Propeller Design

[Guest disperse]

What got me started thinking about this subject, was looking at the prop from Garry Morgan (my Avatar)

 

Why the tapered tip, compared to a flat cut tip ?

 

and also if anyone knows of some good web sites on prop design.

 

also it seems that Airmaster are the only people supplying a CS prop for the Jab engines.

 

 

 

[Deskpilot]

Is that photo for real? I hate the look of the tail dragger Jab but with that prop, it's even worse. Guaging the size, how much ground clearance is there when the tail is up?

 

 

[vk3auu]

Those interested in props might be interested in the comparisons of a few props done by John Gilpin at http://www.stolspeed.com/props-comparison/

 

David

 

 

[eastmeg2]

Troy,

 

Tapered tips reduce tip vortices, contributing to greater efficiency.

 

 

[Guest Teenie2]

H model hercs have flat tips.In a book from the mid 80's 'how to make wooden props" by Alvin Schubert he found the flat (wide) ended props performed better than the tappered version. It really is a black art.

 

 

[Guest disperse]

I've never researched the subject.... But my first thoughts were: the tip of the prop would hold the greatest amount of energy, thus had the potential for the greatest thrust. As I said, just a first impression.

 

BTW vk3auu that kink is good reading !

 

 

[Guest disperse]

another random thought, any theories on using micro vortex generators on a prop !

 

 

[Guest ROM]

Just a bit of useless info! At the end of WW2, the allies made a thorough study of all the german technology.

 

One small item was the fact that for the same engine HP in the high performance fighters and etc, the allied aircraft had a consistent 10 to 15mph speed advantage over the axis aircraft.

 

This was eventually put down the better design and performance of the propellers on the ally's aircraft.

 

As a side issue, Jabiru are currently testing the Sensenich fixed pitch wooden props and are reputedly getting quite a bit better performance compared to the Jabiru props.