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Old Jan 27, 2012, 05:52 PM
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Originally Posted by Burdo View Post
Just to check my own thoughts on this....but why is everyone so keen to get tis fan using 6S and beyond.

What is the real advantage?

A 70mm airframe is really not all that big, so I would've thought the extra weight would be a negative (lipo, ESC etc etc)

So at 4S using Extreme's figures and evidence in video, it would seem to be best suited and probably lighter than the 6S options?
I think some are and some are not. They are searching for a low Amp high Volt setup as that would be the most efficient with this fan. I on the other hand am willing to give away a few amp's and thrust for a solid 4/5s setup that is cost effective. Most of my birds and bat's are 4/5s.
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Old Jan 27, 2012, 06:31 PM
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Simple ohms law... High voltage, low current. Low current means less heat waste thus better efficiency. Low current allows for low C lipo's, lighter ESC etc.

However you're right, there's always a trade off and depending of choices you make a 6s could be too much for a given airframe. The 4s set-up in Extreme's F16 is a close to perfect match I guess.

But given the fact that this fan can push +2kg on a good 6s set up you are not confined to your typical 70mm airframe and you can go to a slightly bigger airframe, think 1100-1200 wingspan with more scale-like inlets. Specially in twin set-ups the higher cell count will be the way to go.
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Old Jan 27, 2012, 07:20 PM
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I like having "Options"!
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Old Jan 27, 2012, 08:03 PM
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Quote:
Originally Posted by hommel View Post
But given the fact that this fan can push +2kg on a good 6s set up you are not confined to your typical 70mm airframe and you can go to a slightly bigger airframe, think 1100-1200 wingspan with more scale-like inlets. Specially in twin set-ups the higher cell count will be the way to go.
+1, hommel;

I am sure that is why the LX Models A-10 (1534mm WS) is set up for 6S with their 2100kv outrunners and 6 blade 70mm fans. That's the way it came stock and it flys with good authority
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Old Jan 27, 2012, 09:11 PM
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Thanks for the explanation, Silly me totally missed the voltage difference.
Look forward to the revised testing, and many thanks for doing it!

Like some I'll be quite happy with a 4S set up for my liner. The CS has looks, performance, and sound over the stock E-flite units.

And all of your input is getting noted as I have a HET Me 262 that is just a slug with the recommended 3w motors on the WeMo fans on 4S. The CS sounds like just the fix for it.
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Old Jan 27, 2012, 11:31 PM
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I would like to get 7-8lbs of thrust out of this fan and put it in a plane that weights 4-5lbs.

That's the way I roll, If I can see it then it's going to slow

No seriously, we have affordable 65c packs and I don't have to have a 5 minute runs when I want to set my hare on fire.

I'm with 901 on the packs, I have 4-5 cell packs coming out of my ears but 5 - 5.5 lbs of thrust when I want to get an arc F18 nasty should be an option
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Old Jan 28, 2012, 06:32 AM
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Originally Posted by erh7771 View Post
On the 2300kv motor, could you do some test with it lipped and see if the motor etc stands up to some harsh treatment and extra watts. 1.83kg unlipped is 2.2kg lipped if you add 20% thrust and that's a conservative number.....that's some REAL nice thrust for 26usd b4 shipping.

You can run it up for a minute and just let it sit for 30 second and take temps. Temps should rise but if it has enough mass and cooling area the temps will start falling before the 30 seconds are up. This cooling effect gets doubled while the motor is running at low RPM cause of airflow from my testing in the past, sometimes it wont allow you to know if a motor can put up with hot days etc. If you smell a burnt oil smell that's the wire laminate starting to melt but even before that look for the windings to get dull looking vs a glossy copper.

Want to know if that 11usd motor can put up with the abuse. I know some have drilled holes in the cone area of some of the LX motors (HKs L series) and they've been able to put more watts through them and help them dissipate more heat.

Would like to know before HK doubles the price on them

They sound REALLY nice in these fans, I like 26usd 2.2kg setups even though it's 6s which I think is too heavy a pack for most 70mm planes.

I posted upthread a 2300kv outrunner that looks JUST like a MB1 but RPM different...might get one just for kicks and try it on 7s if the test with the L2855 2300kv motor is confirmed

Here we go....

Today I tested the 2300kv and the 2800kv.

Fan has lip on it and the difference is as expected.....


Turnigy L2855 – 2300KV
4S 4000 40C
Vm 14.15
Ap 40.77
Wp 884.2
Thrust (Kg) 1.3

5S 4400 65C
Vm 18.46
Ap 65.07
Wp 1248.0
Thrust (Kg) 2.0

6S 4500 25C
Vm 20.79
Ap 70.4
Wp 1511.0
Thrust (Kg) 2.2


I also retested the 2800kv version.

Turnigy L2855 – 2800KV

4S 4000 40C
Vm 14.36
Ap 63.47
Wp 950.0
Thrust(Kg) 1.6

5S 4400 65C
Vm 17.74
Ap 82.84
Wm 1478.6
Thrust (Kg) 2.2


Both motors looked like the could take it but after shutting down the temps rose to 78c for the 2300 and 82c for the 2800kv.

There was a very faint smell of laminate if I put my nose right up to the motor for both at 6S and 5S respectively.

The 2300kv looks good for 5S. I will try it in a plane.

This fan needs really good batteries.....
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Old Jan 28, 2012, 07:08 AM
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United States, TX, Grand Prairie
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Originally Posted by anlucas View Post
Here we go....

Today I tested the 2300kv and the 2800kv.

Fan has lip on it and the difference is as expected.....


Turnigy L2855 – 2300KV
4S 4000 40C
Vm 14.15
Ap 40.77
Wp 884.2
Thrust (Kg) 1.3

5S 4400 65C
Vm 18.46
Ap 65.07
Wp 1248.0
Thrust (Kg) 2.0

6S 4500 25C
Vm 20.79
Ap 70.4
Wp 1511.0
Thrust (Kg) 2.2


I also retested the 2800kv version.

Turnigy L2855 – 2800KV

4S 4000 40C
Vm 14.36
Ap 63.47
Wp 950.0
Thrust(Kg) 1.6

5S 4400 65C
Vm 17.74
Ap 82.84
Wm 1478.6
Thrust (Kg) 2.2


Both motors looked like the could take it but after shutting down the temps rose to 78c for the 2300 and 82c for the 2800kv.

There was a very faint smell of laminate.

The 2300kv is good for 5S. I will try it in a plane.

This fan needs really good batteries.....
nice numbers for 11usd motor

How long did it take for temps to fall after you shut the motors down?

Were you measuring the outside of the bell or the shaft temps?

Also, on these motors are there any cooling holes at the end of the cones?

On HKs site people have drilled holes in the end cones and said it made a notable difference in the way the motor cooled.
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Old Jan 28, 2012, 07:23 AM
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Quote:
Originally Posted by erh7771 View Post
nice numbers for 11usd motor

How long did it take for temps to fall after you shut the motors down?

Were you measuring the outside of the bell or the shaft temps?

Also, on these motors are there any cooling holes at the end of the cones?

On HKs site people have drilled holes in the end cones and said it made a notable difference in the way the motor cooled.
Nice numbers indeed!

They took about 2 minutes before they started to go down. I measured the temperature on the bell cone sticking out the back. There is one hole at the center of the cone.

While switching motors I accidentally unscrewed the cone off one of the motors. They unscrew clockwise. Behine the cone, the motor bell back-plate has some holes. Looks like the cone is there for cooling the bell.
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Old Jan 28, 2012, 07:45 AM
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Having done the tests with the lip on I wonder what can we expect when we put this fan in a plane.

I for one, given that these Turnigy motors come in 3 kv versions don't think we need to push them beyond their limits.

The 2100kv L2855 is perfect for a 6S setup. 2Kg thrust at 50amps is nothing to sneeze at.

The 2300kv gives some decent numbers even with 4S and can be pushed to 5S with some throttle management for longevity. At 4S it's the quietest motor I have ever heard.

The 2800kv is very good in 4S. Depending on the 4S battery used I got anything from 1.1(2200 40c) to 1.6 kg(4000 40c) thrust. Didn't even get hot after extended wot. Wouldn't run this on 5S.

I keep thinking that 6 months ago I was strugling to get anything over 1Kg of thrust with a $30 setup. This fan rocks!
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Last edited by anlucas; Jan 28, 2012 at 07:58 AM.
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Old Jan 28, 2012, 09:36 AM
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Originally Posted by anlucas View Post
Nice numbers indeed!

They took about 2 minutes before they started to go down. I measured the temperature on the bell cone sticking out the back. There is one hole at the center of the cone.

While switching motors I accidentally unscrewed the cone off one of the motors. They unscrew clockwise. Behine the cone, the motor bell back-plate has some holes. Looks like the cone is there for cooling the bell.
Ah, then they're ok at those temps. I measure the temps on the shaft on inrunners then measure the walls cause the shaft usually tells me what an inrunners magnets will take which in my experience has always been lower than the windings and windings laminates for inrunners.

An outrunners stator will take more heat and we don't really have to be concerned with the magnets cause they're spinning in the air. A Scorpions stator can go up to around 400 degrees and so can their magnets on their 28mm motors...so half of that I'm good with.

http://www.innov8tivedesigns.com/pro...roducts_id=157

Did you spin them up after the letting them sit?

How did they act?

The reason why I do this on a motor is cause it kinda simulates a hot day were the motor can heat up to 110deg BEFORE flight. If it's giving out the same thrust after being heated up and sitting for a couple 30 seconds then it's pretty good at that power IMHE.
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Old Jan 28, 2012, 10:01 AM
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Good numbers!

I'm glad you've proved that lower kv motors are the way to go with this fan. That 2100 rocks, regardless of the price and I agree that the 2300 5s is a versatile option.

Mhh... might even be tempted to switch to an outrunner...

Thanks for testing and sharing,
H.
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Old Jan 28, 2012, 10:47 AM
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Originally Posted by erh7771 View Post
Did you spin them up after the letting them sit?

How did they act?

The reason why I do this on a motor is cause it kinda simulates a hot day were the motor can heat up to 110deg BEFORE flight. If it's giving out the same thrust after being heated up and sitting for a couple 30 seconds then it's pretty good at that power IMHE.
Yeah, I did spin them up. They cooled down after spinning them up....
At first, I was just spinning and mechanically writing down numbers. When I looked at the numbers, I thought I must have written down something wrong..... So I ran them again.... That's why you will see that some voltages are lower than expected.

I am really cautious about the temps. On a hot day the air going through is 30 deg C higher so the cool down effect when running is totally different.

110 deg F before flight means that the foamies are starting to bend....
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Old Jan 28, 2012, 11:17 AM
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Originally Posted by hommel View Post
Good numbers!

I'm glad you've proved that lower kv motors are the way to go with this fan. That 2100 rocks, regardless of the price and I agree that the 2300 5s is a versatile option.

Mhh... might even be tempted to switch to an outrunner...

Thanks for testing and sharing,
H.
The "numbers are good" BUT where do you use them?.....

I see the 2100kv being a top budget option for a twin EDF system like an LX A-10 or F-22 where 2 motors are sharing a single 5000-6000mah 45C lipo.

For single 70mm EDF planes this motor needs a 6S 45c battery which is between 500 and 600g to work well. My Sapac T-45 V2 could possibly handle 500g without modifications to move the battery backwards but most 70mm planes will have problems.

The 2300kv with a 4S lipo could be used in light, sub 1kg all up weight foamies that can handle 300-350gr of battery. I was really surpised with the thrust with 4S. With a weaker battery than the 450gr 40c I used, it could still manage 1.1kg of thrust.

The 2300kv on 5S is probably viable in largish 70mm planes that can handle a 550-600g battery.
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Last edited by anlucas; Jan 28, 2012 at 11:39 AM.
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Old Jan 28, 2012, 11:43 AM
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Quote:
...The 2300kv on 5S is probably viable in largish 70mm planes that can handle a 550-600g battery.
I use a LOT of throttle management when I fly lighter high C rated packs, I can get 5mins of run time with my 40c 3000mah 5s pack used on my GWS A-4 with a SAPAC MB1....around the same performance and amps as the L 2855 2800kv motor.

I can cruise around half throttle on that plane all day long with that motor, those ...

Those L2855s have some promise, just have to see if they're durable at 11usd it's worth a try
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