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Post by freethinker on Dec 8, 2013 14:13:08 GMT 12
New to this Forum and looking for constructive thoughts. If you visit www.boatdesign.net/forums/projects-proposals/ground-effect-vehicles-not-wig-48743.html this would explain what I have in mind. I believe it is possible to build a helicopter (or ground effect vehicle) very cheaply and with simple design similar to what our early pioneers tried to do. The flight control would be quiet different to anything yet tried and could not be explained or understood without an in-depth discussion about classical mechanical geometry. |
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Post by suthg on Dec 8, 2013 15:10:30 GMT 12
Just thinking out loud - it sounds like you need two props - smallish you say, (higher revving) fixed or adjustable pitch but not cyclic pitch control. Then with two engines/props running in opposite directions you counteract the inertial response of opposite rotation or reaction rotation so less need for collective pitch control, but you still need direction control. Here the second prop can be ducted to a rudder or to act as a rudder with a directional jet flow. Also possible for vertical control as well? (additonal lift?) Thoughts of the harrier come in here... It all sounds a bit like the Martin jet-Pack, there the problem is weight vs HP and efficiency in the twin props.
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Post by freethinker on Dec 8, 2013 16:02:29 GMT 12
Just one motor and rigid rotor,not coaxial.prefer ducted for safe operation. The flight control is by changing center of gravity. torque control by ducted air flow.Not prepared to spend millions but convert an existing heli for easy quick experiment trial.
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Post by Bruce on Dec 8, 2013 18:07:11 GMT 12
Hi Freethinker, As I'm probably the only one on the forum here who has successfully designed and built their own aircraft, I congratulate you on thinking outside the box. I believe however that some of the fundimental principles behind your concept are flawed. Your concept of a single powered rotor is unlikely to be workable - even with "ducted air flow" you will need form of anti torque - torque is not always proportional to airflow so its likely to spend a whole lot of time spinning in circles - as can be demonstrated by a helicopter on floats - they start dancing around as soon as the rotors start turning, even though they arent generating airflow and the tail rotor is ineffective. Your "simple" rotor head idea is also flawed - the simplest idea is the "rigid Rotor" system which uses flexible blade connections - which are in themselves incredibly complex engineering. A quick check of a wiki page: en.wikipedia.org/wiki/Helicopter_rotor shows that there is no such thing as simple powered rotor head. How are you intending to make your craft move forward? As soon as you do that you get advancing / retreating blade assymetry and the whole thing will roll over. Its something the early pioneers struggled with and they eventually overcame it - with the conventional complex rotor head! Your C of G pendulum control concept is not only unlikely to work, it is deadly - in order to effect the change enough to provide control at a low energy scenario, you are going to have to swing a LONG way - that takes time, far longer than the instability cycle of a powered rotor. You simply couldn't move it quickly and sensitively enough to maintain control. In addition, because of gyroscopic reation, you would need to add control inputs approx 90 deg out of phase with the upset (helicopter swashplates are aligned to counteract this)so the weight shift inputs will be extremely unnatural. An instability "runaway" will be almost inevitable. You say that being only in surface effect you will not be at risk - not so! Helicopter crash statistics show that in ground effect is one of the most dangerous flight regimes. You need to know what is going on, and what you are doing. The energy stored in dynamic components will seriously hurt you - regardless of your height off the deck. factor in the complex interface between the dynamic airflow, the ground and recirculating air and you are really in dangerous territory. I really hope you have a better understanding of rotorcraft dynamics than your posts on the other forum seem to indicate - a project of this nature is really on the edge of the envelope - know whats under foot before stepping off the edge! As a suggestion (based on a design concept for an "ultra Stol" wing I am playing with), how about dual prop / rotors driven by electric motors, in turn powered by a Generator (Gen- Electric drive) this would address the torque issue and allow independent speed control of each prop / rotor for controllability.... You may find that will solve some of the control stability issues, and would work quite well on a surface effect machine. |
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Post by freethinker on Dec 9, 2013 9:19:25 GMT 12
Thank`s for your ideas and comments I will not try to explain at this time the alternatives to your suggestions as I have constantly heard these comments before on this subject which many people are already doing what I would like to do but with different vehicles and most of them are very dangerous in operation even the ones with millions spent on development.
To confuse things further I have experimented with an air Boat with a horizontal fan aiming to create a safer,quieter efficient Air Boat for myself.If you Google Images Air Boat with horizontal fan it may be of interest but you would need to put creative thinking into practice as I am only using basic technology. I have been constantly surprised by the lack of technical understanding of the experts I have had to deal with in Engineering fields filing and receiving Letters Patent and general work practice in Industries
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Post by freethinker on Dec 10, 2013 9:51:03 GMT 12
To understand how an air supports an aircraft you need quantum theory and know that one cubic inch of air contains around 25 billion billion molecules all darting about faster than the speed of sound.Every molecule crashes into another 5 billion times a second and it is this incessant pinball barging that gives air it`s spring.It`s why the billions of bouncing molecules inside a tyre can hold up a truck,and why the weight of air doesn`t just press downwards but acts in every direction.
You also need to understand that Vacuum (low pressure) does not suck but that atmospheric pressure pushes in to replace displaced air from all directions. An aircraft is supported by dynamic and atmospheric pressure on the craft as it moves through the air.The low pressure on the top of the wing does not lift the aircraft because Vacuums do not suck as proved by Galileo and Torricelli Vacuum and Siphon experiments.This also applies to an air-screw. Atmospheric and dynamic pressure pushes the aircraft up into the air.
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Post by hardyakka on Dec 10, 2013 16:44:54 GMT 12
You also need to understand that Vacuum (low pressure) does not suck but that atmospheric pressure pushes in to replace displaced air from all directions. An aircraft is supported by dynamic and atmospheric pressure on the craft as it moves through the air.The low pressure on the top of the wing does not lift the aircraft because Vacuums do not suck as proved by Galileo and Torricelli Vacuum and Siphon experiments.This also applies to an air-screw. Atmospheric and dynamic pressure pushes the aircraft up into the air. Here is a link to a book written by Noel Kruse. The first few chapters are intended to give student pilots an understanding of how aircraft fly. You might find it interesting. Fly Better Book One |
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Post by suthg on Dec 10, 2013 17:04:00 GMT 12
Atmospheric pressure applies equally to all plane surfaces - the top surfaces and the bottom undersides of a wing, fuse etc. So atmospheric pressure has no effect on lift, or movement or support of a plane, only dynamic influences do. Wind is also dynamic - a tiger moth can take off at a standstill balancing the forward thrust of the prop against the head on wind causing drag but the wind also provides lift to the wings, despite the plane being stationary. Nominal Air speed does that.
I am puzzled by the pendulum movement - I can see how it will alter the COG, but it has to be a relative proportion of the flyer plus load, ie as much as 30%, so is added weight which works against the premise of low HP, small prop/fan size. Also the movement of the pendulum mass (PM) creates an opposite reaction to it's movement - ie counteracts a specific imbalance for the balance of the "flyer", however, as the PM has to move, it also has to return which implies another body reaction to the flyer in the opposite direction - you can only move the PM once or twice in one direction before it must return - it cannot be continually moved in one direction if there is a continual "flyer" imbalance in the same vector. And if as a pendulum, it may gain Potential Energy which will force it's return to a steady state position, also causing a momentum reaction.
This is an interesting concept, but I think some out of the square thinking results in an out of this world possibility. Ie impossible for some elements to continue to work.
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Post by freethinker on Dec 10, 2013 18:29:14 GMT 12
I much appreciate your comments ...hardyaka...suthg.. I will printout and compare your comments with what I think is the most up-to-date available info (and confirmed) that I have and (possibly)justify what I have posted. as there is no one who can state with out dispute what is correct or flawed I will have to make that decision for myself.There is a lot of old and invalid info on the web and in books and in practice.Thank`s for taking the time and putting some thought into my brief and half explaind proposal which I am satisfied by trials will work for what I want.
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Post by freethinker on Dec 11, 2013 13:54:09 GMT 12
Without atmospheric pressure the one million people aboard winged and other craft flying at this moment would not be there.
Imagine 7 billion people darting around on the backs of dragonflies in the future.
This aircraft has the inherent inbuilt ability to fly straight and level were the words from my instructor on my first flight.
The pendulum action is what is achieved by adding a keel of a boat for stability so why not on a ground effect vehicle? we use gyro control and some balancing devices are simple. Why build an unbalanced vehicle that will topple over unsupported?
As with the many aerial toys that fly by themselves the craft I would like should have the those qualities.
A single rotor single motor can run an anti rotational torque fan with or without air ducting.
Unequal lift and advancing and retreating rotor blades are not always a problem on some rotor systems and can be added if required.
I have read many aircraft accident reports and in particular helicopter accidents and near ground manouvering is dangerous as is all vehicles running in close contact with other objects it would be nice to make it safer.
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ryand
Warrant Officer
Posts: 40
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Post by ryand on Dec 11, 2013 20:21:05 GMT 12
Whilst I am not trying to discourage you from trying, I would be very interested in any form of proof of a rotorcraft that does not suffer from dissymmetry of lift once in forward flight. Sure there are various ways of solving this problem but as far as I am aware it is always there.
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Post by freethinker on Dec 12, 2013 9:14:41 GMT 12
Keep in mind that in this case I am not trying to fly in the normal sense but to overcome the (influence) of gravity sufficiently to easily move a vehicle in any desired direction quickly enough and precisely.
As with a vertical airscrew and it`s asymmetric thrust and rotational torque reaction ect., the effect can and are countered in that configuration (think spitfire..proving your query) and the same can be achieved mechanically with a horizontal rotor or fan by altering the direction of the thrust,torque and center of gravity.
Describing how this is done is difficult because the mechanical geometry involved needs in-depth discussion and is not understood by anyone I have met even though the components and configuration is in everyday use and has been a long time.I have been using this simple mechanical setup over 60 years.There are more modern versions used in some mechanical devices and development take some keeping up with.I am inclined to think un-equal lift problematic at take off not so much in forward flight because the rotor becomes more efficient in ground effect.
AugustaWestland Zero tiltrotor is an interesting project.
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Post by Bruce on Dec 12, 2013 10:51:08 GMT 12
New to this Forum and looking for constructive thoughts. With all due respect Freethinker, you have specifically asked for our constructive thoughts on this, and we have responded with our thoughts and concerns as requested. If you do have knowledge of an obscure and complex physics phenomenon which negates the well known issues that designers of conventional rotorcraft have faced, I invite you to explain it here. there are some pretty clever people on the forum more than capable of understanding aerodynamic principles who will be able to determine whether your concept is workable. We will however need more detail of your proposal so as not to put it all down to some "Magic Force".... |
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ryand
Warrant Officer
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Post by ryand on Dec 12, 2013 11:15:29 GMT 12
I am interested to see a video of your use if this theory.i also have a basic rotorcraft book which will explain how dissymetery of lift works and how it is not a problem in a perfect no wind hover.it only comes in to effect once in fwd flight.
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Post by Dave Homewood on Dec 12, 2013 11:40:52 GMT 12
Just fly backwards then Ryan.  |
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Post by freethinker on Dec 12, 2013 13:12:12 GMT 12
Thank`s Bruce I am not into magic or mystic forces myself. I will explore this site much more.
I do not think ryand needs to see any of my video or have me explain and update his basic rotorcraft book as he should be able to work it all out for himself as he must have seen airscrews doing what they do in all fields of acrobatics and commercial aviation.
They work at all angles vertical and horizontal and in between there are thousands of working attempts to support a vehicle with horizontal rotors (or fans) so what is wrong with the (principle)it is not a theory.It is just a matter of how you can do it successfully and safely to suit my budget and requirements for a true Hovercraft that does not want to fly..Please do not tell me it will not be efficient.I do not care I just want it to do a job.
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Post by Dave Homewood on Dec 12, 2013 13:28:09 GMT 12
If you're not willing to actually explain any of your principles and theories here Freethinker so others can understand, critique, built upon or challenge them, I don't really see any point to this thread. People are starting to complain to me offline about you and this thread, so either put up or go away please.
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Post by freethinker on Dec 12, 2013 15:42:54 GMT 12
I have explained the principle I wish to use which has been dismissed of-hand but not the mechanics which are not well understood.Surely it is possible to discuss how horizontal rotors or fans can be used to support and hover a craft and what is required to achieve that goal.If you understand the Patent system you should know that prior public knowledge of novel ideas will prevent acceptance for a Patent application.
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Post by Bruce on Dec 12, 2013 16:47:37 GMT 12
I call "Bravo Sierra"...
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Post by Dave Homewood on Dec 12, 2013 17:20:11 GMT 12
If you're worried about spilling the beans on your idea and jeopardising a patent then perhaps you shouldn't be discussing it on a widely read public forum at all?
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