How can we improve helicopter technology with a new flying car design?

[amorphos_b]

My idea for a flying car...The image below shows my idea for what i call a flyer [flying car/vehicle]. The basic principle is to utilise lift instead of thrust momentum as the means of take-off and flight. This means it won't blow air everywhere and doesn't have dangerous blades [also has safety micro-gauze around wing-mesh], thus providing an improvement to helicopters and a greater diversity of landing potential. The essential idea is simple, if e.g. You tied a small rc plane to a pole by wire, it could take off and land as usual but in circular fashion, so if you had hundreds of them they would do the same. Now add a spoke to connect them to the pole and they would lift en masse as a complete unit. Each disk of wings added together [4X4] would give similar amount of lift to a small light aircraft, where essentially we are rearranging the functionality of such a craft into this form.The vehicle would be mostly composed of artificial black diamond [using my carbon manifestor invention idea [like a 3D printer but not that]] and so is extremely light in weight, and 5 times stronger than the finest steel. The method this version uses is what i call a ‘wing-mesh’ which is a collection of small wings in multiple disks, connected by carbon wires in rings such to provide tilting action akin to take off position for aircraft. A small [non-drive] propeller can be added in front of the oncoming rotation segment of the wing-mesh, so as to create greater air density. A set of multiple small main drive propellers are stationed at the rear of the vehicle and are switched on once the vehicle is say 30ft in the air. they are small so as to provide a smaller thrust vector. The ultra-high-speed motors will have carbonado [black diamond] wires for lightness [instead of copper] and greater rotary speed, this due to the material having 5 times greater conductivity than copper.Ideally as the inventor i would make it very reliable with 3D vision provided by cameras [and emergency parachutes] at the four corners, along with all available detection technology.

_

 

[berkeman]

Pretty pictures. Have you built a scale model yet? How well does it fly?

 

[amorphos_b]

I am a 2d artist but not a 3d modeller, so this is at the beginning stages. I wanted to get the idea out there for if anyone wanted to take it further [a tech uni, global car manufacturer or something?], and just because i like sci-fi stuff, and hope one day something like this will be made.

Apart from helicopters with 4 blades at the corners i haven’t seen much out there, and such vehicles would have similar issues to conventional helicopters.

 

[berkeman]

Have you seen some of the latest concept flying cars based on the tilt rotor concept used in the military Osprey aircraft? They seem fairly promising...

http://www.militaryfactory.com/aircraft/imgs/bell-boeing-v22-osprey.jpg

http://www.gizmag.com/terrafugia-vtol-tf-x-flying-car/27402/
http://regmedia.co.uk/2013/05/06/terrafugia_vtol_car_flight.jpg

http://in1.ccio.co/Y2/62/8D/flyingcar10.jpg
http://in1.ccio.co/Y2/62/8D/flyingcar10.jpg

 

[amorphos_b]

Yes and lockhead have a large annular double rotating wing for vtol... The blog link is closed now so i can't linky to it sry

they are not flying cars though, or anything like. I think my idea is closer?

edit; not in terms of similar usage. you couldn't park it outside your house and take off/land etc with any of those.

 

[berkeman]

you couldn't park it outside your house and take off/land etc with any of those.

With the tilt-rotor concept you can. Especially the versions that fold the tilt-rotor assemblies into the body of the car when on the ground.

Here is a recent CNN article surveying current flying car efforts: http://money.cnn.com/2015/05/18/luxury/flying-cars-aeromobil/index.html

 

[amorphos_b]

Well i still think the neighbours would complain if you had those dangerous blades, and immense winds from thrust momentum based systems blowing their gnomes over lol.

Seriously though i think they present similar issues to helicopters, so i would ask if you think my system would be an upgrade? And which you would prefer to use e.g. If you were a business person who currently uses helicopters, wouldn’t you prefer these quieter and less windy and much safer and all round more civilised machines?If you saw a real one, wouldn’t you choose it over any of those others? ...both practically and aesthetically.

 

[berkeman]

i think they present similar issues to helicopters

The better looking designs use ducted fans, so the blades are not exposed. And yes, you'll want to pull into an open space like a parking lot before firing up the VTOL...

 

[amorphos_b]

Hmm well maybe, but i can't see them getting permissions for that, except perhaps dedicated areas. They could add a micro gauss for better safety around families perhaps.Still the question remains as to weather or not my machine is superior, and possibly more efficient? VTOL would probably be the same ~ it takes the same amount of work to do the same job weather we use propellers [thrust momentum system] or wing-mesh [multi-lift system]. However, in flight i would envision my design to have the edge on efficiency, because its essentially flying more like an aircraft, and the speed of rotation could be reduced relative to the speed of movement through the air. My system would be...1.Quieter [thrust momentum is noisy].

2.Safer.

3.More efficient.

4.Has greater utility in terms of landing/taking off.

5.Far less windy.

6.Better aesthetics, and design potential.Is generally an upgrade to bladed systems?

 

[cjl]

No matter how you make lift, you're going to have a large amount of downwash. You've basically just invented a helicopter with enclosed rotors, and your small disk area (and high disk loading) would mean that the downwash velocity would be very high, resulting in a large amount of noise and disturbance to the area beneath the craft. If you want to decrease the downwash from a vertical takeoff and landing vehicle, you need to dramatically decrease the disk loading, which means increasing the diameter of your rotors (a lot).

 

[berkeman]

1.Quieter [thrust momentum is noisy].

5.Far less windy.

TBH, I didn't understand what you were trying to say about your blade design. How could it be "far less windy" while producing the same downward thrust? You still need to move the same amount of air to get the same thrust...

 

[Mech_Engineer]

Amorphos_b, I think your concept might have a fatal flaw... If I understand correctly, you're claiming to use a set of enclosed "wing-mesh disc" to generate lift, but it cannot generate lift without having net downward air flow like a ducted fan. In your concept you have it enclosed; this would result in the disc's net upward force being canceled by a net downward force of the air hitting the bottom of the enclosure. In other words, it can't work; you'll just mix air in the enclosed space.

Additionally, how realistic do you really think it is to use "artificial black diamond using my carbon manifestor invention"? Sounds pretty out there to me...

 

[cjl]

TBH, I didn't understand what you were trying to say about your blade design. How could it be "far less windy" while producing the same downward thrust? You still need to move the same amount of air to get the same thrust...

This isn't quite true - you need the same momentum change to get the same thrust. You can achieve this by affecting a very small amount of air with a very large change in velocity (inefficient and loud) or by affecting a very large amount of air with a relatively small change in velocity. You'll definitely end up with significant downwash no matter what if you're lifting something the size of a car though.

 

[amorphos_b]

CjlI figured that the downwash is mostly caused by thrust momentum. This system is more of a lifting up, rather than a downwards force pushing against the air. The essential principle in lift [especially at the small scale] is the difference between the the lines i.e. The comparative difference between the upper and lower wing surface. This difference draws the object upward relative to that, where in larger wings that creates a vortex in the air to produce lift, what is also occurring is an energy transferral of lateral momentum and force relative to the arrangement of wings/forces. I envision this as a mass of arrows denoting the energy/momentum movements of the system, and they [arrows showing forces] are not all directly downwards, many of them would be lateral divided by slight up/down small localised movements ~ same as with bird flight.I would wager that if someone built this, there would be a significant difference in air moving downwards to thrust momentum [bladed] systems. As such a device has yet to be tested, i would also wager that the maths would change upon measuring the actual differences.Why would it be much different to an aircraft which is noticeably less windy than helicopters? Essentially this is just wings in an unusual arrangement. Consider how a spinning Frisbee floats without much down-force due to the motion of the spinning action.BerkemanIt is not producing the same downwards thrust? Wing lift isn’t the same as thrust momentum. See above.Mech engineerDo you really think i would make such a childish and ridiculous mistake as expecting enclosed wings to work!The semi-transparent part of the wing-mesh pod, is a honeycomb gauss, thus allowing airflow. The base of the pod is the same but you can't see it on the image of course._

 

[berkeman]

This system is more of a lifting up, rather than a downwards force pushing against the air.

This is starting to sound like pseudo-science. The thread will not remain open very long if you insist on making statements like this...

 

[amorphos_b]

also consider the relative lightness of a craft made of black diamond.

 

[berkeman]

also consider the relative lightness of a craft made of black diamond.

That's not helping your cause...

 

[amorphos_b]

sorry, I was trying to say how different the forces would be working.

 

[cjl]

Why would it be much different to an aircraft which is noticeably less windy than helicopters? Essentially this is just wings in an unusual arrangement.

Aircraft don't seem to produce as much downwash as helicopters because of two factors:

1) They aren't staying in place, so the downwash is not felt in a single location
2) They affect an ENORMOUS amount of air. A fully loaded 747 needs about a million pounds of lift force to stay aloft. This means that the mass flux of the air it affects multiplied by the downwash velocity must be approximately a million pounds (4.45 million Newtons). However, at the stall speed of a fully loaded 747, it is traveling about 77 meters per second. With a wingspan of 65 meters, and assuming the wing itself is affecting a region of air approximately 20 meters thick (not a horrendous assumption for now, though this is obviously the biggest fudge factor in this whole calculation), the aircraft is affecting a volume of air equal to 100 thousand cubic meters per second. Since sea level air has a density of about 1.25 kg/m³, the mass of air affected per second is 125 metric tons. To generate 4.45 million Newtons of lift with 125 metric tons of mass flow per second, the 747 is generating a downwash velocity of about 36 meters per second. This is pretty substantial, but probably not the main thing you'll be paying attention to if a 747 flies by at a low altitude.

No matter how you generate lift, you can't get around the generation of downwash. As I said, you can reduce the velocity of the downwash (and the power required) by increasing the mass flow rate of the air affected - aircraft do this by having a larger wingspan or flying faster, and helicopters can do this by increasing the total rotor area. You can't escape this though.

 

[cjl]

Consider how a spinning Frisbee floats without much down-force due to the motion of the spinning action.

A frisbee doesn't make much downwash because it doesn't weigh very much. The spinning isn't helping the lift, it merely makes the frisbee's orientation stable.

It is not producing the same downwards thrust? Wing lift isn’t the same as thrust momentum. See above.

Wing lift is absolutely due to the momentum change of the air. Helicopters don't use any fundamentally different principle from aircraft wings.

 

[amorphos_b]

^^ ok thanks. :)

Would you chaps say that there are no benefits from lateral forces from the propeller over the wings, and from an increased air density. That some of the downwards wind of the upper wings would not be somewhat dissipated by the lateral movement of the wings below?Is the no benefit to this system?

The faster you spin a Frisbee the greater the movement of air around its surfaces, and a volume of air density is increased - i thought? Thus ‘helping’ with the lift. They seem to fly better/more effectively the more you spin them.

 

[berkeman]

The faster you spin a Frisbee the greater the movement of air around its surfaces, and a volume of air density is increased - i thought? Thus ‘helping’ with the lift. They seem to fly better/more effectively the more you spin them.

That is not how a Frisbee works. As said before, the spinning is only for stability. The shape gives a little lift from the translation velocity. That is all that is required to lift it when thrown.

Can you tell us about your aerodynamics learning/training? We can try to help you learn, but you should not make assertions that are not backed up by technical knowledge. Wings and propellers are well-understood technologies...

 

[russ_watters]

...so i would ask if you think my system would be an upgrade?

Sorry, but no. Stacking rotors on top of each other provides virtually no additional benefit over having just one rotor. There is a reason helicopters have a single, large rotor instead of a stack of smaller rotors: it just works better.

 

[amorphos_b]

Two principles...Helicopter; forces air at great velocity such to push itself upwards.Aircraft; forces itself through the air at great velocity to give lift.These are opposites.The wing-mesh system works by the second principle!+If the wing surface area multiplied by rotational speed, is the same as that and lateral speed, the two things will do the same job!Where a light aircraft can gain lift of at say 80mph, then a vehicle of the same weight with the same wing surface area, will gain lift at the same speed but in rotational terms.This may vary somewhat by design, yet the rotational speed required by the wing-mesh would be many times less than that of a propeller or helicopter blades. Ergo less noise, and less wind._

 

[Mech_Engineer]

Helicopter; forces air at great velocity such to push itself upwards.

Aircraft; forces itself through the air at great velocity to give lift.

These are opposites.

Wrong. A helicopter's rotor has a cross-section that is an airfoil, just like the wing of an aircraft. Spinning the rotor makes the airfoil travel through the air, creating lift.

https://en.wikipedia.org/wiki/Helicopter_rotor

The wing-mesh system works by the second principle!
+
If the wing surface area multiplied by rotational speed, is the same as that and lateral speed, the two things will do the same job!

You are describing exactly what a helicopter does, there is no fundamental difference between the aerodynamic principles of helicopters versus airplanes. Your "wing mesh" is in fact probably less efficient than a helicopter due to proximity of the individual air foils in the rotor.

I recommend you listen to the experts on this board, it's clear you do not have the necessary knowledge in aerodynamics to make claims about performance of your concept.

 

[amorphos_b]

I know helicopter rotors are wings, but they have a twist which produces thrust momentum, and that produced much of the downforce and all that wind.I am happy to listen to experts which i why i posted it here, i just don’t think you chaps have had time to think this thing through. Why wouldn’t the same wing surface area work like a plane but rotational rather than lateral? To me this idea is an aircraft and not a helicopter, and you guys don’t seem to be thinking of it in that sense. People always deny new ideas especially if they work in the industry and its not in their favour for something new and better to replace what they are doing. I can imagine that would be quite upsetting. ...but don’t get me wrong, i am listening and i know it could as easily be me getting the whole thing wrong, i would just like to hear from a few more people. Naturally if everyone thinks as you are, then it probably is me getting it wrong and i’ll accept that if the arguments make sense, but so far the comparatives have been incorrect or otherwise pertain to different types of craft and systems. Thanks for your help so far.

 

[cjl]

I know helicopter rotors are wings, but they have a twist which produces thrust momentum, and that produced much of the downforce and all that wind.I am happy to listen to experts which i why i posted it here, i just don’t think you chaps have had time to think this thing through. Why wouldn’t the same wing surface area work like a plane but rotational rather than lateral? To me this idea is an aircraft and not a helicopter, and you guys don’t seem to be thinking of it in that sense.

It does. Kind of. There are some complicating factors with a rotational system because your wing is operating in the wake of another wing (not in clean air), but fundamentally, it does work exactly as you envision. However, as I already pointed out earlier, aircraft have downwash too. Helicopters are exactly what you're proposing here - a rotating airfoil to allow the vehicle to lift while stationary. There's no fundamental difference in the amount of air an airplane must direct downwards compared to a helicopter to stay airborne - you just don't notice the downwash from the airplane because it never hovers over a single spot. You're making a distinction that really doesn't exist here.

 

[amorphos_b]

Ok thank you! All i wish for here is a debate where my points are answered, and i felt they were only part answered. Wings also produce lift [air vortex above the wings pulling it up] which isn’t the same as thrust momentum. I agree that they equally produce down-force, and i am concerned over the dirty air issue. my inquiry pertains to how much vertical force vs lateral and upwards forces multiplied by required rotational speed. The air density propellers move air over the wings [lateral force], and each wing produces a small amount of lift pulling them upwards. If the required rotation speed is lower than propellers or rotor blades, then the thrust momentum [and noise] is reduced respectively.

as I see it forces can move through air without necessarily moving it to the same degree, if we consider how they create waves in water yet the main body of water remains in place. if lift occurs the a fraction of time prior to where the air is moved laterally, the momentum may continue somewhat and a proportion of the lift has already occurred prior to that, and the wind is then moved somewhat laterally. I know air doesn't have the same properties of water though.

 

[Mech_Engineer]

I know helicopter rotors are wings, but they have a twist which produces thrust momentum, and that produced much of the downforce and all that wind.

As discussed planes also have downwash, it's a result of equal-and-opposite force reactions. If the plane's wing has a net lift force keeping it up, then the air must also have an equal-and-opposite force pushing it down. Planes don't concentrate this downwash in a single location however because they're traveling at hundreds of MPH.

Why wouldn’t the same wing surface area work like a plane but rotational rather than lateral? To me this idea is an aircraft and not a helicopter, and you guys don’t seem to be thinking of it in that sense.

Helicopters are subject to the additional constraint of having to design the rotor to put up with (and are stiffened by) centrifugal acceleration because the rotor is spinning. For this reason they have different optimization requirements, but the principles governing their design is the same aerodynamically. A helicopter's rotor is an airfoil traveling through a fluid, the fact that it's spinning is irrelevant; all that matters from a lift standpoint is the tangential speed each portion of the blade has w.r.t. the fluid it's traveling through.

You might notice some helicopters (for example the human-powered helicopter) will have larger blades for operating at lower RPM, and therefore need larger cross-section blades that look more like an airplane's wing.

People always deny new ideas especially if they work in the industry and its not in their favour for something new and better to replace what they are doing. I can imagine that would be quite upsetting. ...but don’t get me wrong, i am listening and i know it could as easily be me getting the whole thing wrong, i would just like to hear from a few more people. Naturally if everyone thinks as you are, then it probably is me getting it wrong and i’ll accept that if the arguments make sense, but so far the comparatives have been incorrect or otherwise pertain to different types of craft and systems.

Your concept is not fundamentally different than a ducted fan. I recommend you try reading a little about ducted fans, their design requirements, and their pros/cons.

https://en.wikipedia.org/wiki/Ducted_fan

[Ducted Fans]
Advantages

• By reducing propeller blade tip losses, the ducted fan is more efficient in producing thrust than a conventional propeller, especially at low speed and high static thrust level (airships, hovercraft).
• By sizing the ductwork appropriately, the designer can adjust the air velocity through the fan to allow it to operate more efficiently at higher air speeds than a propeller would.
• For the same static thrust, a ducted fan has a smaller diameter than a free propeller, allowing smaller gear.
• Ducted fans are quieter than propellers: they shield the blade noise, and reduce the tip speed and intensity of the tip vortices both of which contribute to noise production.
• Ducted fans can allow for a limited amount of thrust vectoring, something normal propellers are not well suited for. This allows them to be used instead of tiltrotors in some applications.
• Ducted fans offer enhanced safety on the ground.

Disadvantages

• Less efficient than a propeller at cruise (at lower thrust level).
• Good efficiency requires very small clearances between the blade tips and the duct.
• Requires high RPM and minimal vibration.
• Complex duct design, and weight increase even if constructed from advanced composites.
• At high angle of attack, parts of the duct will stall and produce aerodynamic drag.[3]

 

[cjl]

Ok thank you! All i wish for here is a debate where my points are answered, and i felt they were only part answered. Wings also produce lift [air vortex above the wings pulling it up] which isn’t the same as thrust momentum. I agree that they equally produce down-force, and i am concerned over the dirty air issue. my inquiry pertains to how much vertical force vs lateral and upwards forces multiplied by required rotational speed. The air density propellers move air over the wings [lateral force], and each wing produces a small amount of lift pulling them upwards. If the required rotation speed is lower than propellers or rotor blades, then the thrust momentum [and noise] is reduced respectively.

You keep wanting to have some mechanism to generate additional lift without additional momentum flux, and it just doesn't work that way. No matter how you make lift, each Newton of lift will require that the vehicle adds 1 kg*m/s of momentum to the surrounding air each second. You seem to believe that the low pressure above the wing is somehow generating lift without adding to the momentum flux, and it isn't. 100% of the lift from a wing can be accounted for simply by measuring the downwash in the wake of the wing.

 

[berkeman]

People always deny new ideas especially if they work in the industry and its not in their favour for something new and better to replace what they are doing. I can imagine that would be quite upsetting.

Please do not try to use this argument here at the PF. We do not allow suggestions of conspiracy theories or other apologia for misinformation.

 

[russ_watters]

You keep wanting to have some mechanism to generate additional lift without additional momentum flux, and it just doesn't work that way. No matter how you make lift, each Newton of lift will require that the vehicle adds 1 kg*m/s of momentum to the surrounding air each second. You seem to believe that the low pressure above the wing is somehow generating lift without adding to the momentum flux, and it isn't. 100% of the lift from a wing can be accounted for simply by measuring the downwash in the wake of the wing.

Indeed, for a helicopter or ducted fan, it should be easier to visualize that, since they create a fairly coherent column of moving air, who's velocity and/or momentum is easily calculated.

 

[amorphos_b]

multiple or aircraft sized winfThat a force has an equal and opposite is a bit like saying; did you know 2+2 = 4. But let me try another approach if i may...Imagine if instead of many little wings i had many little rotor blades or propellers, the thrust vectors would be respectively smaller and the dissipation of air into the general field of air would occur sooner. Ergo there would be less air blowing if you were stood say 10 ft away from it than an equivalent single rotor/propeller with a large thrust vector.The next thing to consider is efficiency whilst cruising at say 100 mph, wings have an element of gliding ability, whereas propellers have very little. Rotors, i agree have some wing like capacity in this sense, but not as much as aircraft wings [or multi-wings of same surface area]. Admittedly with my system only a proportion of the wings are meeting the oncoming air at anyone time, but the whole thing is still moving through air, and even that smaller amount is still far more than props or rotors.

 

[Mech_Engineer]

Imagine if instead of many little wings i had many little rotor blades or propellers, the thrust vectors would be respectively smaller and the dissipation of air into the general field of air would occur sooner. Ergo there would be less air blowing if you were stood say 10 ft away from it than an equivalent single rotor/propeller with a large thrust vector.

Please provide a citation for your assertion, any published result showing proof-of-concept for this claim will do. I think you'll find you are incorrect, but I'm open to being proven wrong.

The next thing to consider is efficiency whilst cruising at say 100 mph, wings have an element of gliding ability, whereas propellers have very little. Rotors, i agree have some wing like capacity in this sense, but not as much as aircraft wings [or multi-wings of same surface area]. Admittedly with my system only a proportion of the wings are meeting the oncoming air at anyone time, but the whole thing is still moving through air, and even that smaller amount is still far more than props or rotors.

I'll quote Akin's Laws of Spacecraft Design: 1. Engineering is done with numbers. Analysis without numbers is only an opinion.

Please provide an analysis or paper which shows this is the case, I think we'll all be better off if you start backing up your claims with reasonable proof via publications or calculations.

Edit- by the way, you need not distinguish between your design and rotors. They are the same thing, you just have a many-bladed design which you're claiming is more efficient through motivated reasoning but without providing any solid facts which prove it.

 

[amorphos_b]

Now you are just attempting to divert the issue, when if you are an expert then you already know the answers...

Noone has built such a device [multiple small propellers] as far as i know [i expect the motors wouldn’t be powerful enough]. I am speaking in theory and simply stating that smaller propellers produce smaller thrust vectors, are you saying this isn’t true? Or do you mean that the collection would be the same as a single blade doing the same job, because that at least would make sense. For it to be exactly the same the mass of blades would have to occupy the same area though, and you could spread them out or layer them such that a proportion of the thrust vectors have dissipated by the time it reaches the next layer of blades. I know we are only talking small differences but that’s all i am stating anyhow.Please answer the question; do wings glide more than rotor blades? A helicopter uses a lot of energy to stay in the air, and only the angle of the blades are driving it forwards. An airplane uses most of its energy to propel itself forwards and the act of pushing itself through the air keeps it up.
Please give me a little leeway, I am only asking simple questions which i know you know the answers to e.g. Small propellers have smaller thrust vectors. I am not trying to insult you or say that anything you have said is fundamentally wrong, i already stated that it would take the same amount of work to do the same job, and now you are asking me to provide existing cases for something that has not been built ~ and you already know that.