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Commentator

Join Date: Jun 2011
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A New & Efficient High-Speed Rotorcraft

10/29/2011 10:48 PM

I have invented a new type of VTOL aircraft; please see tiltplane.com. It takes off with its fuselage vertical but it tilts over as it picks up horizontal speed to cruise with its fuselage horizontal. I have BASIC programs for it written by Ray Prouty. Might someone want to work with these programs and this concept for a masters or PhD? I will be very supportive of the work.

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#1

Re: A New & Efficient High-Speed Rotor-craft

10/30/2011 12:35 AM

The concept is old and tried.

A better one would be one with wings and the contra-rotating blades in the center of the airplane with a gimbal to rotate the motor at any desired angle to obtain the needed torque or stabilize the plane like a helicopter.

Now with the present technology it is best to have 4 contra-rotating blades in a gimbal frame at 4 corners of the plane to obtain fast forward and horizontal stability like a helicopter.

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#12
In reply to #1

Re: A New & Efficient High-Speed Rotor-craft

10/31/2011 2:41 PM

Nando37,

I really don't follow the concept you are describing. It is also possible that I am not as open-minded as I should be because I have already spent plenty on patent attorneys for the present approach. I expect patents to be granted in the US and Canada soon.

jlawren3

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#14
In reply to #12

Re: A New & Efficient High-Speed Rotor-craft

10/31/2011 2:58 PM

The concept using a gimbal single or dual to align the shaft of the contra-rotating blades to an angle desired to behave the plane like a helicopter has been experimented for many years and also the use of 4 sets of blades at the 4 corners of a plane to keep the stability of the platform to keep it hovering or to move forward or to any angle around the horizontal plane like a helicopter has been demonstrated and as well the kits are sold for RC small airplanes.

The single contra-rotating gimbaled blades plane is as well available to experiment with the RC planes and this one behaves like a helicopter and at the same time has the capability of flying like a plane in the high knots ranges of a propeller airplane with the versatility of a helicopter or like.

Investigate the RC = radio controlled airplanes and what is available and will discover what is going on in the small basic research .

There are many ideas that have not been patented for the simple reason that may not be practical at this time due to technology advances or because of certain new designs that make others automatically unpractical or too cumbersome to implement.

Yours in several forms have been tried and have killed several testing pilots, even with designs that are not public from the beginning the reasons as indicated previously.

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#24
In reply to #14

Re: A New & Efficient High-Speed Rotor-craft

10/31/2011 6:38 PM

are you speaking of designs where the entire engine and wing tilts?

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#26
In reply to #24

Re: A New & Efficient High-Speed Rotor-craft

10/31/2011 6:45 PM

Just the motor that it is at midship

A better one would be 4 motors and blades at each corner --

Something equivalent to what was shown in the film AVATAR -

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#16
In reply to #1

Re: A New & Efficient High-Speed Rotor-craft

10/31/2011 3:23 PM

Nando37,

You say that the concept is old and tried.

I did have a flying toy when I was a child which is like what I am now proposing. The toy was a stick with propellers at each end with a rubber band between the propellers. One would hold one propeller and wind up the rubber band using the other propeller and then release it. When it flew it did not fly at all like a "normal" model airplane, but it would continue in the general direction it was pointed when it was launched, whether horizontal or at any up or down angle. But its flight path did show small direction changes due, I trust, to small air currents it would run through.

I was very concerned when I wanted to apply for a patent that the existence of this toy would prevent my getting a patent, but my patent attorney did not think so. And, in the responses I have had thus far from the US and Canadian patent offices, that toy was not mentioned.

jlawren3

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#18
In reply to #16

Re: A New & Efficient High-Speed Rotor-craft

10/31/2011 3:36 PM

All that means is that toy was not patented.

But that toy may well be judged 'prior art' in any future challenge to your patent.

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#19
In reply to #18

Re: A New & Efficient High-Speed Rotor-craft

10/31/2011 3:45 PM

34point5,

Yes, I guess that it could be. But one reason that good patent attorneys can charge what they do is that they have shown good judgement in the past. I trust that will be true in my case, as well. My patent attorney surely charges a lot.

jlawren3

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#23
In reply to #19

Re: A New & Efficient High-Speed Rotor-craft

10/31/2011 6:04 PM

Another reason is They are just someone you hired to write out your application. Their 'judgment' has no standing in litigation. Their 'mistakes' are yours. So They have no experience of, and no interest in, what a Judge might rule.

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#21
In reply to #16

Re: A New & Efficient High-Speed Rotor-craft

10/31/2011 3:53 PM

I flew the same and, as well, with contra-rotating blades with the battery below the flying blades at some distance, I had a couple that went so high that when the unit came down really crashed into pieces, until I learned to place a parachute to open after shutting the motors --

Still, a patent to reference to this toy to a carrying people or commercial packages may have been practical but since I was familiar with some of the previous design I saw that it was not practical to spend the money to patent such design.

It would have been much better for you to spend the money to search the patents for such inventions and like airplanes and what ever.

One basic problem is : start by causing a failure of one of the contra-rotating blades and then tell us how you are going to survive the plane.

Then if you resolve such problem I can give you other failures that need to have recoverable solutions to avoid killing the pilot or passengers.

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#31
In reply to #21

Re: A New & Efficient High-Speed Rotor-craft

11/01/2011 6:46 AM

GA

Some common sense questions that any normal developer MUST address RIGHT UP FRONT.

Someone else posted a few good questions, as of now he (the OP) has not deigned to answer any of the awkward ones like crashing.

My guess is that he will leave CR4 shortly one way or another......

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#2

Re: A New & Efficient High-Speed Rotorcraft

10/30/2011 2:11 AM

Something like this?


1954 Lockheed XFV

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#4
In reply to #2

Re: A New & Efficient High-Speed Rotorcraft

10/30/2011 1:43 PM

Which was a copy of the German WW2 experimental vertical takeoff model if I remember correctly.

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#13
In reply to #2

Re: A New & Efficient High-Speed Rotorcraft

10/31/2011 2:55 PM

Pantaz,

There are similarities: both are tail-sitters that take off vertically and fly horizontally and both have counter-rotating propellers or rotors. But there are also very obvious differences. For example, tiltplanes have no wings and no tail.

jlawren3

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#3

Re: A New & Efficient High-Speed Rotorcraft

10/30/2011 6:36 AM

Perhaps you forgot this?

A Breakthrough Rotorcraft Technology

I think nothing has changed.
Good luck.

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#5

Re: A New & Efficient High-Speed Rotorcraft

10/30/2011 1:52 PM

I would discuss this with the Universities directly as they may be interested. It has similarities to known and proven aircraft technologies, however has some interesting differences that may (at the very least) make a few interesting student projects in a number of aeronautical and software engineering fields.

Anyone know here which universities would be best to approach for these particular (aeronautical) project skill sets?

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#6

Re: A New & Efficient High-Speed Rotorcraft

10/31/2011 12:02 AM

I don't know what I might be able to offer.. but would love to see the programs. I'll pm you my email. I am willing to sign an nda.

Chris

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#7

Re: A New & Efficient High-Speed Rotorcraft

10/31/2011 3:19 AM

How about this one. VTOL capabillities and also get rif of that complicated retractable tail landing. Moreover you can bord the craft horizontally. C'mon, why bother to board the craft vertically? Seems a bit impractical.

http://i50.servimg.com/u/f50/12/60/94/44/virvas10.jpg

http://www.rhcforum.ro/uploads/post-2-1163798423.jpg

This was invented decades ago by Justin Capra, romanian inventor.

PS: This thing actually flew so it's a verified concept.

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#8

Re: A New & Efficient High-Speed Rotor craft

10/31/2011 7:17 AM

There are so many styles of plane around since the dawn of flying almost, designed to do similar to what you feel is new, that I would be most surprised to find out that it was completely new. Though this one has the least chance of actually flying safely and properly of all the ones I have seen over the years...

Anyone can write programs to show something flying that in reality cannot, watch any cartoon with so called planes and rocket ships.....that is all you have, a cartoon......If anyone would like to see it "Fly" go here:-

http://www.tiltplane.com/

It was nicely programmed though and many might be taken in by it.....

I have looked at all your posts, they are all to do with the same idea (to my mind seriously flawed), and as you have not got any form of "natural" stabilization, it might work in a simulation, it might even fly as a model aircraft, though I seriously doubt that personally.

I might have been less hard on you if you had ever read ANY other CR4 blog, other than your own, and commented with us together....no you have a dangerous single mindedness that tastes bad in my mouth......money making bad.....

The other blog you started (on the same idea) has a lot of valuable critic from others, with explanations about missing stability, that you do not seem to want understand....... they were also not impressed......See here:-

http://cr4.globalspec.com/thread/69281

The electronics to stabilize the passenger compartment using the contra rotating rotors will be difficult to design, a failure in them might cause the whole plane to rotate at a speed close to the speed of one of the props....a failure of one prop will cause the same thing to happen, as the props will have a far better "grip" on the air than the body of the aircraft will, due to not having and stabilizing wings or fins.

The failure of both engines will cause it to fall out of the sky, actually the failure of one will probably do the same, as the person inside being swiftly drained of blood due to being in a "spin-dryer".....

Even shutting off the last engine will necessitate a parachute to try and bring the whole thing back to earth in one piece, but as the whole fuselage will/may still be spinning at a high speed, the twisted lines of the parachute may never allow it to open......

Do not try and say anything related to a helicopter, a helicopter has many points of design that offset these problems that your design has.....

To be honest, it looks and sounds like someone with a new "Get rich quick scheme", we see many of them here on CR4.....they usually never come back once we have discovered that!!! We will see what you do, but I can say I will be reporting you to CR4 management if you persist in "fishing for mugs" here, understood?

The CR4 admin's decision being naturally final, not mine.....

The reason I post anonymously is just to stop any unfair attacks you may pose to get your scheme accepted......CR4 admin knows exactly who I am......

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#36
In reply to #8

Re: A New & Efficient High-Speed Rotor craft

11/01/2011 8:24 AM

Anonymous Poster #1,

Yes, my posts all relate to the "tiltplane" concept that I am proposing. I have had other ideas through the years but this one seems to me to have good promise.

As I have stated elsewhere, I expect that the tiltplane concept will be applied first to small unmanned aircraft. Among other things, a passenger-carrying aircraft has to deal with the fuselage changing orientation between hovering and cruising which is not easy.

I apologize for not answering your post earlier.

jlawren3

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#9

Re: A New & Efficient High-Speed Rotorcraft

10/31/2011 9:25 AM

I agree with everything the others have said and the only thing I would like to add is that like the pogo not only was taking off difficult but trying to land backwards with no direct view of what you were doing and where you were going was and would be a major drawback.

In fact the landing backwards concept was one of the main reasons for the death of the Pogo and its later jet powered cousin. Landing was so difficult that it was nearly impossible even for test pilots who are particularly good at handling unusual situations.

My advice would be to forget it, it's been tried before and failed miserably so why not learn by others past failures and try something different, at least that way you would have a chance of coming up with something workable.

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#25
In reply to #9

Re: A New & Efficient High-Speed Rotorcraft

10/31/2011 6:44 PM

I think that the orientation of the pilots is well addressed by this design, as they maintain a constant horizon view.

cheers

chris

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#10

Re: A New & Efficient High-Speed Rotorcraft

10/31/2011 9:53 AM

I think you'd be better off looking into inertial propultion for VTOL.

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#11

Re: A New & Efficient High-Speed Rotorcraft

10/31/2011 12:54 PM

One of the issues the earlier crafts had was it's vision was impeded because the pilot was facing the wrong way during landing, this may be compensated to a certain degree by technology.

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#15

Re: A New & Efficient High-Speed Rotorcraft

10/31/2011 3:17 PM

What is the procedure for a fuel/powerplant emergency?

I see you had a Wikipedia article, but it has been removed. Can you tell us about that?

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#17
In reply to #15

Re: A New & Efficient High-Speed Rotorcraft

10/31/2011 3:34 PM

Doorman,

It is interesting that you can view old Wikipedia articles. How can you do that?

Well, what I understand is that Wikipedia will put something up for a short time but if it does not meet their criteria they will take it down. Wikipedia wants to be an encyclopedia, meaning that they want to publish information which is generally accepted as factual by everyone - not information about someone's latest invention. I respect that.

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#20
In reply to #17

Re: A New & Efficient High-Speed Rotorcraft

10/31/2011 3:45 PM

Many CR4 members have mystical powers. This is why you came here, is it not?

What is the procedure for a fuel/powerplant emergency? What do you forsee as the procedure for a fuel/powerplant emergency?

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#22
In reply to #20

Re: A New & Efficient High-Speed Rotorcraft

10/31/2011 4:06 PM

Doorman,

Unlike a large airplane with multiple engines, which can fly with an engine out, a tiltplane absolutely depends on both rotors always turning in opposite directions and each of the rotor blades continuing to be able to be adjusted in pitch in real time.

One can make the argument that at some point increasing complexity will simply nix a new concept. That is true, but that is not the whole story. Have you every looked at the complexity in a sewing machine? Such a machine could not exist if complexity were the whole story.

I think that a number of things point to tiltplanes finding general use as small robotic craft and not as passenger-carrying craft. One might be the following idea I propose to respond a fuel/powerplant emergency. Inflate large airbags that will surround the craft and encompass the rotors, allowing the craft to float to the ground as a harmless ball.

jlawren3

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#32
In reply to #22

Re: A New & Efficient High-Speed Rotorcraft

11/01/2011 6:53 AM

If a really small sewing machine fell out of the sky and hit you on the head, you would be dead!!!

That is not any sort of comparison with an aircraft, with passengers and a pilot......

If you have not understood that the complexity of such an aircraft exceeds that of a sewing machine probably by at least 1000:1, then what are you doing here?????

Even the "Mars-Lander" idea is inappropriate on a planet with a population......who don't like things landing on them unannounced.....

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#112
In reply to #22

Re: A New & Efficient High-Speed Rotorcraft

11/07/2011 5:57 AM

Could you explain how that would work?

Inflating airbags would not change the mass of the aircraft, and therefore would hardly slow its descent (depending on the shape of the airbags, some drag induced slowing may occur). If it was truly spherical (ball-shaped), drag would be limited and the speed and acceleration the same as before.

Of course, if the resulting arrangement bounced, then that would reduce the damage done to those on the ground by flying debris...

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#30
In reply to #17

Re: A New & Efficient High-Speed Rotorcraft

11/01/2011 6:38 AM

Another leading source of factual information has deleted any comments or hype with regard to this "idea" - what a surprise!

They saw though it first maybe?

You never did reply to ANY of the problems that I noted and posted previously, none of them were difficult to understand if you have even a basic understanding of engineering. Why did you not reply and demonstrate a good working knowledge of the problems mentioned and the possible "fixes"?

This implies one of two things, neither good. Either you have no answer (which would likely be correct) or you feel that answering such critique is "above you".

The second option is the most dangerous as it also implies to me a loss of touch with reality as well........

The final word is, if you REALLY feel that the idea is technically feasible, you MUST show with reasoned technical explanations why it will work. That you aren't doing, which makes me feel that this is just a con trick in the making........

START MAKING REASONED, ACCURATE, UNDERSTANDABLE & TECHNICALLY CORRECT ANSWERS TO ANY CRITIQUE OR GET OUT OF HERE IF YOU CAN'T!!!

LAST CHANCE.......INVESTORS BEWARE......

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#111
In reply to #15

Re: A New & Efficient High-Speed Rotorcraft

11/07/2011 5:33 AM

Wiki says it was removed because:

"18:32, 9 September 2011 Reaper Eternal (talk | contribs) deleted "Tiltplane" ‎ (G11: Unambiguous advertising or promotion: A1: Not enough context to identify article's subject) "

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#113
In reply to #111

Re: A New & Efficient High-Speed Rotorcraft

11/07/2011 6:55 AM

Here's a link to his site on the so called Tiltplane

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#116
In reply to #113

Re: A New & Efficient High-Speed Rotorcraft

11/07/2011 7:16 AM

Thanks - I think AP1 posted it earlier. Vidi. Ridi. Exivi

.

.

.

.

.

.

I looked, I laughed, I left.

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#121
In reply to #111

Re: A New & Efficient High-Speed Rotorcraft

11/07/2011 1:06 PM

Yes, that is the usual explaination given when a Wikipedia article has a major contributor who has some sort of interest in the article subject. In general, those articles will read like an advertisement instead of an impartial discussion of the subject.

I was sort of hoping jlawren3 would provide a link to the deleted article, or at least an abstract or some excerpts. I would like to read what was in the Wiki article.

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#122
In reply to #121

Re: A New & Efficient High-Speed Rotorcraft

11/07/2011 1:52 PM

Doorman,

I think that your opinion about why Wikipedia deleted the article is correct.

When I wrote the article I had in mind that it needed to be very objective, but I guess that it was not as objective as it should have been. Also, an encyclopedic article needs to be able to reflect an intelligent summation of the information that exists on a subject. There is nothing on the web that I know of about my craft that was not written by me, so what I sent in certainly lacked the breadth of sources needed.

But I think that there is another principle involved here. Wikipedia seems to have a running battle with people who want to use them to present their ideas and the need for Wikipedia to remain objective. And I can accept that.

I appreciate your curiosity which is a healthy thing, but what I sent Wikipedia was only a short summary of the information on my tiltplane.com website.

jlawren3

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#123
In reply to #122

Re: A New & Efficient High-Speed Rotorcraft

11/07/2011 2:08 PM

"...but I guess that it was not as objective as it should have been." This is entirely understandable. I rather doubt your submission was intended to be an advertisement but The TiltPlane is, after all, your baby. I have not seen your grandchildren, but I am certain mine are WAY cuter and smarter! This is simply the nature of the beast.

As your idea matures, it will be reviewed by many (sort of what you are doing here at CR4), and the concept - eventually perhaps the craft - can be group reviewed and an independent, objective commentary can be placed with Wikipedia.

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#124
In reply to #123

Re: A New & Efficient High-Speed Rotorcraft

11/07/2011 4:14 PM

The following are some of my thoughts about tiltplanes.

I think that a tiltplane will have a mechanical complexity equivalent to that of a coaxial twin-rotor helicopter.

These are some advantages of the tiltplane concept:

1) Tiltplanes can fly much faster than helicopters because they do not have a retreating blade stall problem

2) Tiltplanes are mechanically simpler than V-22s because (a) they do not have to swing their rotor assemblies and (b) it will be easier to mechanically couple the rotation of the two rotors

3) If V-22s and tiltplanes were made with similar fuselage sizes, tiltplanes would have much less aerodynamic drag in cruise than V-22s because the drag of a tiltplane's rotor blades would be significantly less than the drag of all the parts of V-22s outside of their fuselages.

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#27

Re: A New & Efficient High-Speed Rotorcraft

10/31/2011 7:04 PM

I fear like many others (including myself) the patent agents have yet again stated
this to be a promising / inventive / very patentable idea, only to disclose later, after
taking £$ X amount of money from you, that, very regrettably, it has already been
done / drawn / disclosed / patented, etc. by someone earlier. Which is a shame....

Aaaahhhhhhh!!

jt.


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on to a stool. He ordered a banana split, the waitress asked him " crushed nuts sir?"
No he replied arthritis ..

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#28
In reply to #27

Re: A New & Efficient High-Speed Rotorcraft

10/31/2011 7:45 PM

jt,

My wife and I had a good laugh from your joke. Thanks.

Well, thus far my patent attorney has proven correct: after patents were applied for in the US and Canada, nothing turned up from the US or Canadian patent offices that would prevent tiltplanes from being patented. In fact, there was no concept mentioned that was even close! PTL!

My biggest concern now is not that my aircraft will have already been discovered, but that, after patents are granted in the US and Canada, I will not succeed in finding a large company which I can sell the patent rights to for a good price without first building and demonstrating flying models. From an engineering point of view I believe that the approach is just fine; the programs written by Ray Prouty give very reasonable results. If you give me the dimensions, the desired top speed, flight altitude, weight, RPM, etc. for a tiltplane, then I can give you the power required. One design I evaluated had a cruising lift/drag ratio of 19:1 which is similar to airliners - and I think that even higher lift/drag ratios are easily possible.

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#37
In reply to #28

Re: A New & Efficient High-Speed Rotorcraft

11/01/2011 8:49 AM

jlawren3, you keep mentioning the L/D ratio. The images I have seen in connection with this thread have no apparent lifting elements (wings, for example).

Is this a lifting body that is not apparent, or are there images I am missing?

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#39
In reply to #37

Re: A New & Efficient High-Speed Rotorcraft

11/01/2011 11:21 AM

Doorman,

The rotor blades are the lifting elements. Taking the case of 4 rotor blades per rotor which will be typical, all 8 are lifting when hovering. When flying the horizontal components of the rotor blades provide lift. I am not planning to get any lift from the fuselage.

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#41
In reply to #39

Re: A New & Efficient High-Speed Rotorcraft

11/01/2011 11:55 AM

Well.... okay.

How are you calculating these lift and drag coefficients? I had assumed you may be using Lanchester-Prandtl theory, but it now appears that is not the case.

I can see simply using thin airfoil theory for lift, and being accurate enough (unless using reflex cambered propeller - I doubt you are, a power issue)... but what about Cd?

Forgive me, I am straying from your original question. I am very curious about the reason this machine works in simulation. I can see that it might actually fly, but the power requirements seem overwhelming for sustained flight. Flight control is an issue not yet discussed, but I first want to better understand why it stays in the air.

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#43
In reply to #41

Re: A New & Efficient High-Speed Rotorcraft

11/01/2011 12:47 PM

Hi Doorman,

I am using programs in BASIC written for this aircraft by Ray Prouty who is greatly respected in helicopter design circles.

If the rotors were stopped and the rotor blades had no twist or camber and were aligned fore and aft, then the drag, with no lift being produced, would be essentially surface drag. If the rotor blades were oriented so 4 were horizontal and 4 were vertical and if the craft had a small angle of attack relative to the airflow, lift would be produced by the horizontal rotor blades, right? If the axis of the craft were then make parallel to the airflow and the horizontal rotor blades were given a small angle of attach, then lift would also be produced by the horizontal rotor blades, right? Now if the rotors were made to turn and the pitch angles of the rotor blades were made to produce lift when they are horizontal, then that would also work wouldn't it? And now if the down-going rotor blades were given a larger angle of attack, more lift would be produced by the down-going rotor blades and forward propulsion would be produced. Do you agree?

This is not like other craft that I know of, but I am confident that it works.

jlawren3

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#44
In reply to #43

Re: A New & Efficient High-Speed Rotorcraft

11/01/2011 2:10 PM

Wow.

What you are creating, it seems to me, to be an extreme variant of a coaxial helicopter mixed together with a Pushmi-Pullyu.

It sounds as if no true calculations are available. I hear the phrase "...but I am confident that it works." come through in your comments again and again. We at CR4 have had many, many people come forward with over-unity schemes and devices that they, too, were "...confident that it works." Sometimes confidence alone is not enough.

One thing to remember: The front or nose propeller (or rotor) must ALWAYS generate more thrust than the aft set of blades. A few seconds of consideration should provide the reasoning for this.

Best of luck in your quest for further assistance. There may be a time when I see one of these in the air and regret not jumping on board.

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#33
In reply to #27

Re: A New & Efficient High-Speed Rotorcraft

11/01/2011 6:55 AM

LOL!!

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#29

Re: A New & Efficient High-Speed Rotorcraft

11/01/2011 3:13 AM

This is in response to a couple of posts so I'll include quotes and hyperlinks to the original posts to make it easier to follow.

In post #22 jlawren3 stated

  • "One might be the following idea I propose to respond a fuel/powerplant emergency. Inflate large airbags that will surround the craft and encompass the rotors, allowing the craft to float to the ground as a harmless ball."

Let me get this right what you are proposing is that in the event of an emergency you are going to inflate airbags that will allow the craft to impact the ground at terminal velocity and then hope the airbags absorb the energy. The did use airbags for the final stage of descent on the Mars rovers, but and there are several big ones, the sites were carefully selected so there were no objects likely to rupture the bags, Mars has less than 38% of the Earth's gravity and they used parachutes for most of the deceleration and to limit the terminal velocity before the airbags were deployed. They also bounced several times and covered over a kilometre before coming to rest.

Now on Earth you have things like rivers, mountains, trees, buildings and any number of things that could easily puncture your airbags and make them useless. The gravity is two and a half times greater which means you have to dissipate more energy. Bouncing would be out of the question because you would have no control of where it would go and what it would hit next.

I'm sorry to say it but the airbag concept is just not going to work. The only answers that I could see for your machine would be a ballistic recovery parachute that was large enough to handle the weight of the entire aircraft. However, you would have to add some system that would allow you to sever the propeller blades and jettison them prior to deploying parachute.

The only other option would be the use of ejector seats but then they are really hard on the person using the ejector seat and usually result in the compression of the occupants spine. However, these are designed to be able to be used over a range of situations from zero velocity and zero altitude to supersonic speeds at high altitude. I suppose you could design a less violent ejector seat for your aircraft but that would add to the cost considerably over buying an off the shelf system. They are also bloody dangerous things that require great care when anywhere near them and lots of very expensive maintenance.

In post #28 you stated that

  • "One design I evaluated had a cruising lift/drag ratio of 19:1 which is similar to airliners - and I think that even higher lift/drag ratios are easily possible."

I find that figure extremely doubtful as you have absolutely no lift generating aerofoils therefore all the lift needed to keep the craft airborne in horizontal flight needs to be generated by the thrust from the engines and this would make the lift to drag ratio horrendous and nothing like a jet airliner. Remember an aircraft with wings can glide for a considerable distance without power, your design is going to drop like a rock in the event of an engine/fuel/rotor failure. Even helicopters can do what is called autorotation and glide using the momentum of the rotors and their vertical speed to glide and ultimately land with relatively little vertical velocity. A lift to drag ratio 19:1 of something without wings is just ludicrous.

  • "My biggest concern now is not that my aircraft will have already been discovered"

Yes it has been, back in the 1950s in various forms like the Convair XFY Pogo, the Coleopter, Lockheed XFV, etcetera.

Admittedly they used counter rotating props at the top but that makes it simpler to operate with a single engine. Most of them also had wings because the most efficient way to fly horizontally is to use wings, that's why gliders have wings instead of propellers, but then they would have to have engines to stay airborne and they wouldn't be gliders any more would they.

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#34
In reply to #29

Re: A New & Efficient High-Speed Rotorcraft

11/01/2011 7:12 AM

GA

Many good points.....

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#35
In reply to #29

Re: A New & Efficient High-Speed Rotorcraft

11/01/2011 8:11 AM

Hi masu,

It is true that on my website I show a tiltplane carrying two people and I may have mentioned the possibility of larger tiltplanes. In the far off future this may be possible, but in the near term I believe that tiltplanes will most likely find applications as small robotic craft. For those cases I tend to think of them as having an internal capacity similar to a rural mailbox used in the US, or shall we say, about 8" in diameter and 20" deep? In the event of an unrecoverable failure in such a craft I believe it would be quite reasonable to design airbags which would be ejected from the sides of the craft, engulf the rotors, and permit the small craft to drop harmlessly to the ground.

You say, "A lift to drag ratio 19:1 of something without wings is just ludicrous." Well, a typical tiltplane would have 8 wings.

Now about the lift/drag ratio. If the rotor blades were stopped with four of them vertical and four horizontal and the weight of the craft were evenly distributed between the rotors then why wouldn't conventional aircraft principles apply? This would be a craft with high aspect ratio wings so good lift/drag ratios are possible and even likely. Yes, four of the "wings" are vertical in this case, but the total "wing area" of this craft would still be small.

I can make this comparison because when the craft is cruising the rotor blades are making long slow spirals through the air and the air speed over the rotor blades is not much higher than the speed of the craft itself.

Please note that the wing areas can be a lot smaller than the wing areas of conventional aircraft for the same reason that the rotor blade areas of a helicopter can be a lot less than the wing areas of conventional aircraft: because these lifting surfaces operate at high air speeds.

I do not share your opinion that the "tiltplane" concept which I espouse is like other known concepts. It has things in common with other concepts, but it is not at all the same. Oops! That is not entirely true. There was a flying toy once made that consisted of a stick with propellers at each end and with a rubber band between the propellers. My tiltplane concept is very much like that toy; it has two counter-rotating rotors which turn about the centerline of the fuselage.

jlawren3

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#50
In reply to #35

Re: A New & Efficient High-Speed Rotorcraft

11/02/2011 7:52 AM

Now about the lift/drag ratio. If the rotor blades were stopped with four of them vertical and four horizontal and the weight of the craft were evenly distributed between the rotors then why wouldn't conventional aircraft principles apply?

Ok, what you are saying is that you would lock the rotors so that two of the forward rotors were horizontal and two of the rear the same. These would then be pitched to supply lift as the craft moved forward.

The only trouble with this is that you would have to us symmetrical aerofoils where the lift is solely created by the pitch of the aerofoils. Now according to this paper you could possibly achieve an L/D of 19/1 with a symmetrical aerofoil but to support the mass of you aircraft the rotors are going to need to be a darn side bigger than the ones shown in your animation and it's not going to be easy.

At a rough guess and comparing it to a twin seat glider you would be talking about rotors that were at least 17 m in diameter but they would have to have considerably longer cords than shown in your animation to be capable of generating enough lift with the rotors locked in forward flight.

Then you have the pitch control system, it would have to be a combination of cyclic and pitch control system to be able to do what you want. That's going to be one complicated piece of kit that is going to have an enormous amount of load going through it.

What you are talking about is at a rough guess analogous to taking two medium sized wind turbines and mounting them on the front and back of your fuselage.

It might be an interesting concept but there are far simpler and more reliable ways of going about it that also don't have the reverse landing problem which was the biggest bugbear of the similar systems mentioned in other posts.

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#52
In reply to #50

Re: A New & Efficient High-Speed Rotorcraft

11/02/2011 5:07 PM

masu wrote: " the rotors are going to need to be a darn side bigger than the ones shown in your animation and it's not going to be easy". The rotors are narrow because they operate at relatively high air speeds. (Lift increases with the square of the airspeed.)

Yes, I will need to implement both cyclic and collective pitch in each rotor. But I do not propose using a swash plate for each rotor; it would need to have a diameter similar to the craft's diameter which is unreasonable. I propose controlling the pitch angle of each rotor blade separately giving each its own fast servo motor and angle sensor for feedback. Then the normal pitch functions of cyclic and collective pitch can be implemented under software control, but another feature can be implemented. When the craft dives it will be very easy for the rotor speeds to increase to very high values if conventional cyclic and collective pitch are used. But if the rotor blade pitch angles are independently controlled, in each rotor two rotor blades can be given increased pitch values and two can be given reduced pitch values. This can be used to waste energy in order to keep the rotors from over speeding.

As I have said elsewhere I expect that small robotic tiltplanes will be built first. Then the changing orientation of the fuselage should not be an issue.

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#53
In reply to #52

Re: A New & Efficient High-Speed Rotorcraft

11/02/2011 6:15 PM

I suppose it's time to mention that you can't pick up a helicopter by the blades or should you push/pull an aircraft by its blades.

Alter the pitch unevenly with respect to relative velocity, and you won't have blades.

Think that you can glide on those blades (even given Masu's 'symmetric' fix) and you are in for a structural surprise.

Mind you, I am still totally intrigued as to how you get a bag to encapsulate a rotor disc. And of course why said blades would not just snap off at the root if not held planar by centrifugal force of rotation.

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#54
In reply to #53

Re: A New & Efficient High-Speed Rotorcraft

11/02/2011 11:38 PM

34point5,

You might be correct about my proposed way of preventing rotor blades from over-speeding. (I proposed adding alternating pitch changes to the rotor blades.) Perhaps a better solution would be just to add a servo-controlled drag brake for each rotor hub.

About using air bags: suppose we are talking about a small tiltplane with, say, a 12" fuselage diameter and a 5 ft. rotor diameter which might be used to deliver mail to docking stations on the tops of tall buildings in a large city. If a rotorcraft like that had a failure and became uncontrollable, I proposed stopping the rotors and using multiple air bags to engulf the rotors and the rest of the craft. This should turn it into essentially a large light ball about 6 feet in diameter which would then drop to the ground at a low speed. That sounds to me like a reasonable way to handle failures in small tiltplanes. Hopefully, such failures would be extremely rare.

About the rotor blades possibly snapping off at the root: there would obviously have to be enough built in strength in the roots of the rotor blades for them to be safely cantilevered out when the craft is not flying.

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#57
In reply to #54

Re: A New & Efficient High-Speed Rotorcraft

11/03/2011 1:47 PM

Working blades - note the bend

Stationary blades - note the droop

Area wise;

How do you think you will go trying to fly on '2 locked blades'?

Given you can't even walk on them;

How do you think they will respond (structurally) to 'bag drag'

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#60
In reply to #57

Re: A New & Efficient High-Speed Rotorcraft

11/03/2011 2:25 PM

34point5,

Nice pictures! They do nicely illustrate rotor blades bending under high loads and from their own weight.

In responding to a question I did not meant to suggest that a tiltplane's rotors would not be rotating in some flight modes. I think that I was trying to explain something and used the case of their not rotating as a step in that explanation.

What do you mean by 'bag drag'?

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#61
In reply to #60

Re: A New & Efficient High-Speed Rotorcraft

11/03/2011 4:47 PM

What tasks might programmable and semi-intelligent tiltplanes perform? Suggestions:

Programmed crop dusting. Automatically return to reload and then continue

Fast border patrol. Look for illegal crossings day and night & send back videos

Fast beach patrol. A remote operator could monitor a video from a patrolling tiltplane, identify people who may be drowning, and command the tiltplane drop life preservers

Fast package delivery in cities including to tops of tall buildings

First responder to traffic accidents. Send videos back & drop a medical supply package

Ship-to-shore and shore-to-ship small parcel delivery

Quickly get close to forest fires for good IR pictures to aid in fire fighting

Carry 200 pounds of water to forest fires at 300 MPH and drop it on the fires. Reload & repeat.

Carry 200 pounds of water to skyscraper fires at 300 MPH. While hovering deliver the water to the blaze & repeat

-jlawren3

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#65
In reply to #61

Re: A New & Efficient High-Speed Rotorcraft

11/04/2011 8:12 AM

Almost all of these jobs can be better done with a "Reaper" or similar......particularly the USA has a massive lead in this area......

Also due to the "Reaper" having wings, the load carrying and fuel efficiency will be many times better than anything without wings!!! Look here:-

General Atomics MQ-9 Reaper

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#71
In reply to #65

Re: A New & Efficient High-Speed Rotorcraft

11/04/2011 11:40 AM

I have probably said this before, but the tiltplane concept exists thus far as a concept only. It offers a VTOL capability plus an efficient cruise capability at speeds like 300 MPH. Unlike helicopters, which can't fly that fast, tiltplanes offer lift/drag ratios similar to fixed-wing aircraft. One design I was looking at had a L/D ratio of 19:1 at 195 MPH. A L/D ratio of 19:1 is similar to the value for airliners. Of course, its cruise efficiency may not as good as that of a "reaper", but there should be other applications where its VTOL capability and its relatively efficient high speed cruise characteristics will be welcomed.

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#63
In reply to #60

Re: A New & Efficient High-Speed Rotorcraft

11/04/2011 12:18 AM

"What do you mean by 'bag drag'?

I'll let you answer that;

"I proposed stopping the rotors and using multiple air bags to engulf the rotors and the rest of the craft. This should turn it into essentially a large light ball about 6 feet in diameter which would then drop to the ground at a low speed."

Obfuscation like;

"I think that I was trying to explain something and used the case of their not rotating as a step in that explanation"

will get you nowhere on CR4

Same applies to your 'stop and glide'

Maybe it's time you searched 'tail rotor failure' or even 'the worst Chinook crash ever' and reconsider the drive aspects.

An additional consideration might be how you carry a payload. Then how you might hover and drop it. Then ask yourself, with that 'weight and balance', how the wingless thing will ever fly 'axis near horizontal'.

Then perhaps, how said payload won't snap off the 'tail cone', or spin like the clappers.

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#67
In reply to #63

Re: A New & Efficient High-Speed Rotorcraft

11/04/2011 10:20 AM

When cruising with the axis horizontal the craft's center of gravity must be roughly between the two rotors. Therefore, if is is carrying something that must be dropped, that load also must be located roughly between the two rotors. At least the aft rotor would need to be designed mechanically with an open center to permit this. The forward rotor would also be designed with an open center if there is to be a non-rotating nose of the craft.

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#69
In reply to #67

Re: A New & Efficient High-Speed Rotorcraft

11/04/2011 11:15 AM

Thereby re-raising the drive, mounting and control issues. Best you give some serious thought to how can it be engineered, as even 'light' big bore bearings tend to be heavy and quite rpm limited.

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#70
In reply to #69

Re: A New & Efficient High-Speed Rotorcraft

11/04/2011 11:25 AM

You raise a good point. I have not gone through the engineering details of a large tiltplane design. But most problems have workable solutions. For example, in a large passenger-carrying tiltplane I expect that the rotors could be supported, as they turn, by multiple metal wheels which, in turn, would turn on bearings.

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#55
In reply to #52

Re: A New & Efficient High-Speed Rotorcraft

11/03/2011 9:32 AM
  • "Lift increases with the square of the airspeed."

But the drag goes up as well and in the paper I referred to more than the lift as shown in Table 3 on page 126 that I have reproduced below.

The first column is the airspeed in Mach numbers the remaining columns show the L/D ratio for the various symmetrical aerofoils with a 3° angle of attack.

So while lift increases with speed the drag increases faster and you end up worse off the faster you go which is clearly shown by the table.

Also the lift only increases until you get close to the speed of sound which is called the transonic speed. When this happens things get awfully complicated particularly with rotary winged aircraft or propellers. If the outer regions of you rotors end up travelling faster than the speed of sound while the inner regions don't your rotors will tear themselves to pieces from the shock waves that form.

Considering the size of the rotors you're going to need to get a something big enough for humans to fly in the sound barrier problem is going to seriously limit the diameter of your rotors and thus the upper limit of the size of your craft.

While the Pogo managed to lift itself off the ground with counter rotating propellers these could only supply trust and when in forward flight did not supply the lift, this was done by the wings. So you concept of using the stationary rotors with the symmetric aerofoils to create enough lift to allow the craft to glide just isn't going to work on anything more than a model and even them I'm doubtful.

Being an engineer I'm sure you're aware of the Square-cube law which ultimately sets the upper limit of size. While your toy might of worked scaling it up the human carrying size is a whole different thing. You haven't provided enough information to actually calculate the upper limit of the size of a craft like yours that can use the rotors as stationary wings but my gut tells me that it's not going to be very big.

As for delivering mail to the top of tall buildings, have you ever heard of things called elevators, which by the way are surprisingly efficient. Then of course there's eMail but I suppose that would be too high tech.

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#58
In reply to #55

Re: A New & Efficient High-Speed Rotorcraft

11/03/2011 1:57 PM

Hi masu,

When tiltplanes are cruising at, say, 300 Knots the plane of the rotors would be vertical and the rotor blades would be making long slow spirals through the air. Their airspeed would be only 10% or so higher than the airspeed of the craft itself, so the L/D ratio for the craft as a whole should still be good.

I only mentioned stationary rotors earlier as part of a process of explaining something. I do not envision stopping the rotors of tiltplanes in any of their flight modes.

I think that you are probably right is suggesting that, because of the law of the squares and cubes, tiltplanes may not be practical in large sizes. Lately I am suggesting that smaller sizes should be implemented first with the fuselage perhaps 12" and diameter and the rotors perhaps 5 ft. in diameter. But, as far as I am concerned, the jury is still out on the maximum practical size.

In a large city if tiltplanes were used to deliver high-priority mail and small packages, then it would make sense that these deliveries would be made to the tops of buildings. Tiltplanes then would be replacing courier service, not normal mail service.

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#62
In reply to #58

Re: A New & Efficient High-Speed Rotorcraft

11/03/2011 11:27 PM

"Their airspeed would be only 10% or so higher than the airspeed of the craft itself, so the L/D ratio for the craft as a whole should still be good."

You're forgetting about the rotational velocity of the rotors, it's not difficult to put the tip of a large propeller through the sound barrier and you're talking about rotors much larger than propellers. Don't forget that the speed at which the rotor is travelling through the air increases as you get further from the axis. That's why the pitch of a propeller reduces as you get further from the hub. It evens out the forces on the prop so that the tips aren't producing all the thrust because they are going so much faster than the inner portions of the propeller.

Most helicopters don't have rotors that have a variable pitch along their length and that's one of the reasons you get so much flex in the rotors. The outer portions are going faster than the inner and therefore produce more lift. The outer sections also produce more drag which tends to flex the rotor and make everything worse by increasing the angle of attack of the tips compared to the inner sections which is the exact opposite of what you want happening.

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#68
In reply to #62

Re: A New & Efficient High-Speed Rotorcraft

11/04/2011 11:03 AM

Masu,

What you say is correct for helicopters, but as a tiltplane picks up speed it tilts its rotor disc so that at 300 MPH the plane of the rotors would be vertical and the rotor blades, and even the rotor blade tips, would be seeing air speeds that are only 10% higher than the craft's speed. In another place I said no higher than 350 MPH. To say exactly what it would be in a particular case I would need to run through some calculations.

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#72
In reply to #68

Re: A New & Efficient High-Speed Rotorcraft

11/05/2011 12:38 AM

You just don't get it do you.

Let's say that were working with the 17 m diameter rotors I suggested earlier that would probably be able to work and give you a workable glide ratio in the case of an engine failure.

Now if you have those rotors rotation at 1,000 RPM then the tips of each rotor will be travelling π time 17m for every rotation or about 53.4 metres times 1000 RPM is 53,400 metres per minute divide that by 60 seconds and we get about 890 metres per second which is over two and a half times the speed of sound and would result in shockwaves that would be cataclysmic and tear the rotors to smithereens. That means if you were going to work with a rotor that turned at 1,000 RPM the maximum diameter that you could possibly have would be less than a third of my 17 m suggestion or realistically about 5 metres otherwise the tips would be into the transonic region. Now I can tell you that four 2.5 metre long aerofoils are not going to keep much airborne let alone something large and heavy enough to carry people.

That's why helicopter rotors are limited to about 300 rpm or less because if they rotated any faster their the tips would be travelling in the transonic region and the same thing would happen to them.

However, if you ditched the concept of using stationary rotors to create lift in the event of an emergency by adding fixed wings to the craft then you could use much smaller diameter rotors that could go much faster. It would also be far more efficient in forward flight as the rotors would only need to create enough thrust for the wings to support the craft rather than creating both lift and thrust.

Oh dear, wouldn't that make it pretty much the same as the Pogo which we know was a total failure.

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#73
In reply to #72

Re: A New & Efficient High-Speed Rotorcraft

11/05/2011 4:53 AM

GA from me.

You made some very good points, actually not points, fundamental facts, so thanks, though the OP might not be so happy to hear them, you are calling his baby "ugly!" - (which it is!)

I bet he carries on as though you never ever posted!!! Let us wait and see.....

By the way, if he does that as expected, that is for me personally the clincher that its a badly planned & badly designed scam.....or maybe he gives us one of his "Politician" answers again.....

He is persistent.....but that's is his only good character point that I can see!

But anyone with a REALLY good idea would usually a) keep it quiet till its working and patented or b) sell the idea to a company with the resources to bring it to fruition.....

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#74
In reply to #72

Re: A New & Efficient High-Speed Rotorcraft

11/05/2011 9:09 AM

Where did the 1000 RPM come from? You seem to have arbitrarily chosen a rotor diameter and a rotor speed and then said, in effect, "Look! The rotor blade tips will be traveling faster than the speed of sound! This cannot work!" You are right in your conclusion but very wrong in your choice of initial conditions.

Also, it is not logical to say that the rotational speed of helicopter rotors is limited to 300 RPM or less because a very small helicopter could easily use a higher rotor speed.

The tiltplane concept is self-consistent and can result in an excellent high-speed rotorcraft without the addition of fixed wings. Fixed wings would be of little use in the hover and transition modes. Yes, they could provide lift in the cruise modes, but the rotor blades of the craft can also do that well. If the rotor blades can do that well, then why would fixed wings be needed?

All right, it would be fun to consider using rotors as I have proposed forward and aft but then to consider adding a fixed wing in the center of the craft to, hopefully, improve the flight efficiency at cruise speeds. I think that one would agree that for good flight efficiency it should not be a short wing with less wingspan than the diameter of the rotors and that it should have a very small chord so as to not add much drag at high flight speeds.

Well, first of all it will be hard to give such a wing good root strength without making the wing thick where it joins the fuselage. A fair amount of steel could be used in the wing to help with this, but that would add weight. Turning rotor blades can use the centrifugal forces present to help the rotor blades to resist bending, but, of course, fixed wings don't have that advantage.

But I have another objection to adding a wing midships. In a normal tiltplane the forward rotor provides lift by deflecting the air passing through it down, but it introduces twist to the airstream also. The aft rotor works in that twisted and deflected-down flow and it undoes that twist so that little energy is lost in the exiting airstream due to twist.

I think that adding a fixed lifting wing midships will distort the airflow entering the aft rotor in a way that is inconsistent with what the forward rotor has done. As a minimum, this wing would need to have a built in twist to permit it to work in the twisted airflow from the first rotor and to still produce uniform lift across the span of the wing.

Well, all in all it seems to me that adding a fixed wing midships would just be a complication without significant benefits. Does anyone else think that adding a fixed wing midships would be beneficial?

jlawren3

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#75
In reply to #74

Re: A New & Efficient High-Speed Rotorcraft

11/05/2011 10:22 AM
  • "Where did the 1000 RPM come from? You seem to have arbitrarily chosen a rotor diameter and a rotor speed and then said, in effect, "Look! The rotor blade tips will be traveling faster than the speed of sound! This cannot work!" You are right in your conclusion but very wrong in your choice of initial conditions."

You stated that in the event of an engine failure you would be using the four horizontal rotor blades to sustain flight and allow the aircraft to glide.

Now if it were to take two people I equated it with a twin seat glider which will have a wingspan anywhere from 17 to 30 metres. So adding in the weight of the additional aerofoils, mass of the engine/s and gearbox, loss of efficiency due to the use of symmetrical aerofoils I made a conservative estimate of the rotor diameter of 17 metres which equates to a twin seat glider with a slightly better lift to drag ration than your 19:1.

So two 17 m diameter rotors to support a twin seat craft that could glide in the configuration you described in the event of an engine failure isn't that unrealistic, in fact it's probably smaller than you would need.

  • "Also, it is not logical to say that the rotational speed of helicopter rotors is limited to 300 RPM or less because a very small helicopter could easily use a higher rotor speed."

The smallest helicopter I could find quickly was the Baumgartl PB-63 which has a rotor diameter of 6 metres. Now the fastest you want the tips to go is at most 80% of the speed of sound which works out to be to be about 275 ms-1. If you do the calculations then you find that the maximum speed you can rotate the rotors is 875 RPM and that's for the smallest single seat helicopter I could find.

If we do the same for something like the good old Bell 47 which has a rotor diameter of 11.32 metres we get a maximum rotor speed of 421 RPM. So as you can see for a modern helicopter that is capable of carrying more than two people a maximum rotor speed of 300 RPM isn't that ridiculous.

Let's go back to the 17 m rotor diameter that I estimated would be needed to sustain a glide as described by you. In that case the maximum rotor speed would be limited to guess what? 309 RPM which appears to be considerably slower than the rotation speed of the rotors in your animation.

Finally lets go back to your animation, I couldn't get an exact measurement but I calculated that the rotors had a diameter of around 14 metres. Now without going into the keeping the aircraft airborne in a glide with locked rotors the maximum safe speed you could rotate the rotors at would be 375 RPM which I doubt would be able to produce enough thrust to keep the aircraft airborne in horizontal flight without additional fixed aerofoils. It probably would be able to hover but that's about it.

Not putting the rotor tips through the sound barrier is going to be your major limiting factor and I just can see it working with something much larger than a large model aircraft without the addition of additional fixed aerofoils that would supply the lift for horizontal flight.

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#78
In reply to #75

Re: A New & Efficient High-Speed Rotorcraft

11/05/2011 11:49 AM

GA. Well done.

I bet he still does not want to understand!

A completely lost cause.....

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#79
In reply to #78

Re: A New & Efficient High-Speed Rotorcraft

11/05/2011 3:51 PM

A completely lost cause.....

Not for the patent attorneys. Imagine the attorneys arguing at a common sense level similar to that of masu or the many others in this thread. They would lose their position in the firm for waking up the dreaming and well paying client (patient).

They must have tried or at least hinted that the technical feasibility and then commercialization of such an illusion is not possible or are they that unscrupulous? Nothing would surprise me in that realm.

The name of the real culprit is: The patent attorney .

"John Marshall Lawrence is in the building", I can hear them say or whisper. "Say nothing, otherwise he might wake up", and still have some $$ in his account. I wonder if other investors in this project are following this thread.

If this flying machine would have any advantages other than delivering urgent parcels to some high rise in no time at all, well, ......? I could see it being used as a pipe cleaning device. In a very small version with some wire brushes at the tip of the rotors and then exhaust the dirt, grime with the generated air flow.

The mind boggles, Ky.

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#80
In reply to #79

Re: A New & Efficient High-Speed Rotorcraft

11/05/2011 4:53 PM

LOL!!

...and more than a touch of truth and irons.

Lawyers are simply the worst, any sort of lawyer.....they make Dracula look like he never lusted after blood in comparison.....

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#86
In reply to #80

Re: A New & Efficient High-Speed Rotorcraft

11/05/2011 9:14 PM

Hmm... I think that the proof is in the pudding. After over two years I finally did get a response from the US and Canadian patent offices where I applied for patents. It now looks like the patents on the tiltplane concept will be issued very soon with only minor corrections to the drawings. How great is that considering that this is a radically new aircraft concept? Shouldn't much of the credit go to my patent attorney?

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#87
In reply to #86

Re: A New & Efficient High-Speed Rotorcraft

11/05/2011 11:47 PM

"I think that the proof is in the pudding. ... It now looks like the patents on the tiltplane concept will be issued very soon with only minor corrections to the drawings. How great is that considering that this is a radically new aircraft concept?"

Again, a patent doesn't mean practical. For example, http://www.patentgenius.com/patent/6402088.html

Some other recent "tail sitter" aircraft patents:
http://www.patentgenius.com/patent/6561455.html
http://www.patentgenius.com/patent/7226017.html
http://www.patentgenius.com/patent/6854686.html
http://www.patentgenius.com/patent/5114096.html

How about small, remote controlled or autonomous versions...
http://www.patentgenius.com/patent/6634593.html
http://www.patentgenius.com/patent/5295643.html

These are just a few that I looked at -- there are plenty more.

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#91
In reply to #87

Re: A New & Efficient High-Speed Rotorcraft

11/06/2011 4:43 AM

GA.

I was amazed just how similar the patent:-

http://www.patentgenius.com/patent/6854686.html

was to our friend's design.....could be a problem if either actually flew......

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#93
In reply to #91

Re: A New & Efficient High-Speed Rotorcraft

11/06/2011 11:25 AM

Hi Andy: "I was amazed just how similar the patent:-"

Yes, engineers may see it as 'in effect' the same.

An attorney (& court) would see 'ducted', the 'landing gear' solution, 'entry provisions' as distinctions.

Of interest, this approach could deploy a chute, or balloon, or bail out option/s; without the entanglement/shredding risks of open rotors.

Or 'in essence', the OP by not having duplicated the functionality, his becomes Novel - so can be patented.

But; should a duct, or a circumferential structure supporting a landing function appear, the OP's application would be unlikely to succeed.

It's become a great system. The less practical an idea is - the more likely it is "novel" - so patentable.

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#94
In reply to #93

Re: A New & Efficient High-Speed Rotorcraft

11/06/2011 11:46 AM

LOL!

Exactly my impressions too, thanks.

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#101
In reply to #93

Re: A New & Efficient High-Speed Rotorcraft

11/06/2011 5:58 PM

34point5,

That's a very interesting observation:

"The less practical an idea is - the more likely it is "novel" - so patentable."

But the trick is to discover a novel and practical idea which has not yet been patented.

Jlawren3

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#102
In reply to #101

Re: A New & Efficient High-Speed Rotorcraft

11/06/2011 6:23 PM

Which you have singularly failed to achieve here.....

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#103
In reply to #102

Re: A New & Efficient High-Speed Rotorcraft

11/06/2011 6:49 PM

I show a two-propeller toy in Figure 4 of the paper on my website. What is your opinion relative to that toy and my proposed rotorcraft?

1) You can't extrapolate from that small toy to your proposed craft.

2) In the toy the "fuselage" probably rotates somewhat as it flies. That will probably be the case with your design also.

3) Your concept may work as you propose but it is probably too complex to be useful.

4) Look, it has been since 1903 that the Wright brothers demonstrated powered flying. All useful flying concepts should certainly have been explored by now. Therefore it seems highly unlikely that you have anything useful.

-jlawren3

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#104
In reply to #102

Re: A New & Efficient High-Speed Rotorcraft

11/06/2011 8:31 PM

I disagree. There are things that can be done to make this more workable, and certainly some prototyping is in order.

all he has singularly failed to do, is win much support, for a variety of reasons.

and so he joins a long list of people to have their butt chewed at cr4.

I encourage him to carry on.

I bet the first guy to tight-rope walk across a chasm may have fallen, and people laugh, and claim it impossible... until someone invented a balance pole, which makes it easy... so if a tail sitter is hard to land because the balance is challenging.... what he needs is more horizontal moment. (retractable)

etc etc. what it really takes is some imagination.... which I think he has.

Chris

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#106
In reply to #104

Re: A New & Efficient High-Speed Rotorcraft

11/06/2011 11:21 PM
  • "I disagree. There are things that can be done to make this more workable"

Yes, like adding a couple of wings and a tail fin then only using the rotors to create thrust. Far simpler system, doesn't have the problems with an engine failure because it can glide and would be far more aerodynamically efficient than trying to create both lift and thrust with two telescoping four bladed rotors with separate pitch controls for each blade.

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#108
In reply to #106

Re: A New & Efficient High-Speed Rotorcraft

11/06/2011 11:27 PM

I do tend to agree with that... but it isn't my design.

I really would like to see some more details.. but I will have to wait till the patent lands.

chris

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#119
In reply to #106

Re: A New & Efficient High-Speed Rotorcraft

11/07/2011 11:19 AM

masu,

But if you add wings and a tail you have an airplane with huge propellers!

Also, the wings and tail add air drag. The power needed by an aircraft in its upper speed range is primarily related to the surface drag of the craft, assuming that the craft's shape is streamlined. And one of the main things that the tiltplane concept has to offer is a relatively small amount of surface over which the air flows. This permits tiltplane designs to yield a surprisingly efficient aircraft.

I am sorry that I showed rotor blades that can retract their outer portions. In principle it would help to increase the cruise efficiency by reducing the craft's "wetted area", but the amount of reduction of the wetted area that can be accomplished by doing this is small compared to the total area of the craft including the rotors. And the added complexity is significant.

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#126
In reply to #119

Re: A New & Efficient High-Speed Rotorcraft

11/08/2011 4:44 AM
  • "Also, the wings and tail add air drag."

You would be surprized at how little drag a well-designed aerofoil will create. For example the wings on a glider add about as much parasitic drag (drag induced by the friction of the air moving over the wing) as a piece of pipe about 1.5 cm in diameter which is much less than the drag created by the fuselage.

There is, however, another form of drag that an aerofoil creates and that is called induced drag which is caused by the lift the aerofoil creates. There's no way to get around this and you symmetric rotors would more than likely produce more induced drag than a well designed asymmetric aerofoil.

However, if you add wings and a tail then you run into the problems with patents of things like the Pogo but that was from the 1950s and the patent may have expired by now so you could probably use the concept but not be able to patent it. Then again aircraft designs in general aren't patented as a whole just parts like the design of winglets and the specific shape of the aerofoil. Although you can't copy the design of somebody's aircraft directly as this would get you into trouble with copyright laws so you would have some protection.

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#128
In reply to #126

Re: A New & Efficient High-Speed Rotorcraft

11/08/2011 8:19 AM

masu,

Suppose your young son is learning to ice skate and you want to help so you bring out a chair for him to push around on the ice. He may say, "Dad, I don't need a chair. Can't you see that I am doing OK? I am working on skating backwards now."

I feel the same about adding wings. The proposed tiltplane design does just fine without wings. The total air drag at speeds like 300 Knots is a function primarily of the surface area of the craft. Adding wings would only increase the surface area and hurt the cruising efficiency.

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#130
In reply to #128

Re: A New & Efficient High-Speed Rotorcraft

11/08/2011 8:42 AM
  • "I feel the same about adding wings. The proposed tiltplane design does just fine without wings."

From your descriptions, the information you have given us and the calculations I have done I really can't see your tiltplane working the way you believe it will.

The major mistake you are making is to not correctly allow for the rotation of the aerofoils and subsequent direction of travel of the air over these. I showed you that if you added the forward maximum speed to the rotor's rotational airspeed you would effectively have an angle of attack at the wing tips of about 60° which is way past the stall angle of a symmetric or asymmetric aerofoil for that matter.

Before you spend any more money on patent thieves lawyers I suggest you hire an aeronautical engineer and get him to look at your proposal. My bet would be that he will say pretty much what I have in the thousands of words and numerous posts I have written for this thread.

I also don't think you're a fraud or rip of merchant trying to get money for a non-existent aircraft, however, I don't think you have a broad enough understanding of basic aeronautical knowledge and aerodynamics to understand that your tiltplane will not work the way you believe it will.

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#100
In reply to #91

Re: A New & Efficient High-Speed Rotorcraft

11/06/2011 5:53 PM

Yes, it is similar in many ways. But I think that one can say that in horizontal flight most of the lift to support the craft would come from the shrouds around the rotors, as well as the straightening vanes which support the rotors.

Also, my design will experience much less drag in horizontal flight because it does not have the drag of the shrouds and straightening vanes.

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#85
In reply to #79

Re: A New & Efficient High-Speed Rotorcraft

11/05/2011 8:52 PM

Being an engineer I was surprised at the insight of my patent attorney. When I first approached him, he was not too enthusiastic about the concept, but he later "came around". So I do not feel that he was trying to lure me in by being falsely gung-ho about my concept.

But I do feel that the hourly rate of patent attorneys is unreasonably high.

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#90
In reply to #85

Re: A New & Efficient High-Speed Rotorcraft

11/06/2011 4:35 AM

You are getting there slowly.......think of an attorney as a Fisherman, playing his catch, to get it tired for the final landing and knockout blow.....

When your money is spent, you will not see him for dust......

Even a patent (as many here know) is no guarantee of functionality.....there are millions of patents that simply do not and cannot work......only the lawyer made a buck......

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#95
In reply to #90

Re: A New & Efficient High-Speed Rotorcraft

11/06/2011 3:27 PM

Hi Andy

His patent will turn the idea into a currency which can then be traded. That is a job for the hyenas and shakales of the level playing field not the poor fishermen. You are right though they only leave the bones, if that is what you meant.

Once an idea has reached the stage of being made a reality, definition of return on investment is a requirement. In our retired engineers case the vultures will win and even the prototype stage will not fly, ever.

It is just too ugly to fly, in a maneuverable way

But then again you get these beauty's:

Anything can be turned into a Religion if one is screwed up enough.

I personally think that the fly slow movement, if that's what they call them selves, is the way to go. I have a suggestion for such and will one day, when my thought processes do not create sparks anymore, present it here.

Glad to glide and not to speed, Ky.

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#96
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Re: A New & Efficient High-Speed Rotorcraft

11/06/2011 3:42 PM
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#98
In reply to #96

Re: A New & Efficient High-Speed Rotorcraft

11/06/2011 4:20 PM

Too slow

I'll work on it and send some pics.

Soon, Ky.

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#84
In reply to #78

Re: A New & Efficient High-Speed Rotorcraft

11/05/2011 8:43 PM

Yes, I guess I do not understand the motivation behind most of the objections raised here.

I am recently retired and I have a fair amount of time to work on this. What more could a retired engineer ask for than time and a promising idea to work on?

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#89
In reply to #84

Re: A New & Efficient High-Speed Rotorcraft

11/06/2011 4:31 AM

That is your problem, you don`t understand........now you know!!! Problem solved.

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#81
In reply to #75

Re: A New & Efficient High-Speed Rotorcraft

11/05/2011 6:33 PM

masu,

Below I have put your words in italics:

"You stated that in the event of an engine failure you would be using the four horizontal rotor blades to sustain flight and allow the aircraft to glide."

I don't think I said that. I think that I mentioned stopping the rotor blades in the process of explaining something, but I do not expect to stop the rotation of the rotors except when the craft has landed.

"In that case the maximum rotor speed would be limited to guess what? 309 RPM which appears to be considerably slower than the rotation speed of the rotors in your animation."

I just reran my animation and I did not see where the rotational speed of the rotors was specified. There is a timer on the animation running from 0 to 3 minutes and 19 seconds. Please indicate the time during the animation in which the rotor speed is displayed.

"...the maximum safe speed you could rotate the rotors at would be 375 RPM which I doubt would be able to produce enough thrust to keep the aircraft airborne in horizontal flight without additional fixed aerofoils. It probably would be able to hover but that's about it."

Please note that in horizontal flight the rotor blades are not producing thrust the same way that they are in hover. For one thing, in horizontal flight rotor blades would not be producing any thrust when they are vertical. The propulsion principle is like this. When a rotor blade is near horizontal and is moving up it will be given an angle of attack that produces the needed lift, but the lift vector is angled backward. However, when a down-going rotor blade is angled to produce lift the resultant lift has a forward component. The controls will increase the angle of attack on the down-going rotor blades so that more lift and corresponding forward thrust is produced than on the up-going rotor blades. This, of course, requires that power be applied to the rotor, but the net result is that the craft is propelled forward.

jlawren3

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#76
In reply to #74

Re: A New & Efficient High-Speed Rotorcraft

11/05/2011 11:06 AM

If you don't need the surfaces for control in normal modes, or as a fuel saving effort, then all you need is emergency mode systems. pop out a giant hang glider of light materials...or parachutes, or whatever.

I do agree with others that trying to make wings out of the rotors for emergency modes is fraught with difficulty, and unnecessary.

I do think that lightweight carbon fiber stub wings (in any configuration - even retractable) will assist in flight mode fuel savings, and roll control. similar surfaces will assist in yaw and pitch control.... perhaps it might not fit the clean lines you were hoping for... but it is a simpler and proven method of obtaining that control.

you have some very large engineering challenges to make the rotor system work as it is proposed. (counter-rotating, variable speed, and extensible) perhaps a blended approach will help conquer some of these nagging issues.

but let me reiterate, I respect your efforts and intent greatly. I can't wait to see any prototype testing, and I encourage you to keep posting here of your progress, regardless of outcome. All technological advancement and engineering progress occurs because someone is daring enough to try, in the face of the risks. All practical learning occurs because of this attempt. Reality is the best teacher. Humility is ultimately, the final lesson... for all of us, when we learn how much we don't know.

Chris

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#82
In reply to #76

Re: A New & Efficient High-Speed Rotorcraft

11/05/2011 6:52 PM

Hi Chris,

Your words are in italics:

"I do think that lightweight carbon fiber stub wings (in any configuration - even retractable) will assist in flight mode fuel savings, and roll control. similar surfaces will assist in yaw and pitch control.... perhaps it might not fit the clean lines you were hoping for... but it is a simpler and proven method of obtaining that control."

I may have failed to mention that the pitch angles of the rotor blades are controlled like the pitch angles of the rotor blades in helicopters with both cyclic and collective pitch. What this means in cruise is that each rotor can produce controlled amounts of forward thrust as well as controlled pitch and yaw moments.

I would not recommend adding stub wings. For one thing, in cruise it is best to produce uniform lift across the full diameter of the tube of air that the rotors turn through. For another, even stub wings would add their own drag which would be high due to their low aspect ratio.

jlawren3

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#77
In reply to #74

Re: A New & Efficient High-Speed Rotorcraft

11/05/2011 11:28 AM

I think if you think through the sort of tasks you have in mind, you will always run into the structural and mechanical difficulties of having a rotor at each end.

Even landing gear is a problem in more than a tiny VTOL model.

In essence the large 'hollow drive' on the rear rotor severely limits the cargo through to people carrying applications.

For the wing question; see push/pull light aircraft

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