Economist - Trek Aerospace is adapting a “personal aerial vehicle” concept originally developed for DARPA (DARPA TX Transformer Program.), the research-funding agency of America's Department of Defence, to create a civilian vehicle. This two-seater, the Tyrannos, has ducted propellers powered by petrol engines, with a battery backup. Although it has been possible to make such vehicles for decades, they are notoriously difficult to fly. “It's just basic physics,” says Mr Bulaga. “Any vehicle that takes off and lands vertically is unstable.” To make it practical, computers are needed to make the constant tweaks required to achieve stable flight. Without them, even just hovering is like trying to stand on a beachball, he says.
Logi Aerospace worked with Trek Aerospace on the DARPA version of the Tyrannos (3 pages).
The employees of logi AeroSpace have been working with Trek Aerospace on manned roadable air vehicles for over a decade and have enlisted ZAP and SWRI to help them refine a four person version for DARPA and the Marines.
The DARPA Tyrannos is the first roadable 4-person air vehicle that anyone can literally drive into the air. The driver views on their windshield, a road with concrete barriers on each side, which allows them to drive up and down imaginary ramps that lead hundreds of feet into the air and stretch like Interstates across the country. With this perspective and guidance, they are able to easily and comfortably travel hundreds of miles a day at cruising speeds of 155 mph.
Performance – The Tyrannos does this at a fuel sipping 19 mpg in the air. It can
then land vertically, fold its wings and drive, on normal highway and urban
roads, at cruise speeds of 60 mph using only 43 mpg with its efficient electric
hybrid engine. The electric hybrid engine in concert with its nanotechnology
batteries is able to provide constant electrical power for the vehicle in cruise
mode and the batteries allow it to accelerate to high sprint speeds of 240 mph in
the air and 103 mph on the ground for short periods of time. In addition, the
vehicle can be driven for 46 miles on electrical power alone using no fuel and
creating Zero Air Pollution (ZAP like!).
Structures - The other secret to the Tyrannos’ fuel efficiency is the lightweight carbon fiber composite structures designed by logi AeroSpace. These structures make this vehicle ultralight. With the dimensions of a normal 4-person sedan, it has half its weight and has the crash strength of a NASCAR racecar able to crash safely at 200+mph. This does introduce a complexity.
Depending upon the payload and number of people aboard the gross weight
can vary from 1,900 to 3,750 lbs. while driving. This is a challenge for the
suspension system when crosswinds are high while driving. ZAP Electric will be
using their deep automotive expertise to help design a sophisticated suspension
that will allow us to drive in all conditions and at the full range of gross weights.
Shrouds on the ducts provide 50% of the lift
While working for Trek Aerospace, one of the employees of logi AeroSpace developed one of the key components of the vehicle, the shrouded propellers. They were refined to an extraordinary degree allowing for very lightweight and high performing vertical takeoff aircraft. These shrouds are so aerodynamically efficient, they provide almost 50% of the lift when taking off vertically. Historically shrouds have provided less than a 10% effect.
The aircraft is designed to fly only 1 or 2 thousand feet in the air but at nearly any location above the landmasses of earth. This is tens of thousands of feet below, and out of the way of, airliners. With its supercharged engine, it can easily fly 1,000 ft over 10,000 ft mountains and could go up to around 14,000 ft for short periods of time. Before established air highways are designed, the FAA will control it like a helicopter is today
The entire vehicle, wings, ducts, engines and auto parts are made from either commercial off the shelf parts or parts that have been extensively developed and are highly reliable. The object of this is to assure a vehicle that is as reliable as the family car. Even if one were to lose the engine, it is capable of landing with an engine out using only its batteries. With more serious problems, it has a backup parachute to land the vehicle, and the people, safely on the ground. It can take off vertically with 1,100 lbs of passengers and luggage or up to 1,850 lbs if you allow it to take a 180 ft. running start on a short street. The vehicle with its wings outstretched is 30 feet wide and could land on a three-lane road. When driving, its only 8 ft. 4 inches wide and can easily drive down the narrowest of streets. It’s 8 feet tall and 25 feet long and fits under nearly all bridges and in most parking garages. The wings and tail are easily removable and brings the vehicle down to 5 feet 2 inches tall and 18 feet long. These dimensions allow the cabin to be as spacious as a van and very comfortable seating for four. For military users and civilian travelers, there is plenty of space for rucksacks, suitcases and equipment.
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