Will putting an edge on the blades go faster?

[mickjetblue]

I wonder if putting an edge on the blades of a prop will make it more efficient.
Anybody been there and done that?

 

[steelespike]

Re: Will putting an edge on the blades go faster?

Even if you could do it perfectly,not likely,you wouldn't notice the difference.
fine to remove minor dings but any more can make the edge thickness uneven and blade contour wrong.And in the extreme surely make the prop unbalanced.If your looking for more efficient prop edge/design stainless is the answer.

 

[ivar]

Re: Will putting an edge on the blades go faster?

And done wrong, it may increase turbulence around the leading edge of the blades, resulting in less performance.

To make a prop more efficient,send it out to a reputable prop shop, I've done so with several of my props after getting minor dings in them, they all came back "better than new"

 

[Silvertip]

Re: Will putting an edge on the blades go faster?

Think logically about this! If a knife edge made a prop more efficient, don't you think the manufacturer would do it when they build the prop?

 

[DeepV]

Re: Will putting an edge on the blades go faster?

Even if a knife edge was more efficient it wouldn't last very long. I think there is a balance between efficiency and durability.

 

[fishrdan]

Re: Will putting an edge on the blades go faster?

One of my friends (yes, actually a friend and not me...) did this to his uncles boat thinking it would improve performance. It ruined the prop and made the boat slower, he had to buy his uncle another prop.

 

[QC]

Re: Will putting an edge on the blades go faster?

Trailing edge might be better sharp, but the leading edge is usually semi-rounded. Think about a wing shape. Aerodynamics and hydrodynamics are very similar . . .

 

[Frank Acampora]

Re: Will putting an edge on the blades go faster?

Logic would dictate that a leading edge that was sharp would enter the water easier, and in racing applications where the prop is surface riding it is common practice to have a sharp leading edge, thin blades, and a squared off trailing edge. This practice is even carried to model racing boats where the prop is turning 20,000 RPM. This prop configuration gives the best performance IN RACING APPLICATIONS. BUT: Ask the racers what their props cost and how long they last. Even hitting small twigs in the water will ding a blade and when they are that thin, repair takes an extremely talented technician--and they charge a lot. Model boat racing propellers are irreparably destroyed by hitting floating weeds.

However, for recreational applications--all the above answers apply

 

[Sondar]

Re: Will putting an edge on the blades go faster?

Don't mess with your prop!!

Like everyone else has said, props are built the way they are for a reason and it takes considerable skill to modify or repair them successfully.

 

[mickjetblue]

Re: Will putting an edge on the blades go faster?

I thank you all for your feedback. It happens that I have a river prop guard
on my skeg, and it takes the knocks, if there are any, instead of the prop blades.

So, I got out my file, and I lightly filed the edges of the prop blades at about a 45 degree angle on both sides. This was minimal filing, just to remove the box edge off of the blades and slightly wing shape the edges.

I took the boat out, and noticed an improvement in the zip of the motor power.
Top end was only slightly improved, but I could feel the improvement in power overall. I'm a believer now, that a slight filing to a wing shape is better than a box edge.