sport here is item six from your link for everyone
6. What is the importance
of propeller diameter?
Ideally, the propeller diameter should be
greater for efficient low airspeed operation
and smaller for high airspeeds. A propeller
with a variable diameter would solve the
problem, but the structural and control
problems involved would increase the cost
and weight to a point where the advantage
is not practical. The diameter of a fixed pitch
propeller is generally reasonably large to
favor low airspeed operation. At the same
time, the blade size is kept small to favor
higher airspeeds and permit faster turning at
low airspeeds so that higher power is
available from the engine. The diameter and
blade size of a constant speed propeller can
generally be greater because of the variable
blade angle provision.
like I said you read one thing and then read the first sentance and then base everything on that. Anyway when you make a claim on here and "post" a link the OP asking a question might beleive that and then they are stating only partial information like you are. what you are forgetting is that the prop and engine need to be matched to the desired performance you are looking for. I am done arguing with you sport.
OP my opinion is that two blades for modle airplanes are best. now if your going for a certain look then sure go for a 3 or more bladed prop. I run 3 and 4 blade props on some of my planes. sure I take a performance loss on the same engine but I have more power than needed anyway. all of the pylon and glider planes in competion use a 2 blade prop. Now some of the 3D and pattern planes use 3 or 4 blade props but again its for their need to be quiter and or provide more braking action on a down line that the 3 or 4 blade gives them.