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Old September 27th, 2018, 05:18 PM
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aramis aramis is offline
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Location: Anchorage, AK, USofA
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LA, Detroit-metro, San Diego, Anchorage, Portland, Seattle/Tacoma - all of these have VAST spans of low-height buildings. With VTOL, you only need your clearance vertically for TO/L. Fly up, Fly over, drop down.

Those wires are not a big issue, and in the downtown areas, the wiring is mostly underground, not elevated, anyway. In Portland, Seattle/Tacoma, and Detroit-metro, the biggest issue is the overhanging trees in the neighborhoods. To which the solution is slightly more complex:
taxi to the intersection, take off straight up, fly over the top of the buildings (the already required outside TO/L is 500' AGL (150m), fly to the nearest intersection, hover over the intersection (say, 50m/165'), trigger the demand switch (probably using a directional radio - cost about $50, but will be charged $5000 because it's for an aircraft; receivers will be charged about $1000 because government, probably paid for by license fees on the triggers), then taxi in ground effect to the driveway.

Infrastructure costs for adding a directional radio receiver, or even a ladar trigger, are MUCH lower than adding heliports.

The combination of cost, and demand... and that the business model is being worked on for a curb-to-curb air taxi in greater Portland, and that the wealthy neighborhoods will be the only ones needing it at first... and those tend to be less visible wiring...

There's no economic sense in heliports everywhere, and Uber's going to run into that as soon as it starts looking for places to build heliports. Tall buildings are not the easiest things to land on (ships at sea seem to be, but for the same reasons but flopped relative importance - constant motion and unsteady airflow), and if they weren't built for a helipad, the structural modifications will be expensive. And the Heliports everywhere has to still do the same vertical issues.

Now, in Anchorage, downtown is almost all 2-lanes (12') plus two parking-lanes (8'), where it isn't 3 lanes plus 2 parking lanes (5th & 6th ave). so we're looking at 40' to 52' of above road. The sidewalks are another 8' (4' minimum each side, some areas 6'), and the limit on new construction is 3 stories — by law, not just zoning regulations — and the old construction has at least 50' clearance. Not an issue in downtown for helicopters to fly between the buildings (the police and news do so not too infrequently).
Portland has likewise similar 50'-500' AGL having 50' side-to-side in downtown. (Yes, I've looked up in downtown Portland.)

Smaller cities like Albany, Corvallis, and Eugene, Oregon, all have plenty of spaces open enough to transition from flight to taxi-in-ground-effect. Just add the needed turn signals and brake lights (triggered by the laser altimeter detecting a slowdown in transverse speed), and you're good to go.

Mind you, Uber's design looks like a medium haul - say, 30-200 km trips. Short haulers are going to look more like a sports car, less like a plane, and be the 20-40 km range. (treble that for gasoline, in both cases.)
~ Aramis /trav
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