I have several of the Happymodel Whoop 1S AIO boards (inc ELRS). Been happy with them.

One is in a Dave "C" NanoLR, ROBO 1202.5, 3018 2 blades, powered by 3300mAh Li-ion.

Weighs 60g without cell, 108g with 3300mAh.  Its a 3D print body with carbon insert strips to arms. That weight is LESS than the production Rekon3.

In ground effect 0-8cm up its motors sound rough, otherwise it flies superbly well, quiet, smooth, and relatively powerful, actually capable of power loops in first half battery life.

Cruising is 15 minutes min, and if not windy, nearer 20.


The issue is that in an indoors sports hall or at home while speeds are low the core temp climbs too high and it shuts down. Can get to 85 plus inside a minute hovering or in low forward speed.

Not had it shut down outdoors cruising about, even last summer, discounting current 5-7C max's here currently.

I have done what I think is the obvious, cleared better cooling holes on frame than standard frame, done some adjustments inside Betaflight.

I realise that I might be pushing the FC harder than ideal, but its SO close to being really good so I want to explore if I have any leeway left for improvement.

I won't "lead the witness" with my current Betaflight settings, which were mostly prod and hope conducted!

Ideas please?

Forgot......... CPU load is around 23-25%

Is the FC exposed to the propwash? If you have a canopy, you might try raising it to let in more air. Also is the frame open on the bottom, like the HX115LR/Crux3 frames, they are basically a large empty hole below the FC.

If your printed frame is enclosing the whole 18650 cell, you may also consider cutting it down. I've seen one flyer completely do away with the battery holder contacts, and replace with a simple wired nickel plate held in place with a tiny magnet, so the battery holder becomes basically two clips (he claims they don't come off even in light crashes). There is also the option to put a battery lead on the 18650, I prefer that as it keeps the weight down and on a Crux3 setup it comes in around 90g and allows you to fly easily swap between lipo/lion.

Otherwise if you know the hotspots on your FC, maybe it is possible to put on a heatsink?

(26-Feb-2023, 04:56 PM)mstc Wrote: Is the FC exposed to the propwash? If you have a canopy, you might try raising it to let in more air. Also is the frame open on the bottom, like the HX115LR/Crux3 frames, they are basically a large empty hole below the FC.

If your printed frame is enclosing the whole 18650 cell, you may also consider cutting it down. I've seen one flyer completely do away with the battery holder contacts, and replace with a simple wired nickel plate held in place with a tiny magnet, so the battery holder becomes basically two clips (he claims they don't come off even in light crashes). There is also the option to put a battery lead on the 18650, I prefer that as it keeps the weight down and on a Crux3 setup it comes in around 90g and allows you to fly easily swap between lipo/lion.

Otherwise if you know the hotspots on your FC, maybe it is possible to put on a heatsink?

Its one of these (underside view from Oscar's website):-



I have opened out the sides and more of the bottom so there's a lot more open area.

Its also a single board solution, so there's a LOT less containedin the housing anyway.

That frame does look quite restrictive. I don't have any experience flying "lr" indoors, but maybe an open frame like the Crux 3 would allow enough cooling?





For your VTX assume you are already using lowest setting. Maybe with OpenVTX there is some way to go even lower than 25mw?

Maybe attach little heatsink on the vtx with thermal pad or thermal epoxy.
I did that on Eachine Nano400, because signal would drop after 1-2min, and it felt like it would burn itself if stuck in grass.