Motor prop combinations

Okay, heres the thing, basically I have now burnt out two motors in the last week - I think having too high a kv motor trying to swing too big a prop.
Are there any golden rules on prop/motor sizes, and which suits which size?
another quick question, apart from one spins inside and one spins outside, is there any major differences between inrunners and outrunners?
Cheers all

Golden rule is buy and use a wattmeter
The motor specs will usually give a guideline on prop size, but the most important thing is to not exceed the motor's maximum current (A), and the wattmeter will monitor this for you on the ground testing.

Most outrunners ( but not all ) will be lowish Kv and better suited to props, big and smallish, and most in-runners are higher Kv and better at spinning small props and edf. Generally speaking, outrunners have more torque than in-runners, and they are cheaper

PS remember that upping the cell count and therefore the voltage will increase the current considerably if you keep the same prop.

Tim will be along soon and if you havn't got a Wattmeter like THIS he will slap your wrist and make you sit in the naughty corner
"cross posting"

Tim! What no slapped wrist or sitting in the naughty corner - you going soft in your old age?

You don't absolutely have to have a watt-o-meter, although they are quite useful when it comes to tuning a power setup.

You can go on what people recommend, tried and tested if you like

Andy

Right chaps, will get myself a watt meter then - thanks for that!

Tim wrote:
PS remember that upping the cell count and therefore the voltage will increase the current considerably if you keep the same prop.

This explains the motor burn out yesterday! changed the jumper settings on the esc and swapped the lipo pack from from 2s to 3s but didnt reduce the prop size!

LOL - pity you didnt ask the question BEFORE doing that Ben LOL

Story of my life - always too bloody late!

Watt meter, new engines and range of different size props winging their way to me as we speak!
Cheers for the help!

Engines? You fitting an IC to it?

Motor Mr Stubbs,,,,Motor.

Okay okay - Motors I meant!