Passenger jets aren’t going supersonic anytime soon, but there’s some new tech that might deliver gate-to-gate total flight times rivaling supersonic travel. With a novel electric AC induction motor driving a plane’s nose-gear wheels, considerable time can be saved during pushback, taxiing, and even passenger loading. And here’s the hook that for electric cars or trucks: the motor’s unique design can deliver enough torque to get a 200,000-lbs aircraft rolling while providing light weight and high performance at higher taxiing speeds. In essence, it emulates a gearless “virtual transmission.”
The motor’s innovative winding allows its controller to vary the number of phases, magnetic poles, and alternating current frequency—for example, from the typical AC three-phase, to as many as 12 or 18. This allows it to efficiently deliver the torque of a DC permanent magnet motor while providing the lighter weight, lower cost, and improved performance of an AC-induction motor at higher operating speeds.
Flying Hybrids Mean Big Savings
If this all rings a faint bell among our longtime readers, that’s because we covered the technology in a November, 2008 Technologue column titled “Flying Hybrids!” The “mesh-connected windings” and “fundamental harmonics” at play in this motor were developed by Gibraltar-based Chorus Motors, which has been patiently working to commercialize the technology via its subsidiary WheelTug since well before that 2008 column. Company CEO Isaiah Cox is now reasonably certain final flight certification will be granted by the end of 2021, with new production and retrofit installations beginning in early 2022. A grand demonstration is scheduled at the Memphis International Airport in mid-September.
WheelTug has been demonstrated on airplanes large (Boeing 767) and small (737), with electricity always coming from the standard auxiliary power unit (no batteries need be added). Now the company is targeting shorter-haul narrow-body aircraft like the 737 and Airbus A320. Here’s how WheelTug promises to save fuel and time on a typical flight:
- Eliminate the wait for “wing-walkers” and a tug operator to arrive, connect the tug to the nose gear, attach the communications link, and push back.
- Eliminate the time to disconnect the above and clear ramp personnel and vehicles from the area.
- Begin taxiing immediately, with no need to hold for jet-blast reasons.
- Start engines only in time to warm them before takeoff.
- Land and almost immediately shut off the engines, allowing them (and the brakes) to cool en route to the gate so that ground crew can begin servicing/collecting luggage immediately upon arrival.
- Taxi right up to the gate, with no need for tow-in.
WheelTug pegs the average fuel savings at 36 gallons per flight and a time savings at 8.5 minutes in push-back alone, but more important is the higher predictability of all the time spent on the ground. Today push-back takes 13 minutes or more on two percent of flights, so total scheduled flight time must “bake in” extra time to preserve the airline’s “on-time” reputation. (Note that time spent with engines idling during de-icing procedures aren’t included in these estimates.)
To these, WheelTug forecasts further savings of $100 per flight for push-back fees and $95 in engine wear, while greatly reducing the opportunity for foreign-object damage from detritus sucked in off the runway and collisions caused by tug operators (aircraft movement is still directed from a tower, but the pilot remains in control while monitoring cameras views that afford complete situational awareness). And planes able to push back and taxi themselves will lose far less time “recovering” from weather delays that place a high demand on a limited number of tug vehicles and ramp personnel.
WheelTug Perfects “the Twist”
My favorite party trick for reducing aircraft time on the ground is “the Twist.” In round numbers, the 737 and A320 aircraft are about 120 feet long by 120 feet wide, and with WheelTug powering nose gear that can swivel to allow the plane to nearly pivot in place. That enables “parallel parking,” as featured in airports of the ’50s and ’60s, with front and rear jetways that allow passengers to embark and disembark in half the usual time. A ramp designed to accept a widebody plane generally has enough space for a WheelTug-equipped narrow-body plane to pull in, turn parallel to the concourse, and pull back out. This which makes it conceivable to roughly halve the scheduled time a plane spends in “turn-around” at the gate (from 55 minutes to 27 minutes for a 737/A320).
WheelTug is so sure it can save airlines huge money that it plans to install the system for free and charge airlines half of their savings, using system monitors determining WheelTug usage and calculating savings accordingly.
Where Are the Automakers?
Cox admitted that two automakers known for their civilian and racing hybrids powertrains have approached his company, but Chorus has been so singularly focused on the aircraft business that it declined to participate. He admits to being open to licensing the patent technology, though, and I remain hopeful that someone soon will incorporate these “virtual transmission” e-machines in a particularly big and/or fast electric vehicle for the road.
The post E-Motor Tech Promises Supersonic Flight Times; Virtual Transmission for EVs appeared first on MotorTrend.