ORIGINAL: shutterbug27mkii
Thanks aeajr!
That guide was so helpful that I decided to sign up at RCU and even referred you!
There are still a few questions however..
Well, when I look at the chart for the geared speed 400 I see that,
regardless of prop, at 7.4V I am not going to have enough voltage (
pressure) to push
13 amps into this motor. So the 2 cell lithium won't meet my performance
goal of 100 watts+ per pound using this gear box.
This is still a bit fuzzy. So do motors require a minimum voltage to pull certain amount of amps from the battery?
As for the chart, is this the same chart you provided earlier? If so, that was a dead link
Are there other charts you can refer me to?
I've read about wing loading here and there. Does that come into play when determining a power system for your plane?
Thanks!
Eric
This link should work
[link=http://www.gwsus.com/english/product/powersystem/eps400c.htm]GWS motor charts[/link]
Yes, you need a minimum amount of voltage to get the goal amperage using a particular propeller, as I discussed in the posts above. Voltage is pressure and without enough pressure you can't push the amperage into the motor.
Check the charts and you will see what I mean.
As for wing loading, that has more to do with the manner in which the plane will fly and the minimum flying speed. It is a different discssion. But of course all things on the plane, whether glow or gas, electric or glider, work as a whole so they are all related. But I would not put that into this dicussion. Too many variables and too much to think about. Wing loading will have more to do with minimum stall speed and pitch speed of the prop. Wattage works outside of this as a general tool.
Work from the wattage goal and go backwards.