Misleading description IMHO 
Ahh in my day and ND filter was a piece of acetate, plastic or glass which was fitted to the front or back of a lens, or on the lights or on windows. The filters consisted of various grades depending on how much light youmw8shed to cut. It enabled you to control shutter and iris settings to get a balance between eg God’s light and man’s light.
An ND filter works purely by slowing down the “shutter” so the prop is blurred. There is (of course) no such thing as a “prop filter”. And actually there is no “shutter” in these action cams either; it is simulated by timings on the sensor data extraction.
I suspect Mancival’s requirements (e.g. internal G meter) will be met by very few products.
The overheating issue does exist in the Sony X3000 I have been using, but it happens rarely. I have seen it when in the waterproof housing and in stationary air, on a hot day. After maybe half an hour it shuts down. But only with external power applied; this involved a mod to the waterproof housing so few people will come across it. You could also achieve it running on a battery, if you wrap the camera in a cloth or put it in your pocket while running. Direct sunlight is a huge issue because any object in still air will quickly reach something like +50C to +60C i.e. too hot to touch. I design electronics for -40C to +85C but one would not do that if there is a battery inside
Why would you use an ND filter to filter the prop. An ND grad filter might balance exterior and interior exposures but I don’t see how it will do anything for the prop strobing.
There’s one from Garmin. Maybe that one works better.
It’s a ND filter and it doesn’t work very well. Actually I may have tested a too-cheap one, but it removes the prop at the price of the dynamic range.
It forces the aperture to be high enough that each frame is long enough to “not see” the prop.
Peter wrote:
I don’t have a PC but none of the action cams will remove the propeller.
You can get a prop filter (I know the virb 30 offers one).
@chrisparker might know. He has played with more of these than anybody I know
I have a garmin ultra 30 but not that great. Actually I took it for embedded sensor, but video quality is not great; let auto mode down, you need to set it with smartphone app to get a good setting. I also took it because with a specific adaptor, you can have external mic input from a jack 3.25 and a charge port; but actually it doesn’t work to get ATC in, probably an impedance not really correct. Another nice feature (on the paper) is to have external mic input on left audio channel and internal mic on the other channel, but still not working great; the xiaomi mijia 4k has a better audio mic.
Last but not least, the video angle is too short, and is not the best for in-cockpit cam, gopros are the best.
