The problem with ALL EXISTING electric powered eVTOL concepts, (that are based on batteries), is that they do not have sufficient energy to stay in hover for hours. By using LH2 as their energy source, future VTOLs, acting like flying 2 ton pickup trucks, can be the breakthrough innovative technology that most investors are looking for. This HUB’s point is that liquid hydrogen fueled vertical take off and landing aircraft are best used to provide long endurance HOVER (hours over the point of need) rather than to fly, far away, and fast, with paying customers inside. Or a large LH2 fuel consumption of energy can be used to LIFT unexpectedly heavy loads (provided their breakthrough ultra-light fuel cells and breakthrough super-conducting: cables and especially motors can sustain (thermally) maximum power output. The essential reason for LIQUID hydrogen (vs gas under pressure) is that a LOT (many Gigajoules) of hydrogen does not weight much at all. That will be done in brilliantly designed, but ultralight, tanking systems (extremely cold, compressed gas, sitting on unique physical adsorber materials (like DOE’s “metalized-organic” AERO-GELs). Such tank designs have already been developed by NASA/Kennedy and were called: “Cryogenic Flux Capacitors”. The breakthrough result is that such a craft is the “delivery truck” for JUGS of liquid hydrogen from a HUB generation site to nearby applications (primarily for transportation innovations, like: fork-lifts trucks, buses, trains, and the future of flight).
WHO ARE THE CONSORTIA CONTRIBUTORS?
Why must the electric motors be made of super-conductors?.
This “HUB” is the digital home of diverse innovators working for the next 10 years, cooperatively on the same, singular mission objective. That is not to save the global atmosphere, but to deliver “EMERGENCY VEHICLES” needed to deal with all the disasters that will be created by climate change. These innovators (gov agencies, Universities, big and small corporations and especially AGGRESIVE investors) will be using funds from various charitable R&D trusts as well as tax free city/state development “bonds” to be sold over the next decade.
Most VTOL innovations exploit the “toy-quad-copter” concept of multiple motors (& propellers) based on the high power-per-kilo-of-weight available from permanent-magnet DC motors. Key to that aircraft design strategy has been the 4, or 5 or 6 (or more) “DC-power plants changing the current (RPM speed) to the motors, and/or changing the prop’s angle of attack. That works well for staying stable in a hover mode, but that is energetically very inefficient, so all VTOLs now promote their rapid transition of leaving the hover configuration (for take off) and moving forward horizontally. The Joby aircraft tilts its well designed lift-fan propellers, from vertical to horizontal for efficient forward flight. Others simply shut down completely the multi-motor “lift function” and stability of many horizontal motors, and at sufficient altitude, turn on a forward thrust(s) to enable typical “wing” structures to provide efficient lift, for maximum travel distance on a given Gigajoule of stored energy. Liquid Hydrogen will change that dynamic. It permits a single (or 2 or 3, or 4) lift fan(s) of much LARGER dimension, with LOTS of lift fan blades (more than 5), to provide excellent HOVER efficiency by SLOWLY rotating the unique thrust-fan which, in turn, slows the downdraft airflow and hence the level of noise during near-ground hover. Adding to that, the best aerodynamic efficiency would be to put the lift-fan(s) into a duct, and the best of that is to have two counter-rotating fan-discs in a proper ducting (akin to Bell’s solution). The end result: SUSTAINED HOVERING EFFICIENCY, especially with lots of stored energy, is the real breakthrough.
WHAT CAN WE SAY HERE?
The history of electric powered VTOL flight was in the hands of Mike Hirschberg, editor of “Vertiflite” the association magazine/website for the Vertical Flight Society. (he is seated third from the right (dark business jacket) at the table of innovators who launched the TRANSFORMATIONAL VTOL consortium. On the far left seat of the table, (in his white “smoking”) is the “GODFATHER” of hydrogen powered VTOL aircraft R&D, based on nearly 50 years of obsessive commitment to the subject, starting in 1970 when working effectively as a “venture capitalist” in the Central Research Labs of the 3M company (which has had a LOT to do with the materials issue of cryogenic insulation, fuel cell PEMs, aircraft fabrication adhesives, etc.)
Some Useful links
To be developed
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