<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div></div><div>Hank,</div><div>I was only running it for a short time testing the thrust.</div><div>I previously did a temperature test running it at 30 Amps for an hour </div><div>without a prop in water temperature up to 27C, & it kept below 80C.</div><div>I am happy with the yamaha 2hp prop & will do an endurance test with</div><div>that for 100 or so hours & monitor the temperature again.</div><div>Cheers Alan</div><div><br>On 8/12/2018, at 1:29 AM, hank pronk via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br><br></div><blockquote type="cite"><div><div class="ydp86fb6753yahoo-style-wrap" style="font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 13px;"><div></div>
<div>Alan,</div><div>How is the heat managing?</div><div>Hank</div><div><br></div>
</div><div id="yahoo_quoted_5174481772" class="yahoo_quoted">
<div style="font-family:'Helvetica Neue', Helvetica, Arial, sans-serif;font-size:13px;color:#26282a;">
<div>
On Friday, December 7, 2018, 3:12:00 AM MST, Alan via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:
</div>
<div><br></div>
<div><br></div>
<div><div id="yiv5663440511"><div><div></div><div>Hi all,</div><div>tested another 2 props today. Both 2 hp yamaha 3 bladed. One was a</div><div>plastic 7&1/4 x 4, the other aluminium & similar but with rounded ends </div><div>to the blades.</div><div>They both worked much better than the Vetus prop I tried yesterday,</div><div>the plastic prop being the better.</div><div>By comparison the plastic yamaha prop had 60.62 lb. thrust from 1624 W </div><div>while the Vetus had 45 lb. from 1694 W. Quite a difference; 26.79 Watts per</div><div>pound of thrust as apposed to 37.66 for the Vetus. </div><div>David, again it showed to be a lot more economical on power to run the</div><div>motor slowly. At 11 lb of thrust it used 12.9 Watts per pound of thrust and</div><div>rose up to 26.79 Watts per pound of thrust at full power.</div><div>So if the batteries are low, go slow. </div><div>Cheers Alan</div><div><image1.JPG><br clear="none"></div><div class="yiv5663440511yqt2288011836" id="yiv5663440511yqt26542"><div><br clear="none">On 6/12/2018, at 7:34 AM, Alan via Personal_Submersibles <<a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org" target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br clear="none"><br clear="none"></div><blockquote type="cite"><div></div></blockquote></div></div><div><div class="yiv5663440511yqt2288011836" id="yiv5663440511yqt08088"><div></div><div>Hi David,</div><div>the extension ladder worked but was a bit of an effort pushing it out</div><div>with weight on it. I will grease it before the next prop test.</div><div>As for thrust to watt ratio; I measured this at intervals from 18V to 44V.</div><div>18.2V, 13.2W per lb. of thrust.</div><div>26.8V, 19.5W per lb.</div><div>33.6V, 24.4W per lb.</div><div>38.4V, 29.9W per lb.</div><div>44.6V, 37.6W per lb.</div><div>So definitely a loss of economy as you open the throttle. The Vetus prop</div><div>is designed to work in a tunnel & I didn't have one on it. It will be interesting </div><div>to see how the other props fare in this respect, & if these figures differ much</div><div>when I put a kort nozzle / prop guard on them.</div><div>Alan</div><div><br clear="none"></div><div><br clear="none">On 6/12/2018, at 3:58 AM, David Colombo via Personal_Submersibles <<a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org" target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br clear="none"><br clear="none"></div><blockquote type="cite"><div><div>Hi Alan, l never thought of using a ladder as a test rig. Was the thrust to watt ratio the same base at different speeds?<div>David</div></div><br clear="none"><div class="yiv5663440511gmail_quote"><div dir="ltr">On Wed, Dec 5, 2018, 2:03 AM Alan via Personal_Submersibles <<a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org" target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br clear="none"></div><blockquote class="yiv5663440511gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">Just did the first test on my latest brushless thruster version.<br clear="none">
I started with a Vetus bow thruster which is normally housed in a tunnel, but<br clear="none">
to simplify things I am testing several different propellors without nozzles first.<br clear="none">
I have a 10mm prop shaft & the various off the shelf props need either drilling<br clear="none">
out or sleeves made to fit them.<br clear="none">
I was getting 38.5 lb. thrust from 1,152 Watts & 45 lb. off 1,694 Watts, which<br clear="none">
is comparable with some commercial thrusters but not with others. Some <br clear="none">
manufacturers are quoting thrust per Watt figures I find hard to believe.<br clear="none">
Will see how the other props work.<br clear="none">
Testing came to an end when the automatic pool cleaner (which I had just<br clear="none">
moved to the end of the pool) came down & knocked my prop off while I was <br clear="none">
jotting down notes. First swim of the summer finding the shaft pin. The prop<br clear="none">
was held in place more or less by the force of the prop thrust & a tight fit.<br clear="none">
Picture below is from left to right; load cell mounted on the vertical stationary<br clear="none">
side of black test jig, motor controller, 48V rectifier with oil compensator on<br clear="none">
top, grey load cel display, servo tester to control speed & laptop with Vesc Tool<br clear="none">
program displaying data. <br clear="none">
The oil compensator is just for the testing, a much smaller & different system<br clear="none">
will be on the sub.<br clear="none">
Alan<br clear="none">
<br clear="none">
<br clear="none">
<br clear="none">
_______________________________________________<br clear="none">
Personal_Submersibles mailing list<br clear="none">
<a rel="nofollow" shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org" target="_blank" href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br clear="none">
<a rel="nofollow" shape="rect" target="_blank" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none">
</blockquote></div>
</div></blockquote><blockquote type="cite"><div><span>_______________________________________________</span><br clear="none"><span>Personal_Submersibles mailing list</span><br clear="none"><span><a rel="nofollow" shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org" target="_blank" href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a></span><br clear="none"><span><a rel="nofollow" shape="rect" target="_blank" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a></span><br clear="none"></div></blockquote></div><blockquote type="cite"><div><span>_______________________________________________</span><br clear="none"><span>Personal_Submersibles mailing list</span><br clear="none"><span><a rel="nofollow" shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org" target="_blank" href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a></span><br clear="none"><span><a rel="nofollow" shape="rect" target="_blank" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a></span><br clear="none"></div></blockquote></div></div><div class="yqt2288011836" id="yqt87357">_______________________________________________<br clear="none">Personal_Submersibles mailing list<br clear="none"><a shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org" href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br clear="none"><a shape="rect" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none"></div></div>
</div>
</div></div></blockquote><blockquote type="cite"><div><image1.JPG></div></blockquote><blockquote type="cite"><div><span>_______________________________________________</span><br><span>Personal_Submersibles mailing list</span><br><span><a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a></span><br><span><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a></span><br></div></blockquote></body></html>