<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:10pt"><div><span>Joe,</span></div><div style="color: rgb(0, 0, 0); font-size: 13.333333969116211px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span>I was going to suggest that Marc wade in on this subject, it is one of his fields</span></div><div style="color: rgb(0, 0, 0); font-size: 13.333333969116211px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span>of expertise. I believe he has written books on ducted fans etc.</span></div><div style="color: rgb(0, 0, 0); font-size: 13.333333969116211px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;
background-color: transparent; font-style: normal;"><span>Marc is a very talented guy hidden away in an obscure corner of the Philippines.He may be a helpful</span></div><div style="color: rgb(0, 0, 0); font-size: 13.333333969116211px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span>source of information if you want to get this right.</span></div><div style="color: rgb(0, 0, 0); font-size: 13.333333969116211px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span>We sure have a multi-talented group here.</span></div><div style="color: rgb(0, 0, 0); font-size: 13.333333969116211px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span>Alan</span></div><div
style="color: rgb(0, 0, 0); font-size: 13.333333969116211px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span><br></span></div><div><br></div> <div style="font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-size: 10pt;"> <div style="font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-size: 12pt;"> <div dir="ltr"> <hr size="1"> <font size="2" face="Arial"> <b><span style="font-weight:bold;">From:</span></b> Marc de Piolenc <piolenc@archivale.com><br> <b><span style="font-weight: bold;">To:</span></b> Personal Submersibles General Discussion <personal_submersibles@psubs.org> <br> <b><span style="font-weight: bold;">Sent:</span></b> Monday, October 28, 2013 7:57 PM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [PSUBS-MAILIST] Group
Help Request<br> </font> </div> <div class="y_msg_container"><br>Quick clarification: a properly contoured Kort nozzle, MARRIED TO A <br clear="none">MATCHING PROPELLER, will increase static and low-speed thrust. Of course <br clear="none">it won't increase power, since that comes from your motor. If you just <br clear="none">put a shroud around your existing prop, you will be disappointed, and a <br clear="none">shroud that doesn't do the job is overpriced unless it's free! Key <br clear="none">ingredients for success:<br clear="none"><br clear="none">Prop matched to the shroud<br clear="none">Shroud matched to the speed and thrust requirement of the vehicle<br clear="none">Motor matched to the resulting prop<br clear="none"><br clear="none">Marc<br clear="none"><br clear="none">On 10/28/2013 8:33 AM, Jon Wallace wrote:<br clear="none">><br clear="none">> What is the cost of having a true Kort nozzle machined by a CNC? I think<br
clear="none">> a 30% improvement in thrust for $30 would be great but I suspect<br clear="none">> machining a Kort is going to equate to many hundreds of dollars, if not<br clear="none">> reaching beyond a thousand. When I look at the Snoopy underwater videos<br clear="none">> it is difficult to imagine a kort nozzle really making any difference in<br clear="none">> the operational experience given that the motors are operating very<br clear="none">> slowly and pushing Snoopy around at about 2 knots (estimated). The<br clear="none">> props are designed for power, but that's what we want underwater. True,<br clear="none">> a kort nozzle would increase that power but what is the return on the<br clear="none">> cost? In other words, on a road with a speed limit of 30mph and no<br clear="none">> passing zones it doesn't matter whether you have a 1.6 liter or 5.4<br clear="none">> liter engine under
the hood does it?<br clear="none">-- <br clear="none">Archivale catalog: <a shape="rect" href="http://www.archivale.com/catalog" target="_blank">http://www.archivale.com/catalog</a><br clear="none">Polymath weblog: <a shape="rect" href="http://www.archivale.com/weblog" target="_blank">http://www.archivale.com/weblog</a><br clear="none">Translations (ProZ profile): <a shape="rect" href="http://www.proz.com/profile/639380" target="_blank">http://www.proz.com/profile/639380</a><br clear="none">Translations (BeWords profile): <a shape="rect" href="http://www.bewords.com/Marc-dePiolenc" target="_blank">http://www.bewords.com/Marc-dePiolenc</a><br clear="none">Ducted fans: <a shape="rect" href="http://massflow.archivale.com/" target="_blank">http://massflow.archivale.com/</a><div class="yqt8631189424" id="yqtfd80889"><br clear="none">_______________________________________________<br clear="none">Personal_Submersibles mailing list<br clear="none"><a
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