The AeroRaft (shown right) was conceived early 2003 via LTA Solutions Ltd (LTA-S, now integrated in LSL) as a development step of the StratRaft by LTA-S’s founder. It was intended as a lenticular dirigible buoyant aircraft (BA) with omni-directional (OD) ability to fly below 3,000 m altitude as an aerial-crane for transport of outsized heavy (up to 100 tonne) indivisible payloads. This was to be with precise point-to-point pick-up & delivery (pick&put) operations without mooring or other ground restraints.
Naturally, the design also was to permit transport of people, livestock, freight 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, including ship-to-shore operations. Power for such operations, with its broad regular upper surface, also could be from the sun and/or hydrogen in an upper cell.
Its low suspended gondola module was deliberately arranged to provide strong pendulum stability (keeping the BA upright) for operation as a free balloon. It thus allowed drifting flight in suitable air currents (rafting) at any stage underway instead of using power. The design also incorporated a Rotordyne (a large outer fan system) to generate aerodynamic lift either up or down for payload pick&put purposes or to counter unbalanced buoyancy, as needed underway. Separate propellers at strategic positions then provided thrust to ply desired courses as well as for stability and control.
Even so, from Rotordyne development risk, it later was made an optional item. This brought undesired ballast-exchange back into play for payload pick&put operations unless other ways to counter vertical imbalance were installed. If fitted around the suspended module below, the Rotordyne could 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.
In 2018 LSL 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 and risk.
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 BA 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 LSL’s 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!