O.K. It was possible to compare e.g. blade cord increase beyond that optimizewd one. It could be done in the "analysis" section of Javaprop....
using javaprop using javaprop for finding props for electric boats. Great tool! Some questions: 1. To test efficiency penalty, if blade...
PMG-132 efficiency PMG-132 efficiency curves: For instance here:...
Low drag elboat hull? Played www.DelftShip.net Lenght(wl) = 7.7m, beam(wl) = 0.9m, weight = 940kg (batteries 400kg) Instead of that swedish...
propeller channel Masalai, would you think, that a flat bottom width same as propeller diameter would not be a good enough "cavitation...
Prop tunnel reference http://www.zeroemissionboats.com/batenbilden11.html This is a 120 deg. prop tunnel.There is no keel box as in Atkin...
Thanks TollyWally! Yes, low tech used effectively. The skinny Tornado hull is good to avoid wave drag, but it is too skinny to carry all...
Low energy reference Today I made 14kn with this experimental el-boat. 6m Tornado center hull plus tiny outriggers. Total load 340kg including...
Only one model Ken, what about using only one model? If you really want only to check the prop tunnel contribution, you should use a horizontal...
Atkin Heron Model Wooden model Made a wooden model according to Atkin Heron, size 10:1, weight 0.6kg. This model is suitable for towing tests...
angled axle drag Thanks Gilbert! Would it be possible to learn more of these local builder tests? What is essential, are prop diameter and...
There is no planing at all! Some stupid questions: 1. According to Savitsky, planing lift force is generated by bottom trim angle (4..5 deg...
Thanks Rick! Yeees, used "flat plate blades" as was default in JavaProp! This was a mistake! With real wing profiles I now get 10% better etas....
Played JavaProp for an elboat hull 7m long, 500kg load, 12kn speed. Funny: For a 80% efficiency, one would need a 1m dia prop at 250r/min. Only...
Rick, thank you much for these reference data: 4.5kW, 19kg, ... Speed at 4.5kW? Hull lenght (wl)? Hull beam (wl)? Total load? I have got...
kengrome, the reduction of the shaft angle may well be the key factor in this tunnel design boat: If there is angle in the shaft, the virtual...
Barend, there is that michman.html in the package. You'll need all this stuff. The key file is in.mlt, where all the hull and associated stuff...
Michlet example Electric mono as an example, using Michlet: L = 7.5m B = 0.86m L/B = 8.7 M = 900kg Wetted: 6.64m^2 Section max: 0.207...
Thanks Leo, that "negative dynamic forces increasing the displacement" is what would be useful to understand. These have nothing to do with those...
Hi Leo, for me Michlet works and does not for low L/B. It depends on hull load. It works pretty well for light dinghy hulls, but fails...