Flight times on pure electric power are somewhat limited today. The Ranger of Fritz would be a perfect proof of concept for electric flight. The batteries are the main concern, but it seams that quiet a few laboratories are working on high capacity batteries with up to 8 times the power stored in TESLA Batteries of today. A flight-time of 3+hours in a Ranger on pure electric flight, that would be great. The powerplant a electrical systems are readly available from different sources, only draw back the energy storage, so far. https://www.geigerengineering.de/avionik/produkte Is one of the companies delivering ready to assemble products.