U-NAV altitude hold, elevator jumpy, needs 6V?

[vpatron]

Hi all,

I just got a U-NAV ALT-E altitude hold module and have some questions.

First off, when I enable it with the plane just sitting on the ground (motor off), the elevator jumps up about 10 degrees and back to neutral. Is this normal? Is it just hunting to calculate some type of gain coefficient? As soon as I increase the gain pot from minimum, it starts doing it.

The test flight will be tomorrow morning but thought I'd check with other users here.


Second, it says it needs 6V, recommends a 5 cell radio gear, and the specs say min 5.3V. Why did they design it that way when a lot of RC gear is 5V? I don't use gas, so my ESC's put out 5V. Should I replace them with an external 6V regulator or can I get away with the 5V regulator?

Thanks for any help.

-Vince

[Tom Harper]

Vince,

I have one that I tried to use a couple of times. It definitely requires 6V.

Tom

[vpatron]

Hi Tom, Ok, I tried hooking it up to a variable power supply and you're right. It definitely gets goofy below 5.1V or so. Oh brother.

What did you think about yours? Was it very useful?

I'm using it for aerial photography because once I find the right altitude, I'd like to be able to circle a property and shoot all around it, without having the altitude change on me.

Thanks,

-Vince

[icebear]

Vince,

I have been using the Alt and Nav units with a JETI Spin ESC which gives a regulated 5,5v and this works fine. Actually, mine worked well with a regular JETI 5.0v ESC but I guess that is taking a risk.

The 6v issue I think is due to that these units use 5v PICs and have onboard 5v regualtors.

The Alt units have worked great for me - really stable altitude hold and easy to setup.
Go with a really low gain setting when testing for the first time and keep increasing until you are happy, is my advice...

Good luck!

/Bjorn

[vpatron]

Hi guys, thanks for the info. I lucked out and found basically an LM7806 type 3-terminal linear regulator so I have it on 6V now. I tested it out and seems to work OK.

I tested it out today in some wind and turbulence and it seems to work fine. I can keep a more stable flight that it can, but far away, I think it will do better than me doing it visually.

-Vince