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Retrofit of a H920 / H920+

PatR

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I’m not sure I’d put the time and expense into the conversion if all it was going to carry was a small action camera.
 
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I’m not sure I’d put the time and expense into the conversion if all it was going to carry was a small action camera.
Obviously you think in terms of camera drones.

This platform will serve several purposes. In some applications it will carry a larger camera (Sony A7RII) with a better and lighter gimbal than the bulky thing from Yuneec, in other applications it will just carry some medical payload (1 kg) over BVLOS distances (in areas where hexa redundancy is required), where a little FPV cam (it is no action cam) is totally sufficient.
 
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Very Interesting design, great to see the platform useable with new electronics... we've had similar discussions in other threads, and you're the first to actually apply new electronics within the H920. Congrats, job well done!

I'm interested in your configuration. You indicated LTE, 900 (868) 2.4. Have you had the opportunity to test your flight control and range with both LTE, 900, 2.4. I can understand the LTE and 1 other but why 2 RF? Was the 900 part of the LTE electronics? What country or region are you operating, curious on the BVLOS. Your antennas pointing down looks like a good fit as well.

You changed the ESC & Main board, did that include motors... assuming not. You added temp sensor for what reason or more precisely does it initiate any action if temp zone exceeded? What was used for flight sensors: baro, optical, GPS, gyros, etc.... were they all within the donner Mainboard?

The craft appeared pretty stable in hover and wind. Did you use the H920 prior to modifications, if so do you feel it's improved with new electronics?

The A7Riii would be a great package on the platform, nice choice! Hadn't heard of the gimbal you mentioned, but sounds similar to other 3rd party. With the A7Riii or Med Pak, you're using the FPV camera at all times as the forward view. With the A7Riii, will both FPV & Gimbal camera be operational?

What batteries are you using, that was a issue with the original platform. Are you using the battery bay or changed to larger batteries in a different position?

Probably have a lot of time and experimenting with project, but looks like a nice idea & design.
 
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PatR

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Obviously you think in terms of camera drones.
Actually, I don’t but the use of a tiny camera did not visually demonstrate the load capability of the 920 airframe.

As DCJ mentioned, modifying the 920 in a similar manner has been discussed before and it’s good to see you have done so. The 920 is a heavy lifter and IMO would be better depicted demonstrating that. Having flown Pixhawk for a long time I know you gained a lot of flexibility in making that choice.
 
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Very Interesting design...
Lots of good questions!

Double radio was choosen because in Germany LTE uses several different frequencies. In rural environments, typically it uses 862 Mhz for upstream which is quite close to 868 MHz and it uses much higher transmission power, so 868 MHz gets disturbed by close-up antennas. Here 2.4 GHz provides good range (about 2 km with CE conform power).

In urban environments, it's the other way around: Here the LTE works on different frequencies (e.g. 1.9 GHz), so 868 MHz gets less disturbed. On the other hand 2.4 GHz is heavily disturbed by WiFi WLans.

So my solutions adresses both downsides. Currently BVLOS flights are not generally permitted in Germany but I am working on special permits.

Motors are currently not replaced but may be in the future to get a more efficient setup.

Temperatures are currently only reported on the ground station as part of the extended telemetry. No automatic action taken so far. It was important for me to see how the ESCs behave in the closed body (only getting some minor ventilation by the fans in the bottom).

As you may have seen, all flight sensors of the original design were removed and replaced with up-to-date components.

I did not use the H920 prior to modifications, so I can not compare. From other videos I have seen, my retrofit seems to be more stable and especially the landing is much more painless.

I did not finally decide on the FPV camera. May be, I will just switch between FPV and external HDMI, may be I add an option to mix them together (side-by-side or pic-in-pic or even overlayed (in case second cam is a thermal camera)).

Regarding the batteries I added a post in the replacement battery thread. It is a double battery pack that fits in the given bay.
 
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Lots of good questions!

Double radio was choosen because in Germany LTE uses several different frequencies. In rural environments, typically it uses 862 Mhz for upstream which is quite close to 868 MHz and it uses much higher transmission power, so 868 MHz gets disturbed by close-up antennas. Here 2.4 GHz provides good range (about 2 km with CE conform power).

In urban environments, it's the other way around: Here the LTE works on different frequencies (e.g. 1.9 GHz), so 868 MHz gets less disturbed. On the other hand 2.4 GHz is heavily disturbed by WiFi WLans.

So my solutions adresses both downsides. Currently BVLOS flights are not generally permitted in Germany but I am working on special permits.

Motors are currently not replaced but may be in the future to get a more efficient setup.

Temperatures are currently only reported on the ground station as part of the extended telemetry. No automatic action taken so far. It was important for me to see how the ESCs behave in the closed body (only getting some minor ventilation by the fans in the bottom).

As you may have seen, all flight sensors of the original design were removed and replaced with up-to-date components.

I did not use the H920 prior to modifications, so I can not compare. From other videos I have seen, my retrofit seems to be more stable and especially the landing is much more painless.

I did not finally decide on the FPV camera. May be, I will just switch between FPV and external HDMI, may be I add an option to mix them together (side-by-side or pic-in-pic or even overlayed (in case second cam is a thermal camera)).

Regarding the batteries I added a post in the replacement battery thread. It is a double battery pack that fits in the given bay.
The LTE coverage... any tests yet to estimate range?
As a special new type of service... one that is beginning to get attention in the USA as well, is the medical organ delivery by sUAV from airport / heli pad to hospital surgical unit via sUAV. Reducing the travel time greatly in large metro environments, and they've found that the donor organ is in much better condition compared to road travel.

Even listened to one speculative presentation of using a larger drone with "cooled internal chamber" being centrally controlled & autonomously sent to accident sites to recover deceased and flying them directly to surgical unit... was discussed for both military & civilian usage.

These new services are obtaining BVLOS waivers... granted these are sUAV crafts designed for this purpose but my point is more the LTE radio and the distance.
 
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LTE range is theoretically unlimited as long as the ground unit and the air unit can reach a cellular network transmitter tower. Anything between goes via internet, so that the pilot can sit in Norway and the drone can fly in New Zealand (ok, with some latency...). The other question is, if you have LTE (4G) coverage (3G is also ok for control and telemetry but with more latency) at all in the area where the drone operates.

Within a certain range, the drone can also be operated without cellular network due to the radio module redundancy. Also this range can be extended using relay modules that form a mesh network.

Regarding the organ transport, I think it will require drones with more payload.

We are currently developing a battery powered multi-rotor drone that can fly 10 kg for about one hour.
 
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LTE range is theoretically unlimited as long as the ground unit and the air unit can reach a cellular network transmitter tower. Anything between goes via internet, so that the pilot can sit in Norway and the drone can fly in New Zealand (ok, with some latency...). The other question is, if you have LTE (4G) coverage (3G is also ok for control and telemetry but with more latency) at all in the area where the drone operates.

Within a certain range, the drone can also be operated without cellular network due to the radio module redundancy. Also this range can be extended using relay modules that for a mesh network.

Regarding the organ transport, I think it will require drones with more payload.

We are currently developing a battery powered multi-rotor drone that can fly 10 kg for about one hour.
My error... wasn't suggesting organ transplant payload, just using that as an interesting example of BVLOS with medical.

The LTE may become an interesting tangent in RC development.
 

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