I think the kiwiprop is not the best choice for electric propulsion. Increasing the pitch is not going to help, but will make it worse. When I did my install I had a fixed 3 blade propeller. But as I sail mostly big distances (ocean) I definitely wanted a folding or feathering propeller. I first thought about the maxprop also because I was still tinkering with the reduction. I had a very interesting conversation with the importer of the maxprop, and he advised me not to use his product. Firstly he was afraid an electric motor would kill the propeller with the ability to go from forward to reverse too quickly. Funnily your problem is the opposite. And secondly I wanted it to be the most efficient way op propulsion and he said a feathering propeller is never going to be very efficient. There is a big folding/ feathering propeller test from yachting monthly. If you Google it it sh6be eas6to find. There this is confirmed and interesting enough the flexofold 3 blade was in forward even more efficient than the fixed 3 blade. So I chose that one in the smallest pitch option and the same diameter of the fixed prop. To my surprise the cavitation which I had with the fixed propeller was non existent with the flexofold and to my delight more efficient indeed. In reverse it is the absolute opposite lol. But for me not of much importance. In this same test the kiwi prop was by far the least efficient. I did quite a bit of research into propellers too and my conclusion was for electric propulsion where speed is not the most important factor, but efficiency is it's best to go for the biggest propeller you can fit with a low pitch and match the reduction to that.
I hope this helps.
O btw I have a 18" diameter by 11" flexofold for a 16 metric ton steel long keeled cruising boat with the water cooled thunderstruck motor with a 17cell 300ah lithium bank so at 56 volts this gives me 13kw continuous 15kw max and my cruising speed which I set at 4kn takes 2.2kw in flat calm water and reasonable clean bottom. If I want to make miles on the ocean in a no wind situation I usually motor at 1-1,5 kw. The last ocean crossing from the Caribbean towards Europe I did 27 miles on 50% battery. (Solar panels fully charging)
Op vr 12 aug. 2022 00:05 schreef <jesper.malmberg86@gmail.com>:
Thanks Graham, I figured that would be the case. Hopefully not too big of a project.
BTW, what are your specs on your prop? Mine is 15inch and I get a fair amount of cavitation at higher RPM like around 7-800 rpm on the prop,will try and increase the pitch a bit to get same thrust at lower rpm and see how that goes. Also considering replacing the blades with slightly larger ones to bring overall rpm down on the system.
_._,_._,_
Groups.io Links:
You receive all messages sent to this group.
View/Reply Online (#32096) | Reply To Group | Reply To Sender | Mute This Topic | New Topic
Your Subscription | Contact Group Owner | Unsubscribe [newarmyguitar24@gmail.com]
_._,_._,_
No comments:
Post a Comment