slipkid

My Feedback: (4)

Hi All,
I have equipped a 3D hobby shop Osiris as reccomended ,Hacker A50-14s, 100 Amp CC esc and reccomended digital servos. I fly her with Nano-tech 1 5S 5000 pack ( have 4 of them) and have now logged about 1 dozen flights with an APC 16-10E prop. I have examined the CC output in my graph view and I am noticing that the current draw on the uplines goes to 110A max, and then after about 4 minutes, I can draw about 100Amps on an upline ( Upline to a simple stall turn - lasting 3-5 seconds) -While I love how the plane files, I am a little concerned with current draw ( even though 110Amp uplines are just a few seconds and only if I go full throttle on upline) so I have tried a 16X8E APC - it drops max current draw about 10 Amps at the extremes, but it is not the best prop for forward speed. I as wondering the following

1) Anyone else with this setup? - what are you seeing?
2) While not lasting long, I am nervous about my 110Amp draw on full throttle - I use fixed endpoints - wonder if it makes sense to drop top endpoint - thoughts?
3) Anyone try other props with this setup, or have reccomendations? - While the 16X8E is OK, I like more forward speed in a pattern ship , particularily in the non stop Michigan wind

Any help or suggestions would be welcomed and think you in advance!

Joe F

ytell

From what I hear from F3A-Unlimited, this setup should give you enough power for the Osiris. I would recommend to check if you really need the full throttle on the up-line.
Try to open the throttle just to keep a constant speed without accelerating.
Throttle management in EP is a major issue compared to IC planes.


Yoav

viva_peru

Hello Joe,

Or, try a smaller prop. You can always try a 15x10 and see how you like it. It will probably give you a little more speed and a little less thrust, but your plane is somewhat overpowered at 1900 watts (if I remember correctly).

Flying tomorrow?

Teo

slipkid

My Feedback: (4)

Hey Teo
I do hope to fly tomorrow - I am going to bring out a 16X8 and I like your idea of a 15X10- I think I'll pick one up if I can today

2Sunny

Hey Joe it's Joe


Seriously though, I was just wondering if there couldn't possibly be something else going on. Graphing error, connection trouble, or something totally different 'cuz my first Pattern Ship was an Angel powered with a Hacker A50-12S which has a kv of 500 and I ran it on 5s 5000 with a 16x12 prop and never broke 100 amps even with 100% throttle (although I limited the throttle to 85% for competition) so I'm really surprised to see a lower kv motor on 5s breaking 100 amps. Honestly I don't think that is right and would be looking seriously at finding out what's wrong, but then again I'm probably missing something obvious Anyways, I hope you'll keep us posted and let us know how you work it out.


Joe

2Sunny

Oh and just found a graph of the A50-12S on a 16x10 . . . never broke 80 amps . . . so like I said just wondering []

viva_peru

Hi,

I know that Joe is using the nano tech batteries which allegedly hold their voltage quite well. I have also heard of motors being wound incorrectly so that could be a possibility as well. But you are right, my angel flies on a 515kv motor using a 15x10 prop and it pulls 60+ amps. A 16x10 jumping to a 100 amps seems a bit much.

Teo

slipkid

My Feedback: (4)

Hi Joe and Teo
I am hoping to take some more readings tommorrow - I have posted some images - The first 4-5 peaks are somewhat extended uplines with a stall turn if I remember correctly
I changed my CC now to autothrottle and I am going to try a few different props - notice on the upline peaks, the fist runs peak at > 110 amps - I also uploaded a shot showing the last 4 recorded runs

I obviously have no way to determine if the CC esc valuse are accurate, but I have no reason to doubt them either - I wonder if my esc settings are not optimized

2Sunny

Something doesn't seem right with those graphs, but clearly the esc is seeing unusual spikes. My first guess is as you suggested the esc settings. In particular I would ask: have you set manual endpoints? Then I would look at timing/PWM settings. You are definitely experiencing something out of the "norm", and worthy of investigation. I'm truly interested in knowing the answer myself as I am certain we can all learn from whatever is going on in your setup or data!


Joe

slipkid

My Feedback: (4)

Hi Joe
I am going to try some more flights tomorrow with autoset on the throttle - which is the other possibility with the CC esc - I do not remember going through any setup with the speed control when I set it to end points -THe autothrottle requires I go to full throttle at least for 1-2 seconds before take off so it can memorize end points. I am alos going to use an old astro watt meter I have to verify readings and will also run my 16X10 again

I could not find much guidaence on setting up all of the other parameters on the speed control - I am shooting in the dark here

slipkid

My Feedback: (4)

Hi all
Well, I did som emore experimenting today and used another way to measure current to verify if my CC was reproting correctly

First off, I verified I was indeed ruinning a Hacer A50-12s, it reports a Kv of 498

I left the 16X10 prop on and ran it aginast an older Astro Watt meter. Teo was at the field and pointed out my leads were rather long, so taking that into account, here is what the wattmeter showed

at near full throttle
92.4Maps
18.2 Volts
1690 Watts

So, This is consistent with what my CC is saying

Teo suggested perhaspa bad bering and we both checked and did not feel anything on hand rotating the prop, and I also measured motor temp after each run with a IR thermometer - IR thermometer reported motor temps right at 101-104 degress for each run as soon as I could taxi it to me I put the thermo on it. Battery temps also were in the 95-98 degree range ( slightly warm to touch)


Teo also noticed and pointed out that my Nan-tech 5S packs never dropped voltage below 18, as my graphs below show. I was unaware this is quite good for most 5S packs
I ran 3 tests today, one with the 16X10, one with a 15X10, and one with a 16X8 ( fooling around with the watt meter took rest of CC memory, so 4th run not fully logged.

On flight 1, I flew at near half throttle and it flew great, - in the images, the black curve is throttle input - you can see it near 1.5 uS most of the flight - I had one peak slightly over 100amps, rest were in 90's
On flight two - you can notice I used a higher average throttle (as expected) with the 15X10 prop and I did not like the flight characteristics
FLight 3 was close to flight performance of the 16X10, and was the 16X8 prop. The field had become windy at this point and to me, the 16X10 was a better prop for these conditions, but I was satisfied with the 16X8 - the graph shows it drew ~ 10AMps less

I tried to fly a repeated series of stall turns and some loops, but I certainly cannot gaurentee all flights we identical - I was looking for peak values here

In all flights, I did my berst to never use full throttle, and after working the 16X10 on half throttle, I think this is the way I am going to go

I really do not know what to do or check next, I think my data is correct from my speed control - I am not seeing a hot motor or hot pack either, so apparently, I am not overworking those two components. I cant get a good shot at the speed control though to measure its temperature

Jetdesign

My Feedback: (8)

I saw an Osiris fly yesterday with recommended setup and 15x10; flew nicely.

One question you asked was about using your end points to limit current to the motor. This is not a recommended fix; the ESC sends pulses to your motor, more pulses for more throttle, but all pulses are at FULL CURRENT. The meters read an AVERAGE current to the motor. If you use a huge prop and only fly at 1/4 throttle, you will be sending pulses of 200A or whatever, just for short periods of time with time off in between. This is not good for the motor.

Just a couple of cents worth of info, what I've learned over the past year.

2Sunny

Sounds like we have a Mystery Solved! I agree: prop down to a 15 x 10 and all will be good with the world again

Now I gotta go get me some of those Nano packs . . . they sound awesome!


Joe