Need input on air pump for special use - Page 2 - RC Groups
 Oct 08, 2012, 07:53 PM Life begins at transition What mass flow are you requiring? Just like any axial flow pump, an EDF is built for low pressure rise, high mass flow. As Mike said above, if you try to use an EDF in a low flow scenario, you'll stall it. I'm thinking once you work out the pressure and mass flow requirements, you'll probably be looking toward centrifugal or positive displacement machines, not axial.
 Oct 08, 2012, 09:42 PM Registered User Thanks so much for your input guys. I agree air mass flow is imprtant to determine here, and I will run the math as soon as I get the chance. I also agree about the stalling comment. More and more I am thinking I need to just sit down at Solidworks and pop out something that at a basic level is a 2 stage electrical axial compressor that is designed to produce an increase in pressure at the required pressure ratio and air mass flow. An EAC if you will. Electrical Axial Compressor, powered by a single motor, with appropriate stator stages as well. Not with the goal of producing compression required for combustion mind you, just for pressurizing the air manifold in the jet air delivery ducting. But as Odysis points out, centrifugal and positive displacement are also waiting to be explored. Maybe it will come down to what can pull it off at the lightest weight. Perhaps I should just choose an arbitrary wingspan and an appropriate wing profile, and apply the methods in the reference paper(and several others I have as well) to determine slot width for 3/4 obstruction factor discrete jetting for that span and chord. Then I can calculate what mass flow will be required at that pressure ratio. I am also neck deep in designing a ductwork design that can be easily built with foam and/or composites in a scale aircraft with a wingspan of around 6 feet, so I will just use that same wingspan. And of course, gotta keep ducting losses to a minimum. Last edited by UncleMatt; Oct 08, 2012 at 09:52 PM.
 Oct 08, 2012, 10:21 PM BOHICA! How about this concept for your blown wing idea: "lithium batteries to power a steam generator, an electrode steam boiler"? -or- Maybe a CO2 system? Say about a 2 meter span, built up to save weight, based on 14s or 16s 6500's and pressure ducts fabricated with carbon fibre/high temp epoxy?
 Oct 08, 2012, 10:55 PM smug in granny panties All ya need is a flux capacitor and a mr fusion. And while injecting co2 is an idea, and blown surfaces is another route just remember what they say, Injection is nice is nice but your always better off blown Barry
 Oct 09, 2012, 01:24 AM smug in granny panties Least till his 10-15 is up under close observation!
 Oct 09, 2012, 01:29 AM smug in granny panties But seriously on the topic why use a edf for heavy lifting? Yeah Russians use coamda on jets but whole different ball of wax there. If your doing heavy lifting use a prop, your just trying to build super efficient plane use a better prop! Your not going super sonic so even if ya had active laminar and an air spike you'd never get fast enough to see it. But then again of your just mucking with stuff for kicks tool on!
Oct 09, 2012, 07:46 AM
The blade numbers go up to 11
Quote:
 Originally Posted by monkamarm2000 Injection is nice is nice but your always better off blown Barry
Oh, so true, Barry!
 Oct 09, 2012, 09:40 AM Registered User This project is for fun, but I would like to know if these guys were onto somehting with this dCFJ system. They have many papers out on the net. I will post some when I get a chance. If you could make their design a reality at the scale level, you would have a plane with no exposed prop, lower noise, much more efficient, but still able to fly slow with large payloads. Perfect for UAV use...
 Oct 20, 2012, 11:36 PM Registered User http://www7.miami.edu/ftp/acfdlab/CF...FJ_papers.html As promised, here is a link to a page full of papers and research on this discrete co-flow jet concept. Also, If anyone has a referral to a manufacturer who can produce custom rotors for EDF size motors operating at high rpm, please let me know.