What changes should i expect when changing from a 3-blade 12x4 propeller that comes with an Alpha 60 to a Master Airscrew S-2 Series 12x5 propeller on the Alpha 60? Things like Top Speed or acceleration changes? I want to replace the 3-Blade, because I bought 3 2-Blade props expecting to need to use them, but I never have. However, I wan to give them a try.

Thanks

Your performance should be the same.

When going from a 2 blade prop to a 3 blade prop, either drop 1" in diameter OR 1" in pitch. When going from a 3 blade to a 2 blade either add 1" in diameter OR 1" in pitch.

Multi blade props are not efficient and most people would not suggest them unless you need ground clearance.

FWIW - MOST people run a 12x6 or 12x7 APC on a 61 engine. The additional pitch will prevent you from over revving the engine while providing a little more power.

I suggest checking your rpms with both the 12x5 and a 12x6 or 12x7 before flying the bird. Remember, the engine is going to "unload" in flight so you will pick up a couple of hundred rpms.

Read the second post of this thread (and the other replies by opjose):
http://www.rcuniverse.com/forum/fb.asp?m=7361348

I think you're refering to the special trainer prop that has blades that look like paddles.

Among other differences the plane should glide more freely with a normal prop. This will of course change how landing approaches work out with your alpha 60.

Normally that would be true, but I think the prop he's refering to is the H9 PTS prop. Have a look at one. They are totally different from other props.

You will see much improved acceleration and top speed. However, as said before, you will also notice it not slowing down as nicely for a landing. you will have to pay more attention to your airspeed on final aproach. Be ready to chop the throttle earlier, and then feather the throttle as you bring it in.
I remember when I took the trainer prop off of my alpha 40, and it took off so fast I almost lost it. The acceleration difference was astounding.

Ok, thanks. I think i will be ok with the acceleration and top speed changes, since i will now be expecting them and prepared for them. I actually think this is good, since i starting to max out the capability of my trainer, so a little extra speed and acceleration should help with some of my manuevers

Hi... I'm flying a Alpha 60 right now with a OS 61 and a 12X7 prop. I tried other sizes but this prop does the best all around job for me. I think it will work for you. GOOD LUCK.[sm=shades_smile.gif]