Need input on air pump for special use - Page 2 - RC Groups
Thread Tools
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.
Sign up now
to remove ads between posts
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
Mike Warren's Avatar
How about this concept for your blown wing idea:
"lithium batteries to power a steam generator, an electrode steam boiler"?
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
monkamarm2000's Avatar
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

Oct 08, 2012, 11:16 PM
Mike Warren's Avatar
Grasshopper: This from the master "URIAH" (sadly, not heard from lately )

Registered User: URIAH

939 miles from you in
Twisp Washington USA
Joined Sep 2005
331 Posts
all i'm saying is you guys have no clue about prototyping and the amount of time it takes to come up with a fesable design while dealing in such a sucluded area of science. i'm posting here, to share my project, and get some tips on other areas which i don't know, such as RC planes, all their tricks, and how they precisly work. i do have a lot of respect for RC builders, or engineers of any kind.
also, you are all getting things mixxed up! the capacitor (which can also be made in the form wings) is being tested within a year. now the EHD and exhaust ionization unit are being testing with in a few weeks.
all i'm really waiting on now is the new HV psu, and a specialy sized tube to attatch the EDF unit to the ionization unit. and i gotta get to my friends house to edit and upload some vidio i already have. i have dial-up connection and no video softwear... the EHD and exaust ionization unit will be tested for thrust and turbulence reduction only, as the power supply is a much too heavy one and will have to be on the ground during such tests. i might need to build a tesla coil and rectify AC to DC to get the correct watts, as this psu only puts out 42 watts. A CRAFT RUNNING OFF EHD ONLY weighing only 2.5lbs would need 500 watts of EHD power plus the lift the wings produce to lift off horizontaly, under the correct conditions. The PSU that i will be getting in 2007 only weighs 150-200 grams!!! and has an output of 50kV from an input of 10volts @ 50 amps! so as i said earlier there may be excess thrust apart from the EDF, WITHOUT ANY WEIGTHT PENALTIES, but wait!!!... there is more that i have already said that expains what you are all still asking about.... Hypersonic flight possible? no way! with this amount of thrust only 100 mph max is obatinable... RIGHT?

well using the same array i already have that is charging the air, i replace the wings with new ones... they are made of solid (or heavily coated) material that has a dielectric constant of 60,000-70,000 K. now instead of the negative energy going to move the air molecules around it charges the "wing like capacitors" and produces a lot more thrust... the ionized area around the electrodes remains but is greatly smaller, it helps to minamise turbulence and frictiond due to these charged molecules interactions with the non-charged molecules. this increases the speed the craft CAN obtain while still producing the same amount of thrust from BB effect and the EDF/ scram jet. (pulse, ram or scram jets on large prototypes)

Unfortunately URIAH's tin foil hat did not prevent the penetrating mind probe from a distant galaxy......he has unfortunately and prematurely disappeared from RCG's
Oct 09, 2012, 01:24 AM
smug in granny panties
monkamarm2000's Avatar
Least till his 10-15 is up under close observation!
Oct 09, 2012, 01:29 AM
smug in granny panties
monkamarm2000's Avatar
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
stumax's Avatar
Originally Posted by monkamarm2000

Injection is nice is nice but your always better off blown

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

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.

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Help! Need inputs on winter build projects! RMCCOR7737 Scale Kit/Scratch Built 5 Oct 01, 2012 04:37 AM
Discussion Thread: Grand Cruiser Crash: Need input on investigation F1nut Electric Plane Talk 26 Jun 18, 2012 03:14 PM
Help! Need inputs on (re)building Piper Cub vijayfx35 Electric Plane Talk 9 May 26, 2012 11:02 AM
Found Air Pump for retract systems Doubledog Aircraft - Fuel - Airplanes (FS/W) 0 Apr 18, 2012 05:06 AM
Question Need input on AP build rgoins21 Multirotor Drone Talk 12 Mar 15, 2012 02:27 PM