IXEG 737-300

[Kaan KASIM 54]

Great to hear! :yahoo:

[Jessica Bannister-Pearce 120]

Hi Tom,

 

I can't wait to see this aircraft on my home system. Every flight sim needs a good 737, and this one looks great.

 

Best wishes,

Jess B

[ohsirus 241]

Hopefully there will be some provisions for the Home cockpit builders.

[tkyler 88]

Hopefully there will be some provisions for the Home cockpit builders.

 

 

 

If not right out of the gate, then soon thereafter. The code structure is such to allow for lots of customization options...most of which lie with programming interfaces rather than the 737 itself. Fortunately, I'm a home cockpit enthusiast myself, if not yet a builder...and the 737 is designed to not get in your way when the time comes to look into hardware options. I'm quite sure, once it comes out, that we'll get some sort of a open forum going for cockpit builders to try and come up with solutions.

 

Tom Kyler

Laminar

IXEG

[tkyler 88]

A user on our blog requested an update on the project and perhaps some regular postings to let users know what is transpiring. The team feels that is probably a good idea at this time.

 

Up until this point in time, we have been cautious about posting for a variety of reasons, but the primary reason is (and still is to some extent) our concern about whether or not we could do such a challenging project to the level that we envisioned when we began. A highly accurate airliner project of what has become known in flight sim lore as "PMDG Level" has always been somewhat of the "holy grail" of flight simming....and the team felt like X-Plane was long overdue for such a project. Of course like anything in life, these things can only happen once all the variables are just right....X-Plane technology, developer experience, willingness, timing, etc. The CRJ-200 by JRollon broke the ice for X-Plane in a big way. As much as we love it though, the 737 is more of the airliner standard and is why we chose to do one. We thought that perhaps starting with the classic instead of the NG would serve two purposes. 1.) It showed some deference to the x737 project and 2.) we BELIEVED it would be somewhat easier than the more complex 737ng. Well we were wrong. The NG is probably way easier than the classic. Why? Steam gauges..that's why! Now that we have steamrolled through most of the systems on the aircraft, they are really no different than the NG in complexity, only in their implementation. The steam gauges; however, are not just simple graphics, they're complex animations with rolling digits and wavering needles and flipping flags. We even went so far as to put in motion blur on the DME rolling digits on the ADF. I tell you that a LED readout or computer graphic would be much easier

 

What has transpired though as we have seen the cockpit and systems come together is that we very much have a fondness for the steam gauge elements. This particular variant of classic we are doing uses the modern glass EADI / EHSI and somewhat fancy ECAM and somehow delivers the best of both worlds, modern glass and steam gauge "complexity" and is really a feast for the eyes of cockpit fans. It definitely pushes our techo-geek buttons.

 

So about the state of the project. Given the experience of our team members, we decided early on to pursue systems programming first. It is always the most challenging part of a project and can stop a project dead in its tracks. The downside to this for anxious simmers is that is does not give us much to show. Code is not very exciting to look at, indeed I am finding it quite offensive to look at as of late. It is my guess that we probably have over 30,000 lines of code and counting daily. There is some good news though and that is we have just about every major system "over the hump". Just about every major system means just about every one except the FMS. Of course we have 'punchlist' items' on each of the other systems to do. The FMS framework is mostly implemented though. We have the CDU interface and pages mostly complete, we also have the autopilot mostly done and what remains is the calculation of VNAV and HNAV elements and the building of the flight plan. These elements will integrate with the ESHI display so we work on these elements simultaneously and these will come together at about the same time. We expect to begin this phase "next".

 

As far as the 3D work goes, we believe this is the easiest and quickest part, even though it is the most visible. We have a good portion of the fuselage done and textured but no wings/flaps yet. We do not have the main gear modeled yet either and the engines are about 30% modeled at this stage. The systems accuracy is the heart and soul of our project and to be honest, you probably will not see all the cool 3D screenshots until we are on the final stretch. We are also beginning our documentation process and getting ready to grow that element as the systems punchlist get completed.

 

I cannot stress to you how in-depth the systems will be and why the programming is taking so long. "Systems simulation" has always been a bit of a marketing buzzword by add-on developers but our consultant, a 737 captain of ridiculous attention detail will not let up. We read the real POH page for page, system descriptions word for word and if it says it in the POH, we try very hard to put it in. For example…did you you know that in the case of automatically deployed speedbrakes on landing, that you can advance the throttle levers a bit after landing to "auto-stow" the speedbrakes? Bump the throttles up a bit and watch the speedbrake lever go from "up" to "down" on the throttle quadrant. You cannot do this though if the speedbrakes were not deployed automatically from the armed position. If you move the speedbrake lever manually to deploy them on the ground, the 'throttle bump' will not work. Who uses that anyhow? Our consultant thats who! He lands and bumps the throttle instead of moving the speedbrake lever. So if he does it, we do it. He is really starting to bug us!

 

So to summarize this long-winded post for now, upcoming in the ensuing months is more 3D development of the cockpit / wings / flaps / gear, punchlist items on the major systems: hydraulics, electrics, pneumatics, IRS, etc. Development of hnav/vnav and the EHSI and the documentation. Final work will probably be the 3D cabin, eye candy and user-interface elements. That's the plan anyhow. So we'll include one screenshot (below 400k attached ) of the state of the cockpit, as usual during dusk which x-plane just does a cool job of rendering!

 

Tom Kyler

Laminar / IXEG

 

 

[anthony_d 32]

A focus on systems certainly gets my vote (speaking as a controls systems engineer in the offshore industry myself).

 

I was about to ask a question on the interaction between systems and cascading effects, when I saw your last blog post about hydraulics. That answers that one!

 

Is it possible see system failures cascade down in similar fashion?

[tkyler 88]

Is it possible see system failures cascade down in similar fashion?

 

Well it should work that way (in theory :P), the code was designed to support that. The cascading effects apply to interaction and failures. I can tell you that all of us on the team have been hit with something not working that we thought was a bug when it was a cascading failure that we did not catch (where's the checklist when you need it). On one occasion, I had spent a good amount of time troubleshooting the flaps code only to realize I had the system B pumps turned off and the system was doing exactly what it should do. That is a bad and good feeling all at the same time....mostly good though!

 

Tom Kyler

Laminar/IXEG

www.ixeg.net

[Comanche 417]

That really looks amazing tom! I cant wait for this one. Thanks for keeping us updated on the progress.

 

Rob

[Janov 2,383]

Hi everyone,

 

we have another teeny little piece of news for you. Today I want to show you the work we have recently done on our EHSI.

 

 

 

On the attached picture you can see the EHSI as the lower of the two screens. While the possibilities of displaying data on the EHSI are numerous I would like to point out what you are seeing here.

 

The depicted mode is the "expanded map" mode, showing the area in front of the aircraft. The aircrafts position is the tip of the white triangle at the bottom of the screen. Look closely and you can see the "ground path prediction" lines extending from the tip of this triangle, they represent the path the airplane will take within the next 90 seconds (30s per segment) at current turn rate and ground speed. You can use this to make very smooth intercepts when using smaller map ranges. Comes in handy for the final turn from base during a strong head or tailwind...

 

The selected range is 40NM (you can see the 20 on the mid range ring), the map can be displayed in 6 steps from 10 to 320NM.

 

You can see the two tuned VOR´s show up in green - along with the bearing lines, the green dashed lines. These lines are selectable (tuned VOR´s always show), and a great way to check your map accuracy - since the lines bearings are directly taken from radio signal data (displaying radials) and the green navaid symbols positions are drawn from the map´s database. So if they don´t intersect - your map has probably shifted.

 

Also displayed are the airports within the selected map´s section. You can select to show airports, navaids, fixes, etc. on the map with the help of pushbuttons on the EFIS control panel.

 

The magenta dashed line is the heading bug - you can see the aircraft is turning towards that heading.

 

The white line with the little rhomb at the top is the current track - look how it is influenced by the crosswind from the left. This track line will make it very easy to establish the correct wind angle when tracking along the localizer, for example.

 

The wind is shown on the bottom left - but unlike default x-plane we don´t show the wind while on the ground. Why not? Well, the real airplane can´t do it either - the wind arrow is a result of vector calculation between IRS track and groundspeed versus heading and true airspeed. In other words, the plane needs to "sense" the drift before showing it. On the ground there is no drift - > no wind indication. Now you try explaining that to Austin :-) Of course we also don´t show the wind if its magnitude isn´t big enough - just like the real plane won´t.

 

The top line will show GS and TAS, and also the current magnetic heading.

 

Now if you really look at the bearing line of VOR 1 very closely, you can see another green line with the label "A1" overlay it. That is the bearing of the selected NDB - coincidentally pretty much the same bearing. NDB´s positions are not shown on the map, though.

 

The dashes in front of the NM at the very top are the placeholders for "distance to next route waypoint" - blank in this picture since no route is loaded in the FMS.

 

More to come soon,

 

Jan

[Murmur 3,941]

Hi, I have a question related to flight model / flight performance.

 

Last time I checked, X-Plane atmospheric model was not correct when deviating from ISA conditions. Specifically, density at altitude is not what is should be, when temperature (and possibly pressure) deviate from ISA conditions.

 

Wouldn't this produce discrepancies in cruise performance compared to RL, in non-ISA conditions? Are you taking into account this issue?

 

Marco

[Kaan KASIM 54]

I thought Boeing showed corrected heading unlike Airbus. I may be wrong but all the Boeing aircraft I know shows the heading as where the aircraft is actually going not where it is pointing. Which results in always straight ND.

 

A screenshot would be better than me trying to explain it. :D

 

 

 

This is the ngx but I've seen the same with the classic.

[Janov 2,383]

In reply to the two questions above:

 

I have not noticed a discrepancy in atmospheric modeling, but wouldn´t rule it out. It is well beyond the scope of this project to correct any errors in environmental modeling of x-plane itself. Only Laminar should be responsible for that. As far as performance is concerned - if the density is indeed wrong, our plane will perform as it should at this "wrong" density. Take more gas :-)

By the way - if you have scientific proof (no, wikipedia usually doesn´t cut it) that the atmosphere is wrong, take it up politely with Austin, chances are he will at least consider it for a future update.

Besides - it is really easy to get messed up with what´s wrong and what´s right in the atmosphere. There is an "ICAO standard atmosphere" - but that is just a model and the real one will be quite different on any given day.

 

Yes, the "track/heading" issue. It is actually an airline option and can be switched on the EFIS computer in the E+E compartment. Many airlines fly with "track up straight". This makes navigational thinking a bit easier. However - if weather, TCAS targets or terrain are displayed it will not match "what you see outside" in strong crosswind conditions. So there is some debate which display is "better" - I personally prefer if the nose of my aircraft and "up" on the map coincide.

 

Jan

[Kaan KASIM 54]

Ah, that explains it. Thanks. :) Looking forward to it.

[Murmur 3,941]

By the way - if you have scientific proof (no, wikipedia usually doesn´t cut it) that the atmosphere is wrong, take it up politely with Austin, chances are he will at least consider it for a future update.

Besides - it is really easy to get messed up with what´s wrong and what´s right in the atmosphere. There is an "ICAO standard atmosphere" - but that is just a model and the real one will be quite different on any given day.

 

Already talked about it to Austin, but he said reworking the atmospheric model is not feasible, at least for now.

 

I know the real atmosphere is different than the idealized one, the problem is X-Plane doesn't model the variations in the indicated altitude when temperature deviates from ISA. But this is now off-topic wrt IXEG 737...

 

Marco

[Janov 2,383]

 

...the problem is X-Plane doesn't model the variations in the indicated altitude when temperature deviates from ISA...

 

Marco

 

Oh, didn´t know that - that is unfortunate, as the effect can be quite large in extreme temperatures (key word "cold temperature correction". Perfection is hard to achieve, I guess ;-)

 

Jan