Ice Ice Baby
Good for Rappers, Bad for eVTOLs
Back in 1990, hip-hop/rap artist Vanilla Ice (real name Robert Matthew Van Winkle) extolled the virtues of ice, or at least vanilla ice (aka himself). The song was a huge success, but speak to Jim Sherman and Mike Hirschberg, director of strategic development and executive director at the Vertical Flight Society, respectively, and you’ll quickly learn that ice will not be kind to the eVTOLs in development for the foreseeable future, with eVTOLS already underpowered.
Ice Prevention on eVTOLs
eVTOLS would require a power draw from the system to prevent icing on the rotors, i.e., anti-icing with electrical heaters along the blades. That probably means anti-icing systems are a “non-starter,” according to Sherman. A hybrid vehicle, which could tap into bleed air “a heated leading edge,” would be able to draw power from the vehicle’s turbine engine.
Heating the rotor blades on today’s helicopters has “proven to be very complicated, expensive, and adds additional weight,” Sherman explains. One such solution is the Sikorsky S-92A, which offers a Rotor Ice Protection System (RIPS) that distributes heat to the blades.
Sikorsky’s RIPS monitors the ice accretion rate from its two ice rate probes and cycles heat to the main and tail rotor blades. RIPS may also be selected to one of four “manual” modes of operation to immediately force the system to supply heat to the blades. The pilot monitors ice conditions on an ice rate meter located on the primary flight display. Still, limitations, such as not exceeding 10,000 feet in altitude exist.
NASA on Ice
NASA has also been developing solutions to the challenges icing presents for decades. Not only for aircraft – railroad trains have taken advantage of the chemical processes as well, to successfully operate rail switches in icy conditions.
What testing has been done has not produced favorable results as quad-style aircraft propellers tend to have the ice migrate span-wise versus chord-wise on the blade, which Sherman notes causes “an immediate and potentially catastrophic reduction in aerodynamic efficiency” in addition to the increase in weight.
So, Nome, Alaska, Montreal, Quebec, Rio Grande, Argentina, and other points north and south, don’t expect flying cars in your foreseeable future – certainly not during the winter months. L.A. Dallas-Ft. Worth, Melbourne – keep your eyes peeled. Your flying taxi is just over the horizon.
P.S.: Extreme heat environments aren’t friendly to eVTOLS either, Hirschberg explains. With temps reaching 120 degrees Fahrenheit in places such as Dubai, the power to cool the cabin, electronics, batteries, etc. are a hindrance to getting flying cars off the ground for now too.