NEW U7 motor tmotor

Just as side note, (me being defensive ;-) )) That video was of the very first flight before any setup was done on the A2, and it was pretty windy so yes it might not be 100% setup in that clip.

 

Are you not concerned about the screeching and squealing sound coming from the motors? Have you investigated the cause?

 

I am waiting for the next batch to arrive, as this is just a video i received from a customer (who's has built two of these and they are going well from what he tells me) , i cannot make a true assessment of the noise from the video recorded on a phone,

Tiger motor has however done some more test on the U7 490 KV extract from recent email i received
(1 line removed to protect parties involved)

"

1. U7 KV490 + 15*5" props + T60A ESC @ 6S
   Max Amp: 38.9A in 100% throttle
   The temprature of the ESC is only 38 centigrade degree after running 5 mins in 100% throttle.
2. U7 KV490 + 18*6.1" props + T70A pro ESC @ 6S

Max Amp: 49.8A in 100% throttle The temprature of the ESC is only 51 centigrade degree after running 5 mins in 100% throttle.
(Line Removed)
The sound of the test is very noise. That is ture, as the resonance of the motor and wind cutted by props. As the design of the U7 is for better cooling, so the screaming is from the rotor. "

I have various machines using tiger motors (no UX series as yet),
i do however think that the high pitch noise is caused by the very rigid CF prop mounted directly to the motor combined with the new cooling method of the motor and super rigid Hollow CF frame thus amplifying every last bit of resonance that is produced. similar to the sound of the MN4014's I have on a mother machine that

when the new batch comes in i will double check them with and without props and with props of different materials to get to the bottom of this,

At the end of the day a Multirotos is a fine balance of various factors that more often than not i believe is a bit of a "black art" Some things just work better together than others. i guess that be the reason you don't find a 1300 VW ECU in a 3l V6 BMW.


As always just my 5c worth

BR
Theo

 

What options are there for a replacement for the U7 and what has been tried and tested......Results anyone??

Thanks.

Lance

 

I'm in the middle of stress testing U7 490KV:s with 17X6 qoars in my studio and so far they are looking good and reliable with Castle Edge escs. I don't think there's much alternatives in this size and price class.

 

As far as my reading of the thrust data, the KDE-Direct 4012 and 4014 motors provide the same thrust, and maybe even at a slightly lower current draw than the U7 motors, and at a significant cost savings, too.

 

I think KDE 4012 and 4014 should be compared to U5 or MN4014 rather than U7.

 

Not according to the specs they post. We'll know soon enough when some of our forum members start testing them soon.

 

Thanks for the replies.

I bought a set of KDE-Direct 4014 motors and have just bolted them on and have had a couple of brief test flights.

No more squeeling and they are definitely drawing less current with the same 18x7.6 carbon props and load. I'm getting 10 Amps less hovering with the same load and props than with the U7 420kv motor. Lighter and cheaper too which is a bonus!!

The motors come back only just warm and seem to be quite happy........First impressions they could very well be a winner!!

Regards,

Lance

 

Great feedback Lance! What's the AUW of your copter? What electronics? Where is your throttle stick position in hover while flying manually?

Please keep us posted on your flight testing

 

Awesome news. I hope to do some test flights on a new X8 later in the week(maybe weekend) with the same motors. I don't have anything to compare against though because the X8 is new.

Which power board do you have?
-m

 

Hi Howard, AUW is around 15kgs when testing. I'm using MK FC2.5 and Herc III Throttle stick is just over 1/2 and drawing 97 Amps on the MC-20 telemetry

 

15kg, music to my ears. Thanks!

 

Just did a quick calculations, U7 is compensated in weight 800g heavier. Surprisingly small difference in flight time regarding to this.

 

And here's U5 and KDE 4014

 

Thanks for the figures Kari, did you run the numbers with 2 blade 18 x 7.6 carbon props??

Regards,

Lance

 

Here's with 18 inch props, earliers were 17X6. Calculation is based on xoars as there are no CF props available. We need to notice in max power values that U7 is 40 revolutions faster per V so thurst in that case is a lot bigger in U7 and it hovers @15,5kg weight only 34% power with these props. As U7 are also quite bigger size than 4014 i would expect more torque and faster reaction times with bigger props which obviously affects to stability. But this is just a theory and in real life things might be different, hope i can test them both in air but i also have to notice that my experience from ecalc is that it's been freaking precise comparing with my builds in real life. As a conclusion both motors seems to works quite equally and i would not expect that dramatical difference in flight in these weights.

 

Ecalc is one thing and running a real test is another.
We have to do a bench test on both with different props to see what is realy going on.
THis is just a reference starting point off every build.
Tigers used with t prot or xoar makes a huge difference. TRUST, SOUND, HEAT are totaly different.

 

Lanzar,

I haven't assert anything else, like stated above this is just theoretical part and real life test might differ but my point is i wouldn't expect dramatical difference based on ecalc calculations. I just wanted to share these numbers as there seems to be a quite hype for KDEdirect motors at the moment and not much real life comparison or yet.

Regards,

Kari

 

We are always ongoing beta testers if you think about.