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> Electric Motors > All Outrunner Motors
> Electric Motors > Outrunners by size > Specialised Motors


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 (mm) 8
Total Length E (mm) 84
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Customer Data

Shipped from:
International Warehouse



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 Customer rated 5 crowns   
Total of 7 discussions.
David  5 points - 3/25/2015
What is the diameter of the hole in the front motor's shaft? Can the two motors be separated? I want to be able to use the front motor alone.
Frantisek  5 points - 6/27/2014 according to my experience with CR23L, those contra rotating twin motors are too heavy for their respective thrust
scarborofun  108 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  208 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 497 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 53 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 )
 Colin 1 points
I'm using mine on an own design scale Douglas XB42 Mixmaster, 53" span, made mostly of Depron. I'm very pleased, it performs really well and sounds good too. Although the two blade 8x4 props are the most efficient, I'm using 7x3.5 3 bladers because they look good and go very well anyway. I've bought another because I like it so much. Also because there is no torque reaction, it goes off as straight as a die at launch. Recommended.
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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