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The A320 - A Medium-Ish Update

Lefteris Kalamaras

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Lefteris Kalamaras

Hi all,

I thought I had long escaped Smiffy's quest for "more forum posts" by hiding in his office and actually coding on my laptop there as it's the one place nobody actually bothers to look for me (and we all know how often HE is there), but I got caught when the cleaning crew decided to clean the spider webs from his keyboard, so I guess it's about time I wrote a bit on what we've been doing in the past couple "days" since my last report.

Before I do that, though, I'll start with this:

"I will never again suggest a proximate date of release while being video taped".

"I will never again suggest a proximate date of release while being video taped".

"I will never again suggest a proximate date of release while being video taped".

(this goes on about 1000 times and is on my office's blackboard)

You see, when we had our presentation in Munich about our upcoming A320-X, I was clearly convinced that to fit the entire majestic, beautiful, spectacular, breath-taking, awe-inspiring complexity of the A320 will take "just a couple months more" of development.

Clearly, I was a bit "off" in my calculations. Not to worry, though, because "this time", I know what I need to do: And that is, NOT give out a proximate date of release. Especially while being video taped.

Good. That said, let me give you an idea of where things stand at the moment and where we've been putting our development focus since I last reported:

- Systems complexity: As you know (you *have* been reading my other reports, yes?), we had developed an entirely new code library to allow our aircraft systems to communicate with each other via ARINC 429 protocol variables. This gave our systems the ability to send digital information (32-bit binary and discrete bit variables) around.

This was one side of the coin, however. The systems also rely on analog electrical wiring to communicate things like proximity switch information (is a door open / closed) or good old electrical voltage (such as that from a wheel tachometer) that gets converted into digital information. In the real bird, this is the other means of information transportation that each computer will read and use. As we kept coding various systems, we saw that a lot of those analog components needed to be simulated in order to achieve the fidelity and accuracy we required from ourselves. Rather than going into "guess work" on how these components would be simulated, we turned into the actual documentation and created the exact equivalents in our code based on the actual wiring that takes place in the real aircraft. In fact, we have now about 60,000 (yes - sixty THOUSAND) electrical connections for components talking to each other in the A320-X - from relays to switches to servos, if it makes sense for properly simulating the A320, it's already in our code. While I will *not* go into specifics on how we managed this, I am happy to report that the toll this library takes in performance is quite minimal, compared to the sheer magnitude of what's "in there". To give a couple small (and big) examples (I know people love graphics):

The brake motor fans are included:


as is the PTU, with its Valveblocks:


as well as the Spoiler Servo controls:


together with every other relevant component that makes sense to include on a desktop simulation (that means we do not - yet - have a working lavatory smoke detector - though we do have its connectors :) ).

- Flight Model: Lift and Drag models have been finely tuned to give excellent results in every corner of the flight envelope. This might sound like what every other developer has "once said" (I personally hate those boastful suggestions where "our aircraft has been approved by real pilots", or "three different aircraft engineers verified that our lift curve is really curvy!", etc). As such - and because there's really not much "confidence" in these types of arguments (they sound almost like detergent commercials, where "29 washing machine manufacturers prefer Skip"), I can share a couple graphs that came out of last night's tests.

The usual method for fitting the standard FSX flight model against real aircraft performance is done by tuning mach drag and adjusting mach thrust curves. This solution might be adequate for a standard sim product, but it fits too loosely, being correct usually only around a few main points that are published in FCOM tables so that users can compare figures. After exploring it to its fullest, we weren't too satisfied with that approach, so we introduced a couple new techniques which model flight and engine parameters outside the FSX internal sim engine. This allows us to fit performance tables: altitude, mach, weight, flaps/gear configurations, device configuration and temperature combined, produce the right angle of attack and drag in all directions of the flight domain.

One simple example is the standard idle open descent M0.78/300/250 at 65T and the comparison of unreliable IAS in descent with less than 0.5 deg of error in the chart against the real aircraft.


As we were quite unsatisfied with the internal secondary lift and drag surface simulation model that FSX carries (flaps, slats, spoilers), we managed to create our own... this means the A320-X correctly (and smoothly) adapts to extending / retracting surfaces in a consistent manner appropriate to real aircraft behavior.

- Engine Model: While there are quite a lot of improvements over my last report (data are now quite on the spot for EPR, N1, N2, EGT, Fuel Flow and most other engine parameters) it's worth a mention to also say that we wanted to go a bit above and beyond: Focusing now on items such as the effect that turning on Anti Ice (Nacelle and Wing) brings to engine performance, as well as the implementation of Rated and Unrated N1 modes in IAE engines in what we consider our "current standards" nowadays. In fact, our tech advisor team has often suggested that we leave some of that stuff out - it tends to "spoil customers", they say :).

Here's three indicative examples of the degree of fidelity we've achieved already in our product, compared to real data measurements.




- The Electronic Flight Control System (EFCS) has been modeled in its entirety (Normal Law, Alternate Law, Direct Law and Mechanical Backup), and we’ve carried out extensive testing to ensure that it's modeled to within a very narrow margin of the real thing, using data collected from the real aircraft to fine tune every characteristic. From the calculated speeds computed by the Flight Augmentation Computer, to the C* (C Star) law that uses various algorithms with pitch rate and g load depending on the speed of the aircraft. By taking areas of the default flight model away from FSX and tailoring the simulation characteristics to meet our requirements, we’ve been able to design and implement complex control loops that simulate with accuracy, the fly-by-wire system found on the A320.

Oh - and just in case you've been following that thread over at AVSIM regarding wheel friction: New rolling and sliding coefficients are in use in our aircraft. These are dynamically loaded when the A320-X loads and are back to their normal values once you load another aircraft (but we know you would not want to do that, right?)

Regarding sounds, I would simply be repeating myself... myself... myself... but I want to mention that - indeed, the PTU "barking dog" sound will be there (but only WHERE and WHEN it makes sense for it to be heard... *hint* *hint*) along with some other very cool sounds that add to the immersion level and allows that "I'm there" feeling we all wish to experience.

Now - I understand that a lot of our friends are aircraft-savvy (especially when it comes to the A320) and appreciate how in-depth we're making this product, but I am not forgetting that there are also some of you for whom visual accuracy is quite important. In my every-day schedule, a lot of time is spent on getting the code done, but without the 2d and 3d drawing magic, most of that development effort would be quite hidden - isn't it so? As such, I'd like to actually share a few new images, without too many words, as a little "thank you" note to you all for your patience and understanding while we keep our heads buried deep in our code. (The images I am sharing are very carefully selected as we wish to still keep a few aces up our sleeve. That said, the conspiracy theorists among you are now free to start rumors about whatever you like, but please keep in mind: Everything you see is still in development. This means IT - IS - NOT - FINAL! :) )







I know I've kept you waiting with baited breath for this last sentence, so here it goes:

The date we plan to release the A320-X is:











When it's ready! :)

Cheers all, and thank you for your fantastic support of our products!

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Thank you for the excellent updates and special thanks for addressing the lavatory issue, it was really bothering some folks to death. Cheers and keep up the gr8 work, I am certain your post completely proves why some of us are desperately holding back on getting a fsx bus while others are showing off :)

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Mark Richards

Thanks for sharing Lefteris, I'm patiently waiting for her release and know that it will be hands-down the best simulation available on the market bar none. Please keep up the good work.


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I think a tear has just come out of my eye! Wow! I love the images, but the text telling me what's underneath that gorgeous 3d model is even more amazing! That's what we were in need of! A proper update

Thank you! Now just keep doing these updates once a month and we'll be fine :P

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Marlon Carter

I am speechless......well not really...WOW this is going to be quite an aircraft. keep up the good work. I am a firm believer that a product should only be released when YOU the developer is satisfied, not the impatient public.

I do have one question. With all of this complexity, I am wondering if FSL or another developer will create a training program to help simmers build confidence in handling this aircraft? I am thinking of either Flightdeckproductions or Angel of Attack since they are the best in this area.

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Sure looks like a lot of work is going into this development. If the final product is as promised here, it could be the biggest stap forward since the PIC 767. Then again, Lefteris is no stranger to that, now is he? ;-)

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CASSE Valentin

Sounds Great !

CaptainSim BIM ! :D

I personally hate those boastful suggestions where "our aircraft has been approved by real pilots", or "three different aircraft engineers verified that our lift curve is really curvy!", etc

a+ :)

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Thank you Lefteris, the 320 looks fantastic, it will definetly be my first fslabs product. Well I already decided my First test flight route (Athens-Beirut) :). Take your time and let us hear from you soon.

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Lefteris is it the Real Bus or a simulation? I'm pretty sure that you're developping it at Toulouse and I will download it from there :). there are no words the describe the Awesomness of FSLABS A320X. thank you guyssss. please Please take My Money :)

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Flight Model: Lift and Drag models have been finely tuned to give excellent results in every corner of the flight envelope.

One simple example is the standard idle open descent M0.78/300/250 at 65T and the comparison of unreliable IAS in descent with less than 0.5 deg of error in the chart against the real aircraft.

Hi Lefteris,

That DOES sound very promising :)

I hope that you are using the Airbus LPC-NG in flight performance calculation tool as well besides the very coarse unreliable airspeed table.

LPC-NG results are increadible accurate and can be used for almost every possible speed/conf/spdbrk/gear combination.

Best regards


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rafael fuentes

Thank you very much. incredible.

I think it's very important that from time to time be said ... here we are and this is our progress.

That helps the wait is shorter.

While waiting with credit card in hand. XD

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