Starting to convert my F-22 over to an EDF platform, looking for ideas how to maybe make this better.
I know it is only for a single EDF unit but i am cheap so it won't really be a scale F-22 Attached files

 

Some of us don't like the word "cheap" - We prefer to admit that we are "frugal".

 

Ok, I make some changes, hopefully the air intake and exhaust will work, big at front smaller at the bottom.
Oh, it will have a 2.25 inch fan unit with a 5000kv motor, hopefully should produce some thrust Attached files

 

Interesting looking plane. Kind of an F16/F18 hybrid. Hope it works out.

 

Funny you should ask about the thrust because i have no idea.
I am also totally new to EDF's myself.
I got the Hyperflow unit from somewhere in some deal and just decided to goof off playing with one.
I guess just trying it will be the only way for me
The worst that can happen is that I will lose $2 worth of foam

 

Ok, it is cut but there is going to be a modification to the front intake tube so a battery can be installed.
5 ounces so far WITH EDF unit, less servos, receiver and battery.
I was just going to mount it on top with no ductwork but I just have to fidget or i'm not happy Attached files

 

Hopefully it will quit raining long enough to try her out this weekend

 

Looks good.. In my ducted fan models the ducting is normally pretty uniform throught it's length... This appears to have more of a taper... should be interesting

Looking forward to it's maiden

Happy Hunting
Prosnias

 

Everything I read said to have a noticable taper at the rear, so I will try that route first, then open it up if it warrants it.
This is a total learning experience for me also, I am just winging it so to speak

 

I don't have any practical EDF experience, but from reading about them I think that the exhaust should be between 80-100% of FSW (Fan Swept Area=intake area of the fan) and that the bigger exhaust (100%) will give more thrust and the smaller (80% gives more speed).
This is all theoretical knowledge so regard it only as such!

edit: Found this thread over at RCGroups regarding fan ducting

 

Well, too dang windy to try to fly it but it is heavy with full gear, 20 ounces (ouch)
It may fly but will prob be a turd

****EDIT****
Weight comes in at 12 ounces, helps to put new batteries in the scale every once in a while
Now I am expecting a rather spirited flight.
I put my scale at the end of the nozzle path and it is blowing the scale down 13 or so ounces, blew half the crap off my workbench!!!!

Oh, i did cut the nozzle back to open up the back, had tons of pressure but no real volume choked down so small.
If it works I will redo the changes and post the files along with the gear I am using, maybe someone will have a video camera at the field for some fun video (I hope).

 

Here is a render of the hopefully finished design

Attached files

 

If you taper like that you will increase the airflow but lose thrust so it'll fly fast once up to speed....

It will fly fast but will not stand on its tail. Acceleration will be modest but at least it is light.

 

It has very little taper from the EDF unit back. Around a 10% taper, not much at all

 

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