German props vs. American and British ones

[Zacherof]

What are the advantages of the 3 bladed paddle propS of German usage vs. The 4 blades props of American and British planes?
 

[hitech]

Basic prop theory, less blades = more efficiency.

The issues become can you make a prop long enough to physically stand up to the HP of the engine and still not hit the ground.

Hence when the ground becomes an issue more blades must be added to absorb the HP. Also depending on blade size the efficiency curve will change at difference speeds, hence more or wider blades might improve efficiency at climb speeds, but lower the efficiency at top speeds.

I.E. There really is no best prop, it is more a matter of matching the prop to the plane.

HiTech

[ink]

Basic prop theory, less blades = more efficiency.

The issues become can you make a prop long enough to physically stand up to the HP of the engine and still not hit the ground.

Hence when the ground becomes an issue more blades must be added to absorb the HP. Also depending on blade size the efficiency curve will change at difference speeds, hence more or wider blades might improve efficiency at climb speeds, but lower the efficiency at top speeds.

I.E. There really is no best prop, it is more a matter of matching the prop to the plane.

HiTech

pfft what do you know........

its not like you fly a real plane or made a flying game..........

oh wait........






 


it just keeps getting better

[Volron]

 

[Zacherof]

Well that makes since.

Thanks hitech

[Old Sport]

Here's an interesting relevant article from Widewing's old site - captured from the Wayback...   

http://web.archive.org/web/20050207050453/http://home.att.net/~historyzone/Fisher.html

best.

[Arlo]

Then there's no props but more blades. 

[MK-84]

So what I think I understand is that in theory if ground clearance was not an issue at all a corsair with a stupidly long 2 bladed prop would be more efficient in flight than a 4 bladed, except for landing where it would hit the ground.
Whether to have thinner or thicker blades would be a factor of the type of performance desired, such as higher speed, or a better rate of climb, or a more efficient cruising speed?

[colmbo]

It used to be that control-line "speed" models used a single blade propellor. (it was counter-weighted for balance)

[Zacherof]

How is the spit XIV prop more effective the
a spit VIII at alt? Or a tmpest

[MK-84]

It used to be that control-line "speed" models used a single blade propellor. (it was counter-weighted for balance)

Would you please explain further in more detail?

[colmbo]

Would you please explain further in more detail?

Google "single blade propeller".  Lots of responses.

[GScholz]

With a long-bladed prop you'll also run into speed of sound problems as the tips will be going faster at the same rpm as on a shorter prop. On a Tu-95 Bear going at max power the prop-tips will actually break the sound barrier. Also the lower the prop's speed at max AoA the lower the theoretical top speed of the aircraft. All these things have to be balanced to fit any given engine/plane configuration.