Thread Tools
Old Dec 01, 2011, 04:49 PM
Vapor Trails is offline
Find More Posts by Vapor Trails
DFC~ We Do Flyin' Right
Vapor Trails's Avatar
Help!

Help me understand gas engines and cc rating


I do not understand what a cc means, regarding gas engines. Could someone explain this to me.

For example, how come a 49cc engine on a moped is physically so much larger than my 62cc aircraft engine?

How does CC relate to horsepower?
RCG Plus Member
Latest blog entry: Please kill isis
Sign up now
to remove ads between posts
Old Dec 01, 2011, 05:10 PM
TossinHoss is offline
Find More Posts by TossinHoss
Whirly Bird Fanatic
TossinHoss's Avatar
Quote:
Originally Posted by bsbauman View Post
I do not understand what a cc means, regarding gas engines. Could someone explain this to me.

For example, how come a 49cc engine on a moped is physically so much larger than my 62cc aircraft engine?

How does CC relate to horsepower?
Cubic Centimeter, the volume of space in the compression chamber. Where the piston is inside the cylinder.

Mopeds have geared transmissions which take up space, larger cooling fins and thicker walls on the cylinder. Also if it four stroke (oil seperated from gas or fuel) there is added room for oil routing and also room for valves and rods. Two stroke (gas and oil mixed together) is generally smaller.


Horsepower is not constant with CC, but varies dependent on fuel, delivery method, compression, exhaust and lots of other variables such as piston shape, head shape, etc.

That's just a brief answer, lots more to it. Plus RC engines are made to be compact and lightweight which is not a concern with something where a bit more weight is not an issue. Google "How Stuff Works"!
Old Dec 01, 2011, 06:10 PM
C_Watkins is offline
Find More Posts by C_Watkins
This is NOT a TOY?
C_Watkins's Avatar
Also, our model aircraft engines have a big ole fan out front.
That's something you don't have on the moped, and it has to keep from overheating, even when sitting still.
So, lots of the physical outside size is in the huge fins on the head and cylinder, to carry the heat away.

Knock off the transmission, and trim the cooling fins to about the size we use, and it doesn't look so big by comparison any more

Take our airplane engines, trim off all/most of the fins, fit a water cooling jacket to make a marine motor, and they look even smaller.
RCG Plus Member
Old Dec 01, 2011, 06:58 PM
shadow102 is offline
Find More Posts by shadow102
Registered User
shadow102's Avatar
stroke and bore size are also big factors in power/torque output with a little effect on packaging dimensions
Old Dec 01, 2011, 07:04 PM
Vapor Trails is offline
Find More Posts by Vapor Trails
DFC~ We Do Flyin' Right
Vapor Trails's Avatar
Thanks guys Great responses; much more easily understood
RCG Plus Member
Latest blog entry: Please kill isis
Old Dec 02, 2011, 01:13 AM
killsdeer4fun is offline
Find More Posts by killsdeer4fun
With great pwer comes great 3D
killsdeer4fun's Avatar
Also think about weight difference. Models need to be light so the gas engines are built strong, but light. Mopeds don't really have to worry about that as much so they are built bigger and of different materials. I enjoy that fact that my G-62 is bigger than a moped and can fly.
Old Dec 02, 2011, 07:23 AM
Andy W is offline
Find More Posts by Andy W
Registered User
Andy W's Avatar
I have backpack leafblowers with 50cc and 34cc engines. They're also pretty light.

Horsepower is a function of engine type (four stroke vs two stroke) but also design and state of tune. Engines designed to run at low power for long periods of time are very different to those required to provide a lot of power but in short bursts..
..a


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion help me understand motor specs gioplc Power Systems 9 Oct 22, 2011 12:20 AM
Question Help me understand folding propellor specs UlteriorModem Electric Sailplanes 26 Oct 08, 2011 03:31 PM
Discussion Help me understand flat panel display integration! nyc863 DIY Electronics 5 Sep 10, 2011 12:49 AM
Discussion Edge 540T Help Me Understand Something.... RickShane Batteries and Chargers 11 Apr 27, 2011 07:16 PM
Discussion Glass or Carbon - please help me understand nph Electric Sailplanes 3 Mar 19, 2011 02:13 PM