I say go for it. Frankly I think that looks like hours of entertainment.
Pioneers & crazy inventors God blessem.
an over run clutch would be good.
gears like coupled mountain bike gear sets would be easier? than rowing?
Thought about tethering your contraption then getting an electric motor to find out what works and what doesnt then gear/modify, learn pitch angles etc to make it work? Then apply human power? Is that cheating?
at least you should be further away from the machine of it does fail.
Seriously how bad could this be?
besides..this is the reason why natural selection exists.
Good luck.
HF
"Dear Father, its been 2 years since my last post. I was lost my way and ended up back in mining. I need my shepherd to guide me back to helicopters. I dont know what happened, how I got lost for so long but I shall ammend my ways when you show me the path" Amen.