WheelTug

One way to decrease airline costs is by decreasing power demands (and energy consumption) as the plane moves on the ground. Rather than continuing the expensive propulsion system from wing mounts while taxiing, several proposals have been developed to have the power for taxiing delivered directly from the plane's wheels themselves. There are currently two types, the plane is pushed by motors in the main wheels or pulled by a motor in the nose wheel. The former is the plan of giants Honeywell and SAFRAN, the latter by the tiny WheelTug Corp.

This looks like a clear win for the giants but it is more complex. Power at the main wheels generates a lot of heat as the plane is moved. A rule in flying is that brakes must be cool before the plane can roll for takeoff because, should the plane need to stop for some reason, the brakes will not work or might overheat and hydraulic fluid fire might result. Cooling the wheels takes time and airlines are frantic about being on time. More, time is money; an “airline minute” is worth between $100-150. So the cooling time may eat into the fuel savings.

The nose-wheel solution from WheelTug adds no heat to braking systems and enables the current cooling airflow to operate normally. As a result, there will be no adverse impact on brake cooling times. So additional heat generation--and the time required for heat dissipation-- should be a major advantage to WheelTug.

But WheelTug is very small. And some good ideas remain good ideas. A goal without a plan is a wish.