patternflyer1

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Scratch these numbers.. Scroll down to see graphs..

Oh, here goes, I am an idiot!!
Therapy is really paying off.. lol

C

patternflyer1

My Feedback: (11)

As for pull.. How powerful did it feel?
A back of the leg test is in.
The 22x12 had good hard pull.. Much the same was the 20x15. The 20x13 didn't have as much pull by far. The 21x13 actually pulled two foamies off their wall mounts... And they were 6 ft up and 8 ft away from the plane.. lol

Am I going to stay with the 11T? Not sure really, maybe as a test to see what we can do to it... Probably get a 12T for my new yak though..

Chris

jbudd

My Feedback: (1)

Hey Chris,

Do you have a 20.5x14 to try? That was the prop that worked the best for me on my Abbra with the 6360-11T (actually the motor was labeled a 12T but the kv was clearly higher than my other 12T so we figured it was a mislabeled 11T).

From memory on the 11T (using Mike Greear's Watt's Up Meter) and FP5350's:
The 20.5x14 pulled ~64 Amps
The 22x12 pulled 80+ Amps (remember Saturday night at the Fresno Contest?)

On the 12T:
The 20.5x14 pulled ~60 Amps
The 22x12 pulled ~67 Amps

I did repeat these tests again using TP5300's and the current draw was on the order of 2-3 Amps less, regardless of the prop.

IIRC Jim Oddino's said that his 12T pulls just under 60 Amps with a 22x12 (with TP5300's).

The problem with comparing these numbers is we don't know the accuracy of the equipment we are taking the measurements with, so we really can't do anything more than perform relative comparision tests. Unless of course there is an easy way to calibrate an amp-meter? Jim?

patternflyer1

My Feedback: (11)

As I recall, you did the test at the fresno contest with my meter..
Obvioiusly everyone takes readings from different meters, so variables will always be there.. Motor manufacturers obviously have a different meter than any of us..
Are you running 5300's at all Jerry? Or are you running the 5350's? Or both still? Could be where Jim's number differ from yours..

I am going to email you some pics of the work done on your Abbra in a minute..

Chris

jbudd

My Feedback: (1)

You're right, we did use your meter at Fresno. It was Mike's that I used when I got home and continued trying different props.

I use the 5300's every once in a while, but they have to be pretty warm to put out decent power (I have to remind myself that they're going on 3 years old). Most of the time I use the FP5350's, especially in the winter as they'll still deliver the power in the cooler outside temps.

FYI - Here's the number of flights on my batteries:

TP5300's (#1, #2, & #3 were purchased in April & June 2005, #2 spent the winter (Aug 2005 - Mar 2006) in the desert with no apparent ill effect, and #4 was purchased new in June 2007).
#1) 133
#2) 66
#3) 93
#4) 4

FP5350's (#1 & #2 were purchased last Feb, #3 & #4 were purchased last June)
#1) 46
#2) 42
#3) 19
#4) 13

Here's my motor usage:

Hacker C50-14XL (#1 threw a magnet in Aug 2005 and was replaced under warranty by #2, #3 was thought to have a chronic gearbox problem and was replaced by #4 - interestingly it turned out to be a bad controller)
#1) 41
#2) 257
#3) 30
#4) 50

Hacker A60-24S 3 flights (then the motor shorted out, taking the controller with it, both replaced under warranty)

DualSky 6360-11T 59 flights (threw a magnet and ruptured the motor case, replaced by Mark at 2DogRC under warranty)
DualSky 6360-12T 25 flights (broken propeller shaft at drive pin hole location, still waiting for word on warranty eligibility from Jeff Clack@VampowerPro)

Abbra #1 has 381 flights on it
Abbra #2 has 89 flights on it

I have to give the manufacturers/imports of all of the motors and batteries credit - they've generally been very supportave, replacing pretty much everything I've had fail (and I have certainly had my share!).

patternflyer1

My Feedback: (11)

I hope Jim chimes in here and says "Jerry, why don't you have a meter?" lol
Did you end up buying the medusa.. I'm finally messing around with mine now on the computer.. It's interesting what it does.. Still have alot to figure out on it though..


So my half throttle with the 22x12 on my curve was about 40 amps.. I didn't check what it was when I flip the switch to my upline throttle setting.. Maybe tomorrow.. But I hope that if I keep it under about 60 amps things will be fine.. I can tune it to that as full throttle if necessary.. I would guess my upline setting is around there anyway..

C

serious power

Chris, now this is ,could be, a very interesting thread.
Are you using the same battery, recharged, for each test. the reason I ask is ;20x13 7250 rpm 20x15 8350 rpm ????. 22x12 5900rpm v 21x13w 7800rpm ????.
I would be concerned about that twang .
Also your friends experience , what a tale of disaster.
I tried to have this buzz squawk twang thing discussed on some of these threads and it did not develop.
We were on a path to a story like that with a Pletty,,/schulze set up when we saw references to connectors and commutation problems in the Schulze hand book.
We changed to 5.5's and all our problems were gone.
We think, (now this is speculative ), that when a DC connector failure is bad enough initially (1st squak) it damages the esc in some way resulting in ongoing twangs/squawks
which manifest in that list of physical effects; loose magnets(they are taking the field loads) broken shafts, front end failures and of course mount failures . These things, if
running smoothly, should be easy to tie down. Right now,touch wood, ours are running so smooth on 20x15's NYLON screws would keep them there (wont be proving this).

Look forward to more results and details of experiences.

Regards

Brian

can773

My Feedback: (1)

Chris,

I would try a new tach Its not physically possible unless you change the input voltage for a DC brushless motor to return these results. With a constant (or nearly constant) input voltage which we pretty much always have, the rpm regardless of load should not move much more than about 500.

Its pretty easy to disprove the numbers...

the 12T has a no-load kV of 210 rpm/V, so that is the maximum rpm it will achieve (it will drop with load because of eddy current losses, as I understand it...), so 8350 rpm/210 = 39.76V

Take 2600W/39.76 = 65.4A which doesn't match the load you saw (the watts and amps seem right)

Basically nothing adds up, in the last three tests.

The result for the 22x12 makes sense....

2800W and 78A is 35.9V, and you get 5900 rpm which works out to a loaded kV of
164 rpm/V. Which is in the ballpark of what I have seen over the years for the outrunners.

You can probably use 170 kV for mid 70A draws and almost always predict your rpm (within a few hundred) on this motor before you ever even run it. I would expect that you would spin around 6000 rpm (if your packs can hold 35V which they should) for all these props.

If you boys will be in Phoenix we can have a deeper discussion about it there

serious power

Chad, I was perhaps too polite when I queried the rpm data Chris posted, anyway you have addressed that properly.
We are running Pletty's with 20x15's with modified tips. 12mm / tip removed and some reshaping/profiling.
Getting 6800rpm with fully charged batt,, . Does that sound ok to you?.

To be honest we followed your lead when we decided to go the pletty/schulze route.

May I ask what you think of all this buzz, squawk, twang and chatter that is reported here ?.

Regards

Brian Carolan

can773

My Feedback: (1)

I hope I was not impolite! I was not trying to be, just want to show how to challenge your own results so to speak.

6800, wow, I have never seen that high on my motors. I am usually in the 6400-6500 rpm range on a 20x15, and down to 6300 on a 21x13W, and down to 6100 on a 22x12 (which I dont use but have tested).

I hope that you are happy with the system, it works really well. I dont want to turn this into a comparison thread though.

As to the buzzing, I have always used 5.5mm bullets since they were out and Deans before that but on the old 30-10 motor so a lot less power. I had startup problems where the motor would sort of have a hard time figuring out which way to go and make a grinding sound, but it was very brief and only when starting, once running there were no other noises. Schulze fixed this on the V20 controllers (the problem was on V15). Schulze feels it was related to the radio signal, as they were never able to reproduce it in their shop (they use signal injection to the controller when testing rather than an actual rx).

The only other time I have heard bad things while flying was a time when the small 3.5 mm connectors between the motor and controller made a bad contact, and made a horrible screech in flight. Now I pay attention to the condition of those connectors and have never again had a problem.

Also with the Schulze there is over-current protection in the controllers (maybe there is on the other ones as well), and its quite easy on fresh packs if you throttle up very quickly to set it off, an it sounds like a terrible screeching noise. The new batteries and high power motors make it even worse, and you need to be careful about how fast you ramp up the throttle. I have set it off quite a few times on takeoff Its very loud, at the Worlds Dave set his off during the noise test and the dB meter went well over 100 dB's! Maybe that is what you are hearing.

So I think you are on the right track with suspecting bad connectors....I have had my rear chewed by Schulze and Pletty (Diana and Uwe gave me dirty looks when they saw my bullets in Argentina!) for the condition that I run my bullets in.....so there must be something to it

I think we also have to remember that the controllers have no sensors, and are switching quite fast. Pletty and Schulze test with each other so its a given that they work together, however when mixing and matching various motors and controllers there is no guarantee that the controller will work well with the motor and actually be able to keep phase with it. I think having timing and switch frequency properly set is important and needs to be optimized for a particular combination. So unless the motor or esc manufacturer has already done some of this legwork, its really up to the end user to develop the correct operational parameters. Not an easy task, and will probably require updates to the controller.

patternflyer1

My Feedback: (11)

Chad, this motor is an 11T (235 rpm/v).. Not a 12 T.. Which makes the last 3 sets closer to their numbers and actually the 22x12 set off.. I saw this last night as I sat at the computer after testing.. I knew I would get some fun responses..

I will retry the tests today as last night it was done it the garage with a backlight but the main lighting was fluorescent.. I'm pretty sure the meter is good.. But it could be bad, but I doubt it.. I'm sure you've seen it, but it's the power analyzer pro listed here
http://www.medusaproducts.com/Power-.../pa-60100R.htm

I am trying to figure out how to save the runup's to graphs.. I will work on that today.. The program that comes with it is confusing to a guy like me.. [sm=spinnyeyes.gif]

Thanks for the comments...

Chris

patternflyer1

My Feedback: (11)

I didn't take it as impolite Chad.. I know you know your stuff.. I actually appreciate the info..

As for the twang.. Yeah, I'm concerned about it, as I've seen what it did to Budd's plane.. It very well could be the connectors.. I've had the issue before with the Axi's also, so it's possibly the cause.. Replaced the motors, and it would go away. Could it be that the new connectors on the new motor made good contact for a little while, and then lose it after 50 flights? Possibly.. I have a brand new (2 flights) Esc sitting here and a new 11T, so I will try at least the esc today..

So much to do, so little time..

Thanks,

C

can773

My Feedback: (1)

Hi Chris

Even at 235 it doesn't make sense, as thats the no load (zero amps) kV so you would need to be testing without a prop (and in a vacuum) to get that number. The loaded kV is basically the efficiency which is down under 80% for most of the loads we run at, so 235*.75 = 176. So 76A/2600W gives 34.2V even at 235kV is only 8040 rpm so its still low....but if you use 176 kV (which is probably close to what is really going on)...you will be at 6020 which makes a lot more sense.....give or take a couple hundred.

The loaded kV of 164 from the 22x12 would give you 70% which is probably close considering the higher amps (your peak efficiency is between 25-60A according to the spec). As you run smaller props you will find that the loaded kV that you calculate from rpm and volts will go up because the amps are going down and your motor is getting more efficient.

Do the retest and see what you get, I bet it changes We develop magnetic bearings and DC brushless motors where I work....trust me when I say that your tach (or lightsource) is not showing you the right things! Unfortunately you can only do so much with these things, the laws of physics just wont change for us RC guys no matter how much we try lol

If it doesn't change....hang on to that motor because you are getting more power out of the prop then you are putting into the motor! Then tell me where I can buy one!!

serious power

No, not impolite, just made the point and quite well at that.
Re that 6800rpm, that with reduced/modified 20x15 and warm batt,, (removed 12mm per tip ) .
We reduced the prop to drop the load a little while maintaining pitch speed.
Performance with this prop is great, as slow going down as you set the brake to (using 35%), and going up its like a DZ220 ??!!!.
Since we modified the prop,, and installed the 5.5's we have not had a single buzz, that's 3 pilots 3 models.
We are using a thermistor (I think its negative co-efficient ) attached to the female esc to batt,, connector to prevent the connecting spark. This is only in the circuit for a brief moment 1/100 to 1/10 sec,,.
Does not affect esc volt reading. Now no spark at all ,connectors now perfect/spotless after 150 flights on each of 3 models.
Yes so far all roads, explanation wise, seem to point towards connectors/surge loads.
If you would like to try one of these thermistors its RS pt No;216-1438

Regards

Brian

serious power

Chris, you can not use a light based tacho,, with synthetic light need day light.
Frequency here is 50hz reads 3000 on tacho,,.

Regards

Brian

patternflyer1

My Feedback: (11)

It mentions you can backlight it with a light such as a flashlight in the paperwork somwhere.. Doesn't mean it's right, lol..

Graphs from todays test in a minute..

C

patternflyer1

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22x12 test in daylight this time..

patternflyer1

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21x13w test

patternflyer1

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20x15 test

patternflyer1

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20x13 test

patternflyer1

My Feedback: (11)

Ok, so obviously my first post was off as you all stated.. I will delete it and call myself an idiot[sm=tongue_smile.gif] for posting before I checked my own numbers.. Another lesson learned on RCU for me..
So, now it's your turn to fire back.. Call my meter, equipment garbage. Tell me my batteries and connectors are crap, that I have a one off motor... JUST KIDDING HERE LOL
Heck, send me your precious meters and I'll run the test for ya.. I'll do it standing on my head. With the lights on, off, flashlight, no flashlight. However you want it run.. Wait, I'll do one better, I'll bring my Abbra to your house and we'll run the tests there... disclaimer...Must be in North America.. JUST KIDDING AGAIN.. lol

I hope you got at least a laugh outta this.. As I did while typing it.. You know how these number posts can get.. Just trying to lighten the mood.. [sm=lol.gif]

Seriously now, be easy on me but let me know your comments..

I changed my esc btw.. The noise is still there... I'll have to order some huge connectors.. Chad where are you getting them?

Thanks,

Chris

can773

My Feedback: (1)

Chris

Probably easiest for you to get them directly from Steve Neu,

http://www.neumotors.com/20061222/Connectors.html

Those numbers look good

I have heard that an LCD monitor produces good light for testing with a tach when the sun is not around. I have never tried it though!

OhD

Chris, now you've got to do it all over again with a new 11T and a 12T. A 12T should turn more rpm with less current based on my results. To get a good match with the 11T I believe you need a lighter load that will let it rev up. All my data from last years tests is on my old laptop that went belly up, but I'll see if I can get the data off the hard drive. As I recall my 11T did better than yours so your original comment that yours had lost a step might be accurate.

Good work.

Jim O

patternflyer1

My Feedback: (11)

Thanks for the advice Jim.. I have a new 11T sitting here.. I will put it in tomorrow and run again..

As for the 12, well, if I can ever get my new Yak delivered without UPS tearing it up (twice now) I will order a 12 as I want to try that in it...

If I go to Phoenix, which I just might now, I'll bring the laptop and the meter and we can all run tests[X(]... It would be interesting, and probably the best meeting for testing so many different motors, esc and battery configurations..
I may put the Axi F3A motor back in and run the numbers.. lol
I never used this meter past an amp meter and a voltage meter to check my batteries.. It's actually kind of fun.. It has some really great testing features when you hook the esc up directly and have the computer run the motor..

Chris

serious power

Chris, my apologies, its light from an AC source that cant be used. DC light source is fine.
Those results are great.
The fellow that said the following about statistics was right; 'Statistics are like a bikini ,what they reveal is interesting, but what they cover up is vital.
The thing that I do not get is with the watts dropping so much (~5%) how are the RPM holding so well. I would have expected a similar drop in RPM.
Perhaps somebody can explain.

Regards

Brian