Brushless motor sizes???

I don't know motors very well, but I just ordered a KK board and some 18amp ESC's for the tricopter build. I am trying to avoid HobbyKing because I can not ever get what I need the same year that I order it.

The ESC's are hobbywing (ok the name is not that far away, but they are coming from Northern California)

I am looking at these motors:
http://www.hobbypartz.com/75m50-optima480-3010-910kv-2.html

But how do they compare in size to the HK DT750's?
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=6247

I think the HobbyPartz are 910kv? But I am really interested in how they would handle the 10x4.7 tricopter stuff? Or should I look at something else?

I really like the KDA 20-22L motors from HobbyKing.  They are around 930kv.  Parallax stocks them now for their quad for $21.

http://www.parallax.com/StoreSearchResults/tabid/768/txtSearch/motors/List/0/SortField/4/catpageindex/2/ProductID/815/Default.aspx

This is the motor Rick uses on his tricopter and quad.  It's also what's on my new quad that you saw fly Wednesday night.  I am also using the HobbyWing 18A ESCs that you mentioned.  These things definitely have no trouble swinging my 10-4.7 props as you could see.  These motors are a Hacker knock off and work really well.  You could order them from HK and save a little money, but ordering from Parallax (Sacramento) gets them in your hands in a couple days.  I just got seven more of these on UPS today so if you'd like to borrow three until yours arrive, we can do that.  I think I also might have more of those ESC's.

...Tiger

My question is a little off topic but I've been wondering for sometime, how do you calculate the Kv vs battery for multi-rotor aircraft ... It's easy enough to calc for one motor as w/ helicopters because that's what I know but I have no clue how to calculate for 3 or more motors ??

Any help appreciated, thanks

It should be the same because each motor has it's own dedicated ESC. And they run like an airplane motor, just throttle.

Thanks GC and Tiger, I will look into these Parallax motors a bit more. If you are using them it makes sense to have some uniformity among us. The Hobbywing ESC is known to work well with the KK board and is really the same as a Turnigy Plush. I am trying to avoid HobbyKing so I can get stuff from the USA in a few days as I need it instead of waiting weeks for parts, etc. It may cost more, but not that much really.

PP - HobbyWing actually makes the Turnegy ESCs so yes they are pretty much the same.  If you can't find your ESCs at HobbyPartz, you might try ToySonics.com    If you do get Turnegy or HobbyWing, be sure to buy the $7 programmer that goes with them.  It's possible to program without it, but for $7 it isn't worth the hassle.

...Tiger

Thanks, yeah I have 5 ESC's on the way with a programmer and a V5.5 KK board with it's USB programmer. All is coming from the Sacromento area within a few days. Will just need motors and connectors. I am off work this week so hopefully by next weekend it will be flying.

Thanks anyway but I found some software that should answer my questions. These Flight Calculators are from Castle Creations. hehe, I knew they did flight calculators but didn't notice they had included Multi-Rotor birds in their lineup. Anyhow as always Google is your friend ...

  [size=1.2em][shadow=gray,left]w00d[/shadow][/size]

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Castle Creations eCalc:

• Multirotor - xcopterCalc

More ...

• CCPm Helicopter - heliCalc
• Ducted Fan - fanClac
• Propeller -  propCalc