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Old Sep 26, 2012, 07:52 AM
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Thanks. I ended up moving the Rx behind the battery. It helped move my CG forward.
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Old Sep 27, 2012, 04:55 AM
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How about some SK3 report, how they holding up, how many flights?
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Old Sep 27, 2012, 05:14 AM
Why the dirt on the wings?
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New York
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I just got an e-mail a few days back letting me know that my 2 motors are on their way
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Old Sep 28, 2012, 03:41 PM
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United States, CA, San Diego
Joined Jan 2012
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Just ordered everything for my Funjet.

2w-23
Hobbywing 80amp
4s 35-70c 2650mah nanotechs
Graupner 5.5x5.5

I'm shooting for 135-140mph, does this setup have enough to get me there?
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Old Sep 28, 2012, 06:03 PM
Why the dirt on the wings?
moparmyway's Avatar
New York
Joined Jan 2009
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Quote:
Originally Posted by nofreee View Post
Just ordered everything for my Funjet.

2w-23
Hobbywing 80amp
4s 35-70c 2650mah nanotechs
Graupner 5.5x5.5

I'm shooting for 135-140mph, does this setup have enough to get me there?
Just a few "guesses" ..................

It might have enough on 3 cells (135 mph pitch speed), especially if you like diving

2950kv @ 14 volts ..............41,300 no load
Figure 20% lost to ineficiencies (if you are that lucky)
33k with a Graupner 5.5x5.5 prop takes about 1600 watts (172 mph pitch speed)
You are looking at just about 115 amps static (best guess)
You might want a different ESC ???
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Old Sep 28, 2012, 06:10 PM
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United States, CA, San Diego
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Quote:
Originally Posted by moparmyway View Post
Just a few "guesses" ..................

It might have enough on 3 cells (135 mph pitch speed), especially if you like diving

2950kv @ 14 volts ..............41,300 no load
Figure 20% lost to ineficiencies (if you are that lucky)
33k with a Graupner 5.5x5.5 prop takes about 1600 watts (172 mph pitch speed)
You are looking at just about 115 amps static (best guess)
You might want a different ESC ???
Weird.. My calc is showing about 70 amps and just over 1000watts.
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Old Sep 28, 2012, 06:13 PM
Why the dirt on the wings?
moparmyway's Avatar
New York
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Quote:
Originally Posted by nofreee View Post
Weird.. My calc is showing about 70 amps and just over 1000watts.
So did the on line static thrust calcs ...................

I havent found a calc that is accurate yet at power levels above factory specks

I get my data from in flight ............... I would LOVE to see someone ..... ANYONE spin a Graupner 5.5x5.5 to 33,000 rpm with 1000 watts
It takes about 1100 watts to spin 30k
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Old Sep 28, 2012, 06:28 PM
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Quote:
Originally Posted by moparmyway View Post
So did the on line static thrust calcs ...................

I havent found a calc that is accurate yet at power levels above factory specks

I get my data from in flight ............... I would LOVE to see someone ..... ANYONE spin a Graupner 5.5x5.5 to 33,000 rpm with 1000 watts
It takes about 1100 watts to spin 30k
And that's why I ask here, there are people with much more experience than I.

Once I have everything in I will run some static tests and see what I get.
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Old Sep 28, 2012, 06:31 PM
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nofreee,

I think that your setup has a fair chance of reaching your goals.....but I'm not sure about the required prop size.

Consider starting off with 75-80A static with a 1:1 prop size (diameter to pitch ratio).

If you have Graupner 5.2X5.2 post the static data before first flight and wait for feedback from the folks on this thread.

***Maybe the guys who are more familiar with that same motor on 4S can recommend a better prop.

If you have one of these APC 5X5 , 5.25X4.75 , or 5.5X4.5 then maybe that data can help the folks recommend a good prop for your first flight.


Run a heat sink and use throttle control till you get the hang of the motor temps.


Static testing:
Do only a single 3 second static test starting with the motor at room temp.
Report data from after the first second...read any 2 of these 3 values (A, V, W)
To do another test or re-test wait till the motor is pretty close to room temp.
Be safe.


Good luck,

Gryphon
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Old Sep 28, 2012, 06:35 PM
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United States, CA, San Diego
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Quote:
Originally Posted by GryphonRCU View Post
nofreee,

I think that your setup has a fair chance of reaching your goals.....but I'm not sure about the required prop size.

Consider starting off with 75-80A static with a 1:1 prop size (diameter to pitch ratio).

If you have Graupner 5.2X5.2 post the static data before first flight and wait for feedback from the folks on this thread.

***Maybe the guys who are more familiar with that same motor on 4S can recommend a better prop.

If you have one of these APC 5X5 , 5.25X4.75 , or 5.5X4.5 then maybe that data can help the folks recommend a good prop for your first flight.


Run a heat sink and use throttle control till you get the hang of the motor temps.


Static testing:
Do only a single 3 second static test starting with the motor at room temp.
Report data from after the first second...read any 2 of these 3 values (A, V, W)
To do another test or re-test wait till the motor is pretty close to room temp.
Be safe.


Good luck,

Gryphon
I have all the props mentioned (minus the graupner 5.2x5.2), so I will give them a go, starting the the smallest and working my way up.
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Old Sep 28, 2012, 06:53 PM
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Consider pointing a video camera on the Wattmeter screen if you can....not for posting the video, but for accuracy of data....otherwise some wattmeters will report the tests peak spike values after the test (not so good).
A X V = W
W / A = V
W / V = A
so reading any 2 of the 3 "quickly" will work fine. write them down immediately or you will start to doubt yourself. Been there too many times myself with my first wattmeter.

Please allow the motor to cool down inbetween the tests, and error on side of caution as far as waiting longer and with the battery disconnected.

Do not test over 90A static even though I would go to 100A static. I don't want to be blamed.

3 sec only.

Have fun,

Gryphon
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Old Sep 28, 2012, 07:14 PM
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I use the 2w23 on my Swift with a APC 5.25x6.25 and 65C 4s. It really likes that prop and has very good speed. I have it as using 100A and 1300W but didn't write down if that was the initial, static surge amount, or steady state amount. I do check the temps after each flight and the motor is about 135 F and is holding up well.

While the Swift is not as draggy as the Funjet, I think your guess of mid 130's is doable.
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Old Sep 28, 2012, 07:29 PM
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United States, CA, San Diego
Joined Jan 2012
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Quote:
Originally Posted by GryphonRCU View Post
Consider pointing a video camera on the Wattmeter screen if you can....not for posting the video, but for accuracy of data....otherwise some wattmeters will report the tests peak spike values after the test (not so good).
A X V = W
W / A = V
W / V = A
so reading any 2 of the 3 "quickly" will work fine. write them down immediately or you will start to doubt yourself. Been there too many times myself with my first wattmeter.

Please allow the motor to cool down inbetween the tests, and error on side of caution as far as waiting longer and with the battery disconnected.

Do not test over 90A static even though I would go to 100A static. I don't want to be blamed.

3 sec only.

Have fun,

Gryphon
Thanks, I'll report back when I get everything assembled for testing.
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Old Sep 28, 2012, 07:36 PM
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United States, CA, San Diego
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Quote:
Originally Posted by stanordave View Post
I use the 2w23 on my Swift with a APC 5.25x6.25 and 65C 4s. It really likes that prop and has very good speed. I have it as using 100A and 1300W but didn't write down if that was the initial, static surge amount, or steady state amount. I do check the temps after each flight and the motor is about 135 F and is holding up well.

While the Swift is not as draggy as the Funjet, I think your guess of mid 130's is doable.
I appreciate the real world numbers. I'll play around with props and see what I get. To be honest I'd be perfectly happy with a 125+ setup, but was hoping for 135+. My fastest wing hits about 105 flat and level right now, so I don't want to get too far over my head too quickly.
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Old Sep 28, 2012, 09:08 PM
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United States, NY, New York
Joined Oct 2010
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Need 4 Speed

i decided to sacrifice a rare "hard to find " multiplex twinjet and convert it to a single jet .after readig through countless pages of how to reforce the ship with carbon rods . i did the mods neccessary for the ship to withstand speeds of around 130mph .i used more flat carbon fiber rods(strips) than tubes since i want to keep the ship unaltered , so all that was left was the electronics i went out and purchased a mega motor. i found it to be the only motor worthy of going into my favorite ship. this ship deserves the best parts i can get .so that is why i went all out ,
this is the set up im going with its a set im copying from a member here . MOPARARMY i saw a video on you tube of him flying a stryker with this set up and decided this is what i want not ludicrus speed but fast enough to wow the crowd.
this is the motor ,MEGA 16-40-2ce*
the battery im going to use 5s5000
the prop size ,im going to run 7x6
the ESC is going to be a castle 100 amp i havent purchased it.

im guessing i will hit around 130mph (im guessing that speed ,due to the fact that the frame isnt as streamlined as the funjet ultra . if my guess is right i will be happy since i really dont care to make it any faster than that . i have a couple of flyjet x83 that im going to install some sk3 1900kv motors in it for ultimate speed . .
* the motor will take a few weeks to get here. but im in no hurry to get it since this ship will only be flown on special occasions

[IMG][/IMG]
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