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Morten

IXEG
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Posts posted by Morten

  1. Hi guy's, been a long time :)

    Regarding rotate feeling light, this is mostly an XP issue (at least in XP11 that i knew well).  In short, the 737 has a supercritical airfoil (NASA term, or "aft loaded" airfoil as Boeing calls it).  One of the differences between conventional and aft loaded airfoils is (as the name implies) that the aft loaded airfoils have the center of pressure further aft.  Meaning also the center of lift is further aft than on a conventional airfoil.

    XP does not model this very well, and as far as I know has its center of lift at the 1/4 chord.  So this means XP airliners have their center of lift too far in front which cause problems in the transition phase between ground and flight.  Should be a fairly simple fix for Austin. There are some temporary "hacks" one can do, but it's a can of worms...

    Good to see the old girl in the XP12 skies - great work Jan and Tom B)

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  2. Regarding speedbrake drag, it was calibrated using the real drag data from boeing. (Jan might have adjusted it later)

    It depends on Mach and Cl (aoa).  Gives an increase in Cd between 0,011 - 0,014 in the normal envelope, so not much..

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  3. 55 minutes ago, ZeeMuffenMan said:

    ...it seems like I don't need to add much back pressure anymore at around 15-10ft, where the real 733 would start to require a lot of back pressure, as that nose wants to dive due to loss of lift, of course even more so when you get closer to the ground. 

    On the contrary, lift increase starts at about one CHORD altitude were you need ease off on back pressure (after the flare/break).  Pitch down effect starts about 70' agl.  We have analyzed dozen's of real B733 landings based on real FDR data.  Attach a sample of a few real B733 landings for you. As Jan says, we  had these discussions with Austin many times and provided various documentation.

    So the combination of science, real data, NASA test data and Jan's extensive in type flying experience has given us the result we have today which is the best for any desktop sim.

    Skjermbilde 2020-05-25 kl. 19.30.33.png

    • Like 1
  4. And with those words, we close this topic and wish everyone a nice weekend.

    The aircraft will get further updates, we apologize for the delay which is mainly a result of us doing this a as a hobby besides our "real" jobs.

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  5. 3 hours ago, parsec71 said:

    Why is almost every single developer in the X-Plane world so touchy when it comes to criticism?

    Well, there is a sharp line between criticism and insults.  When someone tells you what you have been working hard on for 7+ years is worth nothing, that is an insult.  It is all about choice of words.  But as you say, those people who react in this way usually have had a difficult past/life or really bad day.  

     

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  6. 23 hours ago, Shobhan Nandy said:

    Most of the issues which I have with your aircraft is related to the functionality

    And most of those we have been very open about.

    If things go as planned we will have an update ready later this year that will address a lot of VNAV stuff and more.  

    Quote

     I'm really sorry but its not even close to a pay ware and you are charging 75 USD.

    You are off course entitled to your opinion.  We have however thousands of very satisfied customers, and the IXEG is one of the most flown aircraft in X-Plane according to Laminar statistics (actually flight time). We have dozens of real 737 pilots flying it and reporting it to be overall the most realistic simulator aircraft they have ever flown!  

    Can it be improved in some areas - off course  - and it will be.

     

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  7. Used to work fine in XP10, although been a year since I tried.  Sounds a bit on the low side yes, at that weight you should drop below 1000fpm around FL300.  You have off course checked you do not have any ekstra drag out, like accidentally extended the gear, flap or spoilers.

    Lately we have also seen examples of 3rd party plugins that are somehow messing with flight model (should be a law against that:angry:)   So try disabling all other plugins and try again.

  8. 3 hours ago, Andrey Novikov said:

    Morten, I fly Zibo 738 in parallel and there is no such significant nose down effect. (IXEG, Zibo ans X-Plane are all the latest public versions).

    Aircraft that do not have a nose down effect, are most likely still using the OLD flight model of X-Plane!  To know you need to have a look inside the airfoils and aircraft files. I suspect IXEG to be one of the few that are using the new flight model atm (which overall is much more realistic).  It does not matter if it's the "latest" version of XP or the aircraft, it is up to the designer to implement it or not!

    ALSO, everyone needs to understand that how much nose down effect WILL VARY with aircraft type/geometry/wings

    • High tail/low tail: An aircraft with a high T-tail (type MD80) will have less or no pitch down at all.
    • High wing/low wing: An aircraft with a high wing low tail (type C172) will have a lot of pitch down
    • A wing with a high L/D ratio or high incidence is likely to have more pitch down
    • A long fuselage aircraft is likely to have less pitch down than a short of the same type (Type 737-800 vs 737-700)
    • A low AR (long chord) aircraft is likely to have more pitch down than a low AR
    • When the effect starts depends on span, so a B738 and a B733 decending at the same speed (700 fpm) will enter the effect at different altitudes, the B733 at a much lower altitude so it will "seem" a lot more dramatic to the pilot as you are closer to the ground.
    • An aircraft with more swept wings will be likely to have more pitch down as the wing tip will create more lift as it enters and center of lift moves back
    • An aircraft with winglets is likely to have less pitch down than one without.
    • etc.

    So Rob and Andrey, even a real B738 pilot cannot predict the nose down effect of a B733 unless he has actually flown it! So the one to listen to with regard to the IXEG 737 is Jan - as always ;)

    As you can see, comparing aircraft in ground effect is pointless, and this goes for the other types of ground effect as well.  This is what makes this area really-really complicated.  What you can be sure of though is that XP does this really well.

    M

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