[bensidus197217]

I use analog servos right now but can digital servos work on a PCM 72 MHz system? Can I have some digital servos and some analog servos working together plugged into the same reciever? What size servos do you need for a Trex 500? Thanks in advance for any and all help

[DO335]

Digital servos came long before there was anything other than 72mhz radios.

That has nothing to do with whether or not your servos are digital.

It also makes no difference if you mix your digital servos and your analog servos in the same aircraft. Generally, I run digitals on the flight controls and an low torque analog on the throttle.

[moo]

Digital servos run on an analogue signal from the receiver.

Once in a while there are some incompatibilities, but mostly with new 2.4 GHz receivers outputting lower voltage signal than the servo requires, but uncommon.

[Spitball]

For some unspecified reason - perhaps sales, ESky say don't mix their digital servos with analogue ones - I can't think why though - anybody got any ideas?

[Real Gambler]

Originally Posted by Spitball

For some unspecified reason - perhaps sales, ESky say don't mix their digital servos with analogue ones - I can't think why though - anybody got any ideas?

Wild guess: digital servos take more current. Maybe when they design a bird, they spec the ESC so it's barely strong enough to drive the Rx and analog servos, so switching to digital may overload the internal BEC on the ESC.

If it's the other way around then sure enough, if you have a bird that is designed to use digital servo (F3P?), you don't want to switch to analog since they will not have enough torque near the zero, and will make the whole plane feel mushy.

Sure enough, to answer the original question: when you use digital servo, you have to make sure your ESC can provide enough current to drive them. In a T-Rex, you absolutely need one for the tail because the gyro will send very fast signal to the servo, and most of the time, the servo will be near the zero point, where a digital will give you a lot of torque, but an analog may have a hard time. For the CCPM, you can go analog particularly for your first flights since you'll likely break quite a few. Then, sure enough, you want digital (same reason, more accuracy and torque near center point). Sure enough, the last thing you would want is to have 1 digital and 2 analog for your CCPM or 2 digital and 1 CCPM. If you do, make sure you take a video, it should be a big hit on youtube!

[bensidus197217]

OK so then it's mostly about amp draw with digitals. I thought of going metal gear digital throughout and will have a 80amp ESC. I don't do 3d only sport flying 3d just doesn't look right. So based on the fact my flying is very mellow do you think that arrangement I mentioned will work?

[Max]

Originally Posted by bensidus197217

OK so then it's mostly about amp draw with digitals. I thought of going metal gear digital throughout and will have a 80amp ESC. I don't do 3d only sport flying 3d just doesn't look right. So based on the fact my flying is very mellow do you think that arrangement I mentioned will work?

Yep, should work fine.

[moo]

Originally Posted by bensidus197217

will have a 80amp ESC.

but what is the current available from the BEC/UBEC?

mild flying shouldn't require metal gears, digital servos, or much current, I doubt you'll have problems