Arugela Posted April 25 Share Posted April 25 (edited) I'm trying to follow the calcualtions given in this thread on stack exchange I can't figure out how he got his answer. https://aviation.stackexchange.com/a/16550 He says it's 4kg of thrust but I can't figure out the other stuff. Ct*p*area*tip^2 0.03*1.225*?*0.6=4kg?! Edited April 25 by Arugela Quote Link to comment Share on other sites More sharing options...
magnemoe Posted April 25 Share Posted April 25 Area is the area of the ducted fan in m^2. who is pi*r^2 =0,0177 m^2 with an 15 cm fan but plugging that into the formula gives 0,000389 tip speed should be 0.6^2 who give an even lower value 0,000234 so something is wrong here Quote Link to comment Share on other sites More sharing options...
Shpaget Posted April 25 Share Posted April 25 (edited) 0,6M I presume is 0,6 Mach, but I'd expect m/s to be the expected unit, which gives us 24,75, so we're at least in the ballpark. Also, he just might have borked the math. Edited April 25 by Shpaget Quote Link to comment Share on other sites More sharing options...
Nuke Posted April 25 Share Posted April 25 (edited) ducted fans are well tuned systems which can be well optimized. but that optimization usually comes at the cost of a vary narrow operational envelope. laminar flow wings have a similar problem. fan design in general is a deceptively complex problem. Edited April 25 by Nuke Quote Link to comment Share on other sites More sharing options...
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