Tethered H

[Photo]

Hi, anybody here with experience of flying "tethered" with a H? What brand can you recommend and is there a time limitation to stay in the air? I need to be up at least 24hrs - if possible.
Best from Sweden.

 

[AeroJ]

The H is not designed for tethered operation, so I'd be worrying about overheating and motor problems if it was ever running for those sorts of periods. The motors get hot after only 10 minutes in the air !!

 

[PatR]

In average climates over heating is not usually an issue for normal flight but for that duration you might consider painting the top and sides white or other light reflective color. Aside from that, if you can keep power to it the H should deliver.

 

[NorWiscPilot]

I realize this is an H480 discussion, but... I recall the H520 was up for a few days in a tethered test, back in the early days.

If that is an option, we do have testimonials to the application.

Jeff

 

[Dr Delta]

Under search function will pop up many threads, as I remember there were a few discussions around this theme.

 

[Photo]

In average climates over heating is not usually an issue for normal flight but for that duration you might consider paining the top and sides white or other light reflective color. Aside from that, if you can keep power to it the H should deliver.

ParR, don't you think the airflow from 6 props will cool down the body enough?

 

[AH-1G]

It will not over heat, you can tether the drone. Tethering systems around 5k.

 

[Photo]

It will not over heat, you can tether the drone. Tethering systems around 5k.

AH-1G

 

[PatR]

ParR, don't you think the airflow from 6 props will cool down the body enough?

The prop blast does little or nothing for cooling the body in hover. Props cause a cone shaped wind vortex opposing the direction of thrust. Radial expansion of that vortex to an extent necessary to surround the body does not occur until below the surface of the body. As a multirotor provides directional flight by altering the speed of different motors, causing the airframe to tilt due to division of thrust, very little of the prop blast ever flows over the body. Internal cooling of electrical components is derived from airflow generated through lateral flight motion forcing air through the cooling vents on the sides of the body.

The shell design of the H provides almost no means for heat to exit the top of the body, with is where component generated heat accumulated, and being black the body acts like a solar energy collector to assist the build up of heat inside the shell. In stationary use we want to minimize thermal collection and retention and use whatever means possible to offset heat generation. Thing of the black body as being similar to a convection oven. Leaving the internal components uncovered would not be adequate for cooling as they would be directly exposed to solar radiation and collect heat. Someone designing a multirotor intended for stationary use would benefit from the installation several small cooling fans similar to what’s used in the ST-16 to force cooling air through and around the electrical components.

The motors are not much of a problem as the props push cooling air through them. Not a lot as the center of a propeller does not generate much thrust and much of the area directly above the motor is concealed by the mounting hub, but what they do is enough for the motors. Just for giggles, there isn’t much frictional heat generated by the motors as the bearings at top and bottom help minimize that. Most of motor heat generation stems from a small electromagnetic arc that occurs between the stator and rotor as motor poles energize and de-energize to cause the motor to rotate.

I’ll prolly get hammered for stator and rotor word choice but I can live with that. A light reflective color would be a good move to reduce heat accumulation inside the body.

 

[Santa]

PatR, that's a good explanation of heat buildup dynamics in the H. I live in the desert & avoid flying during the summer heat out of fear that ambient temperatures will fry the electronics. Do you think that if I spray paint the body of my H gloss white or silver it would actually help?

 

[PatR]

It would but I would avoid silver as the color may employ tiny metal particles to make the color.

Johnno Hennessy recently posted the results of of heat soak tests in his GPS modification thread using different color materials. Not surprisingly, light colors were considerably less hot than dark colors after sitting in sunlight for a period of time. Lighter colors are usually more reflective while darker colors are more absorptive. It’s why solar water heating panels are made using black collectors. Living where you do, if you laid your bare arm on a car sitting in the hot summer sun, would you rather it be a white car or a black car?[emoji6]

 

[Santa]

Oh, yea... That's why all my cars & trucks are white (but my Sleigh is still RED) LOL

Thanks for the tip about silver though. Where can I find Johnno Hennessy's heat soak test results?

 

[PatR]

Tap on the little magnifying glass icon to bring up the search box, type in his name, John Hennessey, then review his recent posts. Or scroll way down the H forum page until you come across he repositioning the GPS thread.

 

[Santa]

Thanks PatR. Happy flying!