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Old Feb 23, 2013, 09:59 AM
What Goes Up...Must Come Down
abjets's Avatar
United States, NC, Oak Island
Joined Jan 2013
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Quote:
Originally Posted by Joe 1320 View Post
Folks, a moment of your time......

Actually, it's Fan Swept Area. The measurement will be different for each fan depending on the impeller's area, not just the total area of the shroud.

You guys might want to read up on the calculations. By not plugging the correct numbers into formulas, you are not getting the correct results..


http://hdflyer.com/how-to-calculate-...rea-of-an-edf/


Let's say you have a small fan of XX diameter and the 12mm inrunner that you are using sure seems to be about the same size diameter as the hub of the impeller. Figure the area of the circle using:

Area = Pi x Radiusē

That Area result gets subtracted from your total shroud area for your further calculations.



Joe,
thanks for the clarification of the FSA...actually just my typo. I was assuming that the folks asking were using the stock JPower set up...and the F-86...therefore I believe my numbers are correct...using the FSA Calculator posted a ways back. It certainly made a huge difference in my F-86!!
Cheers!
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Old Feb 23, 2013, 10:15 AM
What Goes Up...Must Come Down
abjets's Avatar
United States, NC, Oak Island
Joined Jan 2013
875 Posts
Fan Sweep Area Calculator

Building on Joe's previous post...this is a repost for those of you interested....Credit goes to the first author! Thank you!

http://www.rcgroups.com/forums/showa...=5560279&stc=1
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Old Feb 23, 2013, 10:52 AM
always something to learn...
metalguy's Avatar
Tacoma, WA
Joined Jan 2011
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I know the thrust tube requires a taper, and has to start at least at the diameter of the fan shroud. Because of this, the tube I have may, or may not work. I have to look at it, and see if it is big enough to start with, and if it is, all I will need to do is cut a piece out to taper it to my needs. The advantage is that it is already curved, and should be easily shaped further. If it can't work, it can't. I am out nothing. My other Saber is out of commision at present with a bad motor. ------Metalguy
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Old Feb 26, 2013, 07:48 AM
wba
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Austria, Vienna
Joined Jan 2013
40 Posts
my f-86 is ready to go. one more short question concerning static thrust. i always do a quick and dirty test. take one wingtip between thumb and indexfinger and let the plane hang down. increase thrust gradually and carefully until plane points straight up. observe if thrust can support the planes weight. on my steroid-p51 the throttle stick will need 3/4 way up. on the sabre the static thrust is less than her weight. i know edf produces less static thrust than propellers. i still wonder if my setup produces significantly less thrust than it could. cancle that last question, i found charts with static thrust values...
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Old Feb 26, 2013, 09:18 AM
What Goes Up...Must Come Down
abjets's Avatar
United States, NC, Oak Island
Joined Jan 2013
875 Posts
Quote:
Originally Posted by wba View Post
my f-86 is ready to go. one more short question concerning static thrust. i always do a quick and dirty test. take one wingtip between thumb and indexfinger and let the plane hang down. increase thrust gradually and carefully until plane points straight up. observe if thrust can support the planes weight. on my steroid-p51 the throttle stick will need 3/4 way up. on the sabre the static thrust is less than her weight. i know edf produces less static thrust than propellers. i still wonder if my setup produces significantly less thrust than it could. cancle that last question, i found charts with static thrust values...
WBA- with your nano-tech 3s 350mah 65-130C ...she should rip! Should have no problems with hand launch either. Let us know how the maiden goes! Godspeed!
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Old Feb 26, 2013, 08:21 PM
always something to learn...
metalguy's Avatar
Tacoma, WA
Joined Jan 2011
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My new saber is about ready, too. I installed the thrust tube, ESC, and RX.It is ready, other than hooking up the controls to the horns. Ready for 3s.-------Metalguy
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Old Feb 27, 2013, 01:50 AM
wba
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@abjets: thanks dude!
@metalguy: good luck to you, too!
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Old Feb 27, 2013, 09:03 AM
What Goes Up...Must Come Down
abjets's Avatar
United States, NC, Oak Island
Joined Jan 2013
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Metalguy- Excellent! Watch your throws on the ailerons...she likes to roll!
wba- with the 3s set up...it is easy cruising at just over 1/3 throttle...full throttle is NUTS!

Working on a T-45 now to add to the flight line. Cool little bird. Unfortunately, my fan unit is sooo out of balance. Amazing the increase in rpm and the sweet sound these little power systems make when balanced out properly! Not to mention the extended life of battery and motor.

Looking forward to both of your updates!
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Old Feb 27, 2013, 08:22 PM
always something to learn...
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Gotta get some weather without wind/rain before I can fly this.....-----Metalguy
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Old Feb 28, 2013, 12:41 AM
check for reversed controls
alpea 41's Avatar
United States, CA, Chino
Joined Oct 2007
10,279 Posts
Hello guys, I know this info is in the thread probably 20 times But
I dont have time to read the whole thread , skimming thru tho I saw errors in ordering the radio equipment for the basic air frame that I was hoping you experienced 35mm nano pilots could steer me away from making.
Here's what I got
A used Mig 15 airframe, with a
5 blade 35mm fan and motor
on a un-named esc 7 or 10 A that has a standard 3 wire universal J R type servo plug
1- 2.5 g 5 wire servo with a 5 pin connector plug
2-2.5 g 5 wire servos with the plugs cut off
my smallest Rx is a 6110 E Spektrum or similar
A 500ma 2s 20c , or a 350 ma 2s 35c li-po are my closest to stock and they fit

The way I see it if I get 3 -2.5g 3 wire servos from Hobby King I can make this bird fly..
But I'm open for any suggestions as to the most economical and least troublesome way to get this thing going. I gave a guy $25. for it and am willing to put in another $25-$35.
Thanks in advance for any input.
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Old Feb 28, 2013, 04:21 AM
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Joined Feb 2013
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Did I get unlucky or is this thing PNF out of the box anemic? I ordered one because of this thread but dang it hardly wants to stay in the air. Also, the servos are weak and bind, especially the elevator.. pity it looks cool but cheapy cheapy wasn't the best buy I fear.. Maybe I'll make my own some day when I have more time and experience.
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Old Feb 28, 2013, 07:06 AM
Flying is Freedom
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Annandale, VA
Joined Jul 2007
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Quote:
Originally Posted by cubflyingdave View Post
Did I get unlucky or is this thing PNF out of the box anemic? I ordered one because of this thread but dang it hardly wants to stay in the air. Also, the servos are weak and bind, especially the elevator.. pity it looks cool but cheapy cheapy wasn't the best buy I fear.. Maybe I'll make my own some day when I have more time and experience.
Which model did you get?
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Old Feb 28, 2013, 10:04 AM
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Originally Posted by Sky_Captain View Post
Which model did you get?
the mini mig
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Old Feb 28, 2013, 01:21 PM
What Goes Up...Must Come Down
abjets's Avatar
United States, NC, Oak Island
Joined Jan 2013
875 Posts
Quote:
Originally Posted by alpea 41 View Post
Hello guys, I know this info is in the thread probably 20 times But
I dont have time to read the whole thread , skimming thru tho I saw errors in ordering the radio equipment for the basic air frame that I was hoping you experienced 35mm nano pilots could steer me away from making.
Here's what I got
A used Mig 15 airframe, with a
5 blade 35mm fan and motor
on a un-named esc 7 or 10 A that has a standard 3 wire universal J R type servo plug
1- 2.5 g 5 wire servo with a 5 pin connector plug
2-2.5 g 5 wire servos with the plugs cut off
my smallest Rx is a 6110 E Spektrum or similar
A 500ma 2s 20c , or a 350 ma 2s 35c li-po are my closest to stock and they fit

The way I see it if I get 3 -2.5g 3 wire servos from Hobby King I can make this bird fly..
But I'm open for any suggestions as to the most economical and least troublesome way to get this thing going. I gave a guy $25. for it and am willing to put in another $25-$35.
Thanks in advance for any input.
Hi Alpea41-

Your diamond in the rough will be a great lil' screamer with just a few items...
Here is my recommended gear that is proven very reliable, very light weight and worth every penny... (Buddy codes for the Turnigy servos and the Plush 10amp ESC to help with that budget)

HK-282A Single-Screw, Ultra-Micro Servo 2g / 0.2kg / 0.08sec
OR Turnigy TS541A Analog Nano Servo 0.12/0.7kg/4.3g
http://www.hobbyking.com/buddy.asp?c...B-BA5EC5631098

TURNIGY Plush 10amp 9gram Speed Controller (2S or 3S)
http://www.hobbyking.com/buddy.asp?c...1-62223D6EC2B4

OrangeRx R415 Spektrum DSM2 Compatible 4Ch Micro 2.4Ghz Receiver

Turnigy nano-tech 460mah 3S 25~40C (your 2S's will make it very difficult for hand launch/flight...at a minimum I would use Turnigy nano-tech 370mah 2S 25~40C Lipo Pack if 2S is desired)

Also recommended:
- Balance your EDF unit! Makes a huge difference
- Thrust tube!! Simple and VERY effective!!
- Make sure all hinge points are good

WEIGHT is your enemy...as with all of these birds.

ENJOY!
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Old Feb 28, 2013, 01:35 PM
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United States, FL, Sebring
Joined Feb 2006
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I would concur with everything except the lipo. These jets fly like jets once you switch to 3s. On 2s you have to fly the on the wing where as 3s gives enough power for some decent vertical performance.
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