The AeroRaft was first designed early 2003 through LTA Solutions Ltd (now integrated in LBA as a development step of the StratRaft. It is a lenticular dirigible buoyant aircraft designed with omni-directional (O-D) ability to fly 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 would pick up, transport and then put 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 it to drift with air currents (rafting) at any stage underway instead of using power. The original design incorporated a 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 then provided thrust underway as well as stability and control.
From realising the Rotordyne was a risk issue needing separate development, it later was made an optional item, needing ballast-exchange for payload pick-up and put (pic&put) ops. Development then would have been without fitting around the aerostat. If fitted around the suspended module below, it then would help balance the differences between buoyancy and overall weight, obviating need for ballast-exchange.
However, when fitted around the aerostat, greater efficiency was expected from benefits of: bigger 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.
LBA instead now has 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 difficult topography preventing other transport vehicles for whatever reason.
Review the Derived Lenticular Types to see how significantly smaller versions (reducing risk) have been arranged to support future similar buoyant aircraft developments.
Associated Documents:
- 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).
Notes:
- The CargoLifter CL75 AirCrane (paper – available from contact) proved to a certain extent that the AeroRaft is viable; where LBA designs leverage experience from it.
- See our Strategy document for the way similar versions may be provided after development of derived types. We have a progressive way for success that grows!
