The Kickstarter campaign for FlexPV is replete with crisp graphics and slickly produced videos that show users clamping motor, battery, and control modules to a scooter, a bicycle, and even a grocery cart before riding away to an upbeat indie rock soundtrack. What it doesn’t mention is that in 2013, the same team raised more than half a million dollars for a copter that received almost universally negative feedback from backers who say they never received a product, that it was missing parts, or that it just didn’t work.