[cato]

great looking build cato! this has me interested in this frame now 

i have never had tube type arms though. do you like those see any differences? they seem like they might be stronger and be more aerodynamic. im not sure i have any motors that i can spare though. time to ask the wife for more money! , LOL 

harold

Thanks Harold,

I really like the cinetank. I cannot tell you if there is a difference regarding the arms, means the cinetank is very agile and quick, but because of it's size, flying it smooth for video is much easier than with my Nighthawk. The only comparision I have, is a friend's TBS Discovery with Naza controller, and although it's a nice quad, it seems no match to the Cinetank. Basically I never saw any 450 doing things like Andreas does with his Cinetank.

The arms are certainly much more rigid compared to the TBS' plastic arms, but also much lighter, as tubes can be of thinner material than flat arms. They are rigid, but there are limits, one of my arms did not survive a 25m drop right onto that arm. Besides rigidity and aerodynamics a big advantage is, that they hide and protect the cables. The price is double the price of the TBS arms ($12 vs $6). As they will hold much longer the caculation will be more on favor of the cinetank.

As soon as I can fly it FPV (one part still in mail), I will do a few videos, but I won't do Acro so easily, my first tests will be control and speed, lift and camera. So far I can say, with Nylon props you don't do it good and may even get jello, with the carbon mix propellers which I am using the flying and  video are very nice (Aero-Naut CAM Carbon light) !

[cato]

OK,

the first stage of the build is now complete and tested. It's equipped with a fixed Mobius V3, which is connected as FPV camera. Here a photo of the current stage of the build.



Next step will be a Gimbal for the Mobius, together with a fixed FPV camera and video switch.
Today I did a flight test to see how the camera does. Weather was really bad, as it was dark and raining, but still good enough to see the camera quality.

Currently I still have problems with internal mag, so I am back to complementary mode, but this time chose the experimental complementary+mag+gps mode.

[cato]

Another flight test with the cinetank: It flies nice in attitude already, but in rate you see lots of jello at low throttle. The default setup makes heavy use of Thrust scaling, so for now I swtiched that off and configured easy tune. Looks like I have to fully retune the quad for optimal video results.

[cato]

I did some tuning meanwhile, but had no chance to test it in detail, because of weather, work and holiday

Yesterday I got the Cinetank Gopro Gimbal from Flying Cinema. It seems very well thought through: there is a standard setup, but you can put it together in different ways. I could even attach the fixed camera plate beneath the gimbal. That gives the option to add a second, fixed video camera beneath the Gimbal, but the gimbal is blocking it's view for sure, so the planned fixed video camera will need a different place. One option would be a FPV camera holder on the top frame.

My main problem was that I am fan of the Mobius cam, and don't intend to buy a Gopro soon, so I had to modify the Gimbal to use a Mobius. For that I attached the camera holder of the Hobbyking, which fits perfectly, as both gimbals have exactly the same dimensions. You can see the result in the photo below.

What's missing still is the gimbal controller. Currently I am looking for a decent controller which works well with a Revo and/or sparky2.

Attached two possible setups, with two positions of the camera:

[cato]

ok, due to winter the project got a bit stuck. But anyway, I had to decide for a second camera, so I bought a xiaomi Yi instead of a Gopro or Mobius. This way I can use the original gimbal with no modification. I also bought an 8bit Alexmos Gimbal controller.

It turned out that Hobbyking gimbal motors have a wide range of quality: one of the motors just couldn't manage to rotate the pitch axis. I noticed that the roll axis motor felt a lot "stronger", so after swapping the motors (which should be identical), the gimbal started to work nicely. Only issue with the 8bit Alexmos is that it doesn't handle angles around 90° well, so a 32 Bit Alexmos is on the shopping list for next month

Here a photo of my current setup. Currently FPV transmission and rx connection of the gimbal controller are still missing, and everything is still a bit messy.

[ArnhemAnt]

Looking good.

My MK1 is on hold. Turns out the weight of the 3-axis gimbal hanging off the top plate was too much. I've ordered some 163mm legs and David (from Flying Cinema) is currently designing a custom plate so that I can mount my gimbal from the top of the dirty section. This will enable me to mount the gimbal on a part of the frame that has a lot more support and is far less likely to move about.

[cato]

that sounds pretty complicated
I would like to see a photo of the final setup, sounds like it will be quite impressive.

My cinetank was on hold for quite a while, too, one for work, second because I did some testing with both quads, and third because for a while I did not know what to do about the gimbal problem (which turned out to be a motor problem). Now, next will be the rx channel setup: I need 12 channels, but as I need the flexi port for GPS, I need to use PWM or PPM on the Receiver Port. My receiver supports pwm or S-Bus, so I decided to use a S-Bus-to-ppm converter and connect the FC with PPM, while using PWM for the Gimbal, lost plane alarm a.s.o.

Next I need to get a new fixed position FPV camera, as the one I had spare doesn't work with the setup for some reason. Finding a nice place for it, where view is not blocked by the gimbal may also be a challenge.

But first will be a flight test with gimbal and the completely new PID tuning, as soon as weather allows. Looking forward to that, as especially the new tuning felt a lot nicer than the stock version.

[ArnhemAnt]

For my Rx, I went with the FrSKY TFRSP. It is a very impressive unit and allows me to run both PPM and PWM as the gimbal board needs PWM.

[cato]

thanks, @arnhemant. I will definitely take a look at that rx soon. Unfortunately for this month I already used up my toys bugdet, again ...

BTW, I see you are communicating a lot with the flying cinema guys. Seems they are very open for suggestions, isn't it?
Currently I am wondering how to mount a fixed FPV cam for FPV sessions using the flying cinema gimbal (with option to switch both video streams during flight). I am still waiting for a new FPV cam, so I mounted my Mobius on top,  but it's sight gets totally blocked by the gimbal on steep turns. I think mounting it beneath the front extension might be a good start, and I guess I'll end up with gear and FPV cam and vtx antenna mounted on the bottom part.

My focus today is tuning: as I said I got a reasonable basic tuning for the gimbal now. But after some intensive flying I thought that the stock PID tuning of cinetank may  not be so good, it felt pretty sluggish and strange. So I went for a fresh, manual tuning session, starting with a bench tuning (really scary experience), going to flying session, and finally now I am testing Easytune to get reasonable values. With Easytune I could eliminate most of the artifacts I had got in only one short session, while maintaining a very responsive cinetank in rate mode. It actually feels VERY close to my Nighthawk 250 at the moment, which means it is a bit scary for it's power and size

I think in the end I will come up with one pid bench for sharp flying and one using some expo to achieve smooth transitions in rate. I am amazed how aggressive you can tune the cinetank before it starts to misbehave ...

This will certainly need a while and a lot more testing and experience, but it's fun. Now a final session for today, and then some FTT job to do this afternoon

[cato]

I got one step further:

Now the cinetank has a fixed position FPV cam. This is a Runcam TVL 600 mini. The case could easily be mounted to the front of the top section and it's view gets only slightly blocked when the gimbal turns steep to the left. Almost perfect position. Also the size seems like everything was designed for this: the camera does not touch ground on even surface. I might try the cinetank FPV cam case to protect the camera, later, though.

The third cam, the Mobius is just for fun, and because the video switch has three inputs. It will be removed.

The gimbal can now be rotated using the potentiometers on the tx, the video input to the goggles can be switched. The gimbal is now nicely tuned, but the copter needs a fresh tuning, for which I went back to stock tuning and had already one Easytune session.

[hwh]

...The third cam, the Mobius is just for fun, and because the video switch has three inputs. It will be removed....

You could turn it around and have a rear view camera. 

[cato]

You could turn it around and have a rear view camera. 

That sounds like a great idea

[Tongala]

Hi it's been a while since you posted. Just wondering how you are enjoying your Cinetank?
The reason I ask is I have just pulled the trigger and ordered one with L arms. Will be a couple of weeks to get here in Australia.
Have been flying 250's but not really for me.
So any feedback/advice would be welcome.
Thanks

[cato]

Hi,

my cinetank is very fine. Camera and gimbal working quite well, and it also flies very nicely. Unfortunately my work commitments did not allow me to do any much flying recently. That's also the reason why I'm so quiet here. Hope you enjoy your cinetank as much as I do

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