The AeroRaft was designed early 2003 through LTA Solutions Ltd (now integrated in Luffships Ltd – LSL) as a development step of the StratRaft. It is a lenticular dirigible buoyant aircraft design with omni-directional (O-D) ability flying below 3000 m altitude as an aerial-crane for transport of outsized heavy (up to 100 tonne) indivisible payloads with precise point to point pick-up & delivery (pick&put) operations without mooring or other ground restraints.
The design also permits transport of people, general freight, livestock or goods of any type loaded into lightweight containers, which the AeroRaft simply picks up, transports and then puts down wherever wanted as an under-slung load.
Its low suspended gondola module was deliberately arranged to provide strong pendulum stability (keeping the buoyant aircraft upright) for operation as a free balloon. This allows the AeroRaft to drift with air currents at any stage underway instead of using power. The design incorporates an optional Rotordyne (a large outer fan system) to generate aerodynamic lift in either direction (up or down) for payload pick&put purposes or to counter excess buoyancy in a naturally balanced way. Separate propellers at strategic positions provide thrust underway as well as stability and control.
From realising the Rotordyne was a risk issue needing separate development, it was made an optional item. Development then would have been at smaller size without fitting around the aerostat. If fitted around the suspended module below, it then would help balance the differences between buoyancy and overall weight.
However, when fitted around the aerostat, greater efficiency was expected from benefits of: greater disc size, lower Rotordyne speed (so quiet), reduced aerostat blockage, and extra aerodynamic lift from airflow induced over the aerostat (the Coanda effect). Otherwise, more power was needed for the same effect – affecting performance and safety.
LSL today has instead adopted an easier distributed vertical airflow method using individual small fans around the aerostat. These have better redundancy and control, as well as being commercially available – reducing development work.
There’s a need for such buoyant aircraft in regions lacking infrastructure and/or that have unstable conditions preventing other transport vehicles for whatever reason.
- Paper, AeroRaft, AIAA conference, Nov 2003.
- Article, “Argument for Development of an LTA Aerial Crane”, May 2015, (available from contact).
- Article, “Why hasn’t it been done before”, May 2015 (available from contact).
- The CargoLifter CL75 AirCrane (paper – available from contact) proved to a certain extent that the AeroRaft is viable; where it leverages experience from it.
- See our Strategy document for the way AeroRaft versions may be achieved after development of the derived types enabling it. We thus have a progressive way for success!