<div dir="ltr"><div>Alec I am still analyzing the data. I need to do some filtering to take out some noise so don't quote me yet but, after looking again at the curves, it looks like the Kipawa 80/01 prop was getting about 66 lbf and the MKP-33 about 60 lbs. As expected with the Kipawa having a 5 inch pitch compared with the MKP-33 4 inch pitch, the rpm of the MKP-33 is much higher and power supplied to the motor higher for the Kipawa. </div><div><br></div><div>I wish I could get MK to come clean and tell me exactly what their rated thrust means and how they measured it.</div><div><br></div><div>Still lots to learn. </div><div><br></div><div>Cliff </div></div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Feb 6, 2016 at 8:18 PM, Alec Smyth via Personal_Submersibles <span dir="ltr"><<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Great stuff Cliff! Do you know how the Kipawa compares to the standard MK prop without the nozzle?<div><br></div><div><br></div><div>Best,</div><div><br>Alec</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Feb 6, 2016 at 5:29 PM, Cliff Redus via Personal_Submersibles <span dir="ltr"><<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;padding-left:1ex;border-left-color:rgb(204,204,204);border-left-width:1px;border-left-style:solid"><div dir="ltr"><div>Thanks Alan. To reciprocate, attached are our initial test last week. The variable pitch prop is not out of the machine shop yet so main goal was to evaluate test rig with Minn Kota MKP-33 prop ( two blade, 4" pitch, 11" diameter) that matches with the MK-101 lower unit. We are going to use the MK-101 and MKP-33 prop as the control for our new prop. We also tested a Kipawa 80/01 (3 bladed prop, 5"pitch, 11" diameter). The Kipawa prop will fit in my ducted nozzle so measured the bollard thrust with and without the nozzle. We are still analyzing the data but some initial results. Bollard thrust of the MKP-33 of 67 lbs is low relative to the 101 lb rated thrust. A quick look on web shows that manufacture thrust rating are 30-40% higher than a bollard thrust test. Test rig is fully calibrated. With the Kipawa prop, the bollard thrust is about 10% higher when using the nozzle than without. BTW, this is an open water prop and is not designed to be used with this nozzle. A ducted nozzle prop needs to have more of a square tip to keep water from moving from the high pressure side of the blade to the low pressure side. Like you my initial reaction is that we could be having the same boundary or end effect because of the proximity to the pool wall. We did prove the system worked. Not sure why both rpm and current are dropping over time when the measured battery voltage is constant? Next week, we are going to repeat the test with the thruster oriented along the long axis of the pool and see how the thrust compare. </div><div><br></div><div>On your test, a couple of questions:</div><div>1) How long did run each test point? </div><div>2) On the first test sequence, 3800W and 81 lbs bollard thrust for input HP of over 5. This seems like quite a bit of power to develop this amount of thrust. Do attribute most of this to this boundary effect or recirculation affect?</div><div>3) On each of these test points, your are stepping through higher and higher power to the thruster. For any one of these points, how repeatable is thrust?</div><div>4) Thrust is proportional to density * n^2*Dia^4. I think to be able to make sense of data from different props with different diameters and pitches, you need an angular velocity or speed measurement. Can you measure the motor speed with this type of motor. For our test we use a proximity switch and count pulses to measure speed.</div><div>5) Are you planning on testing any ducted props?</div><div><br></div><div>Cliff</div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div>On Sat, Feb 6, 2016 at 2:41 PM, Alan James via Personal_Submersibles <span dir="ltr"><<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;padding-left:1ex;border-left-color:rgb(204,204,204);border-left-width:1px;border-left-style:solid"><div><div><div><div style="color:rgb(0,0,0);font-family:HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif;font-size:16px;background-color:rgb(255,255,255)"><div><span></span></div><div><br><br></div><div style="display:block"> <div style="font-family:HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif;font-size:16px"> <div style="font-family:HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif;font-size:16px"> <div dir="ltr"> <font face="Arial" size="2"> <hr size="1"> <b><span style="font-weight:bold">From:</span></b> Alan James <<a href="mailto:alanlindsayjames@yahoo.com" target="_blank">alanlindsayjames@yahoo.com</a>><br> <b><span style="font-weight:bold">To:</span></b> Personal Submersibles General Discussion <<a href="mailto:seaquestor@gmail.com" target="_blank">seaquestor@gmail.com</a>> <br> <b><span style="font-weight:bold">Sent:</span></b> Saturday, February 6, 2016 11:18 PM<br> <b><span style="font-weight:bold">Subject:</span></b> Brushless thruster test 2<br> </font> </div> <div><br><div><div><div style="color:rgb(0,0,0);font-family:HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif;font-size:16px;background-color:rgb(255,255,255)"><div>This is mainly for Cliff's benefit, as he is going to be doing some</div><div dir="ltr">thrust testing.</div><div dir="ltr">Tested 2 different props out. One being the same as the first test, the yamaha 7&1/4" x 4" pitch </div><div dir="ltr">& the second was a Vetus 6 blade 108 mm ( 4") for 25kg bow thruster. No stats on the pitch but it</div><div dir="ltr">looks about 180mm or 7".</div><div dir="ltr">My watts measurement is done off the battery whereas other people quote their output at the motor.</div><div dir="ltr">I am comparing my motors performance to statistics from commercial thruster brands but not sure</div><div dir="ltr">where they are measuring there power from.</div><div dir="ltr">Had some wacky results from the yamaha prop again. It was the more powerful & I think I am getting what</div><div dir="ltr">is called a "short circuit" effect through having the motor about 28" out from the pool edge & in about 3ft</div><div dir="ltr">of water. Short circuit is where an edi is formed & the water moves from the output to the input in a semi</div><div dir="ltr">circle around the thruster. This is caused by water bouncing off a pool wall, or in my case the inlet flow </div><div dir="ltr">bouncing off the wall or pool bottom.</div><div dir="ltr">I was running off a 40V 5 amp Lipo battery & the voltage dropped a bit during the tests.</div><div dir="ltr">Ist test was 10 kg (22 lb ) at 500 W </div><div dir="ltr">2nd 11 kg at 1000 W & 39 V</div><div dir="ltr">3rd 15 kg at a huge 3,400 W</div><div dir="ltr">4th 37 kg at 3,800 W & 85 amps.</div><div dir="ltr">As you can see some inconsistent results there, and some missing figures like amp draw, as I needed</div><div dir="ltr">an assistant to read the figures.</div><div dir="ltr">Next is the Vetus prop.</div><div dir="ltr">1st 10kg 547 W 39 V</div><div dir="ltr">2nd 11 kg 634 W 11 amps 37.81 V</div><div dir="ltr">3rd 15 kg 998 W 27 amps</div><div dir="ltr">4th 20 kg 1700 W 39 V</div><div dir="ltr">5th 24 kg 2500 W</div><div dir="ltr">It's amazing what a difference a prop makes.</div><div dir="ltr">In conclusion, I need to ditch this rig & buy a longer plank of wood to do tests in the middle of the deep end.</div><div dir="ltr">I have a more sophisticated volt / amp meter that stores results & plots on a computer & I need to employ that.</div><div dir="ltr">I need to buy a similar motor but a sensored version, as there was too much cogging at low speed.</div><div dir="ltr">Sensoreless motors read the back emf produced by the motor to ascertain the position of the rotors & can stop /start<br></div><div dir="ltr">& rotate backwards on low speed where there isn't enough back emf produced.</div><div dir="ltr">I need to replace my motor controller with a sensored controller, probably Kelly & buy a bigger life po4 battery.<br></div><div dir="ltr"> I also want to wire the motor to a WYE configuration which will give me .73 less rpm. So will gear it down a bit.</div><div dir="ltr">Some good news is I have found people on boating forums adapting these RC brushless motors & an absolute</div><div dir="ltr">guru who uses these motors for traction vehicles & has posted pages of information on them.</div><div dir="ltr">Cheers Alan</div><div dir="ltr"><br></div><div dir="ltr"><br></div><div dir="ltr"><br></div></div></div></div><br><br></div> </div> </div> </div></div></div><br></div></div>_______________________________________________<br>
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