Paul Williams Posted July 19, 2008 Share Posted July 19, 2008 Following Tim's advice on pre-testing before flying any thing eletric I cobbled together a test rig versatile enough to test most things.I purchased numerous props of differing sizes and makes and set about coming up with the best combination for current and thrust. I did find that although the testing is paramount for ensuring you don't burn out your electrics the differing props and thrust obtained was not making sense. I found the best power to current ratio was obtained using a master screw nylon which is intended for glow engine use. This leads me to believe the light thin props for electric must be changing contour under load. This is probably due to holding the model stationary while testing. I cant of course measure slip so as to the best prop to use I guess the only true test is to fly it. Quote Link to comment Share on other sites More sharing options...
Bruce Richards Posted July 19, 2008 Share Posted July 19, 2008 Paul,what are the benefits of your rig over standing the model on its wheels and restraining with a balance. Have you managed to reduce friction losses? Quote Link to comment Share on other sites More sharing options...
Paul Williams Posted July 19, 2008 Author Share Posted July 19, 2008 possibly, but the main advantage is I can test fans, motors, before fitting. Plus a few of my models have no undercarrage. sorry very rushed should have been at work 10 mins ago ----------- Quote Link to comment Share on other sites More sharing options...
Bruce Richards Posted July 19, 2008 Share Posted July 19, 2008 OK Paul I see its multi purpose. Where id you get your digital balance?Sorry to disturb your preparation for work. Quote Link to comment Share on other sites More sharing options...
Paul Williams Posted July 19, 2008 Author Share Posted July 19, 2008 the auction site we know and love, £7 with postage bargain Quote Link to comment Share on other sites More sharing options...
Evan Pimm Posted July 22, 2008 Share Posted July 22, 2008 The problem with static testing is that it will not give you any idea how the model will actually fly. The prop that will you the best static thrust might not move the model fast enough to actually take off. It will find the prop that gives the most static thrust, of course. But the best prop to match your engine/airframe/flying? Sadly, no. You will have to take a wide selection of props to the field and fly the things.Evan. Quote Link to comment Share on other sites More sharing options...
Paul Williams Posted July 22, 2008 Author Share Posted July 22, 2008 Never a more true word spoken Evan, you could have told me before I built it. Quote Link to comment Share on other sites More sharing options...
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