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BOEING / GoFly contest: Oh, BOEING


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#1 manolis

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Posted 03 August 2018 - 05:44

Hello all.
 
On Ausust 1, 2018 GoFly / Herox / BOEING (the big sponsor) deleted the Forum wherein the contestants of the GoFly / BOEING contest presented their opinions and their complaints.
 
GoFly’s / BOEING’s best response to contestants’ questions, was to shut down the annoying forum . . .
 
Each one of the contestants has paid 250 or 500 USD to GoFly / BOEING.
In return, all they took from GoFly / BOEING is the list with the ten winners.
No scoring, neither ranking, neither justification from the "97 judges"; just the ten winners alphabetically.
 
 
Take a look at http://www.pattakon....oFly/index.html wherein some of the Open Forum Discussions have been “partially” saved and presented: 
 
 
20 minutes OR 20 miles? - Page 1 : http://www.pattakon....r_20_miles.html
 
20 minutes OR 20 miles? - Page 2 : http://www.pattakon....les_Page_2.html
 
20 minutes OR 20 miles? - Page 3 : http://www.pattakon....les_Page_3.html
 
Note: the “20 minutes OR 20 miles” thread had in total 11 pages.
 
Design Discussion - Page 3 :
 
 
Design Discussion - Page 5 : http://www.pattakon....ion_Page_5.html
 
Debating Results of Phase I : http://www.pattakon....of_Phase_I.html
 
 
The above discussions are indicative and show the appreciation, the trust and the confidence of the contestants for the GoFly / Herox / BOEING contest.
 
 
When you have time to spend, read the http://www.pattakon....GoFly_Forum.htm and give your comments / questions.
 
 
Portable_Flyer_Accel_Decel.png
 
JetPacks_vs_Portable_Flyer.png
 
Thanks
Manolis Pattakos
 


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#2 Greg Locock

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Posted 03 August 2018 - 07:28

So you aren't going to bother with Phase 2 then?

 

Setting up a competition is actually more stressful than you might think, and the results of these design competitions are often rather sad. The X prize for cars succeeded in killing off a reasonably practical  commercial proposition in favor of a car that was designed to win the comp but was not designed for production.



#3 Kelpiecross

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Posted 03 August 2018 - 13:56

I doubt if any of the ten winning designs will be built - and if they are, they won't fly to any practical extent. The designs are a bit disappointing really, more style than novel flying ideas.

#4 Tenmantaylor

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Posted 03 August 2018 - 14:06

The opening specs are blatantly wrong. I'm sure all could achieve 200mph if they fail from high enough.



#5 manolis

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Posted 04 August 2018 - 03:15

Hello Greg Locock

 

You write:

So you aren't going to bother with Phase 2 then?

 

 

 

Quote from http://www.pattakon....GoFly_Forum.htm (it is from the Forum deleted by GoFly three days ago):

 

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



#6 Greg Locock

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Posted 04 August 2018 - 07:39

Oh don't worry, i agree, the situation stinks and I wouldn't have anything more to do with them.



#7 gruntguru

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Posted 06 August 2018 - 00:26

+1

Develop your flyer. Get them manufactured in China. Sell them on E-Bay.


Edited by gruntguru, 06 August 2018 - 00:28.


#8 gruntguru

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Posted 07 August 2018 - 23:07

http://www.pnas.org/...ent/115/31/7913

 

Hi Manolis.

Some support here for your concept of "torso control". The videos are interesting.



#9 manolis

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Posted 08 August 2018 - 03:23

Hello Gruntguru

 

You wrote:

Develop your flyer. Get them manufactured in China. Sell them on E-Bay

 

 

Best advice.

Thanks.

 

Initially the GoFly (BOEING) contest appeared as an opportunity.

 

The final design (that with the two “coaxial” engines and the two-pairs of intermeshing propellers) was ready a couple of years before the contest.

 

HRG_1.jpg

 

In hindsight, the GoFly contest proved a deceit, a fraud, a hook with the “BOEING” (the big sponsor) used as the bait / the teaser.

 

With several internet forums writing about this fraud, BOEING cannot pretend, any longer, that they don’t know what is going on.

 

Thanks

Manolis Pattakos


Edited by manolis, 08 August 2018 - 03:33.


#10 manolis

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Posted 08 August 2018 - 04:39

Hello Gruntguru

 

You write:

“Some support here for your concept of "torso control". The videos are interesting.”

 

 

Thanks.

Yes the videos are interesting (but two of them don’t “play”).

 

 

It seems that the intuitive control, used by birds, bats and bugs, is the best when a person is to fly, with the intuitive “torso control” being efficient and easily adapted.  

 

 

IN PRACTICE:

 

 

Here is the JB11, the last JetPack 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.

 

 

Here is Zapata’s FlyBoard-Air:

 

 

Zapata is not just flying, he is making acrobatics in the air.

And, as Mayman, similarly Zapata is based on the intuitive control.

 

 

 

Yves Rossy with his delta wing and his 4 jet-turbines goes a little further.

He uses his limbs and head for the control of his flight.

No electronics, at all.

 

 

Yves Rossy / Jetman "flies with the grace of an eagle, and the subtle body movements he uses to maintain flight - and perform his loops, rolls, and other maneuvers - mimics a bird of prey".

 

With only an altimeter and timer, Rossy uses his skin and ears as airspeed indicators.

 

"You feel very well, you feel the pressure," Rossy says, "you just have to wake up these senses. Inside an airplane we delegate that to instruments. So we are not awake with our body."

 

“I am the fuselage, and the steering controls are my hands, head and legs,” Rossy says.

 

 

 

Besides the “weight shifting CONTROL” (or “vectored thrust” control) of Zapata, of Mayman and of the GEN-H-4:

 

 

the PORTABLE FLYER has also the “aerodynamic CONTROL” of Yves Rossy.

 

In order to achieve “aerodynamic control” over his flight, Rossy needs to move at high speeds (say, above 100mph), otherwise his head and limbs cannot receive significant forces from the air.

 

In the PORTABLE FLYER the “Rossy like” aerodynamic control of the flight is applicable not only at high speeds, but at all speeds:

The heavy disk loading (thrust to disk area, similar to that of the OSPREY V22) causes a high downwash velocity, with the pilot inside it.

So, either at take off / landing, or at hovering, or at cruising, pilot’s limbs and head are in a high velocity air stream, which allows the aerodynamic control of Yves Rossi.

 

Thanks

Manolis Pattakos

 



#11 scolbourne

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Posted 10 August 2018 - 10:28

Are we at the point where electric ducted fans could be used as an alternative to a parachute.

I could see someone jumping out of a plane or using a wingsuit and then rather than using a parachute they instead slow their descent using the fans until they can land.

 

Obviously would be tested at low height , maybe off a swimming pool high diving board, and then progress to landings over water from a greater height.

 

Not sure if there is any real use for it but it would look cool and be fun.



#12 manolis

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Posted 24 October 2018 - 13:29

Hello all.
 
Here are the moving parts of the OPRE TIlting 2-stroke engine:
 
OPRE_Tilting_1.jpg
 
OPRE_Tilting_2.jpg
 
OPRE_Tilting_3.jpg
 
OPRE_Tilting_4.jpg
 
OPRE_Tilting_5.jpg
 
OPRE_Tilting_6.jpg
 
The above tilting valves have "rectangle" shape for the shake of the easy / accurate manufacturing with a lathe.
 
And here are two youtube videos of the engine (manual cranking).
 
 
 
Thanks
Manolis Pattakos


#13 Greg Locock

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Posted 24 October 2018 - 20:38

Fingers crossed!



#14 malbear

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Posted 27 October 2018 - 20:04

Is the little cutout on the top of the piston for the location of the spark plug in the sidewall?

:clap:



#15 manolis

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Posted 28 October 2018 - 04:38

Hello Malbear.

 

Yes, you are right.

Each piston has such a small cutout.

At the TDC (top dead center) the two opposed cutouts make room for the end-nose (say the last 5-6mm) of the spark plug.

 

In the next cylinder (to be made), the side location of the spark and the thin combustion chamber are changed (corrected) by using a narrowing at the center of the cylinder, like:

 

Flyer3a.gif

 

With the “narrowing”:

the spark goes near the center,

the combustion chamber gets meaty/thick/compact,

and a lot of squeeze is caused,

while the scavenging is not affected because the OPRE Tilting has “cross-uniflow” scavenging (“independent” in each half of the cylinder).

 

With the longer piston dwell at the combustion dead center, most of the combustion will complete in the narrowing (more “constant volume” combustion).

 

 

Simplicity:

 

In comparison to a conventional single cylinder engine having an external balance shaft (to cancel out the –otherwise unbalanced - first order inertia forces) and a pair of synchronizing gearwheels, the OPRE Tilting appears simpler, is perfectly balanced, has substantially lower piston speed at the same rpm, etc.

With divided load (a propeller on each crankshaft, as in the Portable Flyer) the synchronizing gearwheels of the OPRE Tilting remain unloaded during operation and need not lubrication.

Without reed valves it is saved bulk, weight, cost, noise and problems (what is omitted cannot fail).
The tilting valve is reliable, adds no weight, adds no noise, makes easier the lubrication of the wrist pin, etc.

 

 

Tilting valves and gas control:

 

The tilting valves bring a different control over the gas flow of the 2-strokes. 
 

The scavenging starts with a higher pressure just before the transfer ports (outside the cylinder). 
 

At the beginning of the scavenging the fresh gas bursts into the cylinder (which enables an earlier opening of the transfer after to the opening of the exhaust). 
The scavenging starts “positive”: from the opening of the transfer port to the BDC (Bottom Dead Center), the piston (with the tilting valve sealing its back end, and due to the small dead volume in the scavenge pump) displaces the air-fuel mixture into the cylinder positively (it resembles with the exhaust cycle of the 4-stroke engines: no matter what the pressure in the exhaust manifold is, the piston will push positively the burnt gas outside the cylinder). 

Things change near the BDC wherein the tilting valve opens. 
After the BDC the space inside the piston (i.e. the “crankcase” of the OPRE Tilting) is free to communicate with the cylinder through the open transfer port, and the scavenging turns from “positive” to “inertial”. 
With the inertia of the fast moving gas “column” in the transfer - cylinder - exhaust, the transfer continuous strong till the closing of the transfer port, sucking gas from the space inside the piston. 
At the end of the transfer, with the flow of the fresh gas from inside the piston towards the “scavenge pump” (and from the inlet port towards the space inside the piston) already strong, the filling (or overfilling) of the scavenge pump space with fresh gas continues uninterrupted till the closing of the tilting valve near the TDC. After the TDC the already established flow of fresh gas from the inlet port into the “crankcase” (i.e. the space inside the piston) continues uninterrupted, while at the same time the gas trapped into the scavenge pump undergoes a compression by the outwards moving piston.

The bigger the tilting valves, the better the breathing at high revs.
The over-square design enables bigger tilting valves to be used (look at the openings between the tilting valve and the back end of the piston):

 

OPRE_Tilting_gif_video.gif

 

In the prototype (opposed piston) there are two big tilting valves (one per piston), each serving 333/2=166cc of cylinder capacity. 
The over-over-square design (84mm bore for 30mm piston stroke in the prototype) besides enabling big tilting valves, it is also enabling a “cross” (not loop) scavenging (you can call it “cross uniflow” and is normal to the cylinder axis) that prevents the mixing of the burnt gas with the fresh gas (say, similar to the through scavenging along the cylinder axis of the “long-stroke” Junkers Opposed Piston Air engines). 
 

The tilting valve is actually an extension of the connecting rod small end.
With its “pulling-connecting-rod” design, the gas and the scavenging feels, around the BDC, as working into an engine running at, say, 30% higher revs:

 

Tilting_Piston_Position.png

 

which augments anything related with the inertia of the gas.

 

Timing / Asymmetry: 
 

While geometrically the transfer and the exhaust are symmetrical, in practice the transfer appears strongly asymmetrical because it starts true positive (at the expense of some energy for the compression of the gas in the scavenge pump) and continues inertial after the BDC.
The intake is heavily asymmetrical (the inlet port is permanently open, the tilting valve makes the difference).

 

Thanks

Manolis Pattakos 


Edited by manolis, 28 October 2018 - 05:23.


#16 manolis

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Posted 16 April 2019 - 16:24

Hello all.
 
First cast OPRE Tilting parts:
 
EPC_Tilting_1.jpg
 
EPC_Tilting_2.jpg
 
EPC_Tilting_3.jpg
 
Hopefully they will withstand the loads.
 
 
Thanks
Manolis Pattakos


#17 Greg Locock

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Posted 16 April 2019 - 21:11

You machined the cooling fins rather than casting them to shape? I always found designing cast parts was (too) exciting.



#18 gruntguru

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Posted 16 April 2019 - 21:36

I think they are cast.

 

Congratulations Manolis - very impressive concept and execution.


Edited by gruntguru, 16 April 2019 - 21:37.


#19 manolis

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Posted 17 April 2019 - 02:44

Thank you Greg Locock and Gruntguru.

 

 

Everything in the three photos of my last post is cast (and only the piston with the piston rings on it, is machined after cast).

 

In this photo:

 

EPC_Tilting_4.jpg

 

you can see the casing after the removal of the refractory material (plaster / silica) and before the removal of the "gating" system. The cooling fins are ready without any machining.

 

 

The casting is EPC (Evaporative Pattern Casting).

 

 

The material used for the two casings (the parts with the cooling fins) was taken from the casings of an old Nissan Micra 1,000cc engine and from an old Yamaha 250cc engine.

 

The material used for the pistons comes from melting several Smart engine pistons.

 

I would prefer to use LM25 (A356, AB42,000) aluminum alloy for the casings, but this material is not available in the local market.

 

 

By the way, if anybody knows, or can find, what type of aluminum alloy was used for Nissan MIcra and Yamaha casings, as well as for the Smart pistons, it would help in choosing the proper Heat Treatment (required to imrpove ductility and fatigue strength).

 

Thanks

Manolis Pattakos


Edited by manolis, 17 April 2019 - 02:51.


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#20 bigleagueslider

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Posted 17 April 2019 - 08:30

LM25 (or A356) is a very common heat treatable aluminum alloy used for sand castings. I can't imagine it is hard to find a source to buy a small quantity somewhere on the internet. Reasonable choice for a sand cast cylinder head or crankcase.

 

For cast aluminum pistons, a hyper-eutectic alloy (LM30 or A390) is often used. This type of high-silicon alloy requires a controlled die/permanent mold/investment casting process, which is only practical with large production applications. But the alloys do provide the excellent hot strength capability needed for recip engine pistons. Consider machining the pistons from a wrought forging alloy bar stock if possible.

 

Be careful about using production aluminum castings as your raw material. If they are permanent mold or die castings, they are possibly made from an aluminum alloy that will require a carefully controlled foundry process to obtain good metallurgy. If they are sand castings, the material can probably be re-used without any issues. You should be able to look at the parts and determine what casting process was used to make them.

 

The process for most heat-treatable aluminum alloys is to first give the castings a stress relief, then solution heat treat and aging (-T6 is common).



#21 manolis

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Posted 18 April 2019 - 04:18

Thanks Bigleagueslider.

 

The T6 is the case.

A problem is that the temperature and the time required for the solutionizing (before quenching) and for the aging are quite senstive to the alloy used.

 

But if you can't find the proper alloy locally, you have to compromize.

 

Thanks

Manolis Pattakos   



#22 manolis

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Posted 14 June 2019 - 18:22

Hello all.

 

 

"Lost Pattern" casting.

 

Thanks

Manolis Pattakos

 

 



#23 Greg Locock

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Posted 17 June 2019 - 06:31

I think you mean lost wax pattern. Nice.



#24 manolis

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Posted 18 June 2019 - 03:08

I think you mean lost wax pattern. Nice.

 

Greg, thanks for the assist.

 

Here

 

https://www.sfsa.org...ock/GMBlock.pdf

 

is the "Lost Foam" casting process used for the manufacturing of aluminum engine blocks of GM. 

 

Lost-Foam-Casting-Process.jpg

 

There is no wax; but the method / casting is a variation of the ancient "lost wax casting" wherein while the (wax) pattern is lost, the wax can be recycled and used for making the next patterns.

 

In the "Lost Foam casting" the pattern (and the material (i.e. the foam) the pattern is made of) is totally lost (burned).

 

The two OPRE Tilting engines standing on the chair (video, last post of mine) were made using plastic patterns (from PLA (created with a 3D-printer) like that at the back of the two engines). The pattern is surrounded by plaster. The plaster is dried and then it is heated at ~400 degrees Celcious for a few hours. The plastic pattern is burned leaving an empty space / "negative pattern" in the plaster, which is filled with melted aluminum alloy.

 

Thanks

Manolis Pattakos


Edited by manolis, 18 June 2019 - 03:14.


#25 Greg Locock

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Posted 18 June 2019 - 03:42

I'd forgotten about lost foam. Same principle as lost wax. One of the few attractive uses I can see for 3d printing. I worked in a  foundry briefly, in the pattern shop - was a gofer, not a skilled artisan!



#26 Wuzak

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Posted 18 June 2019 - 15:19

Sort of related!

 

https://www.youtube....h?v=U1wEO-pHizQ



#27 manolis

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Posted 19 June 2019 - 04:31

Hello Wuzak

 

 

The video shows some spectacular possibilities, but also some limitations, of the Browning Daedalus Flying Pack (that Adam Savage of MythBusters “wears” and tries to fly).

 

 

In the first post of this thread they are presented the specifications of the Browning “Daedalus Flying Pack”:

 

5 jet turbines (2 per arm plus one at back),

 

59lb dry weight,

 

5 miles range,

 

10 minutes fight duration,

 

32 mph top speed,

 

440,000 USD.

 

 

 

According the Internet, the total power of the above Jet-Pack is 1050hp.

 

Think: 1050hp to lift (and push “slowly” (32mph top speed)) a single person. Is there anything less efficient?

 

 

With the four jets secured on his arms, the arms have a difficult job to do. After a couple of minutes the arms cannot help being tired, and the pilot needs them (and his brain) during the landing.

 

 

In comparison to Mayman’s JetPack and, especially, to Zapata’s FlyBoard-Air, the only “advantage” of the Browning Flying Pack is its “unique” / proprietary architecture.

 

 

In all three cases (Mayman, Zapata and Browning) the 1,000hp (or so) total power of the micro-jet-turbines one thing make sure: the extreme fuel consumption and the small range.

 

With a motorcycle having 100hp of power you can achieve higher top speed (Zapata's case and actual Mayman case; for the case of the Browing jet-pack, even with a horse you can run faster).

 

For a useful transportation device, a reasonable range and an affordable fuel cost are (among others, like the affordable noise level) mandatory.

 

Thanks

Manolis Pattakos

 



#28 Kelpiecross

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Posted 19 June 2019 - 04:42

Manny - why did you choose to cast your engine's structure?  I would have thought machining it from an aluminium  billet  would have been stronger and simpler to do as well as less chance of flaws in the casting.   Will the engine have an iron or steel cylinder liner?  Do the pistons have rings?   



#29 manolis

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Posted 19 June 2019 - 09:16

Hello Kelpiecross.

 

 

Casting vs Billet

 

The following post is from a guy in another forum (F1-technical forum) and answers your question:

 

"The first post of the castings I did not appreciate that they were lost wax castings. I had expected you to cnc them out of billet aluminium - thinking that would be quicker for the pre production engines.

Now I appreciate what you have done. Made a master for the lost wax models so you can now economically & comparatively easily turn out more to order.
I have been really fascinated by this project."

 

 

For comparison, here is the casing of the PatOP Opposed Piston engine (more at https://www.pattakon...ttakonPatOP.htm ) :

 

PatOPpro1.jpg

 

It started with 54Kg (~120lb) of billet aluminum (7000 series) and it ended up with a ~10Kg (22lb) casing. The rest 44Kg (100lb) is waisted into filings. 

 

It takes a lot of material, a lot of time and a lot of money to make the parts from billet aluminum.

 

Another problem is the limitations on the shape, because the CNC machine needs space for its head / cutting tool (for instance, you need to secure covers on the casing to form the necessary passageways).

 

 

By casting the parts, the cost drops a lot (machining cost, material cost, etc).

 

The estimated 3,000 USD cost for a ready-to-fly Portable FLyer cannot be without casting. 

 

 

 

Cylinder liners:

 

Each OPRE Tilting engine has a ductile iron (spheroidal graphite iron) cylinder liner whereon the piston rings abut and slide.

 

A cheaper solution would be to use Nikasil or other aluminum plating (surface hardening), but these things are beyond my reach.

Only today I discovered, by chance,that the material I was looking for (premium A356) is the material the 95% of the aluminum (light alloy) wheels / rims are made of.

 

If anybody can make the Nikasil (or similar) plating, please let me know the details (price, time etc). 

 

For the Portable Flyer it will mean another 2Kg (5lb) weight reduction (which means 10% lighter).

 

 

 

Piston rings

 

Each piston has a ring towards the combustion chamber, and another ring at the oppoiste end.

The second piston ring is to reduce the leackage during the compression of the fresh charge in the scavenge ends of the cylinder (before the opening of the tilting valve).

 

Thanks

Manolis Pattakos


Edited by manolis, 19 June 2019 - 09:40.


#30 Wuzak

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Posted 19 June 2019 - 10:39

Hello Wuzak

 

 

The video shows some spectacular possibilities, but also some limitations, of the Browning Daedalus Flying Pack (that Adam Savage of MythBusters “wears” and tries to fly).

 

 

In the first post of this thread they are presented the specifications of the Browning “Daedalus Flying Pack”:

 

5 jet turbines (2 per arm plus one at back),

 

59lb dry weight,

 

5 miles range,

 

10 minutes fight duration,

 

32 mph top speed,

 

440,000 USD.

 

 

 

According the Internet, the total power of the above Jet-Pack is 1050hp.

 

Think: 1050hp to lift (and push “slowly” (32mph top speed)) a single person. Is there anything less efficient?

 

 

With the four jets secured on his arms, the arms have a difficult job to do. After a couple of minutes the arms cannot help being tired, and the pilot needs them (and his brain) during the landing.

 

 

In comparison to Mayman’s JetPack and, especially, to Zapata’s FlyBoard-Air, the only “advantage” of the Browning Flying Pack is its “unique” / proprietary architecture.

 

 

In all three cases (Mayman, Zapata and Browning) the 1,000hp (or so) total power of the micro-jet-turbines one thing make sure: the extreme fuel consumption and the small range.

 

With a motorcycle having 100hp of power you can achieve higher top speed (Zapata's case and actual Mayman case; for the case of the Browing jet-pack, even with a horse you can run faster).

 

For a useful transportation device, a reasonable range and an affordable fuel cost are (among others, like the affordable noise level) mandatory.

 

Thanks

Manolis Pattakos

 

 

You are right Manolis.

 

There is also the matter of heat and noise!



#31 manolis

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Posted 13 August 2019 - 12:11

 

 

"Lost Pattern" casting.

 

 

Hello all.

 

Here are the youtube videos of the above cast OPRE Tilting engines running on gasoline fuel:

 

 

and

 

 

 

Cast casing, cast pistons, cast connecting rods and tilting valves.

 

 

The aluminum pulley is quite lightweight and is for the manual cranking; i.e. there is no flywheel other than the synchronizing gearwheels and the balance webs (all secured on the crankshafts).

 

Thanks

Manolis Pattakos



#32 pierrre

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Posted 16 August 2019 - 20:34

genius of simplicity, really like this


Edited by pierrre, 16 August 2019 - 20:35.


#33 Greg Locock

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Posted 17 August 2019 - 23:24

Well done Manolis. 



#34 manolis

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Posted 18 August 2019 - 06:19

Thanks Greg.

 

The balancing used in the two OPRE Tilting engines of the videos is static.

This explains the tendency of the operating engines for “walking, spinning” on the floor.

With "dynamic balance" (it takes more time to modify properly the balance webs at the ends of the crankshafts) the operating engines will stay immovable where they stand.

 

Here is a photo of the third (and of better quality) cast aluminum casing:

 

Tilting_Cast_Casing_3.jpg

 

which is not yet turned to an engine.

 

 

 

 

Hello Pierrre.

 

At a first glance, the Portable Flyer seems as a simpler “symmetrical compact GEN-H-4”.

 

But, as the following quote explains (it is from the “DEVICE TECHINCAL REPORT” at https://www.pattakon...oFly/index.html, filed to the GoFly-BOEING contest), there are fundamental differences in the control (and in the resulting safety) of the two:

 

 

 

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:

 

genh4sketch-en.gif

 

In the above GEN-H-4 the only control is the lever that displaces the center of gravity relative to the rotation axis of the two big (13ft / 4m diameter) contra-rotating rotors. The PORTABLE FLYER looks like a symmetrical compact GEN-H-4…

 

Another quite relevant demonstration is the youtube video at https://www.youtube....h?v=y1CVZ-Ir260 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.

 

The heavy disk loading (thrust to disk area) of the PORTABLE FLYER (similar to that of the OSPREY V22) causes a high downwash velocity, with the pilot inside it. Either at take off / landing, or at hovering, or at cruising (low / medium / high speeds), pilot’s limbs and head are in a high velocity air stream, which allows the control over the flight in a way similar to the way the skydivers control their flight / fall.

The PORTABLE FLYER besides the “weight displacement CONTROL” of the GEN-H-4 (mentioned previously), has also the “aerodynamic CONTROL” of Yves Rossy (Jetman, also mentioned previously).

 

Quote from: https://www.thenatio...ae-home-1.62201 :

“Arching his body “like a banana” from head to toe allows him to fly horizontally; subtle movements from left to right will change his flying direction.

 

“I am the fuselage, and the steering controls are my hands, head and legs,” Mr Rossy said.

Similarly, the body of the pilot of the PORTABLE FLYER is the fuselage, and the steering controls are pilot’s hands, head and legs. The PORTABLE FLYER can be displaced, relative to the body of the pilot, either by the shoulders / torso / back / spine of the pilot, or by pilot’s hands pulling / pushing some handlebars. It is significant, at emergencies etc, the pilot to be able to control the PORTABLE FLYER keeping his hands free.

 

End of Quote.

 

Thanks

Manolis Pattakos

 

 



#35 gruntguru

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Posted 18 August 2019 - 22:39

Hi Manolis. How does the Gen-H-4 control yaw? I imagine there is some means to drive the two rotors at different speeds.

 

This could be an issue with the portable flyer. If the rotor torques are not identical, the pilot will need to apply a constant yaw torque input with his legs to maintain yaw "trim".

 

Back to the subject of handle bars. I am convinced the flyer will not be controllable or stable without handlebars.



#36 manolis

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Posted 19 August 2019 - 11:45

Hello Gruntguru.

 

You write:

“How does the Gen-H-4 control yaw? I imagine there is some means to drive the two rotors at different speeds.”

 

Quote from http://www.helistart..._H-4_Helicopter :

Yaw control is achieved by changing the relative speed between counter rotating blades.

 

Quote from Wikipedia ( https://en.wikipedia.org/wiki/GEN_H-4 ) :

Yawing motion is produced and controlled by electronic gyroscopically-controlled differential electric braking of the main rotors.

 

Quote from http://www.aviastar....eng/gen_h-4.php :

Yaw control effected by thumb switch on instrument panel, operating electric motor which differentiates speed of rotors by 1%.

 

According the previous, the “simple” GEN-H-4 is not so simple.

 

It seems that the GEN-H-4 needs an electric motor, electric power, and a controllable differential in order to yaw.

 

All these have cost, add weight and problems. For instance, without electrical power (say due to a short-circuit) can the GEN-H-4 yaw?

 

 

 

You also write:

This could be an issue with the portable flyer. If the rotor torques are not identical, the pilot will need to apply a constant yaw torque input with his legs to maintain yaw "trim".

 

Each combustion chamber of the Portable Flyer drives two counter-rotating crankshafts, each of which drives - through a pair of sprockets and a toothed belt – its own propeller / rotor.

Until here there is no asymmetry, at all.

The counter-rotating rotors / propellers are more or less symmetrical.

Any small asymmetry (say 1%? 2%? 5%?) is cancelled out by aligning the position / pose of pilot’s limbs and head.

 

When you walk on a road holding a heavy bag with the one hand, the brain aligns the commands to the body muscles so that the walking continues in a straight line.

 

When Yves Rossy drives his Delta Wing, the two left jet-turbines cannot provide the same exactly thrust with the two right jet-turbines. The only means for correction is his body.

Quote from the Internet:    

 “Arching his body “like a banana” from head to toe allows Yves Rossy to fly horizontally; subtle movements from left to right will change his flying direction.

 

 

The following animation (from https://www.pattakon...takonPatTol.htm ) :

 

Hover_to_Cruise.gif

 

explains – I hope - the Portable Flyer yaw control.

 

The pilot displacing properly his legs / arms in the downstream of the propellers, is pushed by a pair of eccentric aerodynamic forces that cause the rotation (yaw) of the Portable Flyer about its vertical axis towards any direction.

 

 

You also write:

Back to the subject of handle bars. I am convinced the flyer will not be controllable or stable without handlebars.”

 

What I think is that the handlebars are optional.

 

Like a bicycler who can ride without holding the handle bars,

and like a rider of a unicycle wherein there are no handle bars at all,

similarly the pilot / rider of the Portable Flyer (which is secured to his/her back / shoulders / torso) will be able to control it without using his arms / hands (which are useful in case of, say, a rescue).

 

In Zapata’s FlyBoard-Air, pilot's legs are secured on the board.

 

In Browing’s JetPack, pilots arms/hands are busy to hold – all the time - the four jet-turbines.

 

In the Portable Flyer the hands/arms and the legs/feet of the pilot are completely free; the pilot is like a bee: the “wings” (the Portable Flyer with its propellers) are secured on the back / shoulders / torso, while the limbs remain free.

 

 

But there are handle bars, too:

 

Pilot_wearing_the_Portable_Flyer.png

 

for just in case.

 

Thanks

Manolis Pattakos

 



#37 gruntguru

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Posted 21 August 2019 - 03:40

have you drawn a free body diagram for the system in each of the flight modes? Treat the system as two bodies with a hinge at the shoulders. Ideally the moment at the hinge should be zero if the pilot is to be able to easily control the angle of the hinge.

 

eg the horizontal flight mode - the lift force is provided by the pilot and his wing suit, thrust is along the rotor axis (and through the hinge so no moment), drag is horizontal (no moment) and gravity forces vertically down at the CG of the pilot and the Cg of the flyer. Clearly there is a bending moment at the hinge due to the mass of the flyer which the pilot will need to resist for the duration of the horizontal flight.

 

In hover mode there is a similar issue. The rotor axis does not self stabilise to a vertical orientation under thrust. The thrust vector always acts along the rotor axis and through the centre of the hinge. Hence the mass of the flyer (which is above the hinge) must be maintained vertically above the hinge by the pilot's shoulders. Any compliance in the hinge means the mass of the flyer will tend to "flop" either forwards or backwards depending which side of vertical it sits - keeping it vertical is not a stable state.

 

I know it is only a graphic, but the handlebar grips need to be positioned to conveniently apply a moment at the "hinge" point of the apparatus (which I assume to be the point of attachment to the shoulders).



#38 Kelpiecross

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Posted 21 August 2019 - 04:27

Well done Manolis. 

 

 Yes - well done on the engine Manny - I am not sure I even understand how the bloody thing  works let alone being able to get such a thing to run.   I am still a bit doubtful about the Flyer.  



#39 manolis

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Posted 21 August 2019 - 11:29

Thank you Gruntguru.

 

 

Even without a hinge, the Portable Flyer can still be controlled at all conditions in a pure aerodynamic way, just like the Pogo-XFY-1:

 

xfy-1-pogo-37.jpg?w=830

 

At take-off the contra-rotating propellers of the Pogo send a high velocity air stream (downwash) to its wings, and the ailerons, at the bottom of the wings, deflect the air stream, the reaction of which is a force and a torque, providing full aerodynamic control.

 

The “weight displacement control” of the GEN-H-4 is not possible for the Pogo.

 

If we want to simulate the Pogo by a Portable Flyer, all we have to do is to ask the pilot to remain completely unbent / frozen, and put a pair of swim-fins on his feet. The engines and the propellers are secured / strapped on the “dead” / frozen pilot, who can move only his feet; even so, he can take-off vertically, land vertically and fly at high speeds controllably just like the Pogo does.

 

PatTilt_Flyer.jpg

 

In both, the Pogo and the Portable Flyer, the ailerons (which, in the case of the Porable Flyer, are the head, the torso and the limbs of the pilot) are into the downwash.

 

 

Now let suppose that above the pilot of the Portable Flyer, who is not frozen any longer, is a seal / buckler preventing the downwash from reaching pilot’s limbs.

Just like in the GEN-H-4 there is no aerodynamic control, and just like in the GEN-H-4 the pilot can fly by “weight displacement control”, which requires a hinge.

And there is a “built-in” hinge in the Portable Flyer (actually there are many: all the joints of the body, and especially the spinal cord). The Pilot of the Portable Flyer (without handle bar) can control the hinges at all directions.

 

 

I.e. the Flyer without handle bars and without any external hinge, is more controllable than the:

GEN-H-4,

Pogo-XFY-1,

Zapata’s FlyBoard-Air,

Browing’s Jet-Pack Daedalus,

Mayman’s JetPack,

Yves Rossy’s Delta Wing JetPack,

and Osprey V-22.

 

 

Is there any hinge better than the spinal cord?

Or a more controllable one?

 

I cannot help carrying 3lb (1.5Kg) brains.

I cannot help carrying the spinal cord and all the muscles around it.

Why not to use them instead of adding additional equipment whatsoever?

 

Thanks

Manolis Pattakos



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#40 manolis

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Posted 21 August 2019 - 14:59

Hello Gruntguru.

 

You write:

“eg the horizontal flight mode - the lift force is provided by the pilot and his wing suit, thrust is along the rotor axis (and through the hinge so no moment), drag is horizontal (no moment) and gravity forces vertically down at the CG of the pilot and the Cg of the flyer. Clearly there is a bending moment at the hinge due to the mass of the flyer which the pilot will need to resist for the duration of the horizontal flight.”

 

 

Who is lifting whom?

 

In the horizontal flight mode the propeller axes are not horizontal:

 

Portable_Flyer_Forces_small.gif

 

The thrust F1 from the propellers has a horizontal constituent F2 and an upwards (vertical) constituent F3.

The F3 lifts the Portable Flyer, the F2 pulls the pilot and the Flyer forwards.

 

By bending the spinal cord, the neck and the waist at various directions, and by extending / retracting the limbs into the downwash, the pilot keeps the control both ways:

weight displacement control (as in the GEN-H-4, and in the Zapata and Mayman JetPacks)

and aerodynamic control (as in the Pogo-XFY-1 and in the Yves Rossy Delta wing JetPack).

 

 

You also write:

“In hover mode there is a similar issue. The rotor axis does not self stabilise to a vertical orientation under thrust. The thrust vector always acts along the rotor axis and through the centre of the hinge. Hence the mass of the flyer (which is above the hinge) must be maintained vertically above the hinge by the pilot's shoulders. Any compliance in the hinge means the mass of the flyer will tend to "flop" either forwards or backwards depending which side of vertical it sits - keeping it vertical is not a stable state.”

 

In hover mode the pilot / rider by bending the spinal cord, the waist etc, continuously redirects the propeller axes about the center of gravity, while with the limbs (which are inside the downwash) completes the control (for instance the yaw) aerodynamically.

 

 

 

In both cases, horizontal flight and hovering, the control is a dynamic “non-stop” control.

 

It is like the control of the body muscles by the brain as someone walks or rides a bicycle. If the brain is “switched-off” for just a second, the walker or bicycler collapses.

 

 

Quote from the “Device Technical Report” filed in the GoFly – Boeing contest (at https://www.pattakon.com/GoFly/index.html )

 

Control again

 

When a child begins riding a bicycle, it progressively learns how to react properly to the signals from the eyes, the otoliths and the rest body (i.e. on how to keep the control).

Just like driving a bicycle, the eyes / otoliths / body / brain of the rider / pilot of a PORTABLE FLYER are the sensors and the control system: the rider soon 16 discovers the way to react properly and to keep the control. Because the PORTABLE FLYER is a true neutral propulsion unit: neither vibrations, nor reaction torque, nor gyroscopic rigidity; only a force that can "instantly" and effortlessly be vectored towards the desirable direction.

In a PORTABLE FLYER it is better to be used the body of the pilot as the main sensing and controlling equipment (birds like), than developing and paying and carrying stabilizing and flight management systems. The birds, the bats and the bugs fly because their bodies can provide adequate power for their weight. The power provided by a man's body is not adequate to lift its weight. What a person needs, in order to fly, is neither a vehicle, nor sensors, nor servomechanisms, nor control units, nor transmission shafts, nor differentials, nor gear-boxes, not even a seat. What a person does need, in order to fly, is power provided in a true neutral and manageable way. The body is: the vehicle and the sensors and the control unit and the servomechanisms and the landing system, just like the bodies of the birds, bats and bugs. With a PORTABLE FLYER secured / saddled onto his shoulders / torso, a person can fly like a bird.

 

End of Quote

 

 

 

Thanks Kelpiecross

 

If you want to study the gas flow of the OPRE Tilting engine, the https://www.pattakon.com/tilting/pattakonTilting_Gas_FLow.htm is explanatory.

 

It is a substantially different gas flow than in the conventional 2-stroke engines.

 

Then read at https://www.pattakon.com/pattakonOPRE2.htm the difference the “pulling rods” bring to the “piston distplacement vs crank angle” diagram, providing more time for the completion of the combustion near the TDC (quite importan for efficiency; this is, more or less, what the Mazda tries to do with their SkyActive-X HCCI combustion: to complete the combustion near the TDC) .

 

If the combustion continues until and after the exhaust port opens, the noise increases and a good part of the fuel energy is lost.

 

In the Boeing contest (the final Fly Off is postponed for February 2020), and for some reason that only BOEING knows, the low noise takes the most points.  

 

 

Thanks

Manolis Pattakos

 



#41 gruntguru

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Posted 21 August 2019 - 22:08

Hi Manolis.

Your "free body diagram?" is incomplete. Try drawing it again as two bodies with a hinge joint at the shoulder. (Looking at your photograph above there is an unavoidable "hinge" at the shoulders.) This approximates the hinge which the pilot must control. You will find that F3 does not lift the flyer. F1 (ie F2+F3) is fully reacted by an opposite force acting at the hinge joint. To keep the flyer in the attitude depicted will require a constant moment applied to the hinge by the pilot. This moment is equal to the mass of the flyer times the distance from the mg vector to the hinge joint. This moment is present in all flight modes.

 

In hover mode, the problem is one of stability. To maintain the flyer CG directly above the hinge axis AND the pilot's CG will require not just a movement of the body to the correct position - it will require a "balancing act".  A small disturbance of the flyer CG will initiate a "toppling" moment (when the flyer CG is not directly above the hinge) which must be constantly corrected. It is a little like balancing a pole on your shoulders. It is possible to make the "hinge" joint less flexible - lets say fully rigid - then the alignment will become critical. If the thrust vector does not pass trough the CG, the pilot will have to maintain an awkward angle to trim the system for stable flight.



#42 manolis

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Posted Yesterday, 05:04

Hello Gruntugu.

 

You write:

“I am convinced the flyer will not be controllable or stable without handlebars.”

 

 

If I get it correctly, what you say is that with handle bars the Portable Flyer will be controllable and stable.

 

Let’s take the hovering.

 

The Flyer is above the “spinal cord hinge” and so it has the tendency to “fall” forwards, backwards or aside.

 

When I walk, my upper body (head, shoulders, hands, torso) is above the hinge at the waist and, as the Flyer, has the tendency to “fall”.

The brain controls the muscles around the waist and, without any kind of handle bars, keeps the upper body at the right position.

With the waist (i.e. the low spinal cord) as the hinge, the muscles at the right and left sides of the waist provide the required “restoring to the right position” action (force / torque), similarly for the muscles in front and back of the waist: if the brain feels the body going fall forwards, it commands the muscles at the back of the waist to retract applying the necessary stabilizing action.

 

A person with paralysis below the chest, does need some kind of handle bars to keep his upper body “standing” upright above his waist, otherwise it falls.

 

 

From another viewpoint:

 

Suppose the bars (ie. The frame) that keep the Flyer on the shoulder of the pilot are extending towards his / her waist, and a mass is secured at their free (lower) ends. This mass balances the weight of the Flyer about the “hinge” and cancels out any required torque.

 

Is this what you mean in order to turn, the Portable Flyer, to controllable and stable?

 

 

From yet another viewpoint:

 

The Flyer is as strapped / as fixed / as secured on the shoulders / upper torso of the pilot as it takes, so it cannot help following their (shoulders / upper torso) motion relative to the rest body.

With handle bars this control is more easy (especially when the pilot walks on the ground), but at flight the hands have more useful work to do (rescue, aerodynamic control etc).

The small weight of the Portable Flyer and the small height it has above the head help the walking on the ground without overloading the waist muscles and the spinal cord.

 

The 2-seater “Pogo Flyer”:

 

POGO_FLYER.gif

 

has three legs with aileron, instead of the four legs of the POGO-XFY-1
two pairs of contra-rotating propellers instead of the one pair of the POGO, 
and – optionally - vectored thrust instead of the fixed thrust direction of the POGO. 

 

Cancel the hinge (i.e. the vectored thrust) and you have the POGO-XFY-1 architecture which is fully controllable and stable.

 

Leave the hinge operative (and so the vectored thrust), and you have an improved POGO-XFY-1 wherein the pilot has more control options.

 

Thanks

Manolis Pattakos



#43 gruntguru

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Posted Today, 04:10

The Flyer is above the “spinal cord hinge” and so it has the tendency to “fall” forwards, backwards or aside.

 

No, I am talking about the hinge where the flyer is "fixed" to the shoulders. If there is any compliance in this hinge, the pilot has no control over its position - unless he has handlebars.

 

If this hinge is "fixed" with rigid connections to the torso, the thrust axis of the flyer needs to align with the CG of the system during hovering with the pilot needing to maintain an unnatural posture (trim).

 

Even with fixed connection the problem for horizontal flight remains. The pilot needs to support the mass of the flyer - cantilevered in front of him. Imagine the pilot lying on a table with the flyer fitted but not supported by the table. The "spinal hinge" allows the flyer to droop towards the floor and the pilot's back muscles must support the cantilevered mass. The same forces will apply during horizontal flight.