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KW club

Old 04-20-2012, 02:36 AM
  #276  
Don Sims
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Congrats gents! Jet, I ate all the brownies so no points left!
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Old 04-20-2012, 02:40 AM
  #277  
CHELLIE
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Originally Posted by JetPlaneFlyer View Post
heres my entry into the 1kW club. do i get extra brownie points for winding the motor myself?

Model is the 51" Slick 360 from hobbyking, motor is a Scorpion SII3020-1110kv re-wound to 750kv running on a Gens Ace 2200mAh 4s spinning a Xoar 14x7 prop.

At 3.5lb performance is 'brisk'
Nice Peak Watts Ok, You Get Some brownie Points Too, As I Have Learned from You

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Old 01-13-2013, 01:09 AM
  #278  
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Requesting membership in this exclusive club.

Setup:
Motor: Leopard 5055 720kv
ESC: Land Power 85A OPTO
BEC: ZTW SBEC
Battery: GensAce 4s 4000mAh 25C
Plane: 3DHobbyShop 58" Edge 540

Results:
1066W (actually I got 1096W on a fresh battery but I didn't take a picture to document it)
71.1A
15V

This is actually a bit low for this plane, so I'm probably going to prop it up or go with 5s.

Evidence:

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Old 01-13-2013, 01:11 AM
  #279  
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Originally Posted by NJSwede View Post
Requesting membership in this exclusive club.

Setup:
Motor: Leopard 5055 720kv
ESC: Land Power 85A OPTO
BEC: ZTW SBEC
Battery: GensAce 4s 4000mAh 25C
Plane: 3DHobbyShop 58" Edge 540

Results:
1066W (actually I got 1096W on a fresh battery but I didn't take a picture to document it)
71.1A
15V

This is actually a bit low for this plane, so I'm probably going to prop it up or go with 5s.

Evidence:

WOOHOO! Congrats!
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Old 09-17-2013, 11:14 AM
  #280  
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1KW is getting easy... is there a 5kW club?

The plane in my Avatar photo is an example.
BVM EVF (older version, Neu 1915/xx, Castle 100)
12S 5000 mah Sky Lipo (3X 4S 5000 20C)
105 amps peak, Pulling down to 47.6v on fresh charged pack set for 5000 watts.
This power system can discharge the packs in under 3 minutes. Generally I get 5 to 6 min in the air.

I also have/had others that exceed 1 kW.

I stuck a Turnigy motor (forgot which... same size as E-Flite Power 160) on a "Brio" Pattern competition plane with a 22X10 and using 12S 4400 mah was pulling up to 2600 watts in flight according to the Turnigy Super Brain 100 amp ESC.
I slapped the throttle to full from a full stop on the runway. The prop, spinner and bell went appx 30 yards. The plane went about 3 feet and the ESC burned out (sudden loss of motor resistance)

I'm in process of putting a Power 160 on the nose of an 87 inch span PT-19. It used to have a 26cc gas. 8S LiPo (4000 to 5000 mah as needed for CG) with the Turnigy Super Brain 100 will be more than adequate. I'll probably just use a 18X8. It needs the big motor more for weight than for available power.
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Old 09-17-2013, 12:10 PM
  #281  
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Show us the a photo of your watt meter and we can do 5kw! We need the following so I can document your info when giving the award like this:

Setup:
Motor:
ESC:
BEC:
Battery:
Plane:

Results:
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Old 09-18-2013, 12:13 AM
  #282  
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Originally Posted by fhhuber View Post

I stuck a Turnigy motor (forgot which... same size as E-Flite Power 160) on a "Brio" Pattern competition plane with a 22X10 and using 12S 4400 mah was pulling up to 2600 watts in flight according to the Turnigy Super Brain 100 amp ESC.
I slapped the throttle to full from a full stop on the runway. The prop, spinner and bell went appx 30 yards. The plane went about 3 feet and the ESC burned out (sudden loss of motor resistance)

I'm in process of putting a Power 160 on the nose of an 87 inch span PT-19. It used to have a 26cc gas. 8S LiPo (4000 to 5000 mah as needed for CG) with the Turnigy Super Brain 100 will be more than adequate. I'll probably just use a 18X8. It needs the big motor more for weight than for available power.
Check out those $$$$ Hacker A60 series motors. I've got over 200 flawless flights on my A60-16M, and about 75 flights on my A60-5S. The A60-16M has hit 3000 watts, and on landing is finger touch cool.
This motor has a APC-E 19X12 Wide blade electric prop, that turns over at 7000 RPM, on a 12S2P A123 battery pack.

https://www.aero-model.com/8_72_1127...0-5S%20V2.html
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Old 02-16-2014, 03:21 PM
  #283  
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Originally Posted by Don Sims View Post
Show us the a photo of your watt meter and we can do 5kw! We need the following so I can document your info when giving the award like this:

Setup:
Motor:
ESC:
BEC:
Battery:
Plane:

Results:
Do helis qualify?

I was out test flying my new 700 size Compass 7HV today. Not pushing hard at all but did do a few full collective manoeuvres running higher head speed just to make sure it all stayed together under stress (fortunately it did)

So when I downloaded the Castle data log it tells me I briefly hit 5825W (142A @ 41v) ... see log attached

I might need to get a bigger ESC

Spec:
  • Motor: Compass SZ-4926 510kv
  • ESC: Castle Creations Edge 120HV
  • BEC: None, HV servos running unregulated off 2s LiPo
  • Battery: Turnigy 6s 5000mAh, 40c (2 in series)
  • Plane: 700 size helicopter - Compass 7HV 'Ultimate'
  • Flying weight: 5.7Kg / 12.5lb

The 5.8kW peak was toward the end of the flight when battery voltage was getting low, I'm sure it would go over 6kW if i hammered it early in the flight... Is there a 6kW award?
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Old 02-16-2014, 09:36 PM
  #284  
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5 is the biggest award we currently have.... I think I can whip up a 6 through 10 if need be!
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Old 02-17-2014, 03:55 AM
  #285  
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Originally Posted by Don Sims View Post
5 is the biggest award we currently have.... I think I can whip up a 6 through 10 if need be!
Dang.

Last year, I helped a club member with a electric turbine twin that was pulling 175 Amps each on a pair of 6S 5000 LiPos. That's 7300 Watts. Don't have any proof of it though, the model was lost on its first flight.

Problem was, the electric fan MFG was way the off on how much current their motors would pull on a 6S LiPo. The fan specs indicated 95 Amps. It came to double that. On a pair of Castle Creations 100 Amp ESCs.

The ESC's both shut down when they hit 200 F. The model landed off the field.
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Old 02-17-2014, 04:21 AM
  #286  
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Originally Posted by kyleservicetech View Post
Dang.

Last year, I helped a club member with a electric turbine twin that was pulling 175 Amps each on a pair of 6S 5000 LiPos. That's 7300 Watts. Don't have any proof of it though, the model was lost on its first flight.

Problem was, the electric fan MFG was way the off on how much current their motors would pull on a 6S LiPo. The fan specs indicated 95 Amps. It came to double that. On a pair of Castle Creations 100 Amp ESCs.

The ESC's both shut down when they hit 200 F. The model landed off the field.
No pre-flight current demand and cooling check? That big of a difference from the ESC rating should have been found before flying.
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Old 02-17-2014, 07:01 AM
  #287  
kyleservicetech
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Originally Posted by fhhuber View Post
No pre-flight current demand and cooling check? That big of a difference from the ESC rating should have been found before flying.
Yeah, we did all of that. We did quite a bit of preflight testing.

The pilot decided to fly anyhow, with reduced maximum throttle on the model. Per the CC ESC data printout, at the two minute mark, both ESC's shut down due to over temp.
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Old 02-17-2014, 08:11 AM
  #288  
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Was the word "Screamer" anywhere in the name on those motors?
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Old 02-17-2014, 08:32 AM
  #289  
JetPlaneFlyer
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Originally Posted by kyleservicetech View Post
The pilot decided to fly anyhow, with reduced maximum throttle on the model.
Oh dear, that would have only made it worse if anything. As per Castles own guidance, reducing throttle does not reduce peak amps in the ESC, it only shortens the time that the electrical pulses are turned on. In fact part load is worse for most ESC's than just pegging it at WOT.

6. Can I control how much current passes through my speed controller by limiting full throttle travel on my transmitter with endpoint adjustments/trim? In other words can I use a 25 amp speed controller with a motor that will pull 45 amps but lower my top throttle endpoint on my transmitter so my watt meter only shows 25 amps at full throttle? Will this be OK?
NO!!! A speed controller controls power to the motor by turning full throttle current on and off really fast, 11 to 13 thousand times per second (Pulse Width Modulation or PWM). The percentage of each on/off pulse that is off compared to the part that is on determines how much power the motor sees. I.E. With a pulse that is 50% off and 50% on the motor will see 50% power*. Because each on pulse is 100% of full throttle current, a system set to pull 20 amps at full throttle through a Phoenix 10 will not last if you are throttled back to the point where you only see 10 amps on a wattmeter. The ESC in this case is still switching 20 amps, which it canít do for long. Actually it is worse than the simple example above. Because an electric motor will always to try to pull as much power as is available to get to its rpm (volts times Kv), when you are running the motor below its Kv speed by switching power on an off, each on pulse will actually be way over the full throttle amp draw. That is why ESCs work harder at partial throttle than full throttle and why we underrate our ESCs. We underrate not so they can handle more current than their rating at full throttle, but so they can handle extended partial throttle operation with no problems.
* Actually, electric power is not linear as in this example, but you get the idea.
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Old 02-17-2014, 08:42 PM
  #290  
kyleservicetech
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Originally Posted by JetPlaneFlyer View Post
Oh dear, that would have only made it worse if anything.

Yup

Yup, those peak currents as described by Castle Creations is a big issue on running an ESC at reduced power. Add to that, along with the heating effect from the actual resistance of the MosFets in these ESC's when the MosFets are turned on, is the heat input during the transistion between full "On" and "Full Off" of the MosFets.

This switching time takes place extremely fast, but that switching time is not zero. And during that switching operation, the heat input to the MosFet is increased.

At full power, those MosFets are only switching each time the motor goes past a North or South pole. That would be a switching frequency of somewhere around 3000 or 5000 cycles per second, depending on how many poles the motor has, and how fast it is spinning.

So, when operating at partial throttle, those MosFets are switching on and off perhaps a dozen times when the motor winding moves from a "North Pole" to a "South Pole". Rather than once per pole change. That switching then adds to the heat input to the MosFets.

For those that have access to an oscilloscope, this high speed switching effect at lower throttle setting is clearly apparent. Depending on the brand of the ESC, that switching time can be on the order of about 20,000 times per second. Or even much faster. ESC's such as the Castle Creations product line allow the user to program the switching frequency of their ESC.

In the case of my club members electric jet, even though the motor was pulling 160 Amps on a 100 Amp ESC, the Castle Creations ESC's took a full two minutes before they shut down due to overheating. The ESC datalogger showed the ESC's hit over 200 degrees F. And, once they cooled off, they were just fine. Says a lot about the quality of those CC ESCs. Don't know if you can say the same about some of those real cheap China import ESC's.

Last edited by kyleservicetech; 02-17-2014 at 08:58 PM.
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Old 02-17-2014, 09:11 PM
  #291  
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The only Turnigy ESC I have blown was the motor's fault...

The motor spit the bell, shaft and prop off when the snap ring holding the motor together failed. Losing the bell instantly reduced resistance to current flow in the motor.

Might as well have put a dead short across the ESC's output.
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Old 02-17-2014, 10:08 PM
  #292  
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Originally Posted by fhhuber View Post
The only Turnigy ESC I have blown was the motor's fault...

The motor spit the bell, shaft and prop off when the snap ring holding the motor together failed. Losing the bell instantly reduced resistance to current flow in the motor.

Might as well have put a dead short across the ESC's output.

Yup
The interaction between the motors electromagnets, and the steel bell and its magnets is kinda-sorta-maybe like a transformer action. Remove part of the steel around a transformer, and you've got a dead short on the windings, as far as AC power goes anyhow. It's all due to the inductance of the motor winding dropping way down when the motor bell disappears.

I know the Castle Creations ESC's have the ability to program in the maximum current they will handle before shutting down due to overload. Don't know if those CC ESC's would shut down in time to save themselves if the motor fails though.
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Old 02-17-2014, 10:49 PM
  #293  
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Yes, Castle Creations make nice ESC's

They have got a little left behind compared to some others in some respects though. One thing some ESC's have these days is 'active freewheel'. This effectively removes the part load heating issue. Higher end heli ESC's generally have this feature, even the Hobbyking YEP ESC's have it as they are cloned from the expensive and active freewheel equipped YGE ESC's.

It means the ESC can be smaller and lighter and doesn't need a big heatsink to dump heat, plus it's more efficient.
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Old 02-18-2014, 02:05 AM
  #294  
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Originally Posted by JetPlaneFlyer View Post
Yes, Castle Creations make nice ESC's

They have got a little left behind compared to some others in some respects though. One thing some ESC's have these days is 'active freewheel'. This effectively removes the part load heating issue. Higher end heli ESC's generally have this feature, even the Hobbyking YEP ESC's have it as they are cloned from the expensive and active freewheel equipped YGE ESC's.

It means the ESC can be smaller and lighter and doesn't need a big heatsink to dump heat, plus it's more efficient.
Interesting info. Our Engineers used this technique some 15 years ago in a very high power magnetic actuator circuit design. This magnetic actuator pulled some 100 Amps at 55 Volts DC. The actuating pushrod put out about 600 pounds of force, moving a half inch in about 10 milliseconds. You don't want your fingers anywhere near that thing in operation. The whole actuator weighs about 25 pounds. I've got a bunch of magnets from those things in my workshop. They will lift some 500 pounds on a heavy steel block.

Moving up to ESC's, IMHO, this would not make a lot of difference in motor efficiency, but would be effective in reducing heating effects inside the ESC itself. The video below shows that the motor windings current flows through another MosFet diode circuit during the switching process. Those diodes have about 3/4 volt drop or so. Compare that to a motor with a 6S LiPo at some 20 Volts DC, that 3/4 volt is only a few percent of the energy going into the motor.

For those interested, here is a good video on how that freewheeling works.
[media]http://www.youtube.com/watch?v=uqzOQGiwGnE[/media]

As to whether it is reasonable to put in more circuitry in the freewheeling design, or simply use higher powered MosFets, for the same ESC current rating, who knows.
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Old 02-18-2014, 08:45 AM
  #295  
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That's a good video, thanks for posting. I knew the benefit of active free-wheel, but not how it actually worked.

Seems like there actually isnt any more circuitry. Just that the existing 'off duty' FET is switched on to allow the current to freewheel, rather than to run back through the inbuilt diode.

Kind of makes you wonder why they dont all work like that.
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Old 02-18-2014, 06:46 PM
  #296  
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Originally Posted by JetPlaneFlyer View Post
That's a good video, thanks for posting. I knew the benefit of active free-wheel, but not how it actually worked.

Seems like there actually isnt any more circuitry. Just that the existing 'off duty' FET is switched on to allow the current to freewheel, rather than to run back through the inbuilt diode.

Kind of makes you wonder why they dont all work like that.
That's what I thought.

Taking another look at the three phase "H_H_H" MosFet driver circuit, it would not be hard to turn on one set of MosFets across one motor winding. Then, turn on all bottom MosFets briefly to do the "Flywheel" thing. However, that motor is spinning, so added to that current freewheeling, you've got the motor acting like a generator. So very briefly, you've got a dead short across the motor windings. Making it all work reliably might call for quite a bit of added circuitry.

The problem is, if any two MosFets directly in line with each other ever turn on simultaneously, even very briefly, you've got a dead short across your high powered LiPo battery. I suspect a few microseconds of that condition, and you're going to blow the MosFets.

Proper design of this stuff allows for a "Dead Period" of time, where all MosFets are turned off. This provides time for each MosFet to turn off before the next MosFet turnes on. That way, there is no overlapping of the switching of the MosFets. (I've played with those MosFets in high powered circuits in the past. One thing these MosFets are very good at, is going into self oscillation at frequencies in the Megahertz range. It can be a real pain in the *** to get rid of those oscillations. That is, before they blow out!)

I also wonder if it could affect the sensorless operation of the ESC. Remember the first design of these brushless motors had three extra motor wires to feed back from the motor to the ESC the exact rotation position of the motors permanent magnet structure. The sensorless design eliminated the requirement for those three extra sensing wires.

For those interested, here is a bit of reading of the design of these ESC controls. Some of it gets pretty complex.

http://ww1.microchip.com/downloads/e...tes/01083a.pdf,
http://ww1.microchip.com/downloads/e...tes/01292A.pdf,
[media]http://www.youtube.com/watch?v=ZAY5JInyHXY[/media]

Last edited by kyleservicetech; 02-19-2014 at 03:41 AM.
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Old 03-27-2014, 06:33 PM
  #297  
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OK, I'll put in my application for the kw club. The plane is the E-Flite F-4 Phantom. Stock recommended setup: Delta-V 32 80mm EDF w/EF BL32 2150kv motor, EF 80A ESC, ROC 6S 5000mAh 45C battery. As seen in the wattmeter photo, 1575w. And the scary maiden vid linked below, too, so it has flown, but I've only done 2 flights so far. Getting the courage to take her up again but with the manufacturers recommended CG, not the RCG forum one... Probably nervous for nothing, but it's my first non-foam plane.

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Old 03-27-2014, 11:21 PM
  #298  
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Originally Posted by xmech2k View Post
OK, I'll put in my application for the kw club.


Congrats Tom! Looks spectacular!

J
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Old 03-28-2014, 01:47 AM
  #299  
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Way to go Tom! Congrats!!!
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Old 03-28-2014, 10:34 AM
  #300  
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Nice flying Tom. You did WAY better than most of the videos I see on Youtube for that same model.

What made you think that the CG was wrong?
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