Ira and all,
> Actually as can be seen convincingly in a stroll about Sun and Fun
> today, any new, high performance aircraft , i.e., Cirrus, Cessna,
> Mooney, Lancair, etc., etc., has 3 blades.
>
Apart from what Karl said, the number of blades has something to do with
the prop *solidity* necessary to transfer power. The aircraft you cite
have powerful engines, hence the tendancy to increase the number of blades.
> Just because most aircraft designed 30 years ago or earlier had
> two blades doesn't mean that it was best for aerodynamics,
>
Our airplane and two-blade prop were designed just a few years ago, and
they are quite efficient aerdynamically.
Remember that more blades means more drag (I also owned an unlimited
aerobatics airplane with a 3 blade, and we performed comparative tests
with a 2 blade).
In some cases, 3 blades are needed with low power (100 hp) in order to
reduce prop diameter for clearance reasons.
> In the end I think Graham is correct, it was just about money.
>
Weight, parts count and efficiency also play a role.
Best regards,
--
Gilles
http://contrails.free.fr
|