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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Well, yes.  But more importantly MP is telling you the aircraft is under powered.  65% throttle just to hover coupled with an effective maximum throttle of 95% or so, leaves a scant 30% throttle for maintaining stability and maneuvering. 

If I were you I would either put the aircraft on a diet, or look into upgrading the power system (motors/props/battery)...

yup. :)

Yeah I'm currently running,mars power 2212 920kv with 1045 apc props, 30 amp escs 3s 5000mah 30c lipo.hj 450 Frame, apm 2.8 with gps and telemetry. She has a take off weight of 1285 grams. My guess is the motors don't give the thrust that they say. I may do a thrust test on the bench. Oh and without the lipo I'm 850ish.

Well, if the real wold motor data is even close to what is published here:Mars Power 2212-920Kv, the problem with the current power system is the props...

To hover at 50% throttle each motor must make at least 325.25 grams of thrust. According to the chart I linked to, those motors were not tested with 1045's..

With that frame the longest prop you can use is 12", and if you use 12" props the aircraft should be over powered...



Clifton Hipsher said:

Well, if the real wold motor data is even close to what is published here:Mars Power 2212-920Kv, the problem with the current power system is the props...

To hover at 50% throttle each motor must make at least 325.25 grams of thrust. According to the chart I linked to, those motors were not tested with 1045's..

With that frame the longest prop you can use is 12", and if you use 12" props the aircraft should be over powered...


The charts I found were for 9 x 45 and 10 x 45. I'll check that out. Thx.

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.

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

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 

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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 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.

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

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