Sir Richard Branson: ‘Hybrid airship technology represents an important and exciting aviation milestone.’
Hybrid airships are a completely new type of hi-tech, heavy-lift aircraft that offers a dramatically less expensive and an environmentally friendly alternative to traditional modes of cargo and passenger transportation.
With the ability to take off and land nearly vertically, hybrid airships can operate in the most remote and inaccessible locations without any of the infrastructure needed to support conventional air transportation.
At first glance, because of their immensity and shape, hybrid airships may bear some resemblance to the airships of old but that is about as far as any real comparison can be made - economically, environmentally and technologically the hybrid airships are highly advanced aircraft.
Hybrid airships design combines all the best characteristics of fixed wing aircraft, helicopters and hovercraft with cutting-edge aerospace technology, in an aerodynamically shaped envelope with no rigid structure and filled with non-combustible helium.
Hybrid airships are heavier than air; approximately 80% of their lift comes from buoyant helium and 20% from the aerodynamic lift generated by the shape of the hull and ‘vectored thrust’ from the craft’s four rotatable engines.
Hybrid airships feature a wide range of state-of-the-art avionics, flight controls and navigation systems.
These inherent design characteristics of the hybrid airships provide unique advantages:
No need for a runway or prepared landing surface - hybrid airships can operate from unprepared ground, sand, snow, ice, and even water;
Provide a stable vibration-free cargo bay and passenger compartment environment that lends itself to use as a platform for multiple aerial sensors and imaging equipment;
Due to its unique design and aerostatic characteristics, the hybrid airship is considered one of the safest aircraft available today;
The first airship to utilize the Air Cushion Landing System ACLS which enables operations to/from unimproved, very low infrastructure terrain by using hovercraft technology;
Large cargo capacities
Significant reductions in fuel consumption compared to other air vehicles such as the heavy lift helicopters;
Faster than land and sea transportation system.
Hybrid airships provide an environmentally green alternative to using heavy-lift helicopters by producing a fraction of the carbon emissions at around one tenth (1/10th) of the cost per nautical ton-mile. In addition, hybrid airships reduce the need for environmentally damaging road and rail lines to be constructed through thousands of miles of remote and unspoiled areas of wilderness which permanently scars the landscape.
Hybrid airships low fuel consumption – about one tenth that of heavy-lift helicopters – greatly reduces their carbon footprint.
Hybrid airships are quiet and unobtrusive to operate compared to helicopters and conventional aircraft.
In short, hybrid airships and Straightline Aviation offer the kind of breakthrough, highly cost-effective and environmentally friendly air transport alternative that the rapidly developing world desperately needs.
Remote Operating Infrastructure
Current remote location infrastructure costs can run anywhere from tens of millions of dollars to billions. In many instances these costs are prohibitive, and without significant inward investment remote communities are left cut off from the world.
Hybrid airships enable year round deliveries to remote communities of essentials such as food, fuel and medicines, reducing product costs and risk of shortages when resupply is impossible via existing transport routes due to adverse weather conditions.
Operating from a variety of surfaces including unprepared ground, desert, snow, ice and even water, without the need for infrastructure.
The hybrid airship is capable of carrying more than 21 tons of cargo along with 19 passengers and two crew
The spacious flight deck and up to 19-seat passenger cabin sit atop the forward ACLS pad, which dictated the large size of that section of the gondola.
The hybrid airships fuel and equipment bay is directly behind the cabin, and the cavernous cargo bay is at the rear of the gondola. The 18 x 3.2 x 3-meter compartment can hold up to 21,000 kilograms (21 tonnes) of payload, and is a little bigger than the cargo box of Lockheed Martin’s venerable C-130 Hercules transport aircraft.
It has a fuel capacity of 5,400 litres with a range of 1,900 nautical miles, and can cruise at a speed of 60 knots.
Hybrid airships do not need airports: They can operate safely from unprepared flat surfaces whether it is grass, dirt, sand, snow, ice or even water.
Hybrid airships are marginally heavier than air, which makes for excellent ground handling characteristics.
Hybrid airships lift up to 20 tons of freight (future variants will carry many times this amount) plus 18 passengers, or up to 48 passengers in an all-passenger configuration.
Hybrid airships have extended range enabling them to reach and land in remote destinations inaccessible to helicopters and fixed wing aircraft.
Air Cushion Landing System (ACLS)
The hybrid airship uses hovercraft technology for the ACLS to allow the airship to operate into and out of flat unprepared surface whether it is dirt, grass, sand, snow, ice or even water.
A hovercraft, also known as an air-cushion vehicle or ACV, is an amphibious craft capable of travelling over land, water, mud, ice, and other surfaces using blowers to produce a large volume of air below the hull that is slightly above atmospheric pressure. The pressure difference between the higher-pressure air below the hull and lower pressure ambient air above it produces lift, which causes the hull to float above the running surface. They use this air to balance their weight, allowing the craft to operate efficiently.
Hovercraft technology provides a significant advantage for the hybrid airship as it enables the airship to access remote locations around the world that other cargo hauling aircraft simply cannot due to the lack of appropriate and environmentally scaring infrastructure.
The ACLS consists of three hover pads located on the underside of the airship. These hover pads create a cushion of air that allows the airship to float over the ground almost friction free. The system gives the hybrid airship a unique capability to hover over water, which can make it an asset to search and rescue or coast guard operations.
The ACLS also allow the airship to remain stationery on land by the hover pads ‘grip’ to the ground with light suction pressure to keep the airship from moving in variable winds.
‘Fingers’ hang below the pads to create a seal with the ground. These fingers allow the airship to taxi over obstacles, such as tree stumps or rocks, so extensive site preparation is not needed for a high volume cargo operation. These ‘fingers’ also make the hovercraft a sustainable solution because there is no long-term impact to the ground site.
In the film below Lockheed Martin’s team explain where the ACLS technology comes from, the advantages it brings to the hybrid airship and how it has been modified to improve the performance of the hybrid airship.
Hybrid Airship Envelope and Self-Propelled Instrument for Damage Evaluation and Repair (SPIDER)
To make the hull strong enough to operate in extreme conditions the envelope is made from Vectran, a Kevlar-like fabric arranged in three chambers with two internal curtains down the seam lines. It is lightweight, inexpensive, and highly resistant to puncture. If the hull is breached anyway, the helium is enclosed at such low pressure that the helium should stay inside the airship or would be released very slowly. That being said the conditions hybrid airship is designed to operate in could cause the envelope to develop pinholes and with Helium being a very small molecule it could be problematic in the long run, if they are not repaired quickly.
The process of patching the pinholes over a large envelope is very time consuming and stops operations taking place. Generally inspecting an airship’s envelope is a manual process requiring incredibly bright handheld lights, meticulous attention to detail and the aircraft to be completely deflated, but the Self-Propelled Instrument for Damage Evaluation and Repair (SPIDER) can perform the same inspections while the craft is fully inflated.
The SPIDER consists of two magnetically attached halves, one that sits on the outside of the airship, while the other clings to it from the inside. Using a set of bright LED lights and a camera, the SPIDER can automatically spot pinhole leaks, and then reposition itself to patch them. Photos of before and after the hole is patched, are sent to a central server for further human inspection, but that adds minimal time to the mostly automated inspection process.
The SPIDER robots have the advantage of running continuously and operating on the bottom, top, and sides of a fully inflated envelope where it can be difficult for people to reach. Since SPIDERs have evolved to a rather small robot in order to operate over curved surfaces and climb the envelope, a team of SPIDERs allow for an even faster inspection and repair process.
Importance of Propellers
The hybrid airship has been designed to have steerable, diesel-powered fans for propulsion and control. With four thrusters, each with four different angles of attitude and blade pitches, and four independent aerodynamic controls, the heavy lifting is accomplished by a sophisticated fly-by-wire system. It will stay below 10,000 feet, eliminating the need for pressurization, and can fly up to 1,600 miles without refuelling.
The airship does not require airplane-like speeds for take-off and cruising, due to lift being proportional to the surface area of the aircraft, the sheer size of the airship allows for an excess. Hovering inches off the ground, the Hybrid Airship can get airborne in just 20 feet, compared to the 3,000 feet required by the standard cargo plane.
Like most fixed winged aircraft, the hybrid airship has elevators that allow the hybrid airship to ascend or descend. The elevators provide pitch control and help the stabilizers with pitch stability; they do so by decreasing or increasing the downward force. The hybrid airships ailerons are used in pairs to control the aircraft in roll (or movement around the aircraft's longitudinal axis), which normally results in a change in flight path due to the tilting of the lift vector.
In the video below, you can see the importance of the propellers used on the hybrid airship.