How Sharp Should You Make Your Prop?

[jtexas]

Re: How Sharp Should You Make Your Prop?

When you drove the machette through the water, did you hold it so that the blade was aligned with the direction of travel?

If so, then you have proven that a prop with 0" pitch should be as sharp as possible.

Try paddling your boat with the machette and the baseball bat.

Try it first with the sharp edge of the machette.

 

[cwilt]

Re: How Sharp Should You Make Your Prop?

"yet my boats faster then his"



Consider what the moving leading edge of the wing on some fast aircraft is used to slow them down.

sory there jb i work on f-16's and the lef (leading edge flaps) are only used for lift purposes the trailing edge flapperons are for drag and roll

 

[Pony]

Re: How Sharp Should You Make Your Prop?

How about this. Take a baseball bat and a michette. Drive both through the water with your bare arm's muscle. Which one goes through the easiest?

Rest my case.

Mark

Which one moves more water and creates more thrust though 8) If what you say is true a boat oar is poorly designed........


Edit. I see Jtexas already made this point.............read first then type!

 

[baja power]

Re: How Sharp Should You Make Your Prop?

so i guess all those performance boats running lab finnished props are also loosing speed? im sure thats why they have it done|O

 

[jtexas]

Re: How Sharp Should You Make Your Prop?

It's true that a sharp edge moves through water with less drag, but there's more variables at stake than blade sharpness...a sharper edge is thinner therefore more flexible for example...or prone to cavitate maybe...or more vulnerable to worse damage from a prop strike...or harder to maintain. I'm just not convinced sharper will always equal better. So your lab finished blade runners will have considered all the variables and made an edicated decision. If the experts tell me otherwise I'll believe 'em though.

8)

 

[phatmanmike]

Re: How Sharp Should You Make Your Prop?

make it sharp enough to cut your neighboors truck tires, then just take HIS boat when hes not looking

 

[steelespike]

Re: How Sharp Should You Make Your Prop?

It's impossible to hand sharpen a prop and get optimum
performance.The edge will not be uniform in blade radius or the cross section shape.and after a few sharpenings you have a prop with poor shape and most likely out of balance which hinders performance and can ruin bearings and seals.
Of course a prop with a fine blade and fine factory/lab edge that maintains it shape in use will perform best.
An artifically hand formed sharp edge is meaningless
for performance.Mostly because it destroys the intended flow of water over the blades.