Simon Chaddock Posted March 9, 2012 Author Share Posted March 9, 2012 This setup produces a lot more thrust than the first annular arrangement which is what I had hoped. With a side exit it is not so easy to separate thrust and torque but hand held (a bit scary!) I would judge 4 or 5ozs which of course is pretty miserable for 400W but then I never expected it to be comparable to a normal EDF. The test stand will need a bit of modification to be able to measure thrust accurately. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted March 13, 2012 Author Share Posted March 13, 2012 I have "improved" the snail diffuser with reduced clearances and added a sharp edged nozzle. By mounting the stand on its side so the exhaust is vertically upwards the thrust can be measured on a set of scales. It gives close to 8oz thrust. This may not sound much but the nozzle is equivalent to just a 21mm diam duct. It is of course still pretty inefficient for the huge power input nevertheless the blast is quite impressive. The nozzle size itself is just a guess so I have no idea if it is the optimum for the fan. I need to measure the rpm to get an idea of how fast the stream is actually going. Quote Link to comment Share on other sites More sharing options...
Keith Simmons Posted March 14, 2012 Share Posted March 14, 2012 Interesting. Are you planning to fit both types of fans onto the Vampire and test fly it and please give flying results as well as static. The centrifugal fan somehow suits the vampire as it was built that way and is an early jet. I think the 55 Dia EDF will win as I believe it is more efficient. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted March 14, 2012 Author Share Posted March 14, 2012 At the moment with only 8oz thrust the centrifugal unit is not flyable, at least not in a Vampire. At 48" span the tail end of a scale fuselage will just contain a 50mm dia duct, which fortunately is exactly the fan swept area of my 55mm EDF. To keep the 'fast airflow' part of the duct as short as possible the EDF will be mounted right at the back of the fuselage, something like this. The wing root inlets will have the smallest area (equivalent to a 47mm dia duct) and also the worst shape of the whole inlet duct. The fan is claimed to produce 19oz thrust on a 3s but until tested I don't know if thus is at its continuous rating of 30A or at the max of 38A. I shall be happy if I can get 16oz when its in the duct. For its size it will still have to be a very light Vampire. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.