increase the amount of movement one tick causes you make each tick less precise.

Let's say the radio is set now for 100% EPA and you need 3degrees movement at the surface. And each tick is worth one degree. So you move the stick exactly enough for the surface movement you want and you get 3 ticks for 3 degrees. You've actually got the whole package able to give you accuracy to one degree.

Now you pump the EPA to 140%. And the airplane still needs the surface to be moved just 3 degrees. It's finest accuracy is now roughly 1.4 degrees. So you move the stick as before and it gives you 4.2 degrees at the airplane, and you let off some and get 2.8degrees. And you discover that holding the TX stick accurately isn't as easy now.

Is it a big deal? It is a deal, and you'll probably notice the difference. The airplane will feel a bit nervous compared to before. But it's not a big deal.

On the other hand, it's almost no deal at all to get all the throw you need by adjusting the rigging in the airplane. Moving the pushrod connections in or out on the servo arm and the surface horn is dead simple to do.