what is better for 3D and free stile aerobatics? a flatter pitch prop or one with high pitch ? or is diameter better?

hu?, it depends, engine, size, airplane, etc..... for example on my .81 alpha engine on my Edge i use 14x4W(wide) and it makes good hovers, etc. On my 50cc gasser, i use 22x8 and work perfect. Most of the sport flyers use 7, 8, 10 pitch and 6 or 4 for 3D but as i said depends of the size of the propeller, engine, etc.

ok let me narow it down I have an RCS 140 on a 2m type free style weighing 12lb. need more vertical i am currently useing a 16x8 APC

As a general rule for good 3D performance - vertical performance you want to use the lowest pitch-largest diameter prop your engine will handle. If your running a 16x8 then try a 18x6 prop.
It will give you a slower top speed , but will give better vertical performance. Also try to use a light prop like wood not composite like APC.

That is what i am leaning toward I have a wood 18x6 master airscrew that i am going to try tomorrow the plane is a model tec remedy a 2m freestyle pattern plane it needs better vertical

on gassers the lowest is about an 8 pitch.... on glows the lowest is about 4

for the gasser's i use the vess A series when i need more vertical.they seem to be like a 6 pitch prop with less speed,but more pull. and i have not been able to find any other prop in a 6 pitch for gasser's.

I think the APC will have more thrust..if the RCS can swing an 18x6W APC,you should be able to have unlimited vertical and be able to hover a 12 pounder.

well i tryed the 18x6 today, not good at all it didn't like it at all . tuned the engine in a little better got 8,600rpm on the 16x8 the plane preformed better but still is poor in the vertical just flat runs out after a 200 foot clime

Try reducing some weight in that plane first. A123's/cf lg/lighter wheels/lighter nose cone/lose pilot figure/cf wing tube/remove ballast and move equipment around/smaller tank/etc.

that for the most part has been done the plane is the plane now i am looking for the most efishent prop

Maybe you need more engine?

try an apc 17x6 you'll love it

I thought an RCS140 would have more balls than that. Cant haul a 12 pounder up a short hill? maybe it needs to be tuned better? maybe the 17x6 APC is better. My YS 140 and OS 160 will turn the APC 18x6W with ease and pull around 18 pounds thrust..12 pounds is nothing for them.

I had this engine on a ultra stick light it weighed 10 1/2 lb. vertical was very good even put the plane on floats wich brout the weight up to 12 lb. it still preformed good that is why i felt ok with puting it in the remedy. i have a 17x6 on order i will try it as soon as i can

OK the 17x6 was a good improvement

great....how many rpm's was it turning?

I didn't get a reading but there is a good improvement in the over all flying .