Quick number crunching on the Sunnysky 0705 15000kv thrust data, which I forgot to post

You can get it from Banggood

To be honest, nothing specific to tell about this motor other than it makes good impression out of the box and ran pretty smooth on the thrust stand. It gets pretty loud on high throttle. Keep in mind that Tom was very unhappy with those motors.

The motor stayed relatively cool on all 1s tests, got warm on 2s, but nothing alarming here. Probably the use of bearings allows it to run relatively cool all around.
The stator height is 0.5mm smaller then specified at about 4.5mm (thanks Unseen)

I have tested it with different props:
31mm quadblade and cut to biblade (eachine e010/e011 "whoop")
31mm triblade
40mm quadblade and cut to biblade
56mm generic and cut to 40mm

Last ones are from cg023, not sold anymore, generally they seem to be a bit more powerful and efficient than the ladybirds (compare here), unfortunately all my other "longer" sample props are drilled for the 1103 and don't fit the 07xx motors. Need to get some fresh sets.



Thrust curve examples:





Data taken with an RCBenchmark 1520 thrust stand

40mm quadblade and 56mm prop results:

  sunnysky-10StepsTest_2018-01-20_184402.xls (Size: 12 KB / Downloads: 165)

And some photos:









Sunnysky 0705 (blue base) and Happymodel 0706 (gray):





Size comparison with Happymodel SE0706 and Racerstar BR1103

Just noticed that the 2s test data here doesn't come from a fully charged lipo. Can't find the data sheet from an 8.4v one.

I will try to run the test again tomorrow and update the post.

Thanks for this data Konrad!

It matches up with my experience of using these motors on my Angry Oskie with 40mm quad bladed props.

Your thrust test shows 34.5g thrust, so real thrust at full throttle would be around 24g. That gives me a maximum thrust of 94g. As my all up weight on the Angry Oskie is some 48.5g, this would explain why it needs around 65% throttle just to hover and has poor flight performance.

It would be good to see the complete thrust curves from zero to full throttle. The curve is normally not linear, so I'll be getting less than half of the maximum thrust at 50% throttle. Seeing the whole curve would give me a better idea of whether these motors are going to give me enough thrust with 56mm props on Tom's Bat 110 frame.

It would also be great if you can post any tests with 65mm props on this motor.

Hi Unseen, I have added the thrust curves in 10 steps, each step is 2s long with 20 samples taken/averaged. The curve is not linear, can't be - especially taking the prop profile into account. Most thrust is produced near the hub at high RPM, low throttle produces almost no thrust.


Thrust curve images added to main post, excel file uploaded as an attachment.

P.S. error margin of this load cell is about +-1g, I guess this is the reason for waves appearing on the graph on low throttle.
P.S2 I don't have a 1mm shaft 65mm prop on hand to test. I'll see if I cen get a set locally next week.

Many thanks, that's really helpful!

You're right about the resolution of the thrust stand. It's not really designed for measuring such small amounts of thrust. There's an interesting article on fishpepper.de where Simon replaced the 5Kg load cell that comes with the stand with a 1Kg version so that he could get better resolution.

I hope Simon's OK. His last update on the site is from the 7th of December and from what I've seen, he's not been seen anywhere else either.

Good news is that we have a new post on the fishpepper blog
http://fishpepper.de/2018/01/22/a-pepper...d-of-giza/