SkyJib/AeroDrive 8 Crash Video

R

remyd

Member
Hi Guys,
Firstly sad to hear the problems some of you have had and thank you for alerting other forum members. It prompted me to be very cautious prior to doing a full scale launch as i also bought motors around the same time. I have done a number of tests with my Orbit 15-22 and thought the data might interest some of you. I haven't used the 15 inch props as they wouldn't fit my CS8 in its current configuration but the data through a Wookong controller has showed some interesting results. Anyway if you have a box of these motors it might be worth considering still using them as i think they are excellent well balanced motors and with some further configuration testing and controller settings i think you would be pleased. I agree that the initial recommendations needed some clarification and certainly given what is now known anyone still selling these should be clearly pointing out that these motors can draw significant current.
see
http://www.multirotorforums.com/sho...motors-and-battery-data-and-build-information
Cheers,
Remy
 


DKTek

DKTek

Member
Nice job BUT...those motors and props can draw as much as 60 amps each if full throttle is applied, as in stopping a rapid descent or puching out. That would be 480 amps and would destroy that controller as well as any currently available for the MK FC's with the I2C buss.

Would you care to share any special settings that needed to be changed in order to make this work? Things like limiting max throttle is MK Toolz, etc.
 

I

ichwillnix

Member
You are fully right.
60 A battery current with these motors are easy to get. The motor phase currents are even higher. We measured up to 180A at rapid accellerations. Without limitation this will blowup each ESC.
In Herkules III a lot of tricks are made to stay in safe operating area. E.g. Motor phase measurement, Limitation, variable timing over rpm and lots of things more... I do not want to see this features copied in a few weeks at "far-east" controllers... ;-)
 


I

ichwillnix

Member
Droider said:
And I thought using higher voltages made everything run cooler!
Click to expand...

Also you are fully right!
This is true if you scale everything to the higher voltage, also the motor must be modified!
The Orbit15-20 here in this test has 720kV and is optimized for max 4s LiPo. It is fully understandable when this motor is driven with 6s that it gets hotter....
Use the same Motor with 400kV (higher no. of windings) and the total system performance is indeed better....
 
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DKTek

DKTek

Member
ichwillnix said:
You are fully right.
Without limitation this will blowup each ESC.
In Herkules III a lot of tricks are made to stay in safe operating area. E.g. Motor phase measurement, Limitation, variable timing over rpm and lots of things more... I do not want to see this features copied in a few weeks at "far-east" controllers... ;-)
Click to expand...

So you are implying that the MK FC used in that video is stock settings in the MK Toolz? You haven't changed settings on limits in the MK Toolz and that everything is all controlled on the Herk III boards with it's stock settings?

Are you saying that it will be a, "PLUG and PLAY" system that can handle the Pletty 15-20's swinging a 14x8 inch prop?

Sorry for this anal questioning but I'm sure you can guess why total clarification is needed to be taken seriously. This is a very sore subject for many as thousands of dollars have been lost by many. I'm sure that we all can respect your design secrets but please do not hold back any special settings or adjustments needed to make this work without failure, due to the lack of either set up info or misinformation.

Obviously we are all looking for a solution. If this is a viable solution, then you have our undivided attention.
 

I

ichwillnix

Member
Hi DKTek,

i can confirm that the MK FC was not modified at all. It is as it is "out of the box" without any special settings or max PWM limitations or anything else.
Herkules III takes care by itself that the inrush currents at acceleration are staying in safe operating area until a certain point.

I do not say the 14x8 inch props are the perfect solution for this. Plettenberg released this motor only for max 4s and 13.5ich. And this has a good reason!
The drive set (Motor+Prop+Battery) efficiency with 14.8 props is not really better than with 13 inch. So what is the reason to use 14.8 inch here?
The orbit15-20 is a 10-pole motor and has a bad efficiency at low rpm. This motor was originally used in Heli-applications with high rpm. Here the focus is different.


So:
This motors are not the best in efficency but when driven with reasonable settings it is a reliable drive set.
Slighly higher rpm with 13.5inch will cause a slighly worse efficiency but much higher safety!

what i can say up to now:

Herkules III with Orbit 15-20

a) works 100% safe if:
Battery Voltage is less or equal than 4s and Propeller is 13.5 ich

b) has to limit the peak Motor power (current) actively in case the setting a) is exceeded
e.g. Voltage > 5s and Prop > 14inch

Herkules does not limit the average power (hovering) but limits the peak power (e.g. after fast deccelleration) in order to not beeng destroyed by too much current.

The big big benefit of the latest Herkules software is:
It has no commutation problems even when it is in limiation mode. After the power limitation the board goes back to normal operation. That is at least the target we are working for...

It is simply physics: A heavy copter needs a lot of power for acceleration. A 20t truck can not accellerate like a 500kg car with the same engine....
 
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K

kdoherty

Member
DKTek said:
So you are implying that the MK FC used in that video is stock settings in the MK Toolz? You haven't changed settings on limits in the MK Toolz and that everything is all controlled on the Herk III boards with it's stock settings?

Are you saying that it will be a, "PLUG and PLAY" system that can handle the Pletty 15-20's swinging a 14x8 inch prop?

Sorry for this anal questioning but I'm sure you can guess why total clarification is needed to be taken seriously. This is a very sore subject for many as thousands of dollars have been lost by many. I'm sure that we all can respect your design secrets but please do not hold back any special settings or adjustments needed to make this work without failure, due to the lack of either set up info or misinformation.

Obviously we are all looking for a solution. If this is a viable solution, then you have our undivided attention.
Click to expand...

I am going to wade into this hornets nest with some trepidation. Let me state that in no way do I intend to insult or demean the choices or thought process of anyone who has gone this route. So before I start let me clarify that this is just my opinion (although I think a fairly informed one).

I am an eight time FAI World Champs Aerobatics team member. I was one of the first four people to fly electric at the 2006 World Champs in our class and the first to fly a purpose designed and built electric model. I am fortunate to have many smart people on my advisory team who contributed to the decisions regarding which equipment to use. Three of my advisers are electrical engineers, two of them are Team Futaba F3A Team Members, the third one is a twelve time W/C's team member. The specified system was Plettenberg Motors, Schulze ESC's and ThunderPower Batteries. (disclosure: I am sponsored by Thunder Power).

I am a Key Grip and Gaffer. I have five nationally broadcast commercials running in the last four months for clients with names like Nikon.... I have been raising cameras into the air on masts, cranes, jibs, helis and multirotors for almost eight years. When not on a mast the cameras were lifted by Plettenberg motors.

Diana Plettenberg did not lead anyone astray. I have been watching this play out and the level of research done to come up with the correct system just did not occur on anyone's part. ( It litteraly took some hundreds of hours of research and testing (testing is critical) to arrive at our system) Plettenberg has no idea what you as an individual are going to do with a motor provided to a third party and eventually sold to you. Plettenberg motors are simply the best motors YOU WILL EVER FLY.

Now lets get the heart of this issue. Is there a setup that will let the people using the Orbit 15-20 motors protect their investment and get back to making money? I think there is but lack of knowledge has stopped some from going this route. I am not sure why in articular you "want or need" to swing 14 or 15" props. A 13/4 prop spinning at 11,400 rpm will lift five plus pounds vertically like a rocket!. Correct me if I am wrong but you have eight of these. (six at least) That is one heck of a lot of lifting capacity even if you then take 80% of this number (which you should) as your maximum. Diana Plettenberg told you directly that there would be no problem if you ran a 13/4 prop. So run the 13/4 prop on the 15-20 motor and solve for ESC capacity and battery power. Is the new Hercules ESC board up to the task?? It "looks" like it is. Remember, this is new virgin ground we are all walking on. If you want to go exploring expect some setbacks. (Possibly some expensive setbacks) (I lost a good hexa and camera to "the learning cycle") You WILL need to run 5S.

Now as to exploring. I will be running Plettenberg 20-16 (or other winds) with separate Schulze ESC's running in Governor Mode. (Why Governor Mode? - because without it you are depending on altitude hold or ever increasing throttle stick position to maintain altitude.) Why Schulze? - Because they like the Plettenbergs, are the best you can buy and have the best Governor Mode in the business. I will also be running three blade wooden props as they are lighter (very important - its that inertia thing), They are smaller in diameter and have inherently less vibration. ( I run these props on my aerobatic models)


Kim.
 

DKTek

DKTek

Member
I'd like to thank both of you for your responses. Although please remember Kim that when the original configurations were shown, Pletty had not listed the performance aspects of the 15-20 and all we had to go on was what was being shown and advertised at the time by the so called testers. I agree that this is to be chocked up to test failures, or learning what not to do. I have since changed the way I go forward with this project.

I am currently flying my Skyjib8 with the MK FC and speed controllers with heat sinks and using APC 13x4 props(as per Diana's posted letter). I have changed the maximum throttle limit in MK Tools settings which in turn required a few more changes for flight handling. I am continuing to use my 5S1P 5300mah 30C batteries in parallel.

I am very interested in the new Herk III's as I feel that my set up is not optimum by limiting the throttle configs to avoid over amping situations. I am OK with a little overkill but my config is being wasteful of its resources. I thought about changing motors but I really like the Pletty design and want to stick with them. That leaves the speed controllers and FC's as options to be changed.

Kim, which FC are you using as I don't believe that the Schulze will accept the MK I2C output? I've been considering switching over to the HoverFly Pro for this reason and the fact that they are only 1.5 hours drive away from my home.
 

K

kdoherty

Member
DKTek said:
Kim, which FC are you using as I don't believe that the Schulze will accept the MK I2C output? I've been considering switching over to the HoverFly Pro for this reason and the fact that they are only 1.5 hours drive away from my home.
Click to expand...

Like many I was in love with the WK-M. I had used DJI on my helis and found the mr setup easy and accurate. My ship flew well and I had full confidence in it till one day when...
Out of the blue of the western sky (I was in Calgary filming) came ( no not Sky King) ( wait for it) my hexa !!, headed for the ground at near terminal velocity. ( I had been descending vertically from about 300 feet) Far too fast to track the propeller blades to see if they were turning. SPLAT!! A lot of very good equipment in very small space saving pieces :-(

If for no other reason than I can speak to the owner directly I will also be going the HoverFly route. Less features but I detect less "noise in the bushes" about problems having been encountered.

No I do not believe that the Schulze ESC's can accept the MK I2C signal. I trust heavy gauge wire directly wired to high quality ESC's.

Dual parachutes and an airbag on the next model. (floats??)


Kim.
 

DKTek

DKTek

Member
Thanks for the input Kim. The Hoverfly Pro does have a carefree mode, or will soon. That's something useful along with the RTH feature.
 

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ichwillnix

Member
HI KIM,

i appreciate the opion of experienced users like you really pretty much. But try to be as objective as possible and dont rely on good reputation. I agree with KIM that Plettenberg makes high quality heli motors. But i do not agree that Plettenberg is now saintly for everytime. Especially in this Multikopter application there is some "room for improvement". I think if they (Plettenberg) are also willing to learn and hear on the advice from also other experienced users/customers they are able to build really "the best motor in universum" like you said. But currently they didn't!

Here are some measurements without any trimming, smoothing or else, to talk about facts.

Compared are the Orbit 15-20 with Props Graupner 14-8 and APC 13x4 and an "other motor".


a) Efficiency (gramm/Watt) vs. Thrust (gramm)

=> Fazit:
1) At thrust higher than 1200g, there is no difference between 14-8 and 13-4 Propeller!
2) There is room for improvement.... Other motors can do more here!


b) Input Power (Watt) vs Thrust (gramm)

=> Fazit:
1) 450W at 2200g is really the limit. At 4S this are 32Amps!!! The motors are glowing here! More than 90 degree core temperature!
2) Safe operating of this motors is far below 1500g Thrust in order to stay below 60degree core temperature


c) RPM vs Thrust

=> Fazit:
1) With 13x4 prop, the RPM goes close to 9000 rpm. Means this APC plastic props are not usable for 1500g thrust. Wooden Props are maybe much safer and better here (agree with you)
2) 7000 rpm at 2000g for the 14-8. Maybe the higher RPM is more stable in windy conditions.... Here the user must chose between efficency and stability....


I did not find anywhere in the web facts like this. I share now my knowledge to make some things hopefully more clear and more objective...

Andreas
 
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K

kdoherty

Member
Andreas,

Motors are dumb. The have no idea what you intend to do with them. Companies that make motors are less dumb but still have no idea what you are going to do with them. People who use motors are almost smart by comparison. Only "we" have the total knowledge of what we intend to do with a particular motor. Plettenberg makes motors, lots of them. They make motors for all types of users and for all types of uses. They will even make a "custom" motor for you if you ask nicely. They are not a company who makes "toy" motors. They are an industrial company that makes "professional" motors. Does this make them the "best motor in the world" ? Not necessarily. (I am not wedded to them)

For almost eight years I have used Plettenberg motors. I have never had an issue with magnets, bearings, wiring, vibration or expected performance. As It costs me a fair bit to compete I have come to depend upon my equipment more than anything else. If it does not work, or not deliver what I require then it gets replaced. Perhaps for a different task it would not be as suitable. I trust these components because they have never let me down. If you have faith in other components then go ahead and hang an expensive camera on them and let us know how it works. I am always looking for options. This is the crux of the issue. On set you may spend fifteen hours with five or six setups in five locations day after day far away from home. It just has to work. The client is quite often hanging over your shoulder trying to determine why he is paying your daily rate. In most cases I will never get a second chance to shoot most subjects. The starker reality is that I will just never get a second chance.

The graphs isolate different variables and make empirical comparisons. Do the motors that have better performance in some areas have three bearings?, are they hand wound?, are they dynamically balanced? If so then that is a valid place to start. Saintly no. Reliable yes. That is also a valid place to start - or hang your hat. Note that I would not have opted for a 15 series motor. Plettenberg did not "spec" this motor. It was selected by your vendor and purchased by you. This is not "magic". A 20-16 on 5S swinging a 13/6 three blade would (wood?) be my choice. But the question was what could be done if you already had the 15-20 motor. As I stated at he top of my earlier post this is strictly MY opinion. YMMV.

Kim.
 

I

ichwillnix

Member
kdoherty said:
The graphs isolate different variables and make empirical comparisons. Do the motors that have better performance in some areas have three bearings?, are they hand wound?, are they dynamically balanced? If so then that is a valid place to start. Saintly no. Reliable yes. That is also a valid place to start - or hang your hat. Note that I would not have opted for a 15 series motor. Plettenberg did not "spec" this motor. It was selected by your vendor and purchased by you. This is not "magic". A 20-16 on 5S swinging a 13/6 three blade would (wood?) be my choice. But the question was what could be done if you already had the 15-20 motor. As I stated at he top of my earlier post this is strictly MY opinion. YMMV.
Click to expand...

As you introduced yourself pretty detailed i think i have to clarify now "who i am", too ;-)

I am not a professional filmer or fotographer like you. I am only an electronic engineer developing power electronics for all kind of motors since years. We are developing and building our own BLDC motors (not for commercial, only our internal use) for F3A since years. We have lots of experience and knowledge how to dimension and design a good and a bad motor.

I did not buy any motor from Plettenberg!
We have meanwhile thousands of satisfied customers driving there Multicopter with all kind of motors together with the Herkules Powerboards. Have not heared and complains about our electronic since:
Plettenberg started the delivery of the Orbit 15-20. Meanwhile i got lots of Orbit Motors send for free by customers who did not find any ESC which is able to drive these motors.

We where wondering, what is the reason for this?
A good BL-Motor Design is a balance of Stator volume, winding impedance, magnetic force, the correct choice of the ratio poles to slots, core material, and lots of things more.
We analyzed the Orbit motors in detail. We did FEM simulations of magnetic and electricall behaviour like we do for each of our F3A motor.

Our finding was in fact:

1) the motors are very good mechanical quality, good bearings (triple, if really needed here or not is questionable), good balancing, low vibration and and an.
2) very good, handmade low impedant motor windings

BUT:
3) not optimal number of poles/slots. 10-poles are for higher RPM better!
4) Magnetic strenght not fitting (too low) to the stator volume and the low resistive winding.
5) The RPM/V are a bit too high. could be lower. But with 4s Lipo its ok. Not with 5s

And this is the crux here:
Due to the very good winding, the motor is able to draw lots of current during accelleration. This causes a high magnetic field in the stator, but at above a certain point of load, the magnetic core goes into saturation due to the weak magnets.
When coming to saturation, the problem is that the RPM/V "virtually" increases until a certain point. The motor feels like it has "more power" but efficiency gets lower and when this certain point is exceeded, the Motor goes to magnetic saturation and is like an electrical short circuit.
Now the Current rises even more and now anyone in the chain battery, ESC, Motor looses the game.
If the ESC does not measure and limit this current, it raises to hundrets of amperes.

The next thingn is the pretty high idle current you can measure quite easily. Already this is an indication that something is "not perfect" designed here.

-----
Nevertheless: We invested in the last year lots of free time, payed development time, investments for sample builds and and and in order to build an electronic which is capable these kind of motors.
We get no money from Plettenberg, we only want that the customers of them can use there investment again.
So in fact we are helping all Plettenberg customers. This is our wish!

I expect from all experts and also from Plettenberg, that they appreciate our effort. Currently there is almost no ESC capable of driving these motors safely. Hopefully the Herkules III can do!

We are testing like cracy and optimizing software and hardware step by step. Maybe the solution is not so far away any more....

Nice day!
Andreas
 
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redridinghood

redridinghood

Member
I would like to point out that the motors sold under http://aerialrobot.de/ were a custom wound and not a plain 15-20. At least that's what the guy selling them was telling everyone.

Maybe the Herkules III board and software is not the best combination for this motor.

Some tests done by Holco on rcgroups with the esc32.

http://www.rcgroups.com/forums/showpost.php?p=22291714&postcount=163

http://www.rcgroups.com/forums/showpost.php?p=22322982&postcount=178

http://www.rcgroups.com/forums/showpost.php?p=22390438&postcount=199
 

I

ichwillnix

Member
Thanks for the info.
Even better if there are now more ESCs coming up to handle this motor.

Btw: Orbit15-20 IS the motor from Aerial robot. I got it directly from plettenberg.

Unfortunately your link does not contain any pictures, only text.

From the text only i can see that the behaviour is exactly the same like we measured.
The orbit looses efficency at higher load... The "cheap chinese" is even a bit better than the orbit.

Reason? => Magnets in china are cheaper than in europe ;-) ??


Quote:
###################################################
g/Watt comparison, on the left is the Dualsky and on the right is the Orbit
7,3g/Watt------------------------------------------------------7,8g/Watt
6,9g/Watt------------------------------------------------------7,3g/Watt
6,5g/Watt------------------------------------------------------6,5g/Watt
6,2g/Watt------------------------------------------------------6g/Watt
4,7g/Watt------------------------------------------------------4g/Watt <!-- / message -->
###################################################

Thanks!
 
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I

ichwillnix

Member
redridinghood said:
I would like to point out that the motors sold under http://aerialrobot.de/ were a custom wound and not a plain 15-20. At least that's what the guy selling them was telling everyone.

Some tests done by Holco on rcgroups with the esc32.

http://www.rcgroups.com/forums/showpost.php?p=22291714&postcount=163

http://www.rcgroups.com/forums/showpost.php?p=22322982&postcount=178

http://www.rcgroups.com/forums/showpost.php?p=22390438&postcount=199
Click to expand...

Hey man!

Do you mean this:
- one ESC in full cooling storm of the propeller?
- On the diagrams i see only 45A x 3.8V x 5 = 855W, not 1038W for only 5 seconds!
- max thrust 3.5kg at 855W = 4 g/W

=> 5 seconds are nothing!

Did you ever see an octocopter fly with this motors at 5s with more than 13kg safely longer than 10 seconds?
If yes, please sho us the video where this system flys longer than 5 seconds!

=> Herkules III lifted already 7.5kg with 4 x Orbit 15-20 at 4S
http://vimeo.com/44119804
=> The boards are mounted in a closed frame without ANY active Cooling!

=> Herkules III lifted alread 13kg with 8 x Orbit 15-20 at 6S
http://vimeo.com/49729696
=> Max temp on ESC was 72°C!

Please show me which ESC has the same performance and i am convinced.

Regards,
Andreas
 
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