Cookies used in this website are gluten free, wheat free and dairy free. By using this website you agree to our use of cookies. More Info
Guest
Login Below
Join Us On Social Media!
   
Get The Model Boats App!
Apple App Store
Android app on Google Play


Help Support This Website
£
or enter custom amount

(Non Contributor)

Help support this free
website and donate.



£285 a year is needed to keep the website and apps online. Please consider donating £5 or more to help towards these fees.
All donations are securely managed through PayPal. Amounts donated are not published online.

Many thanks for your kind support.

Model Boats Website Team


Donation History
August 2018: 3 people
July 2018: 8 people
June 2018: 8 people
May 2018: 7 people
April 2018: 24 people
March 2018: 13 people
February 2018: 8 people
January 2018: 25 people
December 2017: 4 people


Unique Visitors This Month

Website Members

Terms and Conditions
Privacy Policy
Advertising
Contact


Model Boats Website
Active Users (14)
Login or Register
To Remove This Ad

Login or Register
To Remove This Ad
>> Home > Forum > Any Other Questions! > Brushless motor selection
Brushless motor selection
(565 views)
Author Message
robhenry
(Chief Petty Officer)





Forum Posts: 10
11th Jun 2018 16:18  
>> Permalink
mdlbt.com/42610

I am hope to change twin prop drive on an old Aerokits 46" Crash Tender to brushless motors. Current drives are Graupner 820 Race motors with "Propshop" 35mm diam. 3 blade cleaver props.
Would like to retain props as they are efficient but can someone with experience recommend some good inrunner brushless motors
for me.
Thanks in advance


Barney
canabus
(Fleet Admiral!)





Forum Posts: 123
12th Jun 2018 14:21  
>> Permalink
mdlbt.com/42629

Hi robhenry
What volt battery are you running at present ??
12 or 24 volts.
If 24 volts those motors spec at 24,000rpm.
Power is 511 Watts on 24 volts.
24,000 divide by 14.8(4S Lipo batteries) equal 1612 kv.
So the closest motor would be 1700kv, eg water cooled 3660SL-1700kv which has a 5mm shaft and 44mm diameter with a length of 60mm( from Hobbyking).
Power rated at 1800 Watts on 6S, so it would be lower than that.
But if you are running 12 volts on the Graupner motor it would be about half the rpms.
These brushless motors are far more powerful so check out the specs on the motors you are looking at !!!
Canabus

robhenry
(Chief Petty Officer)





Forum Posts: 10
15th Jun 2018 12:02  
>> Permalink
mdlbt.com/42741

Hi Canabus
Thanks for your response. Very helpful.
Currently the 820's are running on two 9.6v Nimh
packs in series. Have not clocked amps in running conditions.
I assume that I am not exceeding 20v x 20amps rated
by Graupner spec sheet.
Best regards
Rob


Barney
canabus
(Fleet Admiral!)





Forum Posts: 123
15th Jun 2018 13:47  
>> Permalink
mdlbt.com/42746

Hi robhenry
Your motor would be only running at about 9500rpm 0n 9.6 volts.
The closest brushless motor would be a Hobbyking Turnigy L5055C-700kv on 4S Lipo batteries (10360 rpm), these are 50mm diameter, 6mm shaft.
Note you require a separate ESC for each motor and a Y connector to link them to your throttle channel.
Personally I would use the Hobbyking car 100A ESC's (HK-100A).
Also both the motors and ESCs require no water cooling.
Canabus

robhenry
(Chief Petty Officer)





Forum Posts: 10
15th Jun 2018 14:24  
>> Permalink
mdlbt.com/42750

Hi Canubus
Am running 2 9.6c packs in series.this gives about 18v on load.
Rob


Barney
canabus
(Fleet Admiral!)





Forum Posts: 123
16th Jun 2018 08:54  
>> Permalink
mdlbt.com/42777

HI robhenry
The L5055-700 are 1600watts on 8S, so only about/less than half that on 4S.
I am installing only one in my crash tender with a 2 blade 52mm CNC alloy prop to start with and can upgrade later.
I bought this one without running gear and single shaft.
They only did 28 knots.
Canabus

Haverlock
(Fleet Admiral!)





Forum Posts: 484
20th Jun 2018 20:22  
>> Permalink
mdlbt.com/42935

if you use a "y" lead to couple 2 ESCs ( or if you use 2 different channels) make sure you remove one of the red signal leads from the ESC that way you do not risk you receiver ( this presumes your ESC(s) have BEC)


"that's not a bug its just an undocumented creature."

Sir Terence David John "Terry" Pratchett, OBE (28 April 1948 - 12 March 2015)
ARTH
(Apprentice)





Forum Posts: 1
23rd Jun 2018 06:38  
>> Permalink
mdlbt.com/43014

MY #1 CHOICE WOULD BE A NEU MOTOR . NEU MOTORS ARE A BIT COSTLY BUT HOLD A LOT OF RECORDS . LEOPARD MOTORS ARE NICE TOO .BOTH MOTORS HAVE WATER JACKETS FOR THEM . I PUT A NEW 1515 IN A 27" CATAMARAN RUNNING 4S AND GOT 68 MPH ON THE GPS. ALSO I HAVE AN OLD DUMAS SKI DADDLE 36" RUNNING A LEOPARD LBP3674 - 2650KV WITH 3S AND GET ABOUT 40 MPH . I AM NOW WORKING ON A 36" GENISIS CAT WITH TWO LEOPARDS . PERFORMANCE TO BE SEEN !!!! I HOPE THIS HELPS YOU OUT SOME .