Racing Quadcopter Scratch Build

gadu

Junior Member
Hello world,
So I have decided to step into racing quadcopters.
As usual due to financial constraints and me not being a good enough pilot to justify a good expensive frame I have decided to build one myself.
I had a look at the “proper” frames and tried to replicate it, knowing that I might end up with something heavier and bulkier than Luminier and co.
The main element that I was trying to make sure I keep protected were ESC’s.
I have used 3mm polycarbonate, from which I have cut out a rough shape of the frame.
I have used 10x10mm wood as arms and placed them in the same manner as per David’s tricopter build.
I have decided to use KK2 mini board to run it for the time being, powered by 2200mAh 3S battery.
By now it looks like this.
20150208_142506.jpg 20150208_142543.jpg 20150208_142550.jpg 20150208_142556.jpg 20150208_142632.jpg
Now the question is what motors and props I should be using for this setup.
All you can see on the photo weighs exactly 300g.
I’m open to suggestions.
Thanks
Dan
 

cranialrectosis

Faster than a speeding face plant!
Mentor
Motors will be dictated by prop which will be dictated by boom spacing.

What is the max length prop you can use and leave at least 1/2" between rotor tips?
 

gadu

Junior Member
The shorter distance between two ends of booms is currently just under 10''.
In theory i can always extend the booms by using longer arms, so my main concern is that it lifts off the ground in the first place :) and then so that is pretty stable and not too crazy for the first few flights during the learning process.
 
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jhitesma

Some guy in the desert
Mentor
Sounds and looks kind of big for a racing quad, more like a 380 class than a 250 as normally used for racing, especially with that big of a battery. For what you have I'd say go with 8" props an motors in the 2212 1200-1400kv range. That's about the same as my knuckle quad setup and it flies great - not the best for endurance and my 250's will smoke it...but still a good performer for it's size.


(it's flying even better and more aggressively now but I haven't got video lately.)


For a proper racing quad I'd say shrink that down so you can just fit 6" props, drop the ESC's down to smaller lighter 12a versions, get some 1000-1300 batteries instead of the 2200 brick and then run some 2204 or 1806 2400kv motors:


10602027_10152213664696805_271167496_o.jpg

10614768_10152208394631805_1837315537_o.jpg

(The lexan actaully weighed 10g more than the plywood version...but it was nice being able to see inside :D )

It flew well other than some issues I was having with the ESC's and the mounting of the afromini FC:
 

cranialrectosis

Faster than a speeding face plant!
Mentor
I think I would run the 1450 Suppos with 8045 rotors from Altitude.

jhitesma is right. Your copter is too big and heavy for racing, but 8" rotors should give you an inch between tips at the front.

Is your KK2 mounted up front or just sitting there for the photo? The KK2 should be at the center of gravity and center of thrust to work right. :)
 

gadu

Junior Member
Gents,
thank you for your input.
This is for sure a bit on the "big and bulky" side of things and i would not be able to even get close to 250 quads, but that was not the goal.
Main goal for me now is to learn to fly this type of aircraft and then once i feel comfortable i will drop down the size and perhaps make another scratch build with "guts as per jhitesma suggestions.
As for the KK2 - it is not stuck there. I am planning as i'm building, so it is free to move for the time being.
Now let's see what hobbyking has got to offer :)
Cheers
Dan
 
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