In mission planner it tells me that my throttle hover is 649 or 64.9%. So am I right in assuming I need to set my mid throttle at the same 649?
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In mission planner it tells me that my throttle hover is 649 or 64.9%. So am I right in assuming I need to set my mid throttle at the same 649?
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Replies
For this issue, you just need the basic data logging. This page tells you how to use dataflash logs and how to change the bit mask. http://ardupilot.org/copter/docs/common-downloading-and-analyzing-d...
You are going to want Current and Ctune as a minimum. If you have never used dataflash logging before, you might want to select the Clear Log Files button when your are done to erase your old logs.
The telemetry logs contain much of the data, but I did not see the throttle parameters listed there.
Doug
Jason Greening said:
PWM isn't the issue no less efficient power wise there (maybe a little laggy compared to sbus communication per say but fine none the less).... 27amps at your nom voltage of 11.1 is 299.7watts/4motors which is only 74.925 watts/motor... I don't recall your specific specs but again your only getting half or less of what the number say you should be.. If you look at cell T19 in my little xls it shows you should be close to 63.8 amps at WOT.. 10x4.5 props aint it.. Spredsheet and ecalc says their good... Maybe verify in MP and on your TX that your throttle is actually going to full throttle.. Maybe redo your TX calibration to the FC using MP... All the acronyms LMAO... heheh ok that was too far sry back on point...
Two thoughts I still have... One is are you sure about your take off weight???? It's odd that you have a major power supply and or performance problem yet the drone flys as it should.. I would assume this as you haven't complained of anything other than that... and Second is, are you double sure about the actual props you have (have you measured them, I have gotten the wrong prop in the right bag.....)? The only thing explaining the low draw would be a 9030 or something smaller with low pitch and you're just running out of kv... ok ok three thoughts, battery again...All 3 cells kicking still for sure... Past those things bud I dunno... log could certainly help...
9030 prop has a max amp draw of 29.1 on paper with a twr of 1.7 ish just saying... those numbers seem closer to what your getting.. only way i can make it make sense other than a weigh/mech failure somewhere...
Walt
Jason Greening said:
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Jason,
Can you post a data log of the copter while hovering. You did not say what FMU you are using, but if it is a Pixhawk or something similar, you should be able to download a data log that the community can look at. That is the best way to tell what is really going on.
Doug
I use ecalc very closely in conjunction with my measly little xls file.. I agree with Harry, in that, that source may be easier to understand and use.. I don't think its gonna tell you anything different though in regard to your issue with this seemingly under-powered girl..All things being correct with your posted specs she should be peppy... There is a problem with a spec or your not getting power where it needs to be for whatever reason... According to the numbers she should fly roughly 3 times over :)
Harry Courter said:
IMHO
I don't understand why you are not using a prop/ battery calculator like ecalc.ch
With very little learning curve you can have a reasonable estimate of everything you need to know.
The site has lots of data for specific battery, motors, esc, prop, or you can input your own info.
Easy and quick to switch out a motor spec or try a different prop and see how the entire setup changes.
I would not agree with the under-powered statements, the symptoms yes but the causes you guys are giving the poster here don't jive IMO, and I'd forget the 12 inch prop no motor in that size that I can think of has the cooling for the required amperage you would need to burn in order to spin them with enough force to get up to operating RPM's. Unless you can find 12x1's which would be pointless... See attached spreadsheet for explanation to make sense...
I've posted a spreadsheet here I found online, and have modified a lot, to work better with what I have found to be true in real world usage.... USE AT YOUR OWN RISK!!!!! It's only a template but it will help you understand how the props length, pitch, type, voltage, and a few other variables will effect your models required KV, nom KV, Wattage, and amperage per motor,total thrust, and flight envelope projections. This will give you an idea of how your model will perform on paper if you will.. There are still externals to accounts for so don't go flying it for 22 min because it says so in the hover field for flight time... Odds are it won't bc just after take off you have no longer only hovered and it will ding it time wise, those little dings add up fast especially above the tree line for you smaller fellers.. I find it more useful to work backwards with it to tune my rigs... IE what can i do to improve my flight envelope... If your looking for me more flight time or thrust ect... I have set it up according to your variables you listed in the post and...
Explanation of what I am seeing in the spreadsheet: Looks to me like with a twr of roughly 2.93 the model isn't under powered with the engines he has listed as long as their specs say they can handle a measly 177w of heat... thats about a core 2 dou overclocked for you computer guys out there...IE not much... So these things probly aren't powerhouses... If you want that look here for motors that are pretty darn strong in that size:http://www.ebay.com/itm/281978285215?_trksid=p2057872.m2749.l2649&a...
However, with the payload being only 1.285kg, after I have bashed your motor :(((( so sry, this model should be fine with the engines and props that it has. In fact it should be peppy even. My experience has shown anything close to or above a 3:1 twr will perform fine or fun rather... :) So congrats on the light build.. After all that I have no explanation for you as to why your mid/hover position is so high. With the before mentioned twr you should have a 34.1% throttle position at hover...
My Next Steps: I'd look for the leak... you either aren't getting full throttle to the engines (esc cal maybe), not supplying power accordingly at high draw (wiring issue, dist. board issue, batt issue mabye), or Your motors are simply flawed...
More info would be helpful can you read amperage consumption at hover/WOT and does it jive with the spreadsheet projections or close to it..
Are you sure about your specs especially the weight 100 grams changes things alot, so does a 9045 prop instead of 1045 lol so be sure all is correct with the information, ect...?
I think all this will point you in the right direction or make you ask lots more questions hahah....
Edit: I have your MAH wrong in the spreadsheet I uploaded shouldn't be 4000 doh....
Walt
diy Help.xlsx
Definitely under powered. I am running a flamewheel 450 with DJI 2312E 960kv motors and 9450 props, same battery and similar overall weight. It hovers at under just 50% throttle.
Doug
That chart still does not tell you what the thrust values are at 50% throttle, and because the physics are not linear, you cannot interpolate thrust at 50% based on thrust at 85% or 90%. In fact, full throttle thrust is pretty much meaningless for a multi rotor.
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