Prop efficiency curves

[LostInBoston]

Does anyone have or know where to get prop efficiency curves for surface piercing props? Have any tests been done on them?
Thanks

[Guest625101138]

There is some data in this paper:
http://www.icmrt07.unina.it/Proceedings/Papers/c/44.pdf

If you google arneson or other surface drive manufacturers you will also find some curves.

The peak efficiency I have seen in any of the data is 70%. Well below what can be achieved with a fully submerged prop or air prop but these have certain limitations.

Rick W

[Olav]

These data seem to be quite confidential and I have been searching for quite a long time.

The only documents I was able to find are a test protocol by Rolla, a paper by Marco Ferrandi, Stefano Crotti, and Michele Viviani (which contains some handy regression formulae to produce KT/KQ/η curves; I made little Excel spreadsheet of this), and finally a product leaflet by France Hélices where there are two little diagrams of unspecified surface piercing propellers. However, this seems to be no longer online.

Edit: Oops, Rick was quicker...

[kistinie]

http://zone.sousmarins.free.fr/zone%...%20helices.htm

yes i know this is french but take a look at pictures at the end...can use translator too.
they say water is also pressure injected close inside the fairing to improve flow
i wonder what would be the efficiency of this twin pump prop with fairing around ?
0.9 region, ?

And what would give an approximate home made copy of such a propeller pump ?
Less but certainly a lot anyway, it would be worth trying

A pump jet with 2 propellers can be seen on some jet ski, should we get inspired ?

[drmiller100]

the jetskis are all single impeller with a stator behind it, as are most of the jetdrives currently being made.