I’ve build a Holybro X500 V2 and installed motors that were too underpowered.
I’ve ordered new motors that increase the thrust-weight ratio almost 3 times - using the same props.
I’m wondering if there are any parameters to consider for the first flight with these motors.
Of course I’ll have to do auto-tune again - but I expect FFT should stay about the same.
I’d appreciate any suggestions.
I’m curious about the new motors with 3 times the thrust to weight ratio - do you mean they are 3 times the kv rating (essentially RPM) ? or lower kv and bigger dimensions, able to spin a bigger prop?
The original motors were probably 2216 KV920 with 10 inch props - although sort of low kv they are not big motors.
But anyway - if you keep the same props you might not change anything - try it and see. If there’s good stability check the HNOTCH data and just run Autotune again.
If you change props then just lower the ATC_ACCEL values based on prop size using the Initial Parameters, then check the HNOTCH data and run Autotune.
I’m also wondering how that’s achieved.
Probably more effort has been put into squeezing more/better performance out of these essentially generic 450-500 size frames than anything else and there is only so much you can do. I put longer arms, 380kv motors with 14” props (I think it was years ago) and it was really lipstick on a pig. Flight time was good.
Yes - 3 times is an overstatement - 2.3 times is closer.
Here’s the before eCalc - what I have now:
And here’s what eCalc says with the new motors:
Thrust to weight goes from 1.6 to 3.8. This new motor can swing 12 or 13 inch props and do even better - but I don’t really want to make longer arms right now.
I learned of the SunnySky company about a year ago - my friends at iVue Robotics use their props. They have a much wider selection of motors and props in this class than most other manufacturers. And they’re here in the USA - I ordered the motors today - they’ll be here on Wednesday. And I could call them up and ask them questions. (I wanted to know how long the leads were.)
Note: I’m using T-Motor MS1101 props.
Ah I see. You were starting from the wrong motors for 11" props to begin with. At that weight anyway. 70% hover throttle! You need to add 88g more to the model weight but close enough.
I highly recommend the Master Airscrew MR series props if you have to get new ones. Also buy their prop adapter rings at the same time.
Thanks Shawn -
I have used some Master Airscrew props - both 2 and 3 blade - on my AirGear 400 motors - the ones with the spin on prop adapters.
I found that the standard 2-blade T-Motor props actually work better. That surprised me. I haven’t tried any of the Master Airscrew MR series props. But by using the adapter - I like knowing I have those as an option.
I think Holybro assumes the use of the AirGear 400 series motors on the X500 V2 - same as what comes with the Hexsoon EDU-450 and the Holybro X500 V2 development kit. These are more powerful (and heavier) than the 2806-650 motors I started with. And they are a gram or two lighter than the SunnySky V4006.
I didn’t use the AirGear motors because I didn’t want to be limited to the spin-on props - as there aren’t really any choices in prop length.
Had I started with the AirGear 400 motors, I wouldn’t have gotten such a large increase in thrust-weight ratio by using the SunnySky V4006 motors. But the SunnySky motors 4006 motors give me much more options on prop length if I decide to lengthen the arms. And with the 11x4.2 props, I can carry a 400 gram payload easily - for about 20 minutes. Enough to carry a Sony A5100 or A600 camera. And if I extend the arms, I can use a 12" prop - even a 13" prop if the pitch is low enough. (using the lower KV version, I can even swing 17" props)
The whole exercise has just been an excuse to try another frame of this class. The X500 uses 2mm thick top and bottom plates - and is much stiffer than the EDU-450 - and uses standard tube arms. And I was happy to have a reason to dig into eCalc a bit - something I should have done a long time ago.
My benchmark is the performance of the Phantom IV-V2 RTK. If I weren’t using the fairly heavy HereLink Air Unit - it would be easier. But to have the video feed, I think it’s probably the best and lightest option available.
All in all - it’s just education before I start building larger and more expensive copters.
I really appreciate your input. Thank you!
