Laminar Research

Austin Meyer talks to PCSimulators.org and PCHelicopters.com

austinmeyergood

Who is Austin Meyer ? Why is x-plane called xplane ? Why is his company called laminar reasearch ? Read on and find out the answers to all these questions and more!


Q. What inspired you to create Laminar Research ?

I was not happy with Microsoft flight simulator, so i decided to write my own sim since i assume they would not change their sim for me.

Laminar Research Logo

Q. When was laminar research created?

1995, Laminar Research.

I started X-Plane as a flight sim called "Archer-II IFR", while in college at Carnegie Mellon, to practice IFR flying.

I used blade element theory to simulate the flight of this airplane in the IFR system.

below Carnegie Mellon College where Austin started X-plane

college

Seeing that the laws of physics were the same for all airplanes, I added Airfoil-Maker and Plane-Maker, and re-named the sim to "X-Plane".

Upon college graduation (ultimately Iowa State), I formed Laminar Research and started selling X-Plane, since the idea of trying to find a job working for someone else just did not seem appealing, and I just did not think anyone would hire me anyway. Thank God for that. So I started selling X-Plane right out of college around 1995.


Q. Why the name Laminar Research ?

laminar flow is smooth flow, so i want everything to run smooth while i research how things work in aviation to simulate them

below -Laminar Motion - A sphere in Stokes flow, at very low Reynolds number. An object moving through a fluid experiences a force in the direction opposite to its motion.

laminar flow

Q. What was your first ever simulation that you developed ?

x-plane


Q. How long did the original X-Plane take to write ?

a few weeks to see a horizon line and some basic instruments


Q. How long did it take to develop the latest version of Xplane ?

no such thing as that, we are working on a continuous basis, and coming out with updates continuously

its’ all a continuous process. we don;t do one thing and then after that do another.


Q. Can you tell us how many lines of code xplane has ?

about 450,000 right now

linesofcode2


Q. What's was the first ever simulator you used and on what platform ?

the old basic apple-2 plus flight sim that had one airport repeating on a grid


Q. What decade is your favourite decade in the history of computing and why ?

oh always the current one


Q. What’s is your favourite ever game ?

x-plane

Q. Apart from x-plane what other flight simulator impresses you ?

none, i only like x-plane

Q. Do pilots get involved in the development of x-plane ?

testpilot

oh constantly getting feedback from other pilots on ways to improve the flight model, constantly

this is one of the ways i am always tuning and improving the flight model

this includes data from pilots that are involved in certification of x-plane for various certified installs

Q. Are more helicopters going to be added to x-plane ?

certainly over time 

below (best x-plane helicopters, click image to view video)

best x plane helicopters

Q. Can you tell us if anything is in the pipeline for X-plane?

sure VR and higher frame-rates to make VR good without any stutters in the frame-rate, which is needed for smooth rendering in VR here’s the stuff in testing now for 11.10 that i coded myself (there is more stuff coded by others on the team)

Quick-look views: There used to be 10 pre-saved viewing locations but now we have 20, so enough for plenty of cockpit and exterior presets now.

New airfoil format!

Now you can save all the Reynolds numbers you like in each airfoil file!

So this is pretty cool: To really do a good job of making an airplane, we USED to have to make a LOW Reynolds number airfoil for the low speed flight regime or the root of a prop, and a HIGH Reynolds number airfoil for higher-speed flight regime or the tip of a prop. We had to come up with foil data for the right Reynolds numbers and attach them to the "Lo Re" and "Hi Re" slots for prop or wing in Plane-Maker. This was annoying and cumbersome and nobody ever bothered to do it properly.

So NOW, an Airfoil-Maker, you can enter lift and drag curves for ALL the Reynolds numbers that you want, and they are saved in ONE file. This is especially good because it lets the airfoil-designer enter TONS of data into a single file, and SEE ALL THE REYNOLDS NUMBER PLOTS AT ONCE for a given foil, to really compare them all and be sure they they all lay out just like the real foils.

(NOTE: Reynolds number in millions is: the local air density in kg/mmm * speed in meters per second * wing or prop chord in meters * 0.05588, where 0.05588 is 1/viscosity of air in millionths)

Then, in Plane-Maker, there is no need to fumble around looking for the Lo Re and Hi Re foil... just drop these new multi-Re foils into both slots and X-Plane will find the best Reynolds numbers in there to use and even interpolate for you, without you having to worry about selecting the right foils in Plane-Maker.

So this is really really good: The people that make airfoils can do an amazing job in creating their foils if they are up to it, and the airplane designers can then just drop their foils onto the plane in Plane-Maker without having to worry about Reynolds numbers, and X-Plane will choose the best Reynolds number data to use, interpolating as needed. This can result in more flight-model accuracy because if the person that enters the airfoil data enters curves for 2, 3, 4, or even up to 10 different Reynolds numbers, then X-Plane has more Reynolds numbers to choose from and interpolate between, giving more accurate forces.

As well, a slight improvement in Reynolds number calculation in X-Plane, to make sure we always USE the right reynolds number data!

We now consider the TEMPERATURE of the air to find it’s EXACT dynamic viscosity, which varies slightly with air temperature.

Better propwash DIRECTION, which matters for propeller-powered VTOLs that tilt their thrust vectors around, and helos that might cast downwash onto their horizontal stabs.

Here is how it works: X-Plane USED TO cast wash on whatever was BEHIND THE PROP.

This seems to make enough sense,  but NOW we do it a bit smarter: NOW X-Plane runs wash off the props that flows with the vector SUM of the propwash speed and airspeed hitting the airplane! This is a wake that does NOT simply track aft of the prop disc, but instead flows aft along the airplane as the airplane speeds up, as the incoming speed displaces the propwash stream tube. Whatever wings or bodies are in that new vector-sum flow-field are now affected by propwash. This is probably a bit more accurate than what we had before.

Rotor and propwash dynamics:

More tuning of the propwash (and thus hover power requirement) and vortex ring state and effective translational lift based on momentum conservation and actual helicopter performance data.

Definitely more accuracy there now, based on a lot of testing against very precise Bell-206 performance data in ground effect, out of ground affect, and at various flight speeds as well, and also in various decent rates including settling with power and power-off vortex-ring-state.

SWIRL model

As well, new propwash SWIRL model.

This is tested against flight-test in N844X which is a plane with huge power, very low speed capability, and a very in-efficient vertical stabilizer: All of the ingredients to get huge side-slip from spiralling propwash, so it is the perfect airplane to measure side-slip from spiral propwash, and therefore the spiraling propwash that causes it.

So the propwash speed and swirl are more accurately modelled, with resulting performance improvements in all aspects of propeller and rotor thrust.

NOTE: Now in Plane-Maker, go to the Engines screen, Prop Geo tab. Now on the right you can see the prop advance ratio and

prop “pitch” in inches, as is commonly used by propeller designers.

This is controlled by the prop design speed and RPM in the Engines screen, Location tab as always, but now you can see the prop advance ratio and pitch since that is how prop data is commonly published.

below X-Plane Aircraft, free and Payware, Click image to view video.

xplane aircraft

Flight-control dynamics:

We now have flap and leading-edge flap and slat extend and retract times, all of which can be different, and also a flap speed ratio when retracted, so the flaps can move slower near the small deployment angles, and faster at the larger angles, as real flap systems commonly do. So the flaps and slats are really dialled in here, done specifically for the Airbus project (certifiable flight Airbus A-320 sim we are working on) but with upgrades available to all as always.

Rudder, elevator, and aileron trim now only move the control surface when you have some airspeed over the control surface to really move it, as per real airplanes.

What’s cool is that even if the plane is not moving, you might still have enough speed to move the flight control due to wind or propwash, which would likely be over the rudders and elevators, but not ailerons!

X-Plane tracks the speed over each flight control, so the trim force in moving the control surface and force feedback forces on each control surface are all tracked, even for unusual aircraft configurations.

because X-Plane tracks the airspeed over each element of each wing on the airplane! Cool!

Effective angle-of-attack increase with control-deflection on the elements of the wing with ailerons, elevators, and rudders now a little more tuned (using an average of two DIFFERENT theories to give an averaged result that is known to be correct for very-small and very-large controls, with two different ways of interpolating between those cases that largely agree with each other, and both fit various experimental data).

As well, we have adjusted lift and drag from speedbrakes as per documentation on those.

I also added a new command called “sim/flight_controls/magnetic_lock”: "Controls magnetic lock."

This is for flying helos, which have magnetic control locks to lock the stick down in a given location.

Deflect the controls as desired, hit a button to effectively lock the stick there, and then immediately release the stick. Bang: Leaving your stick centred, hands-off, will effectively hold the stick in that new location.

This is done when flying the S-76 helicopter, for example.

In the controls screen in Plane-Maker, we now have a control-deflection time for the nose-wheel steering, so we can do nose-wheel steering more smoothly on those tiller-equipped airliners.

Flight dynamics:

New vector not trig based geometry for all the lift and drag vectors.

Get in a plane with WING FLEX and hit control-M while puling major G at high speeds to see it in action.. the lift vectors now all bend around with the wing! Cool!

This is so totally tested as being perfect that I have tested it by flying BACKWARDS: That’s right: Tail in the front of the airplane and flying BACKWARDS in reverse to check that all physics are good from 0 through 180 degrees angle of attack and sideslip.

This matters!

Helos hovering backwards?

hoeving backwards

Helos hovering in a tailwind?

Taxiing slowly with a tailwind?

Tailslides?

SPINS, where SOME PART of the plane may be going backwards?

These are all reasons we want to handle flows at ALL angles perfectly… all the way to REVERSE!

Crazy but true, and all part of the obsessive quest for mathematical perfection!

Slight change and clarification in vacuum pumps:

X-Plane simulates the vacuum system for physical vacuum-driven gyros as follows:

->There are two vacuum systems: One for the pilot instruments, one for the copilot instruments.

->If you have no copilot instruments, the no problem: The second vacuum system goes unused, like it is not even there.

->Each vacuum system has exactly one vacuum pump, which may be failed by the instructor.

->For a single-engine airplane, that one engine turns both pumps… and if your plane has only one system, no problem! Just don’t specify any instruments as “Copilot”, which would have them use the second system.

->For a multi-engine airplane, engine one turns the pump on system 1, engine 2 turns the pump on system 2… and if your plane has only one system, no problem! Just don’t specify any instruments as “Copilot”, which would have them use the second system.

->The low-vacuum annunciator goes off if EITHER vacuum system runs low, but if you want to make an instrument that tracks WHICH system has run low on pressure, the simply use these datarefs:

->For airplanes that have TWO vacuum pumps on ONE system, we just don’t simulate that, just like we don’t simulate both the tire and innertube inside it… we only simulate the actual outgoing force that you see.

So, for the dual-vacuum pump planes that have two pumps on one system, simply fail the vacuum pump in the failure list to take out BOTH pumps, since that will remove the pumping pressure from the system.

SOOOOOOOoooooooo there you have it!

Slight jet engine improvement:

Plane-Maker, Engines window, Jet Curves 2 tab: Now you can see your thrust as a function of N1 to dial in the those intermediate thrust settings as well!

Cool!

Slight recip engine improvement:

Now we map the TEMPERATURE and POWER SEPARATELY as a function of mixture.

This means that the mixture for best POWER is above the mixture for MAX TEMPERATURE, as in reality.

So a lean mixture is best economy, then a bit richer is max EGT, then a bit richer is best power… all as in reality.

Generator/Alternator improvement:

We now follow the amperage output-curves of real alternators and generators, and you can now specify how fast the engine has to turn at idle to output it’s maximum amperage.

Do this in the SYSTEMS window in Plane-Maker, ELECTRICAL tab.

Some planes can put out max amperage at idle, but other planes, like the Columbia-400, need to spin the engine faster to output the needed amperage.

So it is pretty cool to set that minimum generator threshold RPM percentage in Plane-Maker, so in flight you have to set the idle as needed to meet the electrical load on the plane, certainly a real part of operating the (wonderful) Columbia-400.

New prop type: Constant tip-AOA.

This adjust the prop pitch to hold a constant average angle of attack across the prop, weighted for dynamic pressure, so this will tend to hold a constant angle of attack near the blade tip, which is probably best for efficiency since that can hold your prop tip at the angle of attack that gives the best lift over drag ratio for the airfoil used by your propeller.

Better prop thrust visualization diagnostics… the first command-m shows wherepropwash is being applied on the airplane, with propwash speed shown.

Then, hitting command-M again, we see the lift vector tilted back due to the forward speed of the aircraft 9lift vector in green) and the red dag line, and the yellow line that is the net force, all drawn in the right directions.

Hit command-M to cycle through the flight models.

Commands are back, because people wanted them:

"sim/flight_controls/left_brake"

"sim/flight_controls/right_brake”

Q. Whats you favourite aircraft for x-plane ?

lancair evolution since it is my real airplane.

it does not ship with the sim though i just have it myself

here is the acf: click to download austin's plane here in acf format!

heres the real plane:

fromaustin2

Q. Whats your favourite helicopter for x-plane ?

the bell 206 is quick to load and fly so it is fine with me.

Q. Consoles lack a decent flight simulator, will x-plane ever appear on a console like Xbox 1 or PS4?

nah, no need, if anyone is serious about it they can get a pc or mac where the joystick interface is correct for the job, unlike those tiny little near-useless thumb-controllers on the consoles

Q. What was you first ever computer?

apple-2
below Austin's first ever computer the Apple II

apple2plus

Q. What programming language is used to develop x-plane?

C++

Q. Favourite movie?

i liked star wars and contact

Q. What do you think is the difference between X-Plane and FSX?

A question I am commonly asked is: What is the difference between X-Plane and Microsoft Flight Simulator?

There is real no comparison at all between them since both sims took completely different evolutionary paths, made by different people for different purposes, so the two sims have really just NOTHING in common.

This is good for consumers since the variety available is considerable, but to me, the answer to "How is X-Plane different from Microsoft Flight Simulator?" is sort of like asking how  a banana is different than train car... they just seem to exist in completely different worlds.

So Microsoft Flight Simulator (and most other flight sims for that matter) act by being programmed with the performance of a given airplane, and then, in virtual flight, simply regurgitating that performance right back to you. The regurgitation can surely be faithful, so many flight sims are able to accurately reproduce the performance of a given airplane... for SOME part of the performance envelope. But what about the corners of the envelope for which data is not recorded? What about the transitions from one part of the envelope to another? What about when things on the airplane break? What about when the pilot is not flying the same way the test pilot did that captured the data? What about, heaven forbid, when you want to simulate an airplane... that does not yet exist?

In all of these areas, the entire construct of simulating flight by regurgitating known performance simply breaks down.

So whaddo we do? Well, X-Plane has an answer: Don't even ASK what the airplane is SUPPOSED to do.

Instead: FIGURE IT OUT BASED ON THE CONDITIONS AT THAT EXACT MOMENT.

Here's how it does it: At each moment in time, X-Plane looks at the GEOMETRY of the airplane (shape of the wings, props, etc) and the speed it is moving. From that, X-Plane finds the airspeed acting on EACH LITTLE BIT of the airplane. Now, once we know the speed and angles at which the air is attacking each little bit of the airplane, we can use well-known laws of aerodynamics to find the FORCE on each little bit of the airplane. On the wings. The props. The tailfeathers. The fuselage and nacelles. The landing gear. The works.

Now, once we have found the forces acting on each bit of the aircraft, we add them all up! This gets the TOTAL forces acting on the airplane at that moment... NO MATTER WHAT PART OF THE PERFORMANCE ENVELOPE THE AIRPLANE IS IN! Bad pilot technique? Flight outside of the recorded envelope? NO recorded envelope cause the airplane does not even EXIST in reality yet? No problem: Geometry is geometry at ANY speed and angle, so the airflow speed and direction can be accurately computed on each bit of the airplane. And, from that, the forces can be computed. And, from that, the forces can be added up to get the TOTAL forces on the plane. As well, based on WHERE on the airplane these forces are applied (in X-Plane, everywhere: ALL OVER the airplane) we can then deduce the MOMENTS (torques) on the airplane. Now that we have our forces and moments, we simply divide by our mass and moments of inertia to get our linear and angular ACCELERATIONS. That is exactly how much, and in what direction, the airplane will accelerate at that very moment. We then do a Simpson integration (Duh-oh!) to integrate that acceleration to velocity. And velocity to position. And that is moving. Which is a thing that airplanes do that we like about them. So, that's what X-Plane does. Other don't. The X-Plane demo is free at www.X-Plane.com

 

Thank you Austin for talking to us at PCSimulators.org & PCHelicopters.com. We appreciate you talking time out to give us this fantastic article for our readers.

 

Further reading

The Best X-plane helicopters article  by pchelicopters.com click here

 

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