can a prop be re-pitched

[smurfsideresort]

I have a stainless 14 1/2 x 24 raker and need a 22. The local prop says the can re-pitch it to almost 22 for $150. Seems cheaper than a new prop to me. Can anyone verify that this is possible?

 

[Ron G]

Re: can a prop be re-pitched

I dont know for sure ,i thought they put more cup in them or less??the gurus will be by to give the right answer.

 

[QC]

Re: can a prop be re-pitched

Yes, very possible and done ALL of the time. I wouldn't necessarily tell him what pitch, I would tell him how many RPM you need to gain and any other quirks you don't like. They can help with blowout and even a little bow lift if they are good and you do a good job telling them what you are experiencing. I understand that it is a harder to take pitch out than to add, but I have had prop shops play with this for me a couple of times.

 

[calkearn]

Re: can a prop be re-pitched

Quietcats got it right, I just got a 4 blade 20 from precision propellers and they said they would make it a 19 if i wanted. also cupping ect, for better bite. Thats whats great about stainless steel props

 

[malagaoth]

Re: can a prop be re-pitched

alum props can be repitched too! by +/- 2inches at about £45 in the uk

 

[walleyehed]

Re: can a prop be re-pitched

I'm going to throw a wrench in here....you add or remove efficiency when a given prop is worked.<br />Pitch change??? No, you have to completely remove the blades and weld them back on to actually "change" pitch.

 

[QC]

Re: can a prop be re-pitched

Kenny,<br /><br />You are definitely the man when it comes to props. Help me understand. When a prop is worked to change RPM is this only done by adding or subtracting cup? Are you saying that the only way to get more RPM, for example, is to increase slip?

 

[MrBill]

Re: can a prop be re-pitched

You would want to decrease slip...get closer to theoretical max speed.

 

[QC]

Re: can a prop be re-pitched

I understand Mr. Bill, but Kenny made the point that the only way to "work" a prop was to change its efficiency. Soooooo if that is true then the way you work an existing prop to gain some WOT RPM is to increase slip %. Not saying it is good (it isn't), but asking if that is what he meant.

 

[walleyehed]

Re: can a prop be re-pitched

That is exactly true...<br />It's basically imposible to take pitch out of a prop because you are not changing the inner portion of the blades. You either flatten out the tips or remove a slight amount of the existing cup...That's why it's always better to error on the low side of pitch (high RPM) because cup can be extended around tip farther, or increased on the trailing edge to bring R's down, and the end result is a double effect because you bring the RPM down but lower the slip ratio, usually increasing speed and holding ability.

 

[umblecumbuz]

Re: can a prop be re-pitched

Kenny - you said:

because cup can be extended around tip farther, or increased on the trailing edge to bring R's down, and the end result is a double effect because you bring the RPM down but lower the slip ratio, usually increasing speed and holding ability.

You mentioned two areas of cupping - increasing side cup or increasing tip cup. Which exactly does what?

 

[walleyehed]

Re: can a prop be re-pitched

The trailing edge cup improves forward motion at a given RPM.<br />Cupping around the tip changes the rake slightly, makes it lift better for less wetted surface, or more trim angle.<br />And, just like "Pitch", the "Rake" is pretty much built into the blade, but cup can be added around the tip, infact both principals are used, or considered when building a prop.<br />Cup can also be added at the leading edge as well..so the leading edge enters the water (or motion thru) with the leading edge slicing with the least resistance, but with these you will see a greater amount of cup following..

 

[EZLoader]

Re: can a prop be re-pitched

I think this may be the best prop out there! <br /><br />It is on-site pitch adjustable (5 settings), on-site repairable, stronger than aluminum, corrosion free, and the hub adjusts to fit almost any engine, making it fully transferrable to your next engine. Watch the video:<br /><br /> http://www.propulse.se/english/index.html <br /><br />

 

[ob15]

Re: can a prop be re-pitched

I have one and agree it's a nice prop, but would not recommend it to someone who is looking for more/better performance. I would think that the composite blades flex quite a bit under load even if it's supposed to be stronger than aluminum. It's like carbon fiber compared to steel. It's a lot stronger but but flexes quite a bit more.