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BOEING / GoFly contest: Oh, BOEING


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#51 gruntguru

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Posted 26 August 2019 - 04:27

Most would say the same of many less-useful contraptions out there - wing suits, jet packs, assault rifles . . 

 

I would have a go at flying it - if it looked stable and controllable (ie handlebars fitted  :lol: )



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#52 pierrre

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Posted 26 August 2019 - 08:25

on the topic of bad weather the vehicle's body would naturally point towards the oncoming force. rather than being blown away or tilted sideways away from the force.. it might look to go against it and straightened.. could this be a positive? i think it is. don't know why the competition didn't see your application go further

how do you see it handle bad weather conditions? maybe you can do a go fund me page manolis? I'd love to see this materialize

Edited by pierrre, 26 August 2019 - 08:27.


#53 manolis

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Posted 26 August 2019 - 13:51

Hello Kelpiecross.

 

Flying with a Portable Flyer 2 meter (6 ft) above the sea seems to me as safer than driving a motorcycle on the road (as long as not many flying fishes come the opposite direction).

Even the best – ever – Variable Valve Timing system needs a car maker or motorcycle maker to put it in the market.

 

Thanks

Manolis Pattakos



#54 manolis

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Posted 26 August 2019 - 13:51

Hello Pierrre.

 

Nice video.

 

But without Newton’s laws, how can be calculated the 2nd order force, and how can be drawn a plot of the 2nd order force vs the crankshaft angle?

 

The total force (from 1:05) seems as looking permanently upwards. Is this correct?

 

The balance web is to partially cancel out the 1st order inertia force coming from the piston reciprocation, and can do nothing at all for the 2nd order force (they are of different frequencies).

 

Thanks

Manolis Pattakos



#55 manolis

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Posted 26 August 2019 - 13:54

Hello Gruntguru.

 

I wish I had a few Gruntguru around the world to read, understand, think and write down their justified objections.

 

 

When it will fly?

I hope it will fly well before the final Fly-Off of the GoFly-BOEING contest (February 2020 according their latest postponement).

 

 

Who will fly it?

When we applied to the contest, they wanted US250$ for one-person teams, and US500$ for teams. So I put only myself.

 

 

The casting was/is a delay (a lot of time-consuming “try and error” lessons), but as I see it now, it was worth the cost.

Now it seems possible the mass production at an affordable – for everyone – cost.

 

 

As for the handlebars for your Flyer, what do you preffer: handlebars from a Harley or from a Ducati Panigale?

 

Thanks again

Manolis Pattakos  



#56 pierrre

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Posted 26 August 2019 - 15:47

Hello Pierrre.

 

Nice video.

 

But without Newton’s laws, how can be calculated the 2nd order force, and how can be drawn a plot of the 2nd order force vs the crankshaft angle?

 

The total force (from 1:05) seems as looking permanently upwards. Is this correct?

 

The balance web is to partially cancel out the 1st order inertia force coming from the piston reciprocation, and can do nothing at all for the 2nd order force (they are of different frequencies).

 

Thanks

Manolis Pattakos

thanks for the compliment, the overall force is the black arrow, 1:05 is just the beginning when forces were about to be added to the model

i forgot to credit the animation though, will do it on the caption



#57 manolis

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Posted 26 August 2019 - 16:36

Helo Pierrre.

 

You write:

"on the topic of bad weather the vehicle's body would naturally point towards the oncoming force. rather than being blown away or tilted sideways away from the force.. it might look to go against it and straightened.. could this be a positive? i think it is. don't know why the competition didn't see your application go further

how do you see it handle bad weather conditions?"

 

 

Quote from the "Device Technical Report" (at https://www.pattakon...GoFly/DTR_1.pdf ) as filed in the GoFly-BOEING contest:

 

 

Safety and high speed

. . .

Flying in adverse conditions, like sudden weather change, gusts of wind, rain etc is a big risk in case of underpowered flying devices having large surfaces exposed to the wind.

 

The ability for high speed flights is mandatory for the safety; at windy weather a big size / slow moving (“hovering”) flying device is a “feather in the wind”.

 

A personal flying device having 30 kts maximum speed and flying along a sea shore, has a big safety risk when the wind starts blowing towards the sea at, say, 35kts.

 

Because every flying object is at the mercy of any gust of the wind, the most important characteristics for safety seem to be: the small frontal area, the small drag coefficient, the high power to weight ratio, and the ratio of the power to the product of the frontal area times the drag coefficient. 

 

The human body is very well streamlined when hovering vertically and when cruising near horizontal.

 

If the PORTABLE FLYER can fly way faster than the wind, the strong wind and the strong wind gusts are not a problem any longer."

 

End of Quote.

 

 

 

 

For the animation: you do not need to credit the animation.

 

Thanks

Manolis Pattakos



#58 gruntguru

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Posted 26 August 2019 - 21:57

on the topic of bad weather the vehicle's body would naturally point towards the oncoming force. rather than being blown away or tilted sideways away from the force.. it might look to go against it and straightened..

In hover mode, provided the centre of aerodynamic pressure is lower than the centre of gravity, the flyer-pilot system will tilt towards the wind gust. Yes - a good thing.


Edited by gruntguru, 26 August 2019 - 22:04.


#59 gruntguru

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Posted 26 August 2019 - 22:03

As for the handlebars for your Flyer, what do you preffer: handlebars from a Harley or from a Ducati Panigale?  

 

:lol:   :lol:   :lol:

 

It needs inexpensive, lightweight handlebars. https://www.wish.com...egaAkqaEALw_wcB

 

The handles should be waist high.

 

Crowdfunding sounds like a great idea.


Edited by gruntguru, 26 August 2019 - 22:15.


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#60 Kelpiecross

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Posted 27 August 2019 - 04:22

Hello Kelpiecross.

 

Flying with a Portable Flyer 2 meter (6 ft) above the sea seems to me as safer than driving a motorcycle on the road (as long as not many flying fishes come the opposite direction).

Even the best – ever – Variable Valve Timing system needs a car maker or motorcycle maker to put it in the market.

 

Thanks

Manolis Pattakos

 

 

  Your valve gear ideas are certainly not the best ever  -  every  type is a variation on a already-known  principle.  But some are better arrangements than some presently in use  examples from car makers.

 

 Your "Flyer" is hugely compromised by your insistence on using such small diameter propellers.   Like the H4 the minimum practical propeller diameter would need to be 13 to 15 feet - and then two this size.  You could easily rearrange your design  so  each  engine drove a central coaxial  propeller  system of a much bigger diameter.  

 

  And of course it needs to be of the "sit-down" variety.  You claim that the whole arrangement weighs 20kg?   I would guess probably twice that.   But even at  20Kg it is probably too heavy (and top-heavy) for a normal  person to comfortably wear and put on - it would need  and assistant.   Whereas a  "sit-down"  (H4) layout would need no assistance. 

 

  I hate to be critical of someone who is so productive of ideas - but your main problem with all your ideas is continually insisting that your particular idea is the "best ever"  and refusing even minor changes.


Edited by Kelpiecross, 27 August 2019 - 04:23.


#61 manolis

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Posted 27 August 2019 - 10:28

Thank you Kelpiercoss.

 

 

You write:

“Your valve gear ideas are certainly not the best ever”

 

I did not write the pattakon VVA’s are the best ever.

 

But, please let me know which VVA is the best ever, and I will tell you its problems.

 

Take, for instance, the MultiAir / TwinAir of FIAT, Chrysler, Alfa Romeo, INA.

It is a hydraulic electronically controlled VVA; maybe, the most advanced today.

The PatAir (at https://www.pattakon...ttakonHydro.htm) , which is the MultiAir with different cam lobe profiles and different programming, provides all the modes of operation of the MultiAir plus an infinity of additional modes which can realize the Atkinson / Miller cycle for better efficiency at partial loads.

 

 

 

You also write:

“Your "Flyer" is hugely compromised by your insistence on using such small diameter propellers. Like the H4 the minimum practical propeller diameter would need to be 13 to 15 feet - and then two this size.  You could easily rearrange your design  so  each  engine drove a central coaxial  propeller  system of a much bigger diameter.”

 

The size of the rotors / propellers is not small.

The disk-loading is less than that of the Osprey V-22.

While the heavy disk-loading requires more power for the vertical take-off and landing, at high speeds it is a blessing (actually for really high speeds it is mandatory).

 

Compare the OSPREY V-22 (small diameter rotors, heavy disk loading):

 

Ossprey.jpg

 

 with the Chinook CH-47 (big diameter propellers and light disk loading):

 

photo2542_large.jpg

 

The first has almost double cruising speed, double range and substantially higher mileage.

 

I.e. the small diameter propellers of the OSPREY V-22 offer great advantages (even though it sacrifices the autorotation and the safety it offers).

 

 

With the small propellers the downwash speed is high.

 

With the pilot / rider of the Portable Flyer into the high speed downwash, the Portable Flyer has more control options.

 

Portable_Flyer_Accel_Decel_small.png

 

Besides the “weight displacement control” of the GEN-H-4, it has also true aerodynamic control (like Yves Rossy Delta Wing JetPack).

 

In the future the diameter of the propellers of the Flyer will be reduced for the sake of even higher speeds.

 

 

You also write:

“And of course it needs to be of the "sit-down" variety.  You claim that the whole arrangement weighs 20kg?   I would guess probably twice that.   But even at  20Kg it is probably too heavy (and top-heavy) for a normal  person to comfortably wear and put on - it would need  and assistant.   Whereas a  "sit-down"  (H4) layout would need no assistance.”

 

The 20Kg total weight is for normal materials (aluminum and steel).

With better / exotic / expensive materials the total weight reduces.

 

 

You also write:

“I hate to be critical of someone who is so productive of ideas - but your main problem with all your ideas is continually insisting that your particular idea is the "best ever"  and refusing even minor changes.”

 

Please keep on being critical.

Criticism is the best contribution in a technical discussion.

It helps to correct errors and it gives ideas for rethinking.

 

 

 

The complete application for the Portable Flyer in the GoFLy-BOEING contest is at https://www.pattakon...GoFly/DTR_1.pdf and https://www.pattakon...oFly/index.html

 

Please read it, be critical and let me know all your objections to help me improve it.

 

Thanks

Manolis Pattakos



#62 Slumberer

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Posted 27 August 2019 - 12:33

How do you transition from high speed cruising to braking?

It would seem to me that the only way would be to throttle back but that might just reduce your altitude and that might not be a great option.



#63 manolis

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Posted 27 August 2019 - 15:53

Hello Slumberer.

 

You write:

"How do you transition from high speed cruising to braking?"

 

 

See in the following video, from 1':52'' to 2':02'', Fraky Zapata accelerating and then decelerating with his FlyBoard Air.

  

 

To accelerate, Zapata leans forwards, so that the exhaust gas from his jet turbines exits downwards - backwards pushing him upwards - forwards.

To decelerate / brake, Zapata leans backwards, so that the exhaust gas from his jet turbines exits downwards - forwards pushing him upwards - backwards.

 

 

 

Quote from https://www.pattakon...GoFly/DTR_1.pdf

 

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 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

 

 

Similarly to Zapata:

  • in order to accelerate towards a direction, the pilot / rider of the Portable Flyer leans towards that direction: the rotors provide an upwards force that takes the weight of the pilot / Flyer, and a horizontal force that accelerates the pilot / Flyer towards the selected direction.
  • in order to decelerate, the pilot /rider of the Portable Flyer leans backwards: now the rotors provide an upwards force that takes the weight of the pilot / Flyer, and a backwards force that decelerates the Flyer.

 

If it is not clear, please let me know to further explain.

 

Thanks

Manolis Pattakos 



#64 Kelpiecross

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Posted 30 August 2019 - 06:49

 Manny - various comments etc.:  

 The Flyer is dangerous.    Imagine the Flyer at take off -  a bloke staggering about  with a screaming engine, four propellers/twelve blades  spinning at around 5,000rpm balanced precariously on his (her) shoulders. Not dangerous?  I think it is self-evident - bloody dangerous both to the pilot and anybody within a hundred yards or so..

 

 The weight of the Flyer:  20kg all up? - and the rest.  The similar (in intended purpose)  H4 claims 70 kg empty/dry weight - allow 10 or 15 kg  for the additional structure - it is still about three times heavier than the Flyer.  With the Flyer you would have to add  10-15 kg for the fuel tank and fuel alone, plus carby/fuel injection  throttle cable and other controls,  starter motor/battery/generator, harness and some structure for the pilot and I am sure there are other items I have forgotten.    50kg  at least I would guess and probably a lot more.

 

 Insufficient lifting power:  I can only refer to previous practice with this.  If you look through all the available information on the internet etc.  you will not find even one example of an unshrouded/non-ducted propeller of this diameter being used. There are a few examples of ducted propellers of this size being used - but generally not very successfully.   The duct apparently adds 40% to 50% extra thrust for the same power and propeller diameter.   

This is a very good  example:           https://www.bing.com...26F38&FORM=VIRE

 Notably- even without a pilot or dummy it still couldn't lift itself off the ground.  The Mythbusters  didn't give the all-up weight - just that it was less than 500lbs. The MBs with their apparently unlimited budget and  engineering assistance  can only manage a weight like this - and yet you claim something approaching 1/10 of this weight.  

 

 You make a lot of comparisons between and Flyer and the Osprey  - I not sure it is valid to make such comparisons between two such widely varying in size airframes.   In any case - the vertical  performance aspect of the Osprey really is pretty terrible  compared to a conventional helicopter -  probably because of its  small rotor diameter.      

 

 Despite all the above the Flyer is an interesting project and topic.  

 

 On the subject of variable valve timing etc.:  I am referring only to VVT systems that are strictly mechanical  (maybe hydraulics or electrickery  to operate it - but the main principle is mechanical).  This rules out your MultiAir (or whatever it is called)  and all similar arrangements and hydraulic/pneumatic/solenoid (or combinations thereof) in general.  Also I rule out two-step systems (even though some of these are very good and very practical).  

  The only (and I mean only) contender I think (and I admit to a slight conflict of interest here) is the Helical Camshaft.    

 

 

 

 

 

.   


Edited by Kelpiecross, 30 August 2019 - 06:54.


#65 manolis

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Posted 30 August 2019 - 16:35

Thank you Kelpiecross.

 

 

You write:

“ Insufficient lifting power:  I can only refer to previous practice with this.  If you look through all the available information on the internet etc.  you will not find even one example of an unshrouded/non-ducted propeller of this diameter being used. There are a few examples of ducted propellers of this size being used - but generally not very successfully.   The duct apparently adds 40% to 50% extra thrust for the same power and propeller diameter.   

This is a very good  example:           

https://www.bing.com...26F38&FORM=VIRE

 Notably- even without a pilot or dummy it still couldn't lift itself off the ground.  The Mythbusters  didn't give the all-up weight - just that it was less than 500lbs. The MBs with their apparently unlimited budget and  engineering assistance  can only manage a weight like this - and yet you claim something approaching 1/10 of this weight.”

 

 

The following video:

 

 

shows the Martin JetPack in China, 2015, flying controllably for five minutes.

 

Worth mentioning:

in the video the pilot is tightly strapped onto the casing as a “dead weight” (neither ability for “weight displacement control”, nor for aerodynamic control by means of pilot’s limbs). The only control is some sets of flaps at the bottoms of the ducted rotors.

 

Specifications:

200Kg (440lb) empty weight,

320Kg (700lb) total take-off weight,

150kW (200PS) from a V-4 2,000cc 2-stroke engine,

two ducted rotors, 0.8m diameter (2 ft 7 in) each,

total “rotor disk area” 1m2,

disk loading: 320Kg/m2 (in comparison, the “non-ducted” Osprey V-22 has three times lower disk loading: 102Kg/m2).

 

According your:

 

The duct apparently adds 40% to 50% extra thrust for the same power and propeller diameter”,

 

and in case the propellers of the Martin JetPack were un-ducted:

 

with the existing (0.8m) diameter of the rotors the total take-off weight would drop to ~200Kg (so it could not take-off),

or,

for the existing 320Kg total take-off weight (and with the same 200PS power), the “rotor disk area” should increase by 50%, i.e. the rotor diameter should increase from 0.8m to 1m (1.5*(0.8^2)=1^2) to make it capable for take-off.

 

So, with 1m diameter un-ducted rotors and 200PS power, the 320Kg Martin JetPack would take-off and fly.

 

The total weight of the Portable Flyer is 1/3 of that of the Martin JetPack, while the power of each engine of the Portable Flyer is about 1/3 of the power of the Martin JetPack, and its rotors are 1m diameter each (as in the un-ducted version of the Martin JetPack).

 

I.e. even with the one engine and the one pair of counter-rotating propellers, the Portable Flyer can take-off and fly (just like the Martin JetPack).

 

With one more engine and one more pair of counter-rotating rotors, the Portable Flyer not only takes-off, but can accelerate upwards with 1g.

The take-off at full power (both engines) would be like falling to the sky, with 1g upwards.

This cannot be called “insufficient lift power”.

 

 

More important is the control:

 

With the pilot having free his limbs / head, and being permanently (from take-off to landing) into the high speed downwash, the control can be any combination of “weight displacement control” (like GEN-H-4) and of “aerodymanic control” (say, like Yves Rossy DeltaWing JetPack).

 

The most difficult moments are when the feet of the pilot are about to touch the ground during the landing, and when the feet of the pilot are un-touching (leaving) the ground during a take-off.

 

In both cases the downwash air stream is directly hitting the limbs / head of the pilot (enabling "aerodynamic control") and combined with the body’s re-posing (enabling "weight displacement control") provide over-control (redudancy of control for errors correction).

 

As for pilot’s legs / feet, they are the most adjustable and sensitive landing gear.  

 

 

 

You also write:

“The weight of the Flyer:  20kg all up? - and the rest.  The similar (in intended purpose)  H4 claims 70 kg empty/dry weight - allow 10 or 15 kg  for the additional structure - it is still about three times heavier than the Flyer.  With the Flyer you would have to add  10-15 kg for the fuel tank and fuel alone, plus carby/fuel injection  throttle cable and other controls,  starter motor/battery/generator, harness and some structure for the pilot and I am sure there are other items I have forgotten.    50kg  at least I would guess and probably a lot more.”

 

Here they are shown the two engines of the videos (previous post) from the ignition side:

 

Tilting_Flyer_both_A.jpg

 

Tilting_Flyer_both_B.jpg

 

and from the sprockets (power output) side:

 

Tilting_Flyer_both_C.jpg

 

Tilting_Flyer_both_D.jpg

 

With 2  carburetors each, and with their ignitions on, the total weight is 21Kg.

 

No extra attention has been paid, so far, for the weight reduction (only from the sprockets / synchronizing gearing can be removed a couple of Kg, while from the cylinder liners (they were made too thick because too much aluminum had to be removed from the cast casings) can be removed more than one more kg).

 

What is not shown is:

the saddle,

the propellers (with their sprockets and toothed belts)

and the pipes whereon the propellers are rotatably mounted.

 

The cranking is to be manual.

Neither electric generator, nor battery are required.

 

The above make the 20Kg total weight for the Portable Flyer feasible (without using special / expensive materials).

 

 

 

You also write:

“The Flyer is dangerous.    Imagine the Flyer at take off -  a bloke staggering about  with a screaming engine, four propellers/twelve blades  spinning at around 5,000rpm balanced precariously on his (her) shoulders. Not dangerous?  I think it is self-evident - bloody dangerous both to the pilot and anybody within a hundred yards or so..”

 

For those who fly (with airplanes, helicopters, paragliders etc), the real danger is the hit the ground after an uncontrolled fall.

The rotors (which rotate at less than 4,000rpm) are the most reliable (and extremely lightweight) part.

 

 

Thanks

Manolis Pattakos



#66 Kelpiecross

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Posted 31 August 2019 - 10:06

  Interesting stuff.

 

  I don't think the Flyer will get off the ground -  you think it will accelerate upwards at 1g.   I think something 

we can both agree on,  and be certain of,  is that the Flyer's performance will lie somewhere between these two limits.  



#67 manolis

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Posted 12 September 2019 - 11:30

Hello all.

 

A few pistons and rods going for the heat treatment:

 

Tilting_Pistons_Rods_before_heat_treatme

 

and here the one prototype (without the aluminum pulley) revving low and high:

 

 

Thanks

Manolis Pattakos