1100mm hex build. Hexacrafter, T-Motor, A2. Oh my.

[Pumpkinguy]

Received my bullets yesterday so I was able to finish wiring. I had a bit of a problem throttle calibrating. A bit of a frustrating few hours but we got it sorted out.
Here is a pic of the esc's mounted on the bottom. View attachment 24939

Test flight went beautifully. After having the kde motors it became pretty clear that these don't react as fast. This was something I already knew but the tmotors just seem to run smoother. I'm sure for something like a 250 racer the kde technology and how quick they are to respond would be a huge edge but for a large ap/av vehicle these (u7's) just seem to have a better balance.
I will load test this week and post a video, take some temperature readings on the esc's

 

[econfly]

Nice!

 

[Pumpkinguy]

3 test flights in. I will go on record to say the tmotors are probably not as efficient as the kde's I had. I don't know how much as I didn't do a comparative test. I do love how they fly though.
I may need help with my gps gains. They are at 150 now. A stop from full speed is rather abrupt. Do I go higher on the gains or lower?

 

[SleepyC]

Are you using A2 or WKM? If so I was sent this guide a while back and it helped a lot:

"Basic controls how the craft reacts to external influences, wind, changes in attitude, altitude etc. ATTI gains controls how the craft reacts to stick inputs. Think of it as expo. The higher the number, the faster it reacts to the sticks, lower is less responsive. DJI test pilots like high ATTI gains but they are in their 20's. You do what feels right for you. For me 90+/- feels good with 30% expo. But that said, I fly the P2 and P2V at default settings. If you are getting too abrupt reaction to flight, then you might want to lower the basic gains. If it seems sluggish, you may want to raise them. DJI suggests raising the gains by 10% and test fly. Continue until it oscillates, then lower by 10% I have raised my Basic gains to over 200 when flying in wind. This is where the BTU and the Assistant App come into play or you can use a knob or slider on your Tx to adjust while in flight. It is up to you."

 

[Pumpkinguy]

A2. So the gains only effect reaction to stick input? Not how the craft reacts when letting go of the sticks? That's how I'm understanding this anyway.

 

[Hexacrafter]

Well it is actually BOTH as the setting does both in a way!!!
With ATT gains, I like to think about it as how quickly the aircraft reacts to right itself.... in reaction to stick commands...see below....
This has been one of those issues of debate for YEARS.....For those of us that came from single rotor helis, it is the same as the old gyro settings!!!......
Here is the DJI explanation:
1) Basic Gain
Pitch and Roll: To the gains of Pitch and Roll, if you release the Pitch or Roll stick after command stick, multi-rotor should be back to hovering state. If the reaction of multi-rotor in this procedure is too soft (large delay), please increase the basic gain slowly (10%-15% each time) until vibration emerges after you release the stick. Then decrease the gain a little until vibration just disappears. Now the gain is perfect, but the reaction of the attitude change is slow. You can follow the way introduced at the end of this section to tune the attitude gains.
Yaw:The way of tuning the Yaw gain is the same as the way of adjusting the Tail Gyro. If you want fast stick reaction speed, increase the gain, otherwise decrease the gain. However, the spin of multi-rotor is produced by the counter torque force, and the magnitude of which is limited. Therefore, large gain will not produce tail vibration like helicopter, but severe reaction at the start or stop of motors, which will affect the stabilization of the other directions.
Vertical: You use two methods to judge if the Vertical gain is good enough: 1) The multi-rotor can lock the altitude when the throttle stick is at center position; 2) The change of altitude is small during the flight along a route. You can increase the gain slowly (10% each time) until the vibration emerges along the vertical direction or the reaction of throttle stick is too sensitive, then decrease 20% of the gain. Now it is a suitable Vertical gain.
2) Attitude Gain
Attitude gains determine the reaction speed of attitude from command stick, the bigger the value the quicker the reaction. Increase it for sharper and quicker leveling action after command stick released. The control feeling will be stiffness and rigid if the value is too high; and sluggish leveling action and slow braking if too small.

 

[Pumpkinguy]

Thanks so much Andrew. I've got them set up on a knob and will play with them.
When in attitude mode I love how she just coasts when I let go of the sticks. It's a nice smooth transition and probably the reason many professionals fly in that mode. In gps she slams on the brakes like a sob. So much in fact that she aggressively tilts in the opposite direction. This after going full speed then letting go of the sticks.
My gains are currently set at 150.

 

[Hexacrafter]

Well... If it is smoothly skidding to a stop in ATT then I would say the ATT gains sound good.
Basic (GPS) gains with DJI products are a completely different story...
GPS mode on DJI product is fairly aggressive in that mid level gains still cause the aircraft to "fight" to hold position....
As you reduce Basic Roll & Pitch gains, you will see that aircraft drift further from the original "hold" position and then see it start to fight to hold that position....
With high gains it will hold position very tightly, but be nervous and obviously fighting to hold the X&Y axis positions....
The "happy" place is user defined, but I like to set the Basic gains to allow about a 5'-0" max circle and this usually reduces the nervousness & fight a bit so it just drifts and then leans into a breeze.
Yes, nearly all of the pros I know fly money shots in ATT mode... much smoother and graceful.
GPS "softness" is where the SuperX shines.... The GPS mode with SuperX is much less aggressive and "less nervous" when trying to hold the GPS position... but A2 is much better than WKM as well....
I would leave the GPS Roll & Pitch on a knob or switch (with endpoint set for a low & high gain) to adjust on the fly between Tight & Loose settings dependent on wind conditions. I you fly 1 man and need to use GPS to allow you to focus on the camera, this allows you to use GPS lock and loosen it to help to smoothen out the aircraft as needed.
I hope this helps.

 

[Pumpkinguy]

Don't ask me why or how but my tmotors just beat my kde's in a no load hover test by almost 10%
8.5kg AUW. 2 x 6s12000 with 17" tmotors props.

Kde did 20:40 and the tmotors 22:40 to the first level of battery warning.
Everything was the same. It was windy today but it was also windy when I tested the kde's.
I will note that both the tmotors and the esc's came down cool today as was not the case when I tested the kde's.

To be honest, these results surprised me. View attachment 24986

 

[Motopreserve]

You're getting close. Congratulations!

 

[Pumpkinguy]

I've researched gimbals since December. They were by far the hardest decision to make. I didn't want to blow the bank but at the same time I just wanted something that would perform without insane amounts of tweaking. So I picked up a Movi M5. This will lift 95% of the cameras I have to use and I have a local source to rent an M10 or M15 if I ever need it.
View attachment 25217 View attachment 25218 View attachment 25219 View attachment 25220 View attachment 25221

 

[SleepyC]

No one can fault this decision... I bet you laughed, then cried a bit when you first dd an autotune and it took 30 seconds.... MUAHAHAHA vs. MONTHS of tuning with Alexmos.

 

[Pumpkinguy]

When you are new in an industry you bust your ass to prove yourself to a new client knowing there probably won't be a second chance if you screw up. There are too many other things to worry about and I didn't want the gimbal to be one of them.

 

[SamaraMedia]

No one can fault this decision... I bet you laughed, then cried a bit when you first dd an autotune and it took 30 seconds.... MUAHAHAHA vs. MONTHS of tuning with Alexmos.

Or CP...

Finally got a new yaw motor mounted on my Quadframe DSLR gimbal and did a "mirror" test while walking around the house, looks good but I am getting a bit of vibration on the tilt axis and I haven't ventured into the tilt control from a rx yet but looks promising...Did take a while for the autotune to go through it's paces though. I realize it is a budget gimbal but hopeful that it will fulfill my needs for now on my Tarot X6.

Looking forward to some time to fine tune things though.

 

[Pumpkinguy]

Got a nice little package today from Andrew @Hexacrafter.

The newly redesigned vibration isolation system which eliminates the standard rail mount type is a thing of beauty. You can see it here in this picture with the movi quick release (male)
View attachment 25493 View attachment 25494
I also received some motor shims to really dial this thing in, as if it wasn't flying awesome already.
The steel shims and a level app on my smart phone made it super easy to get all motors within 1/10 degree maximum refrenced off the imu.

More exciting stuff to come.

 

[Motopreserve]

This is looking like a sick build. Can't wait to see footage!

 

[Vitaly]

Great UFO!)))
One question from UAV-"young blood": how you connect two parallel 12000 batteries to the common circuit - it must be incredable spark!! As a man with technical education, i think it's not safety for all devices: ESCs, IMU. As for me, i'm looking for any solution to prevent this damage. Any ideas?

 

[Pumpkinguy]

Great UFO!)))
One question from UAV-"young blood": how you connect two parallel 12000 batteries to the common circuit - it must be incredable spark!! As a man with technical education, i think it's not safety for all devices: ESCs, IMU. As for me, i'm looking for any solution to prevent this damage. Any ideas?

Anti spark connector but the highest I've seen is 150 amps rated. I am using castle 200 amp connectors and yes there is a spark. Trying to develop a work around for that.

 

[Mojave]

Great UFO!)))
One question from UAV-"young blood": how you connect two parallel 12000 batteries to the common circuit - it must be incredable spark!! As a man with technical education, i think it's not safety for all devices: ESCs, IMU. As for me, i'm looking for any solution to prevent this damage. Any ideas?

Take a look here: http://www.multirotorforums.com/threads/how-do-you-avoid-sparking-during-battery-connection.20644/ at post #8 by @Bartman - touch the positive poles first before you connect the negative poles. You may get a spark but it will not be nearly as destructive as the other way around. If you search the forum ("spark") you will more explanations and suggestions regarding electrifying subject.

Esprit Model has some anti-spark connectors - but they can be pricey. Again search the forum for other "anti-spark" ideas. http://www.espritmodel.com/search.aspx?find=spark

 

[Vitaly]

Well, i think the main problem to protect low-curent circuits (IMU feeding, radio reciever, OSD, FPV trasmitter) from common power surge, because the spark happens in two circumstances: already switched-on electric capacity and big capacitors in input circuits of device. We have the second case (common capacity of 6 or 8 capacitors of ESC). So, i withdraw the separate wire from the common power distribution plate, and with the handle switch i will power on all low-current consumers after sparkling connection of batteries toESCs.