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CR23S Contra Rotating BL System 1700kv

CR23S Contra Rotating BL System 1700kv

CR23S Contra Rotating BL System1700kv

Dimension: 23mm x 49mm (23mm x 84mm with props fitted)
Weight: 64g (Complete with props)
Diameter of shaft: 3.0mm
Length of front shaft: 7mm
Max Amps: 22A
Test data;
Prop: 8x4 As fitted
@ 10V
Amps: 17.4
RPM: 9300
Thrust: 580g

@ 11.1v
Amps: 19
RPM: 9600
Thrust: 672g

@ 12.6v
Amps: 21
RPM: 10500
Thrust: 744g

*Includes props, as shown in the image, requires 2 x 25A Brushless ESC for operation (Not Included)


Kv (rpm/v) 1700
Weight (g) 64
Max Current (A) 21
Resistance (mh) 0
Max Voltage (V) 13
Power(W) 264
Shaft A (mm) -
Length B (mm) 49
Diameter C (mm) 23
Can Length D (mm) 8
Total Length E (mm) 84
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Customer Data

Weight: 80g Quantity: 

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 Customer rated 5 crowns   
Total of 5 discussions.
scarborofun  71 points - 8/27/2013
I don't know how HK can run this system with 8x4 props on 3s, as they will cook the motors. 1700KV out runner and 8x4 prop on 12V won't work. I need to run them on 3s, so the props are useless for me. I didn't have any revers props except 3 bladed 7x3.5. They keep the motors at about 60 deg C with 180W power consumption on 3 s. Couldn't measure the thrust so far. Also, the outer prop struggles with vibrations at even the slightest imbalance. The sound is captivating due to the different revs, quite like a twin engine. 2 x 12 A ESCs should suffice. What are your observations? Your comments invited.
whipper Snapper  169 points - 2/22/2013
Hello Iam planning a pushing delta wing plane and wondering what methods anyone has on mounting this on planes? any ideas on how to mount on plane? any tips or suggestions on an engine mount would be great appreciated thanks
 simplyG 373 points
Hi, wS. It ultimately depends on your choice of plane. I believe the Teksumo or something similar will be a good starting point. The easiest way is to get a 2.5mm aluminum plate from your local DIY store, cut it to size, make an 'L' shape of it, dril as needed and you have a very sturdy mount. I do not believe ply or wood would do the trick here. Great idea, pls keep us posted. Happy flying.
pkbc84  58 points - 10/29/2011
bonjour "elmuchacho" says that he can use just one ESC for this item i am very interrested by the details of connecting ! sorry the web link was cut, can you give it totally
 NOBLER2 36 points
I strongly warn the users of this double engine ,not to use it with a single ESC supplying both coils !!!.
Reason Why=
At the start of running , at Lo RPM , each ESC manage it's coils switching according to a special soft ( when the un-used coil can't indicate any rotor position signal to the *-Processor ) so , two engines both can't have the same position , and the ESC signal just CAN'T drive the 2 engines = at Lo rpm it's an electric mess !! and mechanical as well when you try it !! Very bad in all case anyway!!
So best thing to use this special and very interesting motor , is to use 2 cheap 20 A ESC . But much more efficient : mix the Th channels after Rx => I recommend the channel mixer HK Ref = SKU GW-V-Tail-J .
You plugh the Throt channel on one entry / One Aux Ch (6 or 7 )on the other entry. And the 2 ESC on the 2 output. So you have throttle for the two motors , and the Aux Ch is used to trim the dissymetrical between the engines . Then , with yer own ears and eyes , you can find the exact synchro RPM ( very pleasant noise when they run synchro!!) Cheap and efficient , it's whant I use , since my magnets troubles . This devices allows to synchronize RPM overhead any kind of di-symetrical troubles ( magnets position after re sticking & so on )
hetzer  38 points - 9/14/2011
Any idea how to mount the props?
 Raj kumar 1 points
hetzer for what you want to mount the props?for a quad or a simple heli.
Albert  1 points - 7/9/2011
How does the speed control work? do you need 2?
 T.rex.450 181 points
You need two, one for each motor.
 elmuchacho 54 points
You can also use 1 ESC but it will need to be at least 40amp a 50amp will be better I use one 40 amp esc on the CR23M Contra Rotating BL System1550kv turning 7x3.5 3 blade prop and everything work without any problem. Described in details here
 Pixelboy 6 points
Question, if I use 3 of these on a tricopter, do I still need gyros, or can I just use an adaptor and plug them into the appropriate socket on the Rx via a speed controller for each motor? thx
 elmuchacho 54 points
* Todd. If you use this motor on a tricopter you card must support Y6 programming and the giro on the card are pretty much compulsory but I guess it will not be impossible to make a device without giro stabilisation, good luck though it is going to be challenging to fly. Try the "Co Axial Contra Rotating Brushless motors" and REMEMBER THEY ARE 375WATT BUT MORE AROUND 100W with a gws 7x3.5 3 blade or gws 8x6 this motor are less then $20 :-)
 Pixelboy 6 points
Thx, don't suppose you know if the hoddy king gyro board supports y6 or any tricopter for that matter?
 elmuchacho 54 points
I actually do and sorry but the HK quad support and X configuration for quad only. Other board like the kkmulticopter (black board, red and blue are older version) can be purchased on ebay for really cheap. Remember to pick a usb dongle for the programming or at list for properly maintaining your device flying. If you are lucky to find an open pilot board(openpilot is open source and not affialated to a business) just go for it this board is amazing and the Ground station control software is wicked. The other board I know that will do y6 are FY91Q the classic multikopter one and many other but I don't have all them here.
 Pixelboy 6 points
Ok,thx. The other configuration I was thinking of was a y3 config with the front two blades spinning in opposing directions, and run a contra system as the yaw, is this programmable on the boards? also, to get one of the front motors to run backwards, can I just switch the and - terminals around into the speed controller without damaging it, or is there a proper way to do it? thx
 elmuchacho 54 points
For the Y4copter configuration it is possible but I'm not to sure how you want to do it. You'll need one esc per motor and each esc connected to copter control board. To reverse the rotation of a brushless motor you simply switch around any of the 3 wires connected to the ESC. Doing all this from scratch is pretty difficult and you best choice will be a kkmulticopter/openpilot or a ardupilot (diydrones). The kkmulticopter is currently sold with the Y4 config it is completely possible to program it onto the other one too.
 Pixelboy 6 points
Thx, is there a problem with getting a 60 amp esc and wiring both contra motors together on the same esc?
 elmuchacho 54 points
You can do it. I had a setting like this but with 40amp esc for the CR23M it worked fine but sometime the esc did seems to get confuse at throttle down to just a bit of throttle. The other things you have to consider is that you'll have 1 ESC and if something go wrong you might have no more plane. If you use one esc for your tricopter it will not work! because you need to be able to control the speed of each motor individually from the copter control board.
Customer Reviews
Overall Rating
whipper Snapper
Like it?
It was a bit of a gamble with this purchase as I had no idea how to mount this Motor due to its long length and mounting holes in-between the two motors...but I decided give it a try to have something different from jets, twins, flying boats etc. In end I installed it on my DZ500 using few 5mm spacers and long screws, it just installed in a flash actually and the power is immense I was glad I gave it a shot despite the low score reviews on the similar larger and smaller BL systems here but this was just right size for the DZ500 with 2 25amp esc, changed the props to 7*5 3 blades the escs hold up nicely and power is smooth

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