• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

3D printed quad build with new EMax polymer motors

#1
So hobbyking started selling some new EMax polymer motors that were so inexpensive I had to give them a try. In order to get the most performance out of these motors as possible I decided to design the smallest, lightest quad I could. I included 10 degrees of dihedral since that's a new trend and it seems to work really well. The motors are also preforming really well all things considered. They definitely aren't the highest performing 1806 sized motors but I think they preform very well for the price. All in all the quad weighs in at 350 grams ready to fly which I think is pretty light. I'm curious what other's similarly sized multirotors weigh. If anyone here has any input into the design or any questions about these cheap EMax motors feel free.

You can download the design from Thingiverse - http://www.thingiverse.com/thing:697160/#instructions

Mighty_Mini_preview_featured.jpg
IMG_20150224_143946_preview_featured.jpg
IMG_20150224_144034_preview_featured.jpg

Parts:
Dampening Balls - http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=40612
4x Any small 12 amp ESC - http://www.hobbyking.com/hobbyking/...eed_Controller_SimonK_Firmware_Version_3.html
Male XT60 - http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10414
Battery Strap - http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=11736
2x EMax PM1806 - http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=69296
ZIPPY Compact 1000mAh 3S 35C Lipo Pack - http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=21389
2x 5x4 multirotor props - ex. http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=68701
8x button head M3 x 18mm bolts
8x M3 lock Nuts
4x countersunk M3 x 8mm
Open Pilot CC3D

All set in done your looking at $150 RTF which I'm very happy with :)
 
Last edited:

cranialrectosis

Faster than a speeding faceplant!
Mentor
#2
With that same Zippy 1000mAh 35C lipo my Polakium SSQuad V3 with eMAX 1806 motors (metal) and 6" rotors weighs 348 grams.

Also with that same lipo my 230mm carbon fiber WarpQuad with 2204 SunnySky motors and 6" rotors weighs 340 grams. Of course the WQ wouldn't fly long with this lipo. With a 1300mAh 45-90C lipo the WarpQuad weighs 372 grams.

My Twitchity CF mini-tricopter with the 1000mAh 35C Zippy and SS 2204 motors weighs 371 grams. Of course this copter has three motors, one servo and the plastic motor pivot mount. That plastic mount and servo are heavy.

My Twitchity G10 mini-Hex with 6 Cobra 2204 2300kv motors spinning 6045 rotors with the 1000mAh lipo weighs 513 grams. With the larger 1300mAh 45-90C lipo it comes in at 541 grams.

I would say you are in the ballpark.

Do you have room for 6" rotors? They will really give you some 'pop' if the motors will handle it.

Love the 10* dihedral on the motor mounts. :)

Does your copter fold?
 
#3
That's good to hear. I could probably reduce the weight a bit further by removing the FC isolation housing and just sticking it straight to the frame but I prefer to have the FC enclosed. I wanted to make the quad as small as possible so 5" rotors is the limit, any larger and they would hit the battery. I could modify the design for 6" props though so that's something I might consider. I'm liking the dihedral a lot so far; seems to make quite a difference. Yest the arms fold back to help it endure some crashes. Also helps a bit with portability. This was also my first experience with a CC3D and I'm quite happy so far.
 
#4
Looks like a great build and a great exercise in design. The modest power and light weight of the motors go well with 3D printed parts. Looks like it should be a great flying craft.
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#5
That's good to hear. I could probably reduce the weight a bit further by removing the FC isolation housing and just sticking it straight to the frame but I prefer to have the FC enclosed. I wanted to make the quad as small as possible so 5" rotors is the limit, any larger and they would hit the battery. I could modify the design for 6" props though so that's something I might consider. I'm liking the dihedral a lot so far; seems to make quite a difference. Yest the arms fold back to help it endure some crashes. Also helps a bit with portability. This was also my first experience with a CC3D and I'm quite happy so far.
My Polakium SS Quad v3 is simpler than your copter so even though it is also 3D printed plastic, has landing struts and the rollbar it is pretty light.

I think your design is superior except for the 5" rotor limitation. The hardware for the boom pivots and the extra plastic for tilted motor mounts as well as the cover for the lipo add weight the Polakium does not endure.

The dihedral motor mounts are brilliant though. The copter is beautiful and the 'foldy' nature rounds it out as an excellent build.

How does it fly?

Got any video that lets us hear those polymer motors?

It looks tail heavy. Do you plan to place a camera on the front to balance out the lipo in the rear?
 
#6
I like that build of yours, very clean.

Thanks. It's flow very well so far but I've only put about 3 packs through it at the moment. I'll definitely be shooting some video of the quad once the weather gets a bit better. The balance was actually something I was initially worried about but it hasn't been an issue so far. As I get more comfortable with the quad and push the extremes more the cg could become an issue in which case I will redesign it to move the battery down bellow the frame and at the center of the chassis. I do plan on putting a camera up front eventually but looking to make something small enough like the Horizon mini FPV camera or the one FliteTest built.
 

Snarls

Gravity Tester
Mentor
#7
Awesome build, I really like the battery holder you made, makes me envy owners of 3D printers. Once you get some good flights in with it could you report how the polymer motors perform? I know there are some doubts about plastic motors.

Yest the arms fold back to help it endure some crashes. Also helps a bit with portability.
This is more of a question anyone can answer. If you crash and the arms fold back with the motors still spinning is there any danger of the props slicing into the battery and causing a fire? I ask because my 500 size quad has arms that could fold into the battery in a crash.
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#8
I like that build of yours, very clean.

Thanks. It's flow very well so far but I've only put about 3 packs through it at the moment. I'll definitely be shooting some video of the quad once the weather gets a bit better. The balance was actually something I was initially worried about but it hasn't been an issue so far. As I get more comfortable with the quad and push the extremes more the cg could become an issue in which case I will redesign it to move the battery down bellow the frame and at the center of the chassis. I do plan on putting a camera up front eventually but looking to make something small enough like the Horizon mini FPV camera or the one FliteTest built.
Thank you. Adam's frame makes it pretty simple. :)

If you change the build, please post the updates. It is cool to see how these evolve over time.
 
#9
Once you get some good flights in with it could you report how the polymer motors perform? I know there are some doubts about plastic motors.

This is more of a question anyone can answer. If you crash and the arms fold back with the motors still spinning is there any danger of the props slicing into the battery and causing a fire? I ask because my 500 size quad has arms that could fold into the battery in a crash.
Yes I will. I imagine it's possible for that to happen but as long as you throttle down when you crash I doubt the blades will have enough momentum to slice into the battery

If you change the build, please post the updates. It is cool to see how these evolve over time.
Will do
 
#10
Here is a little clip of the motors spinning up so you guys can hear them. I've certainly head worse.

Also, I remeber why I designed around 5" props, I'm fairly certain these motors can't handle 6" props as there is no data for it on Hobbyking's website. They don't even list 5x4 but I think those are safe as a whole pack only gets the motors warm, not hot.
 

jipp

Senior Member
#11
pretty cool. i watched the video on youtube on hobbykings channel and saw these and i was like gee,, can we get any6 cheaper.. but i guess there is some logic to the idea.. the main sales pitch they said they were consistent.. light mass, more consistent than the metal brothers.. slaped onto a light frame i could see how they would perform well. will they hold up to a crash ? time will tell i guess. i think its pretty sweet you built the 10 degrees into your arms. very well thought out. rock on. now i guess every one should ask santa for a 3d printer.. :p
chris.
 

Twitchity

Senior Member
#13
I like this quad; an all plastic build for the most part. I'll also be interested to hear how well these new motors handle a crash, but for your sake I hope you don't find out.

Very nicely done.
 
#14
Thanks Twitchity!

I have a question for y'all. I made my frame with a square motor layout (all motors equidistant to each other), but ive noticed that many quads out there have a more rectangular motor layout (shorter than it is wide). What's the difference? Is one more stable or agile than the other? Is it an aesthetic difference or performance based? Or am I just crazy?

Also, I added new arms to the page that will let you fly with 6" props with 2204 or similarly sized motors. If my math works out correctly you should still have 10 degrees of dihedral giving you a modest "cone of influence," but the motor layout is no longer square. Again, I don't really know what this will do to the flight characteristics, but I doubt it will change much as many other quads seem to have this design with no ill effect.
 
Last edited:
#15
Thanks to cranialrectosis, I updated the design for 6" props and more standard motors. I also added a top tray to more easily facilitate FPV equipment. It's still a very simple design though it has put on some weight with the extra top trap and equipment. Will start test flights as soon as GetFPV gets my Naze board to me.



 
#16
Designed in Solidworks?
Printed on an Ultimaker 2?

That looks really cool. I like the dihedral. I really would love to design my own multirotor with dihedral, but I get discouraged everytime I open up Inventor Fusion at home and realize it is going to take me twice as long to design something as it would in Solidworks (if you cannot tell I prefer SW ;)).
 
#17
yes and yes. Luckily for me, I have access to the student license of SW from school otherwise I would have to use less expensive software as well. That day will come, and it will be a sad day indeed.
 
#19
The Smaller quad with the EMax motors is using only 10% infill with .8mm shell thickness and .2mm layer height. Resolution does not really matter for this the only important details are bolt holes. The larger one I just built is the same except the arms are printed at 50% infill for a little added strength.