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The Obsidian Files - Preamble

 
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Area-51



Joined: 03 May 2021
Posts: 371

PostPosted: Mon May 15, 2023 2:42 pm    Post subject: The Obsidian Files - Preamble Reply with quote

Red = Maximum
Blue = Minimum...

After some questions from readers here I thought it would be helpful if there was some background information on these “black op’’” studies… its often forgotten that not everybody shares the same level of insight about things but the desire to learn and understand stuff is often there.. in the end its all just stuff and incidental… but we need to fill our time up with something while here… so I guess that is the reason and explanation of the “Why”… I have the time and curiosity to scientifically and empirically explore the efficiency of flight and am very fortunate and grateful to fly a Europa, and to contemplate how good might it be doing what it does?
 
The other aspect about this is reading about all these various Mods Europans have devised, and do they actually do what we think they do? Why don’t we go find out?
 
Flight is such a truly amazing thing… it wasn’t until experiencing weightlessness while scuba diving that I experienced an aha moment of multidirectional movement through a fluid space where there was no up or down, left or right… just movement, and a sense of freedom… so I spent my time tumbling around and being comfortable with being upside down looking at the bottom of the sky and transition layer overhead.
 
For the next 15 years I decided to explore fluid environments and sketch out fresh and challenging ideas of how to move through fluid mediums… several concepts were developed and intensively studied through to proof of concept.. one of the concepts was an aircraft that came out of a doodle one night and set the path for a 20 year study tour of the concept and finding some existing similar correlate ideas to garnish valuable test data from… glider models were built from different materials, which proved very stable with great glide ratios.. the concept was developed further and tuned and sent into a digital environment for further analysis and flight testing within Xplane.. so with the testing proving viable and efficient I thought if this thing is going to be built I better learn to fly before its ready to fly!
 
A few years ago the politicians decided it would be a good idea to lock everybody in their domiciles and shut the world down and destroy small business all over the world… it didn’t work out too well for mostly everybody, but while all this was going on I decided it would be a great opportunity to use this historic moment to learn to fly; and have not stopped since…
 
Starting off in a Samburo was good enough… moving into a MotorFalke was like driving an S2 Landrover all over agian… things were moving too slow so it was off to ultralights and into a Tecnam 2002 Sierra; and they fly really well… after looking at many types of light aircraft I was not really excited about the Europa at first but after reading about it and having an in depth study of its story and comparing it to most other stuff out there in its class purchasing 181 when the politicians unwittingly caused the used aircraft market to dump 50% was a no brainer; haven’t regretted it one bit, but every time I flew it I was not feeling totally confident with my abilities; so after working it out more more training was pegged in.
 
Strapping myself into a Pitts 2A and tumbling around in the sky for a few days knocked me out of the world of two dimensional fatal flying and into a unidirectional appreciation of the fluid medium once again with another aha moment of realising there is no up or down or left or right; just “Attitude”, and that was it… everything else was incidental… and I came out the other end a much more confident aviator for it... I felt confident, I felt sufficient.
 
Experiencing flight in a fixed wing aircraft has brought me to the conclusion that rotor wings have their place and purpose and giant drones as we currently know them have no use-case; it’s an orphaned solution looking around the world for a problem… so my motorbike for the sky idea has been thrown in the bin… it will work, but it has no use-case; like the flying car...
 
There are many ways to test and prove stuff… since the mid 1980’s stuff has been designed and proofed within a digital world of CAD (Computer Aided Design)... it’s a mathematical nightmare that spits out stuff when buttons are pressed in a set sequence… and that’s about all there is to it… knowing what buttons to press takes a while to get right but practice gets results, and more practice gets more results… and it has taken thousands and thousands of hours to get to where I am and I still consider myself a mediocre hack at this stuff, but within the field of Design I’m happy to sit way out back riding the big scary swell of the yet unknown without apprehension.
 
CAD is married to FEA (Finite Element Analysis) or FEM (Finite Element Method), and CFD (Computational Fluid Dynamics), it’s a method of mathematically solving complex relationships between Materials (Model) & Environments (Computational Domain); and that’s about it… The environment and material is contained within a specified 2D or 3D perimeter and divided up into a Mesh… this Mesh is made up of a cluster of mathematical positional points (Nodes) within the Domain…each set of Nodes makes up a Cell of at least three Nodes, and these Nodes are all interrelated interconnected mathematically providing a path of continuity to all the other Nodes. Blah Blah, Blah Blah Blah… All that is important to know is that the finer the Mesh the more accurate the results (Solution) will be to a Real World scenario. Running conclusive simulations involves refining the Mesh to a point where the answer is sufficient to guide the task onto the next step. As the Mesh is refined it takes longer and longer to spit out a result. Getting to 95% accuracy is good enough while developing concepts; 99% is enough to expect bankable results.
 
There are different types of Meshes used for different types of Solutions; Steady State (static) and Transient (moving mesh)… Steady State is fast and generally used for static primary mechanical stress/strain and fluid flow analysis; it is a moment in time study. A Transient Mesh is generally used for Time dependant studies (gas turbine engine op's) and takes a lot longer and consumes a lot more computer power to solve; so it is generally undertaken toward the end of a design cycle using industrial computers or daisy chained servers… In these studies we are mostly using CFD for aerodynamic related stuff, and FEA for structural load related stuff.
 
So what about all these coloured rainbow images and data numbers thrown up; how should they be interpreted? What does it all mean?
 
Blue = Minimum
Red = Maximum
 
Generally there will be a scale attached to an image that determines what type of analysis is being presented (Velocity/Acoustic Power/Pressure/Stress/Strain) along with these Min/Max figures; and the Min/Max numbers can be manipulated to focus into a narrower band of data. This band tuning is done to filter out useless information that may be outside of what is required. For example, an analysis may be undertaken at a free stream velocity of 51m/s (100kt) over an aerofoil, so our Min (blue) will be 0m/s while our Max (red) will be somewhere around 75m/s, so the Max on the scale will be set at 75m/s to reveal higher velocity air moving over the lifting surface; if we set the Max scale at 50m/s most of the surface will turn red and be useless. So the end result is purely a “contrast” of data; and this is pretty much generic with all the rainbow images.
 
With the CFD images there may often be thin dark lines running over the surface. These represent the directional flow of the fluid across the Boundary Layer being the area at the surface and above to about 0.25mm to 1.00mm; it can be any depth specified, but is generally extremely thin and is the critical area where fluid separation is mostly looked for… as we approach the surface the fluid eventually slows down to zero... Other images may be taken from a slice plane in any combination of XYZ direction, and can be used to study the movement of fluid by layer similar to the way a medical CT scan works.

Colour gradient can also be manipulated with the rainbow images; again an element related to Resolution... in most of these images the gradient resolution is selected at 75 gradient steps.

Solution Steps... these are again related to resolution; the more steps the more accuracy... most all the solutions run are allowed 100 steps... sometimes incongruent steps happen toward the end of the solution so the solution is allowed to run out another 50-100 steps to settle out and Converge (fully solved) this aspect is often monitored to determine if the free stream velocity has accidentally been set in the reverse direction. Generally most of the Solutions run are close to Convergence between 50 and 70 steps.
 
Several data sets most used in the above studies are Velocity, Pressure, Acoustic Power, and are all related to how the movement of Fluid is relating to the Model. Mostly Velocity is used to determine areas of stagnant fluid flow and turbulence.
 
Other data sets looked at are Drag and Lift in a very rudimentary way and unless noted will mostly be accessed without adding Sin or Cos equations to the Solution. The reason being that all the Fluid studies are comparative only and not Finite, meaning each Solution result is contrast against another to determine whether or not an adjustment is more or less aerodynamically efficient.

There are also a multitude of algorithms that can be applied to a Solution depending on environment specifics, and all provide a slight variance of results... All the Solutions run are utilising the same algorithm. Again we are not searching for Finite answers, just Contrasts.
 
Everything begins with “Alpha”… Alpha is the “Angle of Attack” of the free stream fluid against the Model… If Alpha = +/-12 then that means the free stream is meeting the model at +/-12 degrees to a specified orientation of the Model within the Computational Domain. Alpha=12 generally will mean the AoA of the wing is 12deg… Pitch Attitude refers to the fuselage orientation relative to the free stream, so Alpha will equal Attitude +\-Incidence... There are a multitude of other Greek scribbling but Alpha and Velocity is pretty much all that is needed to be aware of.
 
Fluid Density… 15C at 0 AMSL unless specified.
 
Turbulence… this is a setting within the Solution setup matrix and is set at 5% because we do not exist or fly within a vacuum, so a little randomness provides for a more realistic CFD related result.
 
Failures… Computer says “no”, often… due to surface issue with the model, so hours are sometimes spent searching through the model for microscopic inconsistencies (Dirty Model) and sometimes its easier to just rebuild the model when they cannot be found.
 
FEA related images are similar to above without the inclusion of a Fluid Medium; they are simply a surface image of the mechanical component or a slice taken through the component.
 
FEA/Mechanical results are looking at Material Elasticity primarily via Stress/Strain, reviewing the Tensile Strength of a component relative to the Material’s Yield Strength (Force applied at which the component material does not return to original state), and Ultimate Strength (Force applied at which the component material fractures)… Other criteria looked at relates to Modal (Harmonic) aspects of a component and which resonant frequencies experienced by a component may lead to early failure or emission of natural occurring frequencies transmitted into a Fluid Medium as Acoustic Power.
 
Every decent scientific study needs a control pig to provide a baseline data point… for this purpose we have two pigs, sorry plugs… one with a wing root flare, and one without; and they may often be referred to for a result's compare/contrast purpose. Both these plug models are devoid of all additional airframe features; so they are as slippery as a Europa can be.
 
FAQ’s
 
What about propeller swirl?  not included and if it is it will be further down the line during Time Dependant solutions.
 
How did you create the digital model? With a plum bob, ruler, set square, tape measure, piece of dowel, CAD program, lots of time, and a pencil.
 
Do you work for the NSA or MI6 as an operative? No…
 
Should I follow your advice or believe any of the information presented within any of the Obsidian Files? Never.
 
And that’s about it for the preamble and FAQ’s… if anyone has anything to add that may have been missed feel free to add it on….


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PostPosted: Mon May 15, 2023 9:22 pm    Post subject: The Obsidian Files - Preamble Reply with quote

An interesting read at 0600 in the UK, I feel as though I have been to a university lecture that was extremely well presented. I mostly read crime who dunits during my down time, a complete waste of my time but a distraction.
I put this down to a damn good read and not a moment of waste.
I would be interested in thoughts on the Motorglider wing, in which I regularly take the propeller out of the equation.
Alan Twigg
Motorglider G-GIWT
Kit 463

Sent from my iPad

Quote:
On 15 May 2023, at 23:42, Area-51 <goldsteinindustrial(at)gmail.com> wrote:



Red = Maximum
Blue = Minimum...

After some questions from readers here I thought it would be helpful if there was some background information on these “black op’’” studies… its often forgotten that not everybody shares the same level of insight about things but the desire to learn and understand stuff is often there.. in the end its all just stuff and incidental… but we need to fill our time up with something while here… so I guess that is the reason and explanation of the “Why”… I have the time and curiosity to scientifically and empirically explore the efficiency of flight and am very fortunate and grateful to fly a Europa, and to contemplate how good might it be doing what it does?

The other aspect about this is reading about all these various Mods Europans have devised, and do they actually do what we think they do? Why don’t we go find out?

Flight is such a truly amazing thing… it wasn’t until experiencing weightlessness while scuba diving that I experienced an aha moment of multidirectional movement through a fluid space where there was no up or down, left or right… just movement, and a sense of freedom… so I spent my time tumbling around and being comfortable with being upside down looking at the bottom of the sky and transition layer overhead.

For the next 15 years I decided to explore fluid environments and sketch out fresh and challenging ideas of how to move through fluid mediums… several concepts were developed and intensively studied through to proof of concept.. one of the concepts was an aircraft that came out of a doodle one night and set the path for a 20 year study tour of the concept and finding some existing similar correlate ideas to garnish valuable test data from… glider models were built from different materials, which proved very stable with great glide ratios.. the concept was developed further and tuned and sent into a digital environment for further analysis and flight testing within Xplane.. so with the testing proving viable and efficient I thought if this thing is going to be built I better learn to fly before its ready to fly!

A few years ago the politicians decided it would be a good idea to lock everybody in their domiciles and shut the world down and destroy small business all over the world… it didn’t work out too well for mostly everybody, but while all this was going on I decided it would be a great opportunity to use this historic moment to learn to fly; and have not stopped since…

Starting off in a Samburo was good enough… moving into a MotorFalke was like driving an S2 Landrover all over agian… things were moving too slow so it was off to ultralights and into a Tecnam 2002 Sierra; and they fly really well… after looking at many types of light aircraft I was not really excited about the Europa at first but after reading about it and having an in depth study of its story and comparing it to most other stuff out there in its class purchasing 181 when the politicians unwittingly caused the used aircraft market to dump 50% was a no brainer; haven’t regretted it one bit, but every time I flew it I was not feeling totally confident with my abilities; so after working it out more more training was pegged in.

Strapping myself into a Pitts 2A and tumbling around in the sky for a few days knocked me out of the world of two dimensional fatal flying and into a unidirectional appreciation of the fluid medium once again with another aha moment of realising there is no up or down or left or right; just “Attitude”, and that was it… everything else was incidental… and I came out the other end a much more confident aviator for it... I felt confident, I felt sufficient.

Experiencing flight in a fixed wing aircraft has brought me to the conclusion that rotor wings have their place and purpose and giant drones as we currently know them have no use-case; it’s an orphaned solution looking around the world for a problem… so my motorbike for the sky idea has been thrown in the bin… it will work, but it has no use-case; like the flying car...

There are many ways to test and prove stuff… since the mid 1980’s stuff has been designed and proofed within a digital world of CAD (Computer Aided Design)... it’s a mathematical nightmare that spits out stuff when buttons are pressed in a set sequence… and that’s about all there is to it… knowing what buttons to press takes a while to get right but practice gets results, and more practice gets more results… and it has taken thousands and thousands of hours to get to where I am and I still consider myself a mediocre hack at this stuff, but within the field of Design I’m happy to sit way out back riding the big scary swell of the yet unknown without apprehension.

CAD is married to FEA (Finite Element Analysis) or FEM (Finite Element Method), and CFD (Computational Fluid Dynamics), it’s a method of mathematically solving complex relationships between Materials (Model) & Environments (Computational Domain); and that’s about it… The environment and material is contained within a specified 2D or 3D perimeter and divided up into a Mesh… this Mesh is made up of a cluster of mathematical positional points (Nodes) within the Domain…each set of Nodes makes up a Cell of at least three Nodes, and these Nodes are all interrelated interconnected mathematically providing a path of continuity to all the other Nodes. Blah Blah, Blah Blah Blah… All that is important to know is that the finer the Mesh the more accurate the results (Solution) will be to a Real World scenario. Running conclusive simulations involves refining the Mesh to a point where the answer is sufficient to guide the task onto the next step. As the Mesh is refined it tak!
es longer and longer to spit out a result. Getting to 95% accuracy is good enough while developing concepts; 99% is enough to expect bankable results.

There are different types of Meshes used for different types of Solutions; Steady State (static) and Transient (moving mesh)… Steady State is fast and generally used for static primary mechanical stress/strain and fluid flow analysis; it is a moment in time study. A Transient Mesh is generally used for Time dependant studies (gas turbine engine op's) and takes a lot longer and consumes a lot more computer power to solve; so it is generally undertaken toward the end of a design cycle using industrial computers or daisy chained servers… In these studies we are mostly using CFD for aerodynamic related stuff, and FEA for structural load related stuff.

So what about all these coloured rainbow images and data numbers thrown up; how should they be interpreted? What does it all mean?

Blue = Minimum
Red = Maximum

Generally there will be a scale attached to an image that determines what type of analysis is being presented (Velocity/Acoustic Power/Pressure/Stress/Strain) along with these Min/Max figures; and the Min/Max numbers can be manipulated to focus into a narrower band of data. This band tuning is done to filter out useless information that may be outside of what is required. For example, an analysis may be undertaken at a free stream velocity of 51m/s (100kt) over an aerofoil, so our Min (blue) will be 0m/s while our Max (red) will be somewhere around 75m/s, so the Max on the scale will be set at 75m/s to reveal higher velocity air moving over the lifting surface; if we set the Max scale at 50m/s most of the surface will turn red and be useless. So the end result is purely a “contrast” of data; and this is pretty much generic with all the rainbow images.

With the CFD images there may often be thin dark lines running over the surface. These represent the directional flow of the fluid across the Boundary Layer being the area at the surface and above to about 0.25mm to 1.00mm; it can be any depth specified, but is generally extremely thin and is the critical area where fluid separation is mostly looked for… as we approach the surface the fluid eventually slows down to zero... Other images may be taken from a slice plane in any combination of XYZ direction, and can be used to study the movement of fluid by layer similar to the way a medical CT scan works.

Several data sets most used in the above studies are Velocity, Pressure, Acoustic Power, and are all related to how the movement of Fluid is relating to the Model. Mostly Velocity is used to determine areas of stagnant fluid flow and turbulence.

Other data sets looked at are Drag and Lift in a very rudimentary way and unless noted will mostly be accessed without adding Sin or Cos equations to the Solution. The reason being that all the Fluid studies are comparative only and not Finite, meaning each Solution result is contrast against another to determine whether or not an adjustment is more or less aerodynamically efficient.

Everything begins with “Alpha”… Alpha is the “Angle of Attack” of the free stream fluid against the Model… If Alpha = +/-12 then that means the free stream is meeting the model at +/-12 degrees to a specified orientation of the Model within the Computational Domain. Alpha=12 generally will mean the AoA of the wing is 12deg… Pitch Attitude refers to the fuselage orientation relative to the free stream, so Alpha will equal Attitude +-Incidence... There are a multitude of other Greek scribbling but Alpha and Velocity is pretty much all that is needed to be aware of.

Fluid Density… 15C at 0 AMSL unless specified.

Turbulence… this is a setting within the Solution setup matrix and is set at 5% because we do not exist or fly within a vacuum, so a little randomness provides for a more realistic CFD related result.

Failures… Computer says “no”, often… due to surface issue with the model, so hours are sometimes spent searching through the model for microscopic inconsistencies (Dirty Model) and sometimes its easier to just rebuild the model when they cannot be found.

FEA related images are similar to above without the inclusion of a Fluid Medium; they are simply a surface image of the mechanical component or a slice taken through the component.

FEA/Mechanical results are looking at Material Elasticity primarily via Stress/Strain, reviewing the Tensile Strength of a component relative to the Material’s Yield Strength (Force applied at which the component material does not return to original state), and Ultimate Strength (Force applied at which the component material fractures)… Other criteria looked at relates to Modal (Harmonic) aspects of a component and which resonant frequencies experienced by a component may lead to early failure or emission of natural occurring frequencies transmitted into a Fluid Medium as Acoustic Power.

Every decent scientific study needs a control pig to provide a baseline data point… for this purpose we have two pigs, sorry plugs… one with a wing root flare, and one without; and they may often be referred to for a result's compare/contrast purpose. Both these plug models are devoid of all additional airframe features; so they are as slippery as a Europa can be.

FAQ’s

What about propeller swirl? not included and if it is it will be further down the line during Time Dependant solutions.

How did you create the digital model? With a plum bob, ruler, set square, tape measure, piece of dowel, CAD program, lots of time, and a pencil.

Do you work for the NSA or MI6 as an operative? No…

Should I follow your advice or believe any of the information presented within any of the Obsidian Files? Never.

And that’s about it for the preamble and FAQ’s… if anyone has anything to add that may have been missed feel free to add it on….




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http://forums.matronics.com/viewtopic.php?p=510802#510802











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Area-51



Joined: 03 May 2021
Posts: 371

PostPosted: Mon May 15, 2023 9:53 pm    Post subject: Re: The Obsidian Files - Preamble Reply with quote

Have not really looked into the glider wing as yet... It uses an alternate airfoil profile and I don't know of any aircraft locally that can be measured up...

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