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BOEING / GoFly contest: Oh, BOEING


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#101 Kelpiecross

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Posted 23 January 2020 - 04:35

  I don't think this discussion is really going any where.   I have said all along that is just a personal  judgement of  mine that No. 88  is very good  -  and the DVVA  not so good. Maybe you are right - but  - I would steal the No.88  (and just might)  but you couldn't force me to take the DVVA for free - or even at the point of a gun.

 

  I will reiterate that I think "desmo"  is pointless and inferior to "spring".  

 

 Sorry to be a bit personal - but you turn out a few very (very) nice ideas and designs,  some "ordinary" ones and a few real "stinkers".  But you seem to defend them all to the death -   just work with the best.  

 

  (What category do you think I put the "Flyer" in?)    



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#102 manolis

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Posted 23 January 2020 - 15:08

Hello Kelpiecross.

 

Thanks.

With your questions you gave me the opportunity to present again (and to further explain) the various pattakon-VVA’s.

 

A technically oriented person can clarify a lot about the Variable Valve Actuation systems reading the previous page, and can decide by himself which is his favorite.

 

Since you like the Lost Motion VVA of post 88 (it is the “lost motion” version of the roller-version VVA used in the black Honda Civic), be my guest and apply it in a cylinder head and present the project here.

 

 

 

For the OPRE Tilting engine and the Flyer:

 

 

Here is another application of the OPRE Tilting engine:

 

OPRE_Tilting_Single_2.gif

 

The (single) OPRE Tilting engine has on its casing two “arms” whereon a holed pipe (yellow) is secured.

 

The one crankshaft drives, by means of a reduction gearing (comprising a pair of sprockets and a “short” toothed belt (not shown)), a propeller which is rotatably mounted on the holed pipe at the one side of the engine,

the other counter-rotating crankshaft drives, in a similar way, another propeller which is also rotatably mounted on the (yellow) holed pipe, but at the other side of the engine.

The two propellers are contra-rotating.

 

OPRE_Tilting_Single_1.gif

 

Through the holed pipe they pass the fuel and the control (like: the gas cable, a cable for the release of a parachute, etc).

 

Here is the engine with the arms whereon the holed pipe is to be secured; at right is the synchronizing gearing and the transmission to the one propeller.

 

OPRE_Tilting_Single.jpg

 

The diameter of the propellers is as large as desirable.

The basis of the engine (say, the flange or the pipe whereon the engine is secured) is rid of gyroscopic rigidity, of vibrations and of reaction-torque.

 

 

The flange at the end of the (yellow) pipe can be secured on the frame at the back of a parachuter replacing the conventional propulsion unit.

 

 

If the flange at the end of the holed pipe is secured on the nose of an ultra-light or of a small airplane, it is a complete propulsion unit having significant advantages.

 

 

If the holed pipe is substantialy extended, then a simple Portable Flyer (say, a "Witch’s Broom" Portable Flyer) is made:

 

Witchs_Broom.png

 

For  safety,

a second OPRE Tilting engine with its own pair of contra-rotating propellers can be secured higher on the holed pipe.

 

Thanks

Manolis Pattakos



#103 gruntguru

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Posted 23 January 2020 - 22:11

I prefer the DVVA. It is no more complex than the other two VVA systems and offers more flexibility in terms of lift and duration combinations. As a bonus, desmodromic operation offers significant performance advantages over a system using springs and even one using pneumatic springs.



#104 manolis

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Posted 24 January 2020 - 04:36

Hello Gruntguru.

 

You write:

“I prefer the DVVA. It is no more complex than the other two VVA systems and offers more flexibility in terms of lift and duration combinations. As a bonus, desmodromic operation offers significant performance advantages over a system using springs and even one using pneumatic springs.”

 

 

Quote from the US patent 8,201,531 titled: “Desmodromic variable valve actuation”, filed June 2008, granted June 2012(!) :

 

DESCRIPTION

The closest prior art is the U.S. Pat. No. 6,892,684 (***: it is the rod-version  pattakon VVA, that in the white Renault). Instead of actuating the central swivel joint by a cam lobe, in the present invention the swivel joint is actuated positively in both directions by a link having a drive pin mounted at one end, the drive pin being engaged in a track to reciprocate therein.

The resulting valve mechanism is rid of restoring springs of any kind, it operates reliably at racing revs because it is rid of heavy fast moving parts like the track, and it is fully variable: it can change continuously and independently the valve duration and the valve lift from a maximum value to even zero, i.e. it can better approach the ideal valve lift profile for the instant operational conditions of the engine in terms of revs, load, air temperature, coolant temperature, fuel quality, driving mode, altitude etc, i.e. it can optimize the operation and the thermal efficiency along a wider rev and load range.

 

Thanks

Manolis Pattakos


Edited by manolis, 24 January 2020 - 04:37.


#105 Kelpiecross

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Posted 24 January 2020 - 04:39

I prefer the DVVA. It is no more complex than the other two VVA systems and offers more flexibility in terms of lift and duration combinations. As a bonus, desmodromic operation offers significant performance advantages over a system using springs and even one using pneumatic springs.

 

  I am sure Manny would be happy to accept your investment monies.  



#106 Kelpiecross

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Posted 24 January 2020 - 04:53

  The "Witches'  Broom"  variation  on the basic "Flyer"  idea  is one of the cleverest things I have ever seen  - where can I buy one?    



#107 gruntguru

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Posted 24 January 2020 - 07:50

  I am sure Manny would be happy to accept your investment monies.  

 . . and yours.


Edited by gruntguru, 24 January 2020 - 21:07.


#108 manolis

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Posted 26 January 2020 - 06:13

Hello all.
 
This photo shows a windsurfer:
 
Wind_Surf.jpg
 
From Wikipedia:
 
“In 1948, 20-year-old Newman Darby was the first to conceive the idea of using a handheld sail and rig mounted on a universal joint so that he could control his small catamaran—the first rudderless sailboard ever built that allowed a person to steer by shifting his or her weight in order to tilt the sail fore and aft.”
 
Doesn’t it remind the way the pilot of the Broom Flyer controls his flight?
 
Thanks
Manolis Pattakos


#109 Kelpiecross

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Posted 26 January 2020 - 10:52

 . . and yours.

 

 

    and mine.



#110 Kelpiecross

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Posted 26 January 2020 - 11:43

 Manny - a few suggestions:  convert the "broomstick"  into a simple tripod and seat arrangement  -   double or triple the propeller/rotor diameter  and the bloody thing might fly. 



#111 Kelpiecross

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Posted 26 January 2020 - 11:52

   Manny - can you give a direct link to the EPO patent covering  design No. 88?  I can't (yet) figure out the EPO systems.         



#112 Kelpiecross

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Posted 27 January 2020 - 04:29

  Manny -  my first thought about the "Witches' Broom"  layout  was that it was horrifyingly dangerous  (and it is of course - but so are  all these small, one person, VTOL  flying devices - and looked no more into the design.  (My comment above was meant to be sarcastic - referring to the danger).   

 

  But - on further study - I think  that it is quite a practical idea - far more so than the original "Flyer".  For the following reasons:

 

  It would be freestanding - meaning you would not have to carry  the whole contraption on your shoulders - meaning the minimum weight could also be a bit higher.

 

 Being coaxial the propeller/rotor size could be whatever it needed to be  -  also meaning the necessary power could be less - or to have more power in reserve.   Maybe about 15 feet or so rotor diameter? 

 

 The "Windsurfer"  body/weight-shifting   control at first seemed silly - but would probably  be very effective.    

 

 However - I would make one important change: - have the engine/reduction gearing etc.  at the very bottom   under the platform that the pilot stands on.  and have coaxial shafts running up to the rotors.  This would lower the centre of gravity  and give "pendulum" stability to the whole thing both when flying and on the ground/taking off etc.

 

 The idea of the pilot not being strapped in etc.  seems very dangerous - but in a way could be safer than not being  strapped to the accident etc.  in a take-off mishap.

 

 Maybe a lightweight  "safety hoop"  around the pilot?  - just so he/she doesn't accidently fall off in flight.    It could actually carry two people maybe? 

 

 The whole idea is still deadly dangerous -  but I think plenty of people would try it  - you might be starting a new craze.



#113 manolis

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Posted 27 January 2020 - 08:52

Hello Kelpiecross.

 

Here is the original WIPO / PCT document https://www.pattakon...00127091758.pdf and here is the granted European Patent https://www.pattakon...EP1697619B1.pdf

 

Alternatively you can go to EspaceNet and Search for EP1697619.

 

Thanks

Manolis Pattakos


Edited by manolis, 27 January 2020 - 11:18.


#114 manolis

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Posted 27 January 2020 - 08:58

Hello Kelpiecross.

 

The purpose of the Portable Flyer is to travel fast at long distances, not to loiter hovering for fun. The hovering is to be used for special cases (like rescue).

 

With the big (~15ft diameter) propellers you suggest,

it would be good to hover but not to travel fast,

say,

like the Chinook CH47 which is better for hovering / auto-rotation than the OSPREY V22, but worse for covering at high speed / high mileage long distances.

 

 

As for the “pendulum stability” you talk about, it is wrong.

 

Intuitively it seems correct, however it is wrong.

 

Like you, Mayman (JetPack manufacturer and pilot) thinks the same:

 

(the following is from another forum)

 

Quote from Mayman’s interview with New Atlas’ Loz Blain (https://newatlas.com...-speeder/58822/ ) :

 

Jetpack Aviation's David Mayman on his upcoming Speeder flying motorcycle

. . .

 

Loz:

 

Indeed, he's become one of the four superhero horsemen of a new personal flight revolution. Mayman, with his calm, methodical aviator's approach and multi-turbine jetpack, plays Buck Rogers. On the other end of the scale is Frenchman Franky Zapata, an extreme sports nut and former jet-ski champion whose turbine-powered Flyboard Air has been seen thundering across air and water throughout Europe and the US. Zapata makes a natural Green Goblin.

Then there's Richard Browning, a British martial arts master with a multi-turbine jet suit and a company called Gravity. Browning's suit places jets not only on his back, but on his arms, making him a shoo-in for Iron Man. And standing slightly apart from them all is ex-Swiss military pilot Yves Rossi, whose extraordinary Jetwing literally lets him dance with aeroplanes in the sky. It needs to be launched out of a plane, though, so while it certainly looks like an incredible experience to fly, it can't lift straight off the ground like the others.

 

The-Speeder-696x392.jpg

. . .

 

Mayman:

 

But the pilot has to be on top. So the thing is literally dynamically unstable. Inherently unstable. And it has to be flown by computer. So that's what we're building. And the prototype is exactly that. The engines are clustered together, we purposely put the weight above that, and then we try to fly it.”

 

End of Quote.

 

 

In the specifications of the Speeder of Mayman, while the take-off weight is unknown, the price is US700,000$.

 

*********************************

 

Gruntguru:

 

This is nonsense. In a hover situation with an axial thruster, the stability is the same no matter how low or high the CG might be relative to the thruster. An axial thruster always exerts its force along the same axis as that axis tilts. Although somewhat non-intuitive the situation is not the same as a parachute where the thrust remains upwards as the system tilts. (A parachute needs to be above the CG)”

 

*********************************

 

 

For most people the situation is “heavily non-intuitive”.

 

Despite his long flying (and manufacturing) experience, Mayman can’t get it.

 

So let me help with a drawing:

 

Broom_Two_Engines_Flyer.png

 

It is the “Broom Flyer” of a previous post modified by adding another OPRE Tilting propulsion unit at the bottom of the (yellow) pipe.

 

Suppose for a moment that the pilot is aerodynamically “transparent”.

 

Case 1: upper engine running, lower engine stopped.

Case 2: lower engine running, upper engine stopped.

In either case the pilot feels the same, and controls his flight the same way.

 

The force from the spinning propellers is along the yellow pipe in both cases.

In the one case the power unit is above the pilot, in the other case the power unit is below the pilot.

 

 

But the pilot is not aerodynamically “transparent”, which brings a significant difference of the two cases.

 

With the running engine above the pilot (i.e. with the pilot inside the downstream of the propellers), he has not only “weight displacement control”, but he has also aerodynamic control over his flight: his head and limbs act as flaps / ailerons / fins: deflecting a part of the downwash, they receiving reaction forces which give full control over the flight (yaw, pitch and roll).

 

With the running engine under the pilot (say, as in Zapata’s Jetpack) the pilot at take-off, at landing, at hovering and at low / medium speeds is based exclusively on “weight displacement” to control his flight. And this is not a full control.

 

Thanks

Manolis Pattakos



#115 Greg Locock

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Posted 30 January 2020 - 07:19

His feet got chopped off



#116 manolis

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Posted 30 January 2020 - 12:05

Hello Greg Locock

 

Not only his feet, but also his hands, ears and nose got chopped off.

Nevertheless he still can fly.

 

So:

Is it more stable with the upper or with the lower engine running?

Is it more controllable with the upper or with the lower engine running?

 

Thanks

Manolis Pattakos



#117 Kelpiecross

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Posted 30 January 2020 - 13:31

And lost his wig. 



#118 Kelpiecross

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Posted 01 February 2020 - 06:27

  I have to admit that I was not aware that a low(er)  CoG  doesn't make a helicopter more stable.  Judging by the internet, very few people in the world  do (or did) know - some still refuse to believe it.

 

 I think there is a lot to learn about helicopter aerodynamics etc.   Problem is if you find out in real life  you (or one) will end up like the bloke in your drawings -  footless/handless/wigless and possibly dickless.    

 

 Although the CoG  doesn't add to stability it may alter the moment of inertia etc.  possibly making the  rolling rate etc.  of the craft too quick to respond to just by weight-shifting etc.   Maybe that is why the "Speeder"  needs a copmputer - its low MoI  makes the roll rate to quick to respond to.

 

  Possibly having the engine etc.  at ground level  and the rotors at the other end of the pole/broomstick/fuselage would increase the MoI and make the whole thing more controllable rather than having everything at the top end.  It also would make it a lot more stable on the ground. .   

 

 Maybe the craft should have "built-in" stability?   Presumably having a fixed dihedral  ("coning") on the blades/rotors would give added stability  - I can't find anything on the net about this but it seems a reasonable idea.  

 

 I don't think there is much point  in having a relatively small diameter rotor - losing lift efficiency and possibly gaining  some speed.  The GEN H4  has a rotor diam. of 13 feet and yet has a claimed top speed/cruising speed of about  120/62MPH - which I think is fast enough for most purposes. 

 

 I hate to say it - but a lot of people have tried to make a small  one-person  helicopter but without much success.  Even the H4  seems to have been something of a failure despite (presumably) spending millions on development.

 I doubt if you (or I) could do any better -  especially with reasonably limited resources.  

 

 Having said all the above - I have an old lawn mower engine, some fence palings and an old rotary clothesline  - should be able to make a helicopter from these bits.  

 

    

 

 I think I personally would attempt to make a small VTOL craft  using some sort of "bladeless" (for safety)  technology.

 

 Maybe a centrifugal fan with entrained air type of gadget?  Did you know the front lift outlets on a Harrier are "cold"?  - straight from the engine compressor.      


Edited by Kelpiecross, 01 February 2020 - 06:38.


#119 manolis

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Posted 01 February 2020 - 15:13

Hello Kelpiecross

 

Landing Gearing

 

When the engine / propellers are above the pilot / rider (i.e. when the pilot / rider is in the downstream of the propellers), it is not only the aerodynamic control that is added to the “weight displacement” control, it is also that the legs / feet of the pilot can be used as the landing gear (the most adjustable and weightless landing gear).

 

Flyers.gif

 

 

 

You write:

“I don't think there is much point  in having a relatively small diameter rotor - losing lift efficiency and possibly gaining  some speed.  The GEN H4  has a rotor diam. of 13 feet and yet has a claimed top speed/cruising speed of about  120/62MPH - which I think is fast enough for most purposes.”

 

62mph / 100Km/h is a very slow speed for flying devices.

At such speeds almost all the energy of the fuel is consumed for “hovering”, i.e. to keep the flying device from falling.

  

 

 

You also write:

“I have to admit that I was not aware that a low(er)  CoG  doesn't make a helicopter more stable.  Judging by the internet, very few people in the world  do (or did) know - some still refuse to believe it.

 I think there is a lot to learn about helicopter aerodynamics etc.   Problem is if you find out in real life  you (or one) will end up like the bloke in your drawings -  footless/handless/wigless and possibly dickless.    

 Although the CoG  doesn't add to stability it may alter the moment of inertia etc.  possibly making the  rolling rate etc.  of the craft too quick to respond to just by weight-shifting etc.   Maybe that is why the "Speeder"  needs a copmputer - its low MoI  makes the roll rate to quick to respond to.

  Possibly having the engine etc.  at ground level  and the rotors at the other end of the pole/broomstick/fuselage would increase the MoI and make the whole thing more controllable rather than having everything at the top end.  It also would make it a lot more stable on the ground. .   

 Maybe the craft should have "built-in" stability?   Presumably having a fixed dihedral  ("coning") on the blades/rotors would give added stability  - I can't find anything on the net about this but it seems a reasonable idea.”

 

Now that the “pendulum stability” issue has been clarified, let’s proceed deeper.

 

Increasing the moment of inertia is not a solution.

It slows down the response to an external disturbance (say, to a gust of wind), but it also slows down the restoring to the initial position.

 

On the air there is nothing to abut on.

 

The only thing a pilot has is the thrust force.

If the pilot can instantly and effortlessly vector the thrust force towards any desirable direction, the problem of the flight control is about solved.

But to be able the pilot to vector instantly and effortlessly the thrust force, there are some requirements:

 

Quote from Portable Flyer “DEVICE TECHNICAL REPORT” at https://www.pattakon...oFly/index.html :

 

Zero vibrations, zero gyroscopic rigidity, zero reaction torque:

 

• The symmetry of the engine, the zero phase difference between the two synchronized and counter-rotating crankshafts, the common combustion chamber (same instant pressure on the piston crowns of the two opposed pistons, same (and opposite) instant torque on the two crankshafts), and the symmetrical load (two counter-rotating symmetrical propellers) rids the saddle (and the pilot) of all kinds and orders of vibrations (zero free inertia forces, zero free inertia moments, zero free inertia torques, and zero combustion vibrations of all kinds). This is an absolute requirement when a powerful high revving engine is to be tightened to the body of a person.

 

• The reaction torque is also permanently zero: no matter how wide the “throttle” is opened, or how abruptly the “throttle” opens or closes, there is no reaction torque (the only that happens is the increase or the decrease of the thrust force provided by the propellers).

 

• The symmetry and the counter-rotation of the propellers and of the crankshafts maintains the gyroscopic rigidity of the PORTABLE FLYER zero. Even when only the one engine is running (for instance due to a malfunction of the other engine), the gyroscopic rigidity is zero. Zero gyroscopic rigidity means that the pilot “instantly” and “effortlessly” can vector the engine/propellers (i.e. the thrust force) towards the desirable 4 direction, which is an absolute requirement for a safe, accurate and instantaneous control of the flight.

 

• Without zero inertia and combustion vibrations, without zero gyroscopic rigidity, and without zero reaction torque at the changes of the “throttle”, the control of the flight becomes slow, inaccurate, unsafe, uncomfortable and exhausting.

 

End of Quote.

 

Thanks

Manolis Pattakos



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#120 manolis

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Posted Yesterday, 12:25

Hello all.

 

Take a look at this video:

 

 

and then notice the number of its views.

 

Thanks

Manolis Pattakos

 



#121 gruntguru

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Posted Yesterday, 22:45

Is that Ken Wallis?

 

Much adored by 24gerrard AKA Autogyro AKA Rotodyne etc etc



#122 Kelpiecross

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Posted Today, 09:33

Is that Ken Wallis?

 

Much adored by 24gerrard AKA Autogyro AKA Rotodyne etc etc

 

 It is indeed Old Ken.   I saw him demonstrating his autogyro in Oz in the 1960s -  he really did throw that thing around the sky  - and he lived to 97!

 

 24G etc. was a bit of a  pain in the arse  but he shouldn't have been banned  (and neither should have  Cheapy been banned as well).  The Rotordyne was a good idea  (but very loud)  and he was right about  F1 gearchanges  having a slight gap in power flow despite being described as "uninterrupted".  

 

 Manny - why did you show the video?  This is a proper aircraft  - not two propellers on a stick.  


Edited by Kelpiecross, Today, 09:36.