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understanding prop pitch?

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Old 08-24-2004, 04:08 PM
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Default understanding prop pitch?

Currently I have 15x23 3 blades on SSM 2. What would happen if I went with a set of 15x25 3 blades with everything else being the same. I found a really great deal on them and was thinking of gettng a spare pair of props.
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Old 08-24-2004, 04:17 PM
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Default Re: understanding prop pitch?

If the 23's were the perfect prop, ie low slip and the rpm's in the correct range, then you would go slower because the engine would now be below the correct rpm range. If things are less than perfect, ie there is too much slip, or the engine is above the desired rpm limit, then you should go faster with the 25's. If the engine is below the desired rpm then you will go slower because the engine will be bogging. Ultimatly, if the price is right, just make the sale contingent on you being able to try them. Naturally, you should pay shipping both ways. If you damage the prop in any way, then you own them, so be careful.
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Old 08-25-2004, 08:59 AM
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Default Re: understanding prop pitch?

Well said Cord!

The 25P props will spins about 400 RPM less than the 23P props if the diameter is the same.

Julie
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Old 08-25-2004, 10:18 AM
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Well, I've been on this board for 3 years now and I finally got one right. Go figure.
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Old 08-25-2004, 10:25 AM
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Default Re: understanding prop pitch?

So if I'm running 23p at 4700 rpm WOT should I drop to 21 and try to get more RPM out of the engines (last post potentially 400 more RPM)? Thus potentially picking up a little more speed
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Old 08-25-2004, 10:27 AM
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I HAVE 86 SCARAB PANTHER. JUST PUT IN NEW GEN 6 502s LOOKING TO PROP FOR MAX. SPEED. PRESENTLY USING 24 PICH 4 BLADE MIRAGE. BOAT JUMPS OUT OF WATER. SPEED @ APPROX. 68-70 MPH
 
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Old 08-25-2004, 11:58 AM
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Default Re: understanding prop pitch?

Pier3pressure,

What engines do you have? You will indeed pick up about 400 PM by dropping to a 21P, if your 23P props are true.

Julie
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Old 08-25-2004, 12:00 PM
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Default Re: understanding prop pitch?

rtjack,

What is your WOT RPM, trimmed for speed? Are your props Bravo I 4B props?

Julie
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Old 08-25-2004, 12:02 PM
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Default Re: understanding prop pitch?

Cord,

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Old 08-25-2004, 12:15 PM
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Default Re: understanding prop pitch?

Throttle Up

I'm running twin Gen V 454 mag efi's, 385hp
Actually just found a slight ding in the starboard side prop, I'm going to need a little assistance in getting it back true

Phughes69,
Sorry to jump in your thread, thought my question was similar in nature.
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