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Jan 06, 2017, 05:46 PM
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Ruminations on Urban Air Taxis

Please forgive me, this story isn’t about VTOLs, nor is it about model aircraft. It’s about the future of urban air taxis, and it does have a small roll for VTOLs.

Some of you may recall, that I earlier published a white paper by Uber detailing their ideas about urban air taxi service. If you care to read it, it can be found in this forum under the title “Uber White Paper”.

Briefly, the idea is to have numerous small VTOL terminals throughout the city. They might be as little as 10 miles apart, and might be located at the tops of parking garages, inside the loops of freeway interchanges, and of course at existing airports. This would be a terminal to terminal solution, so it does not attempt to fly to your home or place of business, although it might take you directly to the airport terminal to catch a commercial jet. The so called “last mile” is handled by the fleet of self driving cars that most people will eventually use instead of buying a vehicle of their own.

In theory, you would use your smart phone to tell the system where you want to go and that you are willing to pay extra to fly. An Uber self driving car would pick you up, take you to the local VTOL terminal, you would exit the car and immediately get into the self flying aircraft with no significant delay or security. You would then fly 20 minutes to the terminal nearest your destination, overflying 60 to 100 minutes of traffic. Another self driving car picks you up at the terminal, also without security or delay, and 10 minutes later you are at your destination. The total travel time from door to door is about 40 minutes as compared to about 80 to 120 minutes by car, and you pay about twice as much.

Regardless of whether you like the idea, or believe it is even possible, there are people out there working to make it happen. The biggest barriers are not the aircraft, or even the landing terminals. It is government regulation and the air traffic control infrastructure. I won’t address those issues at this time but there are serious people working to solve those problems as well.

I said earlier that VTOLs would play a small roll, and that is because I believe they are not usually necessary to get the job done. It turns out that STOL (Short TakeOff and Landing) technology can do it more simply and cheaply.

In 1929 the Curtis Tanager won the Guggenheim Safe Aircraft Competition. You can look it up on Wikipedia.

This revolutionary aircraft, for its day, never resulted in any direct sales, but the features it demonstrated have become commonplace. They include Fowler flaps, Leading edge slats, floating ailerons, and long stroke compliant landing gear. At almost 2,000 pounds empty it could carry 2 people, fly in control at 31 MPH, and land in 90 ft. In short, it was the early version of the modern Carbon Cub with similar low speed performance at about half the empty weight. I mention the Tanager to demonstrate that this is not new technology, although it has been refined over the years.

This sort of aircraft works well in combination with an airport on top of a parking garage, and therefore meets the requirement of the mission described above. As much as I love VTOLs, they aren’t necessary to get the job done. All things being equal, simpler is cheaper, and in this case, I think safer as well.

To be Continued...
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Jan 06, 2017, 09:38 PM
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I will now shift my focus to the features of the terminal, and then come back to the aircraft. Bear in mind that the terminal and aircraft are made for each other. This is not a general purpose solution for whatever type of aircraft wants to land. It is a private airport for privately owned aircraft of a very specific type.

The terminal is a parking garage like structure of at least 3 stories. It measures about 150 ft. square, or larger. The flight deck on top measures 200 ft. square, or preferably 250 ft. in diameter. The round flight deck is preferred because it allows operation in any wind direction. Depending on the building size, the flight deck overhangs the building.

At the center of the flight deck is a small “tower”. It is not manned, but contains lights, antennas, cameras and sensors including LIDAR that allow the terminal control computer to track aircraft movement in, on, and in the vicinity of the flight deck to the inch and to the millisecond. The remainder of the flight deck is flat and unobstructed. On either side of the tower are 2 ramps that lead from the flight deck to the hangar deck below. They are 30 ft. wide and 40 ft long, dropping 14 ft. to the hangar deck below. They each have a 15 ft. wide powered rubber belt that safely carries aircraft and their passengers up/down the 20 degree slope. The ramps have large hydraulically actuated doors that provide some degree of weather protection.

The flight deck itself is covered with steel plate and is compatible with magnetic tie downs. The steel plate is covered with an all weather renewable friction grip surface. It also has electric resistance heaters that melt snow and ice. Aircraft are not stored on the flight deck but immediately taxi to the ramps and exit to the hangar deck. With the exception of maintenance personnel, people are not allowed on the flight deck unless they are in aircraft. All boarding and disembarking of aircraft takes place in the hangar deck.

The outer edges of the flight deck are rounded to prevent unwanted wind related turbulence. The outer edge of the flight deck is surrounded by a retractable barriers. These barriers are normally folded out in the flat position, but under the control of the terminal computer they can be rotated to vertical in less than 1 second. They are an emergency safety precaution to prevent aircraft from falling off of the edge of the flight deck, and are rated to withstand an impact of up to 60 MPH.

The flight deck supports operations on 2 “runways” that are nominally 60 ft. wide and 200 ft. long. The runway concept only loosely applies to the round flight deck as take off and landing operations can be in any convenient direction. The square flight deck supports operations in 4 directions. There is also room for 2 VTOL pads between the runways, on either side of the ramps.

Beyond takeoff and landing the building must be located to provide a reasonable “glide path” to the platform from most direction. Obstructions from terrain or other buildings are tolerable if they are far enough away or low enough so the aircraft can safely fly around or over them. These aircraft are extremely nimble so this is generally not a problem.

There is an external platform elevator of 25 ft. by 30 ft that provides access to all levels from ground level to the flight deck. For the round flight deck it is part of the flight deck surface and is normally stored at the flight deck level.

The hanger deck is 14 ft. below the flight deck with a minimum of 10 ft clearance. The two powered ramps are located on either side of the central core containing 2 elevators for people. Surrounding the ramps is a 30 ft. wide corridor for aircraft to travel to parking. Aircraft Parking and charging is closely spaced along the 20 ft deep outer perimeter. A building of this sort can hangar 34 aircraft or more per floor. Emergency access stares spiral up the outside surface of the building.

In some cases, multiple hangar decks are available with similar powered ramps from the hangar deck above. A portion of one or more of the hangar decks is available for aircraft maintenance. Lower decks are also available for parking of self driving cars. Within reason, the taller the building the better.

Next, I will describe the aircraft...
Last edited by; Jan 06, 2017 at 09:46 PM.
Jan 07, 2017, 03:30 PM
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The Ford model-T was a car for its time. Simple, rugged, and most of all cheap, it created a market that previously didn’t exist. Likewise, the aircraft I will describe is simple and cheap. It will soon be replaced by better, faster, and more comfortable designs, but those designs can’t exist until the market is created and demonstrated to be profitable.

The aircraft is a fully autonomous electric parasol monoplane of composite construction. It has side by side seating for 2 adults. The doors and side windows are very car like, except that the windows don’t roll down. There is only opaque structure where the wind screen would be. Passengers do not need to see where they are going, and in some cases, not seeing will reduce their level of anxiety. The lack of a windscreen also greatly strengthens the structure and reduces solar heating.

The seats are very car like in every respect, including seat belts. They are also compatible with custom baby carriers and child seats which are quick and easy to install. There is a small storage area behind the seats for a brief case or laptop. A small trunk area is located behind that with room for a couple of small suite cases. The design insures ease of entry and exit as passengers are expected to do so quickly. The seating height is similar to a full size SUV with provisions for short people to enter and exit safely.

The wing is mounted on a central pylon above the top of the fuselage. This places it above head height for almost all passengers. The wing is also supported by 2 external struts. The outer 6’ of the wing tips fold down and partly in along the wing struts via a fully automatic mechanism. The wingspan is 35’, 23’ when folded. The central wing section has a large fowler flap of the sort that extends down and back to increase the wing area. The outer wing sections have large full length ailerons that can also be lowered as flaps or raised sharply as air brakes. All surfaces are electrically controlled with redundant servo actuators.

A minimum of 8 flight motors are mounted below the wings on short pylons, Altogether they blanket the entire wing with propwash. The inner 4 motors, 2 on each side extend well forward of the wing making room for fixed pitch folding propellers. These large 4.5’ propellers are used for takeoff and landing, but are shut down and folded during cruise flight. The outer 4 motors, 2 on each side, blanket the folding wing tips at 3’ diameter. These fixed pitch propellers do not fold and are aligned with the wing tip for storage. The large number of low RPM propellers with low tip speed make the aircraft exceptionally quiet. Reverse thrust is available when needed by running the motors backwards.

The bottom of the fuselage, below the passenger compartment, consists of a belly pan containing the main flight batteries. They are designed for quick replacement by fully automated robotic tenders and can also be charged in place. In the unlikely event of a fire, the entire battery pack can be ejected leaving the aircraft to land as a glider, or to drive away if on the ground. This implies that there are additional batteries on board as an emergency power source for the control systems. Both the batteries and the passengers are located near the aircraft center of gravity.

The tricycle landing gear is of conventional design. In the unlikely event of a hard landing it is designed to progressively sacrifice itself to prevent injuries to the passengers. Otherwise it is relatively stiff for good ground stability with the expectation of making near perfect landings on a smooth hard surface. There is 1’ of clear space below the aircraft to allow for compression of the landing gear.

The main gear has electrically powered wheel hubs and electrically actuated brakes. They are capable of driving the aircraft up to 5 MPH in any direction and can free wheel for higher speeds. The nose gear is of the castering type with electric brakes. Altogether the landing gear allows the aircraft to pivot in place, drive backwards, and park itself. Wheel pants are included as the gear is not retractable. The tires are not pneumatic but are of the molded type similar to that used on a fork lift. This allows the wheels to be smaller for reduced drag. Strain gauges in the landing gear allow the aircraft to compute its center of gravity and make any necessary adjustment to its control parameters.

The fuselage is 20’ long with a conventional tail. The horizontal stabilizer is somewhat larger than usual and of the fully flying type. The leading edge of the horizontal stabilizer has fixed inverted slats allowing it to generate a large down force when necessary. Small vertical surfaces at the tips of the horizontal stabilizer provide additional lateral stability in addition to the vertical stabilizer. The top of the vertical stabilizer is no more than 9’6” as needed to provide adequate clearance within the hangar deck.

The flight control electronics and backup batteries are located in the tip of the nose and dashboard area. As flights are typically no more than 30 minutes, the passenger amenities are limited on this early model. Due to power limitations, there is no air conditioning, however cabin airflow is adjustable. There is also no cabin heat beyond electrically heated seats and footrest. Most user functions are via direct voice command. The UI is capable of speaking and understanding multiple languages. Available user actions include requests for emergency assistance, in flight rerouting and basic cabin environmental controls. Power is available for operation of personal electronics. Limited in flight entertainment is available including music, video, news, weather, etc.

I will cover safety features next...
Jan 08, 2017, 07:13 AM
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There are a good number of people at NASA working on technologies that will support the ideas you have envisioned above. Google "NASA Maxwell X-57". I think your assessment that the technology will precede the regulations is correct , as it currently is with small multicopters, autonomous small UAS and FPV beyond line-of-sight flight.

I think the regulations situation is an age-related thing. As the older generation (i.e.people my age ) moves out of the "system", the younger generation will accept and demand the new technologies and make appropriate regulations. The current system of giant hub and spoke air travel obviously has reached its capacity. Nobody likes air travel anymore because of the huge hassle. I think we will see a movement over the next 50 years toward more point-to-point, on-demand air travel. Exciting times for aeronautics innovators IMHO !!
Jan 08, 2017, 12:38 PM
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Originally Posted by OwlCity
I think we will see a movement over the next 50 years toward more point-to-point, on-demand air travel.
Obviously we agree, except on the time frame. I think this system will be up and running in many locations within 20 years. There is just too much money to be made to hold it back. Initially the money won't be for passenger transport, but all the other uses for drones (not my favorite word) will drive the infrastructure.

I expect self driving cars will also lead the way. In 20 years they should be ubiquitous and there will be a generation of soon to be young adults that will strongly consider never learning to drive. That should solve the public acceptance problem. I think self flying airplanes are mostly a simpler problem than self driving cars. There are additional safety concerns, but the technology is capable.

I think you are at least somewhat right about the age issue. They say public opinion changes one funeral at a time. I also think we are well up the conceptual adoption curve. The latest generation of college graduates has been coding since 3rd grade, and their smart phone is pretty much required for breathing. They will not balk at creating this technology.

I figure I have 10 to 20 years left, so there is a good chance that I will get to ride one.
Jan 08, 2017, 12:54 PM
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Please forgive the poor pencil sketches, but this should give some idea of what the aircraft could look like. It would make a fine flying model except for the tiny wheels.
Jan 08, 2017, 01:39 PM
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Safety Features

The biggest and most important safety feature is the programming of the flight computer. It has thousands of provisions for insuring passenger safety, avoiding accidents, and dealing with possible hardware failures. While nothing man made is ever perfect, it is vastly superior to even the best human pilot and will only get better over time. As a triple redundant fly by wire system it is constantly testing itself to insure proper operation.

Multiple cameras and microphones in the cabin allow contact with a human dispatcher in case of emergency. They also protect the service operator from liability claims related to passenger misconduct.

The entire cabin is a safety shell with multiple airbags in addition to the seat belts.

A BRS (Ballistic Recovery System) is installed. This is basically a rocket launched parachute for the entire aircraft. The BRS system will probably be eliminated over time, as unnecessary.

An electromagnetic drag brake. It is basically an electromagnetic “tail hook” that drops down from the tail of the aircraft, sticks to the steel plate of the flight deck and drags the aircraft to a rapid halt. It is not used for normal operations and like the BRS will likely be eliminated as unnecessary in time.

The entire aircraft is designed with multiple redundant systems. The main power battery is actually 2 batteries providing power to redundant motors and control systems. A 3rd backup battery in the nose provides emergency power for the control and safety systems. Safe flight and landing can be achieved even with the loss of multiple motors or control systems. This might require an emergency landing at a conventional airport though.

When on, or in the vicinity of the terminal, all of the terminal safety systems are immediately accessible to the aircraft. This includes fire fighting robots, the retractable perimeter fence, and thousands of provisions in their joint programming to prevent accidents.

The ATCS (Automated Traffic Control System) also provides a large measure of safety by providing up to the minute weather and traffic control information. This is a distributed control system, not a centrally controlled system. In other words, it is not a single point of failure for the entire air traffic system but provides mostly guidance to improve overall system safety.
Jan 08, 2017, 03:47 PM
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The attached shows the round and square flight deck. The runway directions are arbitrary with the round flight deck. The flight deck shows 4 VTOL pads 2 of which would be operational with any given runway direction. 2 hangar deck options park 28 or 46 aircraft per level. Extremely tight parking is possible because the aircraft park themselves under the direction of the terminal control computer and they cooperate to let each other in or out as necessary. The actual parking configuration is dynamically variable and need not relate to any marking on the floor. Parking spaces are assumed to include charging facilities, possibly induction plates built into the floor, or just sitting on the floor.
Last edited by; Jan 08, 2017 at 04:07 PM.
Jan 09, 2017, 05:33 PM
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So when is a VTOL necessary or preferable over a STOL solution?

One obvious issue is when the terminal is surrounded by tall buildings on all sides. This would be a problem for a VTOL as well as a STOL. Unless the aircraft has a low disk loading, like a helicopter, hovering is very energy and power intensive. Climbing straight up to get out of a hole is going to be challenging for most VTOL designs and will reduce their limited range considerably. This might be mitigated by climbing in a small spiral as even a small amount of forward airspeed reduces the power required.

Even if it is technically feasible the FAA has guidance criteria for an unobstructed glide slope in the proposed departure and arrival path. A helicopter has a pretty steep “glide slope” but some VTOL designs do not. Tilt wings are known to have a very poor (flat) glide slope due to wing stall buffeting. Tilt rotors, SLT designs and even helicopters can get into a so called “vortex ring state” where they get caught in their own downwash. In general this requires a minimum but still very steep glide slope to avoid.

Within reason a STOL aircraft can spiral down into a hole if it is large enough. Likewise it can spiral and climb out. The exact size of the hole that can be managed depends on the aircraft, but it would presumably be considerably larger than for a VTOL of some sort.

The truth is that a terminal surrounded by tall buildings is a bad idea regardless of the aircraft type. The swirling winds and turbulence in such an area can be extreme. The better solution would be to put the terminal at the top of the tallest building although that is obviously not possible in many cases.

So what about a less extreme situation? What if the terminal is surrounded by tall buildings on one or two sides, or more generally there are various buildings of various heights blocking various approach paths? It’s true that a VTOL can hover and point its nose into the wind regardless of direction but that doesn’t really solve the problem. Climbing straight up is not a good option from an efficiency point of view. In general, a VTOLs want to transition and become an airplane as quickly as possible. Many VTOL designs have a narrow transition corridor. That means they have a limited range of safe speeds and maneuvers that they can perform while in the process of a transition. This is similar to a STOL aircraft flying near stall speed. It would be much better to fly faster and gain control authority.

For example, let’s say that there is a large building immediately upwind of the terminal. If the winds are strong this is a problem for both aircraft types as extreme turbulence is likely. The VTOL is likely to fare better until it starts to transition and then things are going to go from bumpy to scary. The STOL actually benefits from wind but not turbulence. Given the light wing loading the ride is likely to be scary from the get go, though not necessarily unsafe. The obvious strategy for a STOL would be to take off into the wind and then turn to avoid the building. This is quite possible in most cases but depends on how far away the building is located. These STOL aircraft would be unusually agile. A landing under these conditions would be difficult for both aircraft as well. Once again, the VTOL probably fares better. For an upwind building in more reasonable wind conditions both aircraft should be fine. The STOL aircraft can take off cross wind or into the wind and turn.

Ultimately the possible landing configurations, wind conditions, and aircraft limitations are too complex to fairly discuss. It would be necessary to simulate operations in any proposed location under various weather conditions and set reasonable minimums. Those minimums might be limited by passenger comfort more than safety. Both aircraft types are probably capable of safely doing things that most passengers would not tolerate. It is probably fair to say that VTOL aircraft would have a broader range of acceptable conditions, but not by a wide margin, and that flight operations within that narrow additional margin would be rare.

I should point out that if flight operations at either end of the trip requires a VTOL then a VTOL is required for the entire trip. This increases the odds that a VTOL is required.

In many cases flight operations will be limited by airspace restrictions, such as local ordinances limiting overflight of buildings, etc. These ordinances are often based on noise or perceived safety. Both of these issues are not necessarily rational. In some cases the limitations would need to be renegotiated, but in general it would be helpful to have the facts on your side. The safety related issues would mostly be in favor of reducing these restrictions, but noise related issues are not so easily resolved. In general the STOL will win this argument. It takes a lot of power to hover, even more so with a high disk loading. Electric motors are presumed quiet, but propellers are not. The faster the tip speed the greater the noise. A STOL would have a relatively low disk loading (to the extent that such a concept even applies) and could be relatively quiet. A VTOL is likely to be much louder in hover and to a lesser extent during transition.

Per the Uber White Paper, NASA has considered conventional, short, and extremely short runway vehicle solutions in their Urban VTOL Air-taxi studies but found those approaches wouldn’t be feasible for built-up metropolitan areas because of the extensive land purchasing costs and other land use issues such as ensuring the avoidance of overflight of neighboring private property at altitudes below 500 feet. I find it hard to believe that a VTOL solution would not have the same problem. Climbing vertically or near vertically to 500 ft. is not an efficient solution. Some of the rules would have to change either way.

The Uber white paper also discounts STOL or E-STOL (Extreme Sort Takeoff and Landing) solutions due to the danger of dealing with crosswinds while flying on the edge of a stall. They claim this would require runways in multiple directions, and I agree. If, however, the runways are very short, like 200 ft. or 250 ft. then this is less of a problem. They also point to the relatively shallow climb angle of a STOL as compared to a VTOL. This is only true by degrees. It is true that a VTOL can climb vertically. A properly designed STOL aircraft could climb vertically as well, but the passengers would not like it. A more reasonable limit might be a climb angle of 30 degrees which is likely compatible with most terminal locations.

VTOL and STOL aircraft both benefit from technology advances such as multiple electric motors so the difference between the aircraft types becomes blurred. A STOL aircraft might have the power to hover, but not the control. A VTOL aircraft presumably has both. The difference in performance between the two types can become quite narrow. Ultimately the practical difference might come down to what the passengers are willing to tolerate. For example, A tight spiral to an abrupt landing might be practical and safe, but would probably make a lot of people sick. Also, a 3 G pullup and a 45 degree climb might be fun for some, but others would just find it scary.

None of this is meant to imply that these extreme maneuvers are frequently necessary. The requirement for something like this would almost always cause the terminal to be built somewhere else. It only becomes an issue in the most extreme cases such as in the center of an already fully built up city. There will be cases where a micro-air-terminal is not feasible regardless of aircraft type.

A VTOL is an STOL that can also hover. It almost always prefers to be operated as an STOL which means it can operate more efficiently, carry more payload, and fly more safely. The facilities I have described would serve VTOL aircraft well. There is a high price to be paid for the ability to hover though. In general, it requires twice the power, larger batteries, and a generally larger aircraft to carry the same payload. A VTOL is also generally more complex which ultimately relates to the cost of the aircraft and the cost to keep it flying. Greater power can make a VTOL safer in some respects, but also poses a greater risk in terms of complexity and the stresses on the various systems. An STOL is almost always flying in a way that can immediately recover from a loss of power. In many cases it can glide to a safe landing. A VTOL can probably become a glider from a hover, but only if it has enough airspeed and altitude, and it takes a lot, probably more than would be available unless it was already in forward flight. VTOL’s are also generally optimized for forward flight, meaning they glide fast. By contrast a STOL can glide slowly and land safely in a small space.

Ultimately a STOL is cheaper, and even more so if it is built in high volumes. All of this implies that VTOLs will only be used when necessary, and with proper design of the entire system it is rarely necessary. So long as we are talking about a terminal to terminal solution, it will be cheaper to build STOL capable terminals than VTOL capable aircraft. If at some point this evolves into a door to door solution, or even a door to terminal solution, then VTOLs become necessary. The cost of that solution will likely prevent it from becoming a widespread option. As with business jets, and helicopters it will be limited to those with more money than time. Most of us will not be willing to pay the cost, which means the volumes will be low, and the cost even higher. There is also the NIMBY factor (Not In My Back Yard). Very few neighbors will want a VTOL dropping in near their home. That means it has to fly and then also drive the “last mile” on public roads, which is an additional challenge.
Jan 10, 2017, 03:34 PM
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Specifications Summary

1. Conventional high wing layout.
2. 35’ wing span, 5’ chord, 175 sq. ft., 221 sq. ft. with Flap extended.
3. Powered wing fold, Outer 6’ folds under, not flat, for 23’ storage span
4. 20’ length
5. 8.5’ max height
6. Empty weight < 1,200 lbs
7. Max Payload, 650 lbs
8. 2 passengers, no pilot, 2 reclining-folding seats w. seat belts, compatible with child seats
9. Luggage compartment behind seats.
10. Fixed, main gear with wheel pants
11. Fixed castering nose gear
12. Main gain, drive motors and electric breaks in hubs, urethane non-pneumatic wheels.
13. Nose gear, electric break in hub, Small Urethane wheel, not pneumatic
14. Fully Blown Wing with 4 or more motors/props per side
15. The inner 2 props on each side are low pitch folding fixed pitch climb props.
16. The outer 2 props on each side are smaller diameter, medium pitch, cruise props.
17. All props are capable of reverse rotation for reverse thrust
18. Fowler flaps on the inner wing section corresponding to the climb props. 23’ x 2’ = 46 sq. ft.
19. Self retracting leading edge slats.
20. Flaparons on the outer wing section corresponding to the cruise props
21. Flaparons can go up for extreme crow and air brakes.
22. Full flying horizontal stabilizer w. fixed inverted leading edge slats. 51.5 sq. ft.
23. Electric motor driven wheels up to 5 MPH with free-wheel clutch, reverse taxi capable.
24. Electric wheel brakes
25. Stall speed, 35 MPH at full load in level flight with full control in all axis
26. Cruise speed, 90 MPH, top speed 110 MPH
27. Fully autonomous flight computer
28. Fully autonomous instrumentation package
29. Fully autonomous parking and charging
30. Belly pan quick replaceable battery pack.
31. Retractable electromagnetic “tail hook” (Not Necessary?)

Flight Deck

1. 200 ft. x 200 ft. square or 250 ft. diameter. 2 runways 60 ft. wide by 200 ft. long, allowing operations in 4 directions.
2. Flight deck may overhang smaller underlying parking garage like structure, minimum 3 stories high.
3. High speed deployable perimeter barrier. 8 segments, 2 per corner or multiple segments for round flight deck.
4. Steel flight deck compatible with magnetic hold downs and drag brakes.
5. All weather renewable friction grip flight deck surface
6. Fully autonomous operations, no one on the flight deck except maintenance personnel
7. 2 each Powered belt entry and exit ramps. 30 ft. wide x 30 ft. long (belt is 15’ wide)
8. Hydraulic actuated ramp cover doors.
9. Central “light House” for lights, antennas, sensors including LIDAR, etc.
10. 10 ft. clearance inside hangar deck.
11. 25’ x 20’ external service platform with access from ground level to flight deck
12. 2 each elevators in central core.
13. External access stairs.
14. Automatic vehicle crossing gates at entry/exit.
15. Fully autonomous computerized flight and ground control system
Jan 10, 2017, 09:28 PM
Registered User
And this is what the VTOL version might look like:
Jan 10, 2017, 10:38 PM
Registered User
Handicapped persons accessibility?
Jan 10, 2017, 11:53 PM
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Originally Posted by PlumbBob
Handicapped persons accessibility?
It's a fair point but no, not really. I am not sure if Uber cars or taxi cabs really deal with that either. Assuming a large enough fleet (of cars) then there would probably be some self driving vans with chair lifts, etc. It's a little hard to imagine an aircraft fleet large enough to support a special handicapped version, at least not for a while.
Jan 11, 2017, 01:28 AM
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My guess is that autonomous aerial vehicles would more likely be utilized by first responders and air ambulance services (your 20 years) than by the general public, at least initially. Given the rate of technological innovation, by the time the idea might be integrated into general public transportation policy (Owl City's 50 years) your concept might require an extensive, if not complete, redesign. (Did you say that already??) Inspirational, none the less.
Jan 11, 2017, 09:56 AM
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Originally Posted by PlumbBob
My guess is that autonomous aerial vehicles would more likely be utilized by first responders and air ambulance services (your 20 years) than by the general public, at least initially. Given the rate of technological innovation, by the time the idea might be integrated into general public transportation policy (Owl City's 50 years) your concept might require an extensive, if not complete, redesign. (Did you say that already??) Inspirational, none the less.
It's an interesting thought, and a completely different application for autonomous flight capability. Since life flight helicopters already exist you may be right about it being developed first. On the other hand, it is such a niche market that there isn't much money to drive the development.

One aspect of possible air-ambulance operations involves emergency vehicles to the home, office, or scene of the accident. Since we have lots of ground vehicles for that then the driving issue would presumably be gridlock traffic preventing the ground vehicles getting through in a timely manner. I know it happens on occasion, but my impression is that mostly those guys run on the shoulder, push through lights, etc. and get to where they need to go. I am sure there are delays, but I don't know if there is enough money to drive the new technology. There are also life-flights to pick up injured people in remote areas where ground access is limited, or a long bouncy ride would further harm them. There are also transfer flights from one facility to another though I think that is almost always done via ground transport. Finally, there is emergency organ transport for transplants, etc.

These are mostly door to door, not terminal to terminal applications. That implies a VTOL solution like a helicopter. They are also ad-hoc requirements meaning they need to drop into forest clearings, unprepared landing zones, driveways, back yards, hillsides, parking lots, etc. In some cases they might require extensive hovering. All of these things suggest the need for a helicopter, not a VTOL. They also suggest the need for a human pilot to make ad-hoc decisions about where to land, what risks are acceptable, etc.

Also, the size of these vehicles is relatively large. The ground vehicles are typically big trucks or vans. The helicopter versions are pretty cramped, but still have room to carry at least a single gurney. The current helicopter versions involve a separate pilot and EMT (not claiming to be an expert here..). If it was fully autonomous, then that would eliminate the pilot, but 2 people might be required anyway just to safely deal with the situation.

I am also thinking that this needs to be a "wet" vehicle, not battery powered, for reasons of range and raw power. Helicopters have difficulty at higher altitudes and high disk loading VTOL's even more so. Electric vehicles still can't compete with the range and raw power of a turbine powered aircraft.

I think I have talked myself out of it. Emergency vehicles don't seem like a good fit for this technology, at least not for quite a while. That is my guess anyway.

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