2 stroke thread (with occasional F1 relevance!)

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
roon
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by roon » Tue Aug 07, 2018 8:04 am

PlatinumZealot wrote:
Tue Aug 07, 2018 3:38 am
:D
The portable flyer looks like the best design. It doesnt look as far developed as the other designs though. Its only in 3D model stage it seems.
The model missing hands and feet adds some realism.

manolis
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by manolis » Tue Aug 07, 2018 9:10 am

Hello Roon

You write:
“The model missing hands and feet adds some realism.”


The following Q&A from the http://www.pattakon.com/GoFly/Posts_to_GoFly_Forum.htm reply to you, too.



Question:

“By the way - I highly recommend the rotors being out of hands reach - all I keep seeing is a lot of potential shredding.”


Answer:

Quote from the submission (http://www.pattakon.com/GoFly/index.html abstract).

“The saddle prevents the pilot from lifting his hands above his shoulders, thereby protecting them from the propellers.”

If it is not clear, see the photo:

Image

and the drawing :

Image

The metal frame comprises two “epaulets” (the “horizontal” semi-circular pipes a little above the armpits) which make impossible the hands to reach the lower propeller (no matter how hard the pilot try to).



Question:

“Sooner or later some limbs will get into those rotors, they are open and within reach of people.
You can probably put them higher and add a pedestal to compensate for imbalance. Still it will take a daredevil hero to ride it.”


Answer:

The spinning rotors/ propellers are not in the reach of the pilot (because he first “wears” (tightens on his body) the PORTABLE FLYER and only then he can “crank” the engines).

So the problem is with the people who are within the reach of the spinning propellers.

Small airplanes have the same exactly problem (the spinning propeller is within the reach of “people”).
Helicopters have the same exactly problem (either the main rotor or the tail rotor are within the reach of “people”).
The paramotors / pararapente have the same problem: the spinning propeller is within the reach of “people”.

Having said that, can you spot on why the spinning propellers of the PORTABLE FLYER are more danger than the other spinning propellers?



Question:

“Have you been striked in the face or naked parts of the body by relatively larger insects guys , even with speed much lower than 100 mph ? I have ( and the expirience isn't pleasent )but haven't been striked by bird yet and probably that's why still alive .”


Answer:

This is a minor problem for the motorcyclists and for the passengers of convertible cars.
Even when you walk on the ground, a bird can strike you, or --- on you.
And a bee can sting you.
And a dog can bite you.
Etc, etc.

Come on.

The real danger when you fly is to fall and strike the ground.
All the rest are like jokes.
The safety should minimize the possibility of such an event (to strike on the ground).
The accidents happen mostly when the flight is in bad weather conditions.
And this danger increases a lot for big / underpowered / slow moving Flying Devices.
Your passenger is “protected” inside the cockpit, but he is in a big underpowered vehicle which is at the mercy of the winds, a “feather in the wind” when the wind blows strongly.
. . .
When flying in the air, what matters above all is to master the air, to stay in the air and to land safely.

A compact, lightweight, overpowered, high speed Personal Flying Device is far safer than a big, heavy, underpowered, slow (but comfort) one.

If I had to fly in adverse weather conditions (say for a rescue) I would pick the smallest, the lightest, the simplest, the most powerful, the easiest to directly control device.

Thanks
Manolis Pattakos

manolis
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by manolis » Tue Aug 07, 2018 9:22 am

Hello PlatinumZealot.

You write:
“The portable flyer looks like the best design”



In the GoFly / BOEING contest, the PORTABLE FLYER was (among others) the (by far) most lightweight “Personal Flying Device".

“Was” because as it is now the contest, the participation in the next phases is meaningless.


Quote from http://www.pattakon.com/GoFly/Posts_to_GoFly_Forum.htm (wherein they are saved my posts (from 15 June 2018, to 1 August 2018) to the deleted forum of GoFly):

Hello Mokren. (9 July 2018)

To participate in the rest phases?
Only when BOEING will decide to take over and to turn this challenge to a decent and transparent one.

The credibility GoFly earned so far is for laugh.
They pretend their goal / vision is to foster thinkers and tinkers make people fly.

The 250 USD I paid them is nothing, but make me a sucker: that some guys, hiding behind a big name (BOEING), have deceived me is frustrating.

It is a shame for BOEING to continue as the big sponsor of GoFly.

To put it simply, what I purchased with my 250 USD is the following info:
“You are not in the ten winners of the Phase I. Period.”


Neither scoring, nor ranking, nor justification of the decision, nor a clue for the weak points the judges find in my solution, nothing at all.
Just that I am not in the ten winners of phase I. . .

And now they try to trap again the contestants with cheap “tricks” of the kind:

"Dear contestant, in order to get a REVIEW of your Phase I submission, you have first to register to phase II; and in order to register to phase II, you have, among others, to create a company, to pay insurance fee, to pay “team” fee and to give equity rights to GoFly.”

IMPORTANT:
The trick / the cheating is double.
By “REVIEW” they do not mean the “fully justified resolution / verdict / decision of the judges”.
They just mean “a” review from “some” guy who is nominated as a “mentor”.

As you remember, they promised to give the scoring and ranking, and they never deliver.

Would you characterize the guy who thought the above “double trick” as a “decent guy whose vision is to foster people fly”, or as a scam?


Thanks
Manolis Pattakos

End of Quote

Tommy Cookers
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by Tommy Cookers » Tue Aug 07, 2018 11:45 am

well the PatTilt looks less dangerous and more convincing than the PatFlyer

and less dangerous than jet jobs that poorly segregate commanded tilting of the lift vector from uncommanded tilting
on Sunday my TV showed a UK multi jet flyer - the creator flew at 3' and said below 500' was a death zone (parachutewise)
his footage of transition to high speed looked very dangerous
he does gym work for strength - having 100 lb engine thrust per arm
consumption 1 gallon/minute
hovers upright at 3' (ground effect ?) with arms inclined - arms by sides and he is a 300 lb thrust 'human rocket'
(TV also showed the newly rebuilt Bluebird K7 - that did an uncommanded transition 50+ years ago)

mostly flying accidents are not falling - they are with intended (landing) and unintended controlled flight into ground
weather problems are usually visibility related not wind related
yes some rules for amateur flying drive the misperception that slow is safe (which it isn't in average W.European winds)

it's all laughable when a $500 drone has automatic stability and control systems and can be flown 'out of the box'

manolis
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by manolis » Tue Aug 07, 2018 3:52 pm

Hello Tommy Cookers.

You write:
“well the PatTilt looks less dangerous and more convincing than the PatFlyer
and less dangerous than jet jobs that poorly segregate commanded tilting of the lift vector from uncommanded tilting
on Sunday my TV showed a UK multi jet flyer - the creator flew at 3' and said below 500' was a death zone (parachutewise)
his footage of transition to high speed looked very dangerous
he does gym work for strength - having 100 lb engine thrust per arm
consumption 1 gallon/minute
hovers upright at 3' (ground effect ?) with arms inclined - arms by sides and he is a 300 lb thrust 'human rocket'
(TV also showed the newly rebuilt Bluebird K7 - that did an uncommanded transition 50+ years ago)”



If I had to justify the 440,000 USD price of the Browning Daedalus Fly Pack, I would say that it is extremely expensive to prevent people from buying it (and be killed flying with it).
Among others:
it requires a powerful pilot and a lot of continuous effort from the pilot,
it has a very small final speed,
it has a very limited range and duration,
it is a unique design and a very bad one.


If you compare it to Zapata’s FlyBoard-Air, it is like comparing the day with the night:



Without noticeable effort, Zapata literally dances in the air. He makes all kinds of acrobatics. He takes-off and lands confidently and safely.


The same if you compare Browning’s Deadalus with the JB11 of Mayman



Quote from https://www.digitaltrends.com/cool-tech ... ion-jb-10/

“It’s like a Segway, Mayman explains.
If you want to go forward, you just lean forward.
If you want to stop, you just lean back.
It’s incredibly simple.
If you wanted to fly a helicopter, you’d need 150 hours of training — but with this, you can learn everything you need to know in about 3 hours.”

End of Quote

According Mayman’s experience on training “ordinary people” to fly with his JB10 JetPack,
some 3 hours of tethered tests / training is considered adequate before the initial low height free tests above water.
The pilot can fly at small height over the sea (or over a lake) for as long as it takes to get familiar and confident.
Only when the trained pilot feels ready, the pilot can take-off to the sky.

According Mayman, flying with his JB-10 is intuitive and easy: it is as easy and as intuitive as bicycling.

A motorcycle rider is not necessarily safer than a pilot flying with a JB-11: the one has all three dimensions to escape from a collision, the other has from one to none.


So, don’t start with the worst of the kind.
Start with the best of the kind (Zapata for now), i.e. with the state-of-the-art, and write down the weaknesses you see.

For instance,
the extreme noise is a big issue,
the extreme fuel consumption and emissions is a big issue,
the extremely short range and small flight duration is an issue,
the extreme price is also an issue.

But the controllability is not an issue, neither for Zapata, nor for Mayman.



Is the OSPREY V22 a really safe airplane / helicopter?

Image

Quote from the submission of the PORTABLE FLYER to the GoFly BOEING contest (more at http://www.pattakon.com/GoFly/DTR_1.pdf ):

Two Independent power units

Each engine driving its two counter-rotating propellers comprises a complete / independent / autonomous and perfectly balanced propulsion unit.
Each engine, alone, is capable (driving its two counter-rotating propellers) to power the PORTABLE FLYER.
This makes the safety of the PORTABLE FLYER during a vertical take off / landing better than the famous V-22 Osprey of Bell-Boeing wherein a malfunction of the transmission, or a broken / destroyed wing of the one rotor, equals to a crash.
In comparison, a fallen apart propeller or a destroyed engine will not cause an accident or a crash of the PORTABLE FLYER, because the other engine-propeller-set can operate independently and is capable, alone, for a safe landing.

Parachutes

Even in the case both engines of the PORTABLE FLYER fail (or run out of fuel), there is still the option of the parachutes into the (fixed on the frame pipes) spinners for a safe landing.
. . .

Take-off, landing, hovering and cruising The stability and the controllability at vertical take-off, landing and hovering of the PORTABLE FLYER have no reason to be worse than in the GEN-H-4:

Image

The PORTABLE FLYER looks like a symmetrical compact GEN-H-4, and can fly like the GEN-H-4
. . .

Another quite relevant demonstration is the youtube video at



wherein a GEN-H-4 ultralight helicopter having two contra-rotating-fixed-pitch-rotors is perfectly controlled by the pilot pure-mechanically (the pilot displaces the center of gravity relative to the rotation axis of the two rotors).
The stability of the above GEN-H-4 Flyer at the fast take-off (14’’ to 18’’ of the video) is remarkable.
At hovering some 30ft / 10m above the ground, the stability is excellent; this excellent stability is achieved without any noticeable effort from the pilot: From 1:02 to 1:15 of the video the pilot of the GEN-H-4 looks around calmly, as if he is seating in a chair in the veranda of his 4th floor apartment.
He seems so relaxed that if he had a newspaper with him, he would read the news, too.

For comparison, in the

https://www.youtube.com/watch?v=ey5gPKRWbmU

youtube video it is shown the vertical take off and the vertical landing of the high-tech, no budget, OSPREY V22 of Bell Boeing.
The variable pitch rotors and the numerous electronic control systems cannot hide the stability issues (from 7’’ to 17’’ (take off) and then from 1’:05’’ to 1’:25’’ (landing)). It reminds a fat cow trying to break-dance.
The oscillations of the OSPREY V22 are not harmless.
The catastrophe shown in the



video is the outcome of over-corrected oscillations about the long axis of the OSPREY. The simple mechanical control of the GEN-H-4 (i.e. the displacement of a lever) and the human brain (the control unit) appear far superior and safer.”

End of Quote


The BOEING (GoFly) contest should ask for something better than the state-of-the-art FlyBoard-Air of Zapata (in terms of noise, of mileage, of range and of cost, because in the rest, the FlyBoard-Air looks perfect).

Thanks
Manolis Pattakos

PlatinumZealot
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by PlatinumZealot » Wed Aug 08, 2018 1:27 am

manolis wrote:
Tue Aug 07, 2018 9:10 am


If I had to fly in adverse weather conditions (say for a rescue) I would pick the smallest, the lightest, the simplest, the most powerful, the easiest to directly control device.

Thanks
Manolis Pattakos
You have to admit you are a stubborn engineer though. :wink:
The critic made very good points. The propellers are a danger to the limbs. Unexpected forces can bend the frame... Or your arm could come out of joint for whatever reason. As per insects being projected down onto the rider, that is also a good point. Remember people will want to take out insurance with vehicles like these so every risk has to be minimized. Just modify your design to address these and you will be fine. No need to fight back so much.
"The true champions are also great men. They are capable of making difficult decisions, of admitting their mistakes and of pushing harder than before when they get up from a fall."

- Ferrari chairman Sergio Marchionne

manolis
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by manolis » Wed Aug 08, 2018 4:44 pm

Hello PlatinumZealot

You write:
“Unexpected forces can bend the frame...”


If “unexpected” forces can bend the frame at such a degree, a crash will follow.

More useful is to deal with the expected loads.

For instance, strong moments are created and try to bend / twist the frame of the PORTABLE FLYER at every change of the direction of the propeller rotation axes.

The zero gyroscopic rigidity of each propulsion unit (comprising an engine and its two propellers) means that the pilot can almost “instantly” and “effortlessly” change the direction of the propeller rotation axes to vector at any direction.

Internally this fast change of the direction of the propeller (and of the crankshaft) rotation axes creates strong inertia moments requiring a stiff / robust “backbone” interconnecting the bearings wherein the propellers (and the crankshaft) are rotatably mounted.

Image

This “backbone” is formed by securing the casings of the two OPRE Tilting engines to each other: it adds no weight and it is more rigid and robust than required.




You also write:
“As per insects being projected down onto the rider, that is also a good point.“


No, it is not a good point.

In the presentation of a new pill that, according its creator, cures / heals the cancer, it is not a good point to ask about the taste of the pill.

The insects is a common (but not serious) problem for the motorcyclists and for the driver / passengers of convertible cars.

A helmet protects the face of the pilot of the PORTABLE FLYER.

Thanks
Manolis Pattakos

Pinger
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by Pinger » Wed Aug 08, 2018 4:49 pm

Manolis - am I correct in thinking you have built a working engine for this? If so, can you give more info on it and/or point in the direction of where you have posted it before?

manolis
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by manolis » Thu Aug 09, 2018 4:11 am

Hello Pinger.

You write:
“Manolis - am I correct in thinking you have built a working engine for this? If so, can you give more info on it and/or point in the direction of where you have posted it before?”

The closest “proof of concept” engine built is the OPRE Tilting presented at http://www.pattakon.com/pattakonTilting.htm (the “gas flow” is explained at http://www.pattakon.com/tilting/pattako ... s_FLow.htm ):

Image

333 cc, bore 84mm, stroke 30+30=60mm
(same bore to stroke ratio with BMW's boxer R1200GS of 2013)
weight: 8.5Kp (19lb) without the exhaust pipe and the carburetor
height: 250mm

See the videos in the above web page showing the OPRE Tilting prototype running on gasoline / spark ignition.


Besides its extreme “bore to piston stroke” ratio, the Tilting valve:

Image

is the other big difference from the original OPRE design.


Here is an OPRE (but not tilting) compression-ignition prototype engine running on Diesel fuel, free on the floor:



It is the "father" engine of the OPRE Tilting.


Back to the OPRE Tilting.

The following video shows the assembly process:

http://www.pattakon.com/tilting/OPRE_Ti ... sembly.mp4

Image


The PORTABLE FLYER of the submission to the GoFly BOEING contest needs two OPRE Tilting engines secured to each other, with their cylinder axes collinear, 350cc each (the bore is increased from 84 to 86mm) and two-stage ignition (PatBam).

The only new is the “lean burn” PatBam HCCI combustion. We work on it.

Thanks
Manolis Pattakos

Pinger
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by Pinger » Fri Aug 10, 2018 1:51 pm

Thanks Manolis.
Just one observation. Your scavenging model - unless I've missed something or the drawings don't adequately show it, the transfer and exhaust porting don't seem to me to be sufficient to prevent charge short-circuiting. Either a deflector piston (with shown porting) or transfer ports more angled away from the exhaust port (as per loop scavenge) is what I'd expect to see. Possibly you have it covered and it's just not obvious to me. Have you measured UBHC at the exhaust at all?
Good effort getting the prototypes built and running.

manolis
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by manolis » Fri Aug 10, 2018 8:01 pm

Hello Pinger.

You write:
“Thanks Manolis.
Just one observation. Your scavenging model - unless I've missed something or the drawings don't adequately show it, the transfer and exhaust porting don't seem to me to be sufficient to prevent charge short-circuiting. Either a deflector piston (with shown porting) or transfer ports more angled away from the exhaust port (as per loop scavenge) is what I'd expect to see. Possibly you have it covered and it's just not obvious to me.”


The bore to the (overall) stroke is typical (the same with BMW's boxer R1200GS of 2013).

The combustion chamber of the OPRE Tilting consists of two “over-over-square” halves, with each half having its own transfer ports, its own exhaust ports, its own gas and its own gas flow.

I.e. in the two halves of the combustion chamber there are two independent / symmetrical flows, say as in the following animation wherein they are shown the two piston crowns at the BDC and the cylinder liner (yellow transparent) with its transfer and exhaust ports :

Image

The “over-over-square” design of each half (2.8 bore to stroke ratio) makes from difficult to impossible the short-circuiting between the anti-diametrically arranged transfer and exhaust ports of the half. The fresh charge entering through the transfer ports can reach the exhaust ports only after displacing the burnt gas out of the exhaust.

It reminds the through-scavenged / uniflow Opposed Piston engines wherein the transfer ports are at the one end of a long cylinder, while the exhaust ports are at the other end of the long cylinder, eliminating the short-circuiting.

While the Opposed Piston architecture of the OPRE Tilting eliminates the cylinder head(s) reducing the wall area and the thermal loss,
the arrangement of the ports offers improved scavenging efficiency, eliminates the short-circuiting and reduces the quantity of the residual gas.


You also write:
“Have you measured UBHC at the exhaust at all?”

The low-cost prototype is not for measurements; it is just a proof-of-concept prototype.



By the way,
here are three videos (just uploaded to youtube):

the OPRE Tilting prototype running at low revs:



the OPRE Tilting running at medium revs:



and the internals / assembly of the first OPRE Tilting prototype



Thanks
Manolis Pattakos
Last edited by manolis on Sat Aug 11, 2018 3:12 am, edited 1 time in total.

Pinger
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by Pinger » Fri Aug 10, 2018 8:55 pm

Thanks Manolis. I'd overlooked the significance of the BSR. Don't though, discount a domed piston crown to help direct the incoming charge upward to enable thorough scouring of the spark plug(s) of residual exhaust products.

manolis
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by manolis » Sat Aug 11, 2018 4:37 am

Hello Pinger.

You write:
“I'd overlooked the significance of the BSR. Don't though, discount a domed piston crown to help direct the incoming charge upward to enable thorough scouring of the spark plug(s) of residual exhaust products.”


The arrangement of the spark plug(s), or of the injector(s), on the periphery of the cylinder have always been a problem of the Opposed Piston engines:

Image



The following solution softens the problem bringing the spark plugs and/or injectors closer to the center of the cylinder. The “neck” (the narrowing) in the middle of the cylinder is a problem for the through scavenged opposed piston engines, but not for the OPRE Tilting with its cross-scavenging wherein the flows inside the two halves of the cylinder are separate / independent:

Image

Image



With the PatBam HCCI two-stage combustion, the combustion starts at the very center of the cylinder:



is tolerant to the quality of the mixture (it enables the efficient / complete / fast / clean combustion even of extremely lean mixtures (with, say, lambda above 5), also of mixtures containing big percentages of residual gas),

and completes with the pistons being still near their TDC (with the pulling rod architecture of the OPRE Tilting, the pistons remain near their TDC (say at the “last” 10% of their strokes) for some 30-40% more time as compared to the conventional push rod architecture):

Image

Image

In the following video demonstration:



the one set of play cards represent the molecules in the cylinder when conventional progressive combustion happens (the flame front is between the falling play card and its neighbour play card that is still standing) ,
while the other set of play cards represents the spontaneous HCCI combustion wherein there is no flame front: each fuel molecule, independently, reacts with its neighbouring oxygen molecules.

Image.

Image

The idea is to operate the engine at as lean mixtures as possible to increase the brake thermal efficiency and to keep the emissions low.

Mazda is close (early 2019) to put in mass production their SP-CCI HCCI SkyActiv-X engines:



and claims, at lean mixtures, efficiencies close to 50% and emissions (well to wheels) better than hybrids and electrics.

The PatBam HCCI two-stage combustion (more at http://www.pattakon.com/pattakonPatBam.htm ) can be looked at as a simple mechanical version of the SP-CCI SkyActiv-X of Mazda.

Thanks
Manolis Pattakos

J.A.W.
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by J.A.W. » Mon Aug 13, 2018 11:18 pm

Wow Manolis, seems that Boeing/Go Fly deal.. really is some kind of ghastly 'post modern' orchestrated scam..

Such a bogus-biased set-up, with totally 'rubbery' reg/rules.. being maleficently obfuscated..
akin to Lewis Carroll's 'Humpty Dumpty' character.. "Words mean whatever I choose them to mean"
- rather than proper FAI-standard technical usage norms.


Boeing's top exec's must be seething at this appalling PR debacle, so very likely someone will get fired for it..

You certainly have my commiserations..
Dr Zachary Smith sez..
"Yes.. spare us your ridiculous remarks, you insensitive idiot!"

manolis
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by manolis » Tue Aug 14, 2018 8:16 am

Hello J.A.W.

It's nice to hear from you again.


Enjoy the following quote (end of the http://www.pattakon.com/GoFly/Posts_to_GoFly_Forum.htm ) which is my last post in the GoFly Forum (it was posted a few hours before GoFly / Herox deleted the complete Forum):


Hello all (August 1, 2018).

As it seems,
the “transparency” of the “Phase I Awards Issue” and the “clearly defined rules”,
continue in the phase II of the GoFly contest.

From the so far posts about the “equity”, it seems that nobody really knows what equity means here.

To be in the safe side, when you sign a paper / a contract, you have to consider the “worst case scenario”.


Flapping Flight’s scenario is an interesting one:

“When you sign the agreement doesn't matter if you are the winner in the competition or winner out of it
GoFly will be your "partner" ”



At first, the GoFly contest, with the BOEING involved as the big sponsor (remove the name “BOEING” from this contest and think if you would ever think to participate), was presented as a contest among thinkers and tinkers, with goal to make people fly.

Now it appears as a contest for lawyers.


Compare the GoFly / BOEING contest with Sikorsky’s contest for a human powered helicopter (more at https://en.wikipedia.org/wiki/Igor_I._S ... ompetition ) wherein the first who achieved “a flight duration of 60 seconds, reaching an altitude of 3 meters, with the center point of the aircraft hovering over a 10-by-10-metre square, was immediately declared the winner and took the big prize.

A clear / honest / transparent contest against the GoFly / BOEING contest.

I wonder, nobody in BOEING reads this forum?

Thanks
Manolis Pattakos