Why do I need to brake the prop after the motor shuts off? Won't the prop just free wheel and have no effect on anything? Allot of set ups I see have almost immediate 100% strength, seems severe to me. After brakes release it free wheels anyway, why brake at all?

MM

Why do I need to brake the prop after the motor shuts off? Won't the prop just free wheel and have no effect on anything?

MM

In short.. it'll glides longer.  If the prop is free wheel it'll slow the plane down more as Tim said above.

Why do I need to brake the prop after the motor shuts off? Won't the prop just free wheel and have no effect on anything? Allot of set ups I see have almost immediate 100% strength, seems severe to me. After brakes release it free wheels anyway, why brake at all?

MM

If the braking is turned on, then as long as a battery is connected, it should resist prop rotation,,
however there are a couple settings,
 one is braking speed, how fast it stops
another is braking affect or strength,, the actual resistance to rotation

If you intend to fly competitively you'll want to attain a long, smooth landing, and if the wind is up you may want to whip it a bit to put the plane down in the ideal spot.  Both of these are easier with less drag.

Put the brake at 100% and the ramp at slow.
This way the prop stops slower, none of that instant stop that could strain motor mounts etc.
BTW, in FAI the prop is allowed to free-wheel for landing so long as the judges can see the individual blades rotating.

it did seem like an air brake but why is a free wheeling prop more drag?

MM

Are you running a 2-blade or 3-blade?

I had the brake at 80% today and the prop spun pretty good, it did seem like an air brake but why is a free wheeling prop more drag?

100% strength with slow ramp sounds good, I'll try that tomorrow.

MM

MY unscientific explanation,, Howard may correct me
the simplest way to look at it is ,, with the blade spinning at some rpm, you are presenting more blade area to the oncoming air. the faster it spins, the more blade area you present.. I think in terms of the airplane moving forward through one foot of forward motion. every revolution makes a slice through that foot of air. the more revolutions the more slices , hence more blade area presented to oncoming air.

So why are rubber powered free flight planes built to allow the prop to free wheel after the powered phase of the flight? 

First, serious rubber powered free flight planes have folders.  The only performance-oriented classes that don't use them are things like P-30 where they aren't allowed for simplicity's sake.  Second, the freewheel is a lot freer on rubber power.  Third, pitch to diameter ratios tend to be higher than 1, meaning the prop isn't spinning nearly as fast in the glide.

There's probably subtler reasons than that, but that's as much as I know.