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jedi

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Wait, you want ornithopters...? :whistle:
Can humming birds fly?

Do you want something that works?

Is there a reason that quad copters and humming birds are small?

Can Giraffe's really talk?

Can the horse whisperer talk to a horse? Does the horse listen and talk back.

Can we do the impossible?

Will man ever be able to fly?

Did you pass this test?

No, I just want something that works better than what I already have. Still trying to figure out if today's equipment can be improved upon.

Ok, now that we agree that there is room for improvement can we work outside the box on a solution?

First step is to define the problem. There appears to be a general agreement among HBAers that Boeing is not doing a good job at that with their press releases.

Is this done for publicity or as a smoke screen?

Thanks for the challenge.
 

Aesquire

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A helicopter in descent is not the aerodynamic nightmare of a tail sitter. Arrows going backwards sums it up.

Admittedly the helicopter is it's own aerodynamic nightmare. And mechanical, as the thread repeatedly states, correctly.

The complication of variable pitch props would go a long way to improve efficiency in using the same motor/prop for hover & forward flight. The response & lag times in controlling pitch historically can be challenging to prevent out of control feedback loops/PIOs.
 

Victor Bravo

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Well then everyone please forgive me for being so resistant to the way most of these eVTOL attempts are being done.

With that, what is so wrong or untenable about an electric version of the jump-takeoff gyroplane like Pitcairn created?

If Dana's answer to my previous question (why can't a modernized R-22 helicopter work for this mission?) is essentially the reduced parts count and simpler parts count of multiple motor/rotor units, I will accept that for the moment.

I believe the jump-capable gyroplanes do have a lower parts count and fewer critical/complex parts than a fully articulated powered-rotor helicopter. The rotor is more or less un-powered (except for the pre-rotator, which is very simple and not flight-critical). I also believe the rotor head on a gyro is far less complex than the swashplates and hinges on a traditional helicopter, even when you add in the jumping pitch change.

The jump gyro is 99.9% VTOL, just not capable of extended hovering, and apparently this trade-off results in a far less complex mechanical system. Instead of an actual textbook "pinnacle landing" on a Jetsons style perch, it would of course require a small flat space about 40 x 40 feet. But that seems very reasonable in return for the real-world ability to take off and land in the middle of a city.

Using electric power for a modernized gyroplane seems like it would check most of the boxes for this mission without the cost/complexity of a helo?

Am I off my rocker thinking this way?
 

Aesquire

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The downside of gyros ( jump or simple ) is the high drag, requiring high power to get the same performance as a fixed wing. That's why there are no commuter gyros. Helicopter commuter flights are rare, as power required is higher than a gyro, ( more power, more fuel ) and there are few routes that are profitable. Even less with local regulation making VTOL ops impossible.

But! You'd think a hopper gyro would then get better economy, and he able to operate from most heliports, including tops of skyscrapers!

True. And if you don't have really noisy tip jets like the Fairey Rotodyne, you would be quieter than 'choppers.

So the answer to why not? ( Why no commercial gyro commuters? ) Is inertia, prejudice, lack of interest, fashion, ignorance, and cost. Pick some of all the above, depending upon specific example.

And your question as to "why multicopter instead of hopper gyro?" Has similar answers. Fashion, perhaps being #1.

Everyone sees drones. It's easy to make a website with pretty graphics and bold claims, with no actual product, to con big money from ignorant people, if the technology looks cool & leading edge. You'd need to be a pretty smooth salesman to sell 1930's tech to IPhone generation consumers & crowd investors.

Be aware that there is incredible technical ignorance with today's young consumers. Few know how to change a tire , much less tune a carb, ( ancient, obsolete technology, like moving stones with ropes & pulleys ) . The motorcycle industry is facing a major downturn. Performance isn't a desire. Ease is. ( see Incredibles 2 for super villain rant ) Scooter sales are good. Commuter cheap chic! Lifestyle Hogs? That's older folk making $90k.

Part of techno ignorance ( with great comfort playing software ) is that the portable gizmo market is fluid, and ossified, at the same time. Processors change, operating systems update, but swipe left is sacred.

So ignorant consumers buy click bait human Cuisanarts as fashionable future.
 

Aesquire

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So, no, you are not crazy.

You are behind, or sideways to the fashions & times.

There are hot rodders who put Chevy V-8 engines in Mazda RX-7 Wankel powered sports cars. They lose some nimble, but gain in power, and gas mileage. It's a poor metaphor, but I hope you get your relative position. Not wrong, just fringe.
 

Aesquire

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Question on the OP Ava?

Since the prop design for efficient forward thrust is different than hovering thrust, ( simply input air velocity, mostly ) and the quad/octo system is divided, electrically, top & bottom, Why not use hover props on top, and high speed props on bottom?

Is there enough power to overcome the efficiency loss with cruise props to still transition/hover/& land?

( I am assuming they can transition with available power from all 8 motors. Not yet tested )
 

BBerson

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Rotors flying apart and falling on pedestrians is what killed inner city operations in New York.
I don't see a solution to that yet.
 

Victor Bravo

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Rotors flying apart and falling on pedestrians is what killed inner city operations in New York.
I don't see a solution to that yet.
For business-level commuters going in and out of the city from homes in the suburbs...

1200 foot STOL runways within the city limits, and STOL-specific fixed wing transports that are optimized for 120 MPH cruise speed and 40 MPH STOL operation using big DH multi-slot flaps, leading edge slats, Krueger Flaps, prop blast over the flaps, etc. etc. to make a viable commuter system. The DH Twin Otter and Dash 7 are halfway capable of this already, so it is an easily achievable "next step" to create something similar for a shorter strip.

These short runways can be built on concrete or steel pilings just like bridges or elevated freeways ABOVE the industrial or junkyard areas of the city. Or they can be built on concrete pilings on the river/ocean/lake that is next to 80% of the world's big cities.

No large multi-billion dollar purchases of land, no "Eminent Domain" buying up houses or apartment buildings. You would build these platforms above the parts of the city that are already unsightly or polluted with toxic waste.

The aircraft would be reasonably low tech and reasonably fuel efficient. If they can eventually do it with batteries or fuel cells then fine, but until then they can now use seaweed diesel fuel or biodiesel or LNG or whatever is cleaner than dinosaurs.

For white collar criminals wanting to fly from one office building to another, they are still stuck with the helicopter until George Jetson finally shows up with something that works.
 

Vigilant1

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For business-level commuters going in and out of the city from homes in the suburbs...

1200 foot STOL runways within the city limits, and STOL-specific fixed wing transports that are optimized for 120 MPH cruise speed and 40 MPH STOL operation using big DH multi-slot flaps, leading edge slats, Krueger Flaps, prop blast over the flaps, etc. etc. to make a viable commuter system. The DH Twin Otter and Dash 7 are halfway capable of this already, so it is an easily achievable "next step" to create something similar for a shorter strip.

These short runways can be built on concrete or steel pilings just like bridges or elevated freeways ABOVE the industrial or junkyard areas of the city. Or they can be built on concrete pilings on the river/ocean/lake that is next to 80% of the world's big cities.
A few observations:
1) Yes, objectively, this would be a low-impact way to shuttle people to/from the city from as far out as 100 miles or so. Over a long-term, big-picture timeframe, paying the cost of the infrastructure to allow short horizontal TO and landing acft to operate would facilitate air vehicles that are more efficient at moving mass over a horizontal distance.
2) Let's be sure to add in the space needed for parking the planes, for the fueling trucks, for crash/fire/rescue, for the connecting transportation links, etc. 1200' x 100' is a tiny part of the total requirement. And if we are building everything on piers, the cost is a lot. And we'll have to keep the approaches at eaither end free of vertical development. Flaps, slats, and powerful engines make a lot of noise.
3) It wouldn't be mass transit, it's not going to be cheap enough for the guy making $20/hr. That guy/gal is stuck on the train or in 6 backed-up lanes of traffic.
4) Because of #3 above, it is hard to get public money for this. The tide is going the other way-- cities are doing all they can to bulldoze their handy close-in airports. Santa Monica, Meigs Field, etc, etc.

If these little 4-10 person VTOLs can operate off a rooftop or some "junk land" in a road, rail, storm drain right-of-way, then it overcomes a lot of real-world problems. A small number of folks might just meet up with a parked van for onward movement, so a very light footprint at the site. A bunch of small VTOLs moving 2-10 people will be less efficient and more expensive than moving X number of people 100 miles with (possibly larger) STOL aircraft, but if scraps of infrastructure can be used and it can be done incrementally, that's a huge practical advantage over needing to take on a deliberate, large infrastructure project in/near a downtown area. And, once there's a population of these VTOL air taxis operating, there will be a commercial incentive to provide handy spots from which they can operate.
 
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Jay Kempf

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Question on the OP Ava?

Since the prop design for efficient forward thrust is different than hovering thrust, ( simply input air velocity, mostly ) and the quad/octo system is divided, electrically, top & bottom, Why not use hover props on top, and high speed props on bottom?

Is there enough power to overcome the efficiency loss with cruise props to still transition/hover/& land?

( I am assuming they can transition with available power from all 8 motors. Not yet tested )
Very astute questions...
 

jedi

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It might make a deafening cacophony.
Passengers are not going to rotate 90 degrees and hang from their seat belts nor will they takeoff and land in a tail sitter. High speed forward motion needs variable pitch or separate lift and forward thrust propulsion or at a minimum Harrier or YC 14/15 type of airflow deflection.

Seattle is tearing down it's old waterfront elevated highway 99 as we speak. It would easily provide the surface area proposed above but it would never survive the local politics. Kenmore Air runs a profitable seaplane operation within the city that is an example of how things would work. No need for VTOL but does demonstrate a cost/efficiency/safety equation solution. The lake provides a necessary clearway and noise buffer for Kenmore and Elliot bay would do the same for highway 99. Operations from the center of the city from rooftops is what killed the New York Pan Am operation when the Helo fell off the roof. Their waterfront operation could have continued but they lost the economy of scale and changing times were against them like the Concorde SST once it was no longer in the vogue.
 
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BBerson

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I don't think city people will approve any structures or flight operations overhead. Gravity always wins.
Like jedi said, the tunnel is what Seattle built.
 

Jay Kempf

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I don't think city people will approve any structures or flight operations overhead. Gravity always wins.
Like jedi said, the tunnel is what Seattle built.
Have you ever heard of the High Line Park in Manhattan?

It is universally loved in NYC. If one could cordon off 100 yards of this thing it would be perfect for urban commuting.
 

BBerson

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No, never heard of it. Doesn't matter. The public doesn't really want any part of their city to be overflown.
So they likely won't grant anymore landing areas at all to make sure of no overflights.
My helicopter instructor said avoid low flights over any house.

Might be possible if descents to the pad were vertical from 15,000 feet or something so nobody would notice.
But still need approval for the pad and that is political.
 

Andy_RR

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Cities have people flying over them every day. I don't see it as terribly political if the price comes down to a level that most can afford at least sporadically. The cynic in me would say that when the politicians can afford it it will cease to be political...

As far as the New York Airways crash (N619PA), that's a very interesting case study on things that go wrong. Strangely enough it wasn't the whirly bits that failed but a landing gear strut that caused the aircraft to roll over. Because they were disembarking and boarding with the rotors turning and some negative collective applied the accident was worse than it might otherwise have been. All of the casualties were caused by flying rotor debris I think, which is not surprising because that was where all the energy was at the time.

No, it didn't crash in flight. No it didn't fall off the top of the building and no, the Jesus nut didn't let go. None of the failure modes conceived by conventional thought were involved. Instead something relatively unexpected caused an issue of considerable consequence.
 

jedi

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Seattlelites liked the overhead highway too but it is gone anyway creating great expense for a tunnel replacement and terrible congestion.

Buses (electric and hybrid) and light rail are the 100 year old solution. Yes, there is also a new street car.

King county has a regulation preventing construction of any new airport within the county.

And can you believe this is (or perhaps was) Boeing country?
 
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