Information about a propeller

[pr2501]

What is the propeller pitch of next propeller?

data on the propeller:
17x??
6 92
MI/FED
DJ/EP

MM0156

Thank you

[Wotname]

Hmm... the pitch is a bit hard to read isn't it.
It is contained in the 17LH1? which tells us the diameter is 17, it is a left hand prop (i.e. rotates CCW) and the pitch looks like 11 or 10 or maybe was repitched at some stage and the 11 was overstamped with 10 or ???

[pr2501]

Votname Thank you
And the manufacturer is it Federal propellers or Dyna jet?

[Wotname]

^^ sorry, that isn't something I know!

[boatpoker]

Looks like that second pitch digit has been re-stamped more than once.

[pr2501]

Thank you

[DougR]

Michigan Propeller bought Federal Propeller sometime in the middle of the last century....

Today they produce props under both brand names, but they are very similar. The Michigan trade name "Dyna Jet" is basically the same prop as the Federal "Equi Poise"..... That being a three blade prop commonly found in power boat applications. Similar props are available in four blade configurations as well.

As you know the pitch marking is illegible, but a compentent prop shop can easily measure it for you.

DougR

[pr2501]

Thank you

[pr2501]

I made some calculations and I think that I am around 10 of pitch
(65 x 55). But I am not sure, because propeller has a specific shape.

[GordMay]

To measure propeller pitch, you need to take several measurements. These measurements are going to be much more accurate if you have the prop off the shaft and can lay it flat on a table.

First, find the widest part of one blade and draw a line across the face from edge to edge. Then measure the distance from the front of the hub to the points where your line meets each edge of the blade. You can do this best while viewing the prop from the side. Take the smaller measurement and subtract it from the larger.

Next use a protractor, angle gauge, or carpentry square to measure the triangle formed by the two points at either end of the line drawn across the widest part of the propeller blade and the center of the hub. The narrow, pointy end should be at the center of the hub. Measure the angle between the two lines radiating out from the center of the hub.

Now take the first measurement and multiply it by 360. Then take the result and divide it by the angle you found in the second measurement. The resulting number is the pitch of the prop.

There are also inexpensive prop gauges available, but where is the fun in that approach.

➥ https://www.soinc.org/sites/default/.../pitchgage.pdf

[pr2501]

Pleas, check A,B,C on attached picture? How must I move them?
Check first image of this post to see where point A should be.

The result is 15.

Lets presume that my propeller is 17X17.

What difference would it make if I would use 16X18 ?

[pr2501]

At one shop were teling me after checking with PC that pitch is 11".

But I went to another place at the end, and there were telling me :

The pitch was all over the place, we had to set it at 12”. The prop is now
17LH12

What did they meant with this?

[FPNC]

I have taken brand new 3 blade Michigan propellers out of the box and each blade measured to a different pitch. An old prop that has pitch variance between the blades would not surprise me. Sounds like your prop shop is on the ball.

[PeterS]

The pitch was all over the place, we had to set it at 12”. The prop is now
17LH12

What did they meant with this?

The pitch of the propeller is generally set at the 7th radius, that is 70% of the dimension from the CL of the shaft to the furthest tip of the propeller blade.
This is the Nominal pitch that is stamped on the hub.

from the picture you supplied the diameter is 17" x 11" pitch LH rotation which would be on the Port Shaft in a twin engine installation.

When your propeller was measured, they would have established the base pitch on each blade at 7R, which were apparently different from each other (very normal on used props).
They appear to have averaged the pitches measured to arrive at 12", most propeller shops would have set the pitch back to factory original or at least asked you what you wanted them to do.

Hopefully their equipment would tell them what pitch would be needed at every radius on the blade.