"Did a little simulation on the school computers and found the best combo is larger upper props and high pich smaller low props the smaller the better obviously.
Other combinations include low kv top motor and high kv bottom motor and when in…"
"My guess is that you can get the overall efficiency improved somewhat by working on the prop combinations a bit more.
All other things being equal, the prop on the bottom should have a higher pitch than the one on top and the larger the diameter…"
"I did a bot of research and found you loose 25% of your power and efficiency through this setup, so what you gain through redundancy you loose in flight time and power to weight, however i would rather have a copter that ;ands more often than a…"
"After testing Y6 setups for long time, I can tell there is no need for different speeds or prop sizes with prop size up to 12", also it much better to use E-props and not SlowFlyers, on 800-900KV motors with 4S lipos.If you want…"
"@Ian: Yes, it's a bit more abrupt initially as a motor power failure allows the prop to autorotate a bit to give the controllers time to adjust. With a prop snap, you lose power immediately and it will lean immediately to an uncontrollable…"
"The motor out recovery looks impressive. Having had the misfortune of losing a propellor blad on my quad I was wondering whether the Y6 configuration would be able to recover from a propellor failure. I am thinking the resultant excessive vibration…"
"John, you are definitely correct. There is an efficiency loss, but the gains overall are worth consideration. Joe did a bunch of testing and found that a 11x4.7 prop on the bottom and a 10x4.7 on the top are the best setup for the Y6."
"Very neat video!
On a Y6 configuration is there any adverse aerodynamic effect to having the lower propeller working in the airstream of the upper propeller? Seems like the thrust of the upper propeller will constantly be slamming against the lower…"
"We'll get another one up soon. The flight ops guys down in San Diego are up here in the Bay area to attend Maker Faire this weekend. When they get back to home there will be more tests.
Here is an onboard view: