Hi Max,
Thanks for your replies I'm also not quite sure where I read that - before I ordered the Cortex I read no end of threads on coax systems, some said you need bigger props on top, some said the opposite, likewise for the pitch, with user reporting advantages of every combination! ... In the end I gave up reading and just went with a platform that had been flown and seemed to work well by all accounts.
Yes you've interpreted correctly - all the top props are 15x5 and spin one way, and all the bottom props are 16x5.4 and spin the other. I believe the reason is that the Cortex manufacturer uses DJI flight controllers and that's the prop arrangement they require. Not ideal I admit, but it's what I've got to work with at the moment!
I only linked to those videos as it seems to me the current prop arrangement doesn't make the platform unflyable, in fact it seems to fly well.
What is the reason behind making changes to the mixing table when using different props on the same motors? Doesn't the control algorithm just give as much power as is required to the different motors until the vehicle responds as it's commanded to? Sorry if I'm being dense
Many thanks again for your help David