Android engineering science

Well we have to assume that David 8 has two power sources or his power is in his head.

So that his head can function seperately of the main body, it is after all Sci Fi and in many movies a Robot/Androids had can work when seperated from its body, this includes in Star Wars and Star Trek too.

We have to remember David is a Machine, so its not like he is a living organism in which needs a blood supply and has complex nerves etc, so that if we lose our head then we die, right away but the body can still work for a short while as electical impluses are sent to the nerves and mucsles... (why sometimes a chicken can run around after its head  has been cut off).

With David we have to assume he does not need his circuits in his body to be connected to the head for the head to work independently.

Maybe, but my confusion has become aroused even more cause when we see Shaw entering the alien spaceship's cockpit David's body moves when he speaks with his body parts having been torn apart. Wi-Fi? Even if to assume that his innards, circuits and units were designed and placed in the same order and places that human's organs are and that his CPU was located in his "brains" in his head, then his voice modulator had to be somehere in the rest of his body ("chest" or "back"), but I still can't understand how his head alone could produce a voice.

The same thing happened with Ash in Alien, his head functioned independently of his body. The speaker was in David's face obviously.  

It would appear that the android's body needs the head to function but the head can function on its own. It's power cells must be in its head.

@scrutinizer1

This may give you some clues..

http://www.weylandindustries.com/david

This states that Davds Frame is made of cadmium alloy endoskeleton, the thing is cadmium is not a ideal metal to use, its lightweight and strong...  but it realistically is not ideal at all as it has a low boiling point and it is also similar to other metals like Zinc, Magnesium and mercury.

Basically why dont we use these metals for structures or car frames etc... because they melt easy with fire...

But they are used in a way to coat other metals to benefit the properties of the new Alloy and i think this is what is meant, that some other metal or even polymer compound is used as a Skeleton and its coated in cadmium to add strength and also cadmium can protect against rust and also acid etc.  But not fire but having only been coated another Alloy or Strong Polymer compound could withstand not being melted to to a liquid when the cadmium starts to at  about 760 Degrees °C

What powers David 8 are zero-loss lithium ion cells now we have to assume that there could be a power source both in the head and body, this would benefit the Android so as that if it suffers some serious damage then the Head can still operate to communicate and record and log what had happened to its body.

Makes more sense than having a Android that if it suffers a Accident and gets damaged then it simply shuts off... But having the head able to still opperate even if the body is badly damaged means the Android can record details of what had occuried to it.

You know that could be spot on!

Maybe David 8 is not much different to....

On a serious note yes, i agree and its as i said that it would be beneficial if the head could work independant in case of a malfunction to his Body.

In the image below Ash was connected to his body through several cords, BTW.