cooling in hot climates

[jackwrangham]

We've got a possible job coming up in Abu Dhabi, in September which is the one of the hottest times, i'm told we can expect up to 45/50 deg c! We're based in the UK, where it rarely gets above 25... especially this 'summer'.

So my question goes out to all you guys in hot climates, do you have any issues with ESC/Motor temps? - The machine we'll be running is an SJ8 with Axi 4120 Motors on 6S and Hobbywing 60A ESCs, runs great and cool over here... but im thinking we could run into issues in such high ambient temps. We'll use heat sinks - but does anyone have any good ideas/things they've done in the past? Was thinking maybe cooling fans... but 8 of those and wiring starts to get interesting.

Thanks

 

[Droider]

I would also be wondering about the batteries as well. When I was in `finland in-32 I kept them warm with gel packs.. I know you can get cooling ones but I guess you could keep them in a cool box. As for the Esc's and I have had great success with heat sinks on the Pentiums I use. The hottest I have flown in was +28 45/50 is a different ball game thats the max mine run at!

Dave

 

[jes1111]

All other things being equal, if you raise the ambient temperature by 25ºC then the running temperature of your ESCs/motors will also rise 25ºC. Unfortunately, those "other things" are never equal

I'd strongly recommend that you model your craft in eCalc. Get it to the point where eCalc's calculation are more or less agreeing with your current experiences. Then alter the ambient temperature, altitude and air pressure parameters to indicate your best estimates of the flight site and see what it says.

I'd say the ESCs are going to be more problematic than those motors. Newton's law of cooling says that the cooling rate will be proportional to the difference between the ESC temp and the air temp - so you can expect less efficient (i.e. slower) cooling. The danger will be in reaching a critical point where the heat input rate exceeds the possible heat loss rate. Fans are not going to do much IMO - you may need to move the ESCs out onto the arms so they're under the props (airflow being a critical element in maintaining maximum heat dispersion) and consider fitting oversize heat sinks to the ESCs (surface area being another critical element). You can also consider fitting aluminium heat sinks under the motors (with thermal paste between) to increase the effective dispersion capability of the motors.

Remember that the whole damn thing is basically black, so don't leave it sitting in the sun for one microsecond longer than necessary. Keeping it in an air conditioned car until the moment you're ready to fly would also help.

Critical temperature is about 80ºC for motors and ESCs - beyond that stuff will start to fail spontaneously. For example, maximum operating temperature for the processor in an ESC is 85ºC. The epoxy holding your motors together starts to soften at about 80ºC too.

 

[ChrisViperM]

We've got a possible job coming up in Abu Dhabi, in September which is the one of the hottest times, i'm told we can expect up to 45/50 deg c! We're based in the UK, where it rarely gets above 25... especially this 'summer'.

So my question goes out to all you guys in hot climates, do you have any issues with ESC/Motor temps? - The machine we'll be running is an SJ8 with Axi 4120 Motors on 6S and Hobbywing 60A ESCs, runs great and cool over here... but im thinking we could run into issues in such high ambient temps. We'll use heat sinks - but does anyone have any good ideas/things they've done in the past? Was thinking maybe cooling fans... but 8 of those and wiring starts to get interesting.

Thanks

I can't tell you more than jes1111 about cooling your bird, but I've been to Abu Dhabi a few times...the hottest month there is August, in September it's cooling down already. It also depends on where you shoot...coastline has a bit lower temperature than going inland towards the deserts. Your second enemy could be humidity which can reach 80% and more at the coastline....get enough fresh T-shirts with you.... Depending on the footage your customer is after, the best bet would be shooting early in the morning.

Chris

 

[fayrwerks]

Im in dhahran, Saudi Arabia and you just cant escape the heat... no way you can have the same performance on your multi as where you are... you can either prop down or be one cell down on you lipo.. if your doing aerials... its 39-42 in early morning and if your shooting in coastlines it will be blanketed by smog of humidity.. august is not the best time to be in middle east...

 

[kloner]

I fly in up to 45c and the only thing different i've done is keep the batteries in the cooler on ice but on top in a bag and i let it rest in the shade. put that thing in the sun and the motors get too hot to touch sitting still. I've never noticed anything temp wise act any different, most my stuff runs just over ambient so running 120-130 isn't a big deal. batteries hate it though. i ice em charged and discharged, keep as much out of the sun as possible

 

[jackwrangham]

Thanks Dave and jes1111, we'll keep the batteries as cool as possible for sure. We'll def try and keep everything in the shade/air con as much as possible and probably limit ourselves to shorter flights than normal.

Chris - we'll be shooting by the coast and in the desert - thanks for that, def planning on plenty of fresh clothes, I hate the heat, so its going to be interesting!

So thanks everyone, hopefully we'll be all good keeping everything cool/out of the sun when we can, using some big heatsinks, and shooting in the morning where possible. Got a few days of testing over there, so should be able to get everything sorted!

 

[ChrisViperM]

If your client let's you, show us some footage once you are back. Good luck....

Chris