Propeller Stamped "1719R465" What does it mean?

[Baddox]

This is stamped into a 4-bladed propeller. What do the numbers refer to? I don’t think that it is a manufactures’ part number so guess may refer to size and pitch. I’m intrigued.

 

[Len Ingalls]

Normal stamping would be 17R19 = 17" diameter Right hand 19" pitch. Not sure abt 465-could be mfgr code

 

[Sailfree]

Normal stamping would be 17R19 = 17" diameter Right hand 19" pitch. Not sure abt 465-could be mfgr code

Probably means the person doing the stamping was dyslexic then!

 

[PuffTheMagicDragon]

The "465" could be the projected area of the blades divided by the area of the full disc. (0.465 = 46.5%)

 

[Len Ingalls]

Yes! Yes you have it cyphered! Cheers/Len

 

[Nigel_Ward]

The "465" could be the projected area of the blades divided by the area of the full disc. (0.465 = 46.5%)

I think it is 4 blade 0.65 area ratio

 

[Len Ingalls]

The "465" could be the projected area of the blades divided by the area of the full disc. (0.465 = 46.5%)

I think it is 4 blade 0.65 area ratio

Sounds reasonable. Thanks.Good to know./Len

 

[PuffTheMagicDragon]

I think it is 4 blade 0.65 area ratio

It could well be but I think that stamping "4" on a prop just to show that it has 4 blades is rather superfluous.

 

[Nigel_Ward]

It could well be but I think that stamping "4" on a prop just to show that it has 4 blades is rather superfluous.

It is common practice to quote propellers in terms of blade numbers then Area ratio usually in the form of e.g. 3.50 for a 3 blade 0.5 area ratio.

Most of the old prop design diagrams were based on NSMB standard series from 1960s and this is their designation.

 

[Len Ingalls]

It is common practice to quote propellers in terms of blade numbers then Area ratio usually in the form of e.g. 3.50 for a 3 blade 0.5 area ratio.

Most of the old prop design diagrams were based on NSMB standard series from 1960s and this is their designation.

On the left side of Atlantic,we only see the Dia.,Hand & Pitch stamping,except for the outboard-stern drive folks,who mention pitch only(as in "I have a 16pich prop for sale". Would be nice to have a reference to blade area. What is NSMB? Tks/Len

 

[Nigel_Ward]

On the left side of Atlantic,we only see the Dia.,Hand & Pitch stamping,except for the outboard-stern drive folks,who mention pitch only(as in "I have a 16pich prop for sale". Would be nice to have a reference to blade area. What is NSMB? Tks/Len

NSMB is the Netherlands Ship Model Basin, part of Wageningen University. They did a lot of analysis of propeller data over 50 years ago and provided design charts enabling the easy calculation of optimum diameter and corresponding pitch for a wide range of blade numbers and blade area ratios.

 

[Baddox]

Thanks for all the replies, the diameter and pitch make sense. I’ve checked again and there is definitely no decimal point in the 465 so it’s either 46.5 or 4 bladed 65% area.