Czech engineers set to build six-prop Flying Bike
By Paul Ridden
June 19, 2012
From the Jetsons to Back To The Future, hopping onto or into a personal flying vehicle has been on the engineering "To Do" list for a good many years. We've seen a number of noteworthy attempts at defying gravity and taking to the skies here at Gizmag (many of which are featured in this roundup from 2010) and now another possible addition to that growing collection has landed on our desk. Known simply as the Flying Bike (or FBike), this collaborative effort from a bunch of Czech companies and enthusiasts is still very much in the early stages of development, but the proposal is to fit a number of electrically-driven propellers to the custom frame of a two-wheeler that will allow the pilot to rise above the traffic for as long as the batteries hold out.
The FBike project began in the autumn of 2011 with a proposal to create an e-bike, but enthusiasts from Czech companies Technodat, Evektor and Duratec set their sights on loftier designs instead. Inspired by the stories of Jules Verne and Czech author Jaroslav Foglar (who penned a trilogy of works featuring a flying bike invented by a young apprentice locksmith), project members Jan Cinert, Jindrich Vítu, Martin Dršticka, Michal Krivan, Filip Plešinger, Milan Duchek and Jozef Lajda have been using 3D modeling tools from Dassault Systèmes to create a number of concept renderings of a multicopter bicycle (think somewhere between Chris Malloy's Hoverbike, the Gamera human-powered helicopter and Larry Neal's Super Sky Cycle). It would operate exactly like a normal bike while on the ground, but would also be capable of vertical take-off and landing - and of course, flight.
An early design featured eight propellers mounted to the bike, but two of the stabilizing propellers have been sacrificed to cut down the weight of vehicle. Calculations by FBike engineers have shown that four 10kW compact brushless electric motors for the 1300 mm (51-inch) diameter front and back twin propellers surrounded by composite casing and two 3.5kW stabilized motors for the 650 mm (25.5-inch) blades at the side should be enough for vertical lift-off (which will be performed from a static position rather than while on the move) and flight.
"Theoretical power needed to lift a weight of 5-grams (0.17 ounces) is about 1-watt," explained Vítu. "We have in total 47kW of power (and the motor can be overloaded for a short time), so theoretically the maximum lifting force is 2350N (235kg/518 pounds). The flight weight has been determined as 170kg (374 pounds), including the pilot, the difference being the losses (efficiencies of the components) and some for a power backup."
The current design features 50Ah Lithium-polymer batteries positioned below the crossbar of the roughly mountain bike-shaped light alloy frame. They're arranged in ten accumulator blocks positioned one above another, each containing 14 cells connected in series, and will weigh more than 20 kg (44 pounds).
When on the ground, the FBike will have all of the features commonly seen on everyday pedal bikes. The side props and telescopic stabilizer, though, can be rotated 90 degrees to provide the rider with a boost if needed. According to Vítu, the four main motors will be disconnected from the batteries in this mode. When the rider pulls over to prepare for take-off, the side props are returned to the horizontal position to ensure maximum force is applied to lift the bike off the ground, and telescopic dampers are extended for balance. The rider's feet will be placed on supports during the flight.
Vítu also told us that gyroscopes and accelerometers housed in an onboard control unit will keep stability in check, automatically adjusting the speed of each propeller for a smooth and steady flight. As there are to be no mechanical parts for controlling the flight, he says that forward motion of the vehicle while in the air would be achieved as with a helicopter. It's expected that the FBike will be capable of a flight time of three to five minutes, or an assisted ride time on terra firma of between 30 and 50 minutes per charge.
"We have completed the final design and are about to start with the production," Vítu told us. "The very last thing to be done is to select LiPol batteries manufacturer. So we are expecting the production will start this or next week. It follows the 3D model presented at the press conference held on 24th May."
A special composite seat has been designed to cater for the rider, to be strapped into the vehicle for safety and comfort. Work on the control unit and related elements is still being considered, with options including the installation of a third-party box unit integrating the main unit and sensors or an in-house, tailor-made solution.
The FBike team states that the vehicle is not expected to ever go into production, it's just being created for marketing purposes. Vítu has revealed that the first flight tests are expected to take place in mid-August, so we'll bring you more on this project then.