Calculating Electric engine sizes... - RCCanada - Canada Radio Controlled Hobby Forum
RCCanada - Canada's Radio Control Hobby Forum
Beginners / Newbies Interested in getting in the hobby. Not sure where to start. Post your questions here and one of the RCCanada experts will be glad to help you out!

Thread Tools Display Modes
Old 08-08-2011, 07:51 AM   #1
I am: Adrian A.
Join Date: Jun 2011
Location: what a joke some Maac members are.
Radio of choice:
More stuff than you can imagine
# of RCs: 1

Feedback: 19 / 100%
Posts: 287
Total Props: 5
Question Calculating Electric engine sizes...

       Remove this ad - become a site supporter!
Newb questions start here:

I'm back into the RC plane hobby, it's freakin addictive. I've a few RTF foamies, and some trainers, all came with electric motors and esc's.

My question is, how do you calculate what size (kw) motor you need? I've looked it up on the great Google, and it's a bit of confuzilmenti , I kind of understand it. Kinda.

For an example, I have a 6lb model I want to power with an electric motor, (its' not going to be aerobatic), I figure 4s or 5s lipo at 2200mah or more would be good, with a 60 or 80 esc (these are guesses) and I used the HK Turnigy perfect match sysem to find a motor (.50 match). How would I figure the motor out without using the Turnigy perfect match?

Any insight would be great, or an excell spreadsheet... cheat sheet...

cr8tive_leo is offline   Quick reply to this message.

Sponsored Links - Subscribe to remove this ad.
Old 08-10-2011, 09:14 AM   #2
I am: Philip A
Join Date: May 2009
Location: Cambridge, Ontario

Feedback: 21 / 100%
Posts: 1,325
Total Props: 15
Re: Calculating Electric engine sizes...

One of the easiest methods to determine how big a motor you need is calculating watts/lb (model weight). E-Flite makes a great little guide on choosing electric power systems and explains watts/lb calculations. It's a good read:

I typically try to power my scale models at 80-100w/lb. In your case you need ~600watts.

When selecting motors from places like Hobbyking, a simple rule of thumb you can use if you are unsure of the motor specs:

3 watts/gram of motor weight. ie a 200g motor is good for 600W


Try a google search to see if anyone has converted your particular model to electric.
philipa_240sx is offline   Quick reply to this message.
Old 08-10-2011, 10:30 AM   #3
RCC Supreme Contributor
I am: eric q
Join Date: Jun 2005
Location: Crawford Lake, Ontario
Radio of choice:
# of RCs: too

Feedback: 9 / 100%
Posts: 7,159
Total Props: 26
Re: Calculating Electric engine sizes...

how-to's have been done to death, just gotta know were to find 'em
desiderantes meliorem patriam
To err is human, to moo is bovine
moo is offline   Quick reply to this message.

Quick Reply

Register Now

In order to be able to post messages on the RCCanada - Canada Radio Controlled Hobby Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

Member names may only be composed of alpha-numeric characters. (A-Z and 0-9)

!!ATTENTION ADVERTISERS!! If you intend on advertising anything on this forum, whatsoever, you are required to first contact us here . Additionally, we do NOT allow BUSINESS NAMES unless you are an Authorized Vendor. If you own a business, and want to do sales on this site via posting or private message, you will need to follow the rules. Shops, Stores, Distributors, Group Buys without being authorized will see your account terminated.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Your Name
Your first name and last initial is required if you plan on using the forum.
Which city & province you live in. This is mandatory for classified listings.
Radio of choice?
Which radio is your current favorite to use?
Number of RC Vehicles?
How many boats, cars, planes do you own?


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
vBulletin Message

Thread Tools
Display Modes

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Servos sizes? offroader Electronics 3 11-21-2008 10:14 PM
prop sizes micman General RC Aircraft Discussion 9 12-11-2006 11:48 PM
Calculating Flight Time orenda635 Electric Flight 2 01-28-2005 08:40 PM
calculating engine CC jeang Engines 5 07-21-2004 01:26 PM
Ski Sizes? Chris Cann General RC Aircraft Discussion 5 03-22-2003 10:57 AM

All times are GMT -5. The time now is 10:50 PM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.