Post by Burkeomatic on Jul 23, 2023 1:21:34 GMT
Since Mr NCT posted about his ongoing journey, I popped over to the FT Forums and poked around a bit. Not alot going there. Anywho, I saw some dude doing efficiency tests on props on a motor. Saying he was getting x.xg of thrust per watt vs some other number.
Ok, efficiency is cool and stuff, and matching your set up to your plane is important, but I think it can go too far.
I want a discussion on this, because I think about it a lot. What do you all think? I have opinions on it, mainly that efficiency is airframe driven.
It is always going to take "x" amount of work to move "X" airframe through the air at "x" speed.
That isn't to say that you can't get a grossly inefficient set up, like trying to fly a 1m wingspan warbird on a 2207 quad motor with a 5 inch prop. Yeah, you're using the same amount of power but it won't fly well.
But on a couple of FPV planes (where you can monitor the current draw and such) I have found there isn't a whole lot of difference. I have swapped from the cheapie off brands to the good ones, and in those situations... there doesn't seem to be much difference.
What seems to slightly help (and I mean slightly) is a lower KV with a steeper pitch prop seems to help.
Speaking of the prop pitch, that doesn't necessarily make it most efficient everywhere.... that just seems to move your efficiency speed up. For instance, on my RDV2, wanting to cruise 45-50 mph there was zero difference in amp draw between a 7056 and a 7040. So I just stuck with the lower pitch as it was pretty easy to get into ESC frying territory with the steeper props.
What are your experiences?
Ok, efficiency is cool and stuff, and matching your set up to your plane is important, but I think it can go too far.
I want a discussion on this, because I think about it a lot. What do you all think? I have opinions on it, mainly that efficiency is airframe driven.
It is always going to take "x" amount of work to move "X" airframe through the air at "x" speed.
That isn't to say that you can't get a grossly inefficient set up, like trying to fly a 1m wingspan warbird on a 2207 quad motor with a 5 inch prop. Yeah, you're using the same amount of power but it won't fly well.
But on a couple of FPV planes (where you can monitor the current draw and such) I have found there isn't a whole lot of difference. I have swapped from the cheapie off brands to the good ones, and in those situations... there doesn't seem to be much difference.
What seems to slightly help (and I mean slightly) is a lower KV with a steeper pitch prop seems to help.
Speaking of the prop pitch, that doesn't necessarily make it most efficient everywhere.... that just seems to move your efficiency speed up. For instance, on my RDV2, wanting to cruise 45-50 mph there was zero difference in amp draw between a 7056 and a 7040. So I just stuck with the lower pitch as it was pretty easy to get into ESC frying territory with the steeper props.
What are your experiences?
