How to interpret motor spec sheets

[DucktileMedia]

In looking at the Tiger motor spec sheet for the 2814-11's, this applies to all motors, the voltages are rated at their lowest safe voltage for that cell count. i.e. 4s is 14.8, 6s is 22.2. When a lipo is fully charged you are flying at 4.20 volts to start with minus voltage drop so are they rating the specs at 3.7/cell to give you a conservative reading? If i saw my packs drop to 3.7/cell I would land.

With prop sizes, you see it says "HOT 62C-78C" example, the 2814 with an APC 12x3.8 says HOT, but the 11" is not. The efficiency is rated higher than the 11 but it runs much hotter. I would think heat is a loss of efficiency. I also wonder what temp they consider to be normal? I generally just go by feel but as for trusting a spec sheet it seems odd to be so vague about that variable.

What percentage do most of you calc your needs at? I shoot between 50-65% to be at AUW. But I am also taking into consideration that my voltage is higher than what they list it at and therefore going to have more thrust.

It's always been confusing to do this accurately. I just get the feeling these numbers are all ballpark and vary from machine to machine quite a bit.

 

[Motopreserve]

This is a really great question. I've been wrestling with the lack/varied of info on particular motors, even within the same company. Very frustrating.

I know that the "normal" temp is based on the individual motor build. Certain motors can be expected to handle higher temps based on better (more robust) components. The little I've found about it mentions that the better motors are typically rated at an acceptable temp that is higher than we'd ever push it.

Unfortunately thats not very definitive, but it makes me feel a little better, and helps me swallow the "holy cow those motors are expensive!" pill

 

[DucktileMedia]

I've always gone off the theory that if you can hold them that you are safe temp wise. Some of my helis have been barely warm and others have been on the warmer/hot side. Although the motors get warm they have never really worried me as I know it's not that hot as far as things go. It's the esc that worries me since thats where the electronics are and heat is always a bad thing. Maybe someone can chime in who knows more about the spec sheets. I know ecalc is going to come up but the point is that it would be nice to take your AUW/motors and figure out what you need to hover at 50-60% throttle based on these numbers.