Skyhawk940

Building a Mini Kaos and the plans call for a 061 to 074 engine. I'm going electric and need info for the correct size motor and ESC. Would a 370 and 18 amp be too much? I'm thinking it would be. I'm old school and have always used nitro. New to electrics. Battery most likely going to be a 3S 2200mA.

Skyhawk
Sandusky, OH

ron_van_sommeren

By choosing a smaller prop, a power system cannot be too much. You cannot overrev a motor with too small a prop.


Plane type and mass are leading when choosing a power system.

• Rules of thumb for electric power
  Magic numbers for e-flight - WFF
• Gibbs Guides
  → Articles
  → How to choose an electric power system
• The Ampeer
  → E-book: Everything you wanted to know about electric powered flight
  → Chapter Sizing Power Systems for Electric Airplanes
• How to choose a power system - RCG
• Beginners Guide to Motor and Prop Selection - RCG
• System power - RCG, several messages
• Several design papers
  rcaeronotes.wordpress.com/design-and-analysis-notes

ron_van_sommeren

Not a specific answer for you, but in general ...

It is a good practice to have some headroom built in.
About derating motors, controllers, batteries, electronics in general:

• Derating, starting at ... Then there is the 75% rule of thumb ...
  Questions and Answers.... - Page 928 - RCG
• Motorcurrent is proportional to voltage squared, and proportional to Kv cubed.
  A 10% change in battery voltage will give a 20% change in current, a 10% change in Kv will give a 30% increase. Not quite, because battery voltage will sag more due to higher current, but you'll get the idea.
• extra current with one or two cells added, simple table
  A.k.a. "Why did my motor and/or controller and/or battery go up in smoke ??? ¨.
  In depth discussion
  www.theampeer.org/ampeer/ampnov15/ampnov15.htm#ADD
• About de-rating controllers and motors, starting at for everyone else:
  Questions and Answers.... - Page 290 - RCG

ron_van_sommeren

Some well-structured reading for rainy/windy days, and some handy e-tools as well. Will save you, and us a lot of questions. Notably the 'what went wrong?' kind of questions Will also prevent you from burning up several controllers and/or motors and/or battery:
E-flight primer and tools

And pleasepleaseplease, do your RC equipment, wallet, ego, battery, controller, motor, house/garage/car a big favour ... get a watt-meter. It will more than pay for itself, will save you at least one fried motor and one fried controller. Will also help you finding optimal setup.

Without a watt-meter you are in the dark. Until something starts to glow
close out sale Hyperion Emeter II, with optical and electrical tach, servo tester, local&remote logging - RCG

Vriendelijke groeten Ron