• Thanks Roccio, I tried the AOA index for a few approaches and 0.45 gave me about 100-105 knots which was MILES slower than I had been using. 0.23 AOA gave me range (similar (a bit slower than) to climb?) speeds of 175, 185 and 195 knots with idle, bottom of the green and top of the green RPMs.



    I tried a landing configuration power off stall and got a speed of about 80-82 knots. Times 1.3 for a Vref gives 104-106.6 knots so the relation to the 0.45 AOA seems sound. Do these speeds make sense Roccio?



    Not a good location for HASSEL stall checks!

  • Yes, the speed looks spot on. I think we should start a new thread as these are MB339 are infos and not bugs. Maybe in the near future we can create a sort of manual for this aircraft.

  • The lack of information is a sort of bug, MSFS gave basic performance data. It is a really nice Aero' sim plane and a manual or pilot notes would be a useful service. I am most grateful for your excellent help and I'm looking forward to any more material that you can provide. Perhaps someone using the forum has experience of flying (semi) basic or advanced military jet trainers?

  • Here some performance info:


    Performance:
    • Structural limits:
    Max speed: 500 kts
    Load factors: +8 -4 g


    • Performance in clean configuration:
    Take off distance: 1805 foots
    Climb rate: 6900 ft/min
    Max altitude: 46000 ft
    Max speed in level flight: 496 kt
    Constant load factor: 5.9 g
    Max turn rate (at 15000 ft): 12° /sec
    Landing speed: 102 kt
    Landing distance: 1575 ft
    VNE: 500 kt/ 0.82 M
    VLE (max landing gear extraction): 175 kt


    • Stall speed:
    Clean configuration (200kg of fuel): 96 kt
    Full fuel load (1400 kg): 107 kt


    • Take off speed: 103 kt
    • Landing speed: 100 kt
    • VY (best rate of climb):
    Sea level: 280 kt
    10000 ft: 265 kt
    20000 ft: 0.55M (255 kt)
    30000 ft: 0.55M (210 kt)
    40000 ft: 0.55M (160 kt)


    • Max flaps speed:
    T/O: 175 kt
    Full down: 160 kt


    • Speedbrake: no speed limits

  • The lack of information is a sort of bug, MSFS gave basic performance data. It is a really nice Aero' sim plane and a manual or pilot notes would be a useful service. I am most grateful for your excellent help and I'm looking forward to any more material that you can provide. Perhaps someone using the forum has experience of flying (semi) basic or advanced military jet trainers?


    Maybe a pop-up quick reference card / kneeboard would be really nice for this.

  • Maybe a pop-up quick reference card / kneeboard would be really nice for this.


    This whould be a new feature for the devs that is really not needed.
    All the info you need may be printed on paper and you can have a "real" kneeboard.

  • Brilliant Roccio, my enjoyment of the 339 is transformed! My 'best guess' speeds were way off and now it feels so nice when landing.
    Could you check the stall speeds with flaps and the no flap take off speeds -if ever used- please? Is the second AOA ("0.33 is maximum autonomy hourly") bug the Vx maximum climb gradient/minimum thrust required angle? It would be a slower airspeed than with the first bug, for a given thrust.
    Have you any information on engine managment? The full flap with gear down descent needs the engine running at a rpm below the green arc, is there a time limit at this setting?
    Your help is much appreciated, thank you so much Roccio!

  • This is for stall speeds



    For climb best speed is 275 kias or 0.55 mach.


    Engine management is a bit more complicated, I will try to extrapolate more infos as soon as I can. But one thing to note (and this can be considered a bug) is that the throttle position indicats thrust setting and not RPM. So at half way of the throttle movement you should have half thust and the RPM should be circa 86%.

  • Roccio you are very kind, thanks a lot for sharing your valuable knowledge. It's nice seeing performance graphs after many years.


    I'm a bit lost about the single engine jet performance, take-off speeds used. The short undercarriage will prevent a vigorous rotation but the tyre limit is a factor too. For a flat but clean unstick, is a highish speed used?, perhaps followed by an AOA gauge 0.33 index climb for an initial steep climb gradient, accelerating to the best rate of climb speed?


    The wing looks rigged at a reasonable angle to the fuselage, does a moderate rotation rate avoid tail strikes? Tail strikes seem easy enough in Aerofly!


    So for a maximum weight take-off with take-off flap, what would be the Vr rotation speed? Is the 103 kt speed you have quoted, the speed for a medium weight take off, perhaps roughly 4.4 tonnes?
    I am guessing (badly no doubt) at about 115 knots for maximum weight, based on 106 minus 5 for full power in use, to give a 101 knot stall speed. For a safety margin of (??? big, big guess here) 'plus 30% of the load', adding 14% of the speed or using the 40 degrees of bank speed minus the full power 5 knots to give 115 knots?


    Lift is proportional to the velocity squared.
    1.3^.5 = 1.14
    (106-5) x 1.14 = 115 kt


    Loading = 1/ cos bank angle
    1.3 = 1/0.77
    Cos 40 degrees = 0.77
    Max wt stall with take off flap at 40 degree bank = 119 kt
    119 -5 = 114 kt.


    It is just the get off the ground speed, safety margin above the stall that I can't guess, I presume the best rate of climb speed is the immediate goal.

  • In training configuration (aircraft clean, crew of two, full internal fuel = 4400 kg) the rotation speed is 85 kias.


    1. ROTATION & LIFT OFF


    * Perform rotation by gently apply aft stick to raise the nose at 7° above the horizon.
    * The aircraft will fly off the ground at approx. 100 kias.
    * Hold the wings level and 7° avove the horizon.
    * at AGL altitude (30 ft and 120 kias) apply brakes and retract gear.
    *retract flaps (min 120 max 150 kias)


    2. ATTAINMENT of "ACCELERATION CHECKPOINT"


    * maintain 100% RPM in slight climb (1000 to 1500 FPM on VVI)
    * maintain flaps T/O; AOA 0.65; 120 kias



    This is how to perform a basic take off. I think it will be better to put all the procedures in a doc file as reference.


    For the rotation I think there is a little bug in the AeroFly FM so that at that speed you don't have the autority to pull up the nose. Only devs can solve this.

  • You are welcome! This plane is may all time fav, so I hope to have a perfect rendition in this wonderfull simulator. I await event the SDK to reproduce instruments on a second monitor/PC for maximum reality. And in the end I hope we can enjoy even a full clickable cockpit for a full experience with a cold & dark plane.

  • Roccio you are an outstanding star of the fan group community.* Did you ever encounter the (!) remarkable Lockeed F-104 starfighter which seemed to have been more widely adopted in European NATO countries than in the USAF?* It's wing loading must have caused field length limitations and therefore take-off speed consideration. Was it handled differently from the 339 or did it just assume a pitch attitude and wait for lift-off?

  • Love the 104 'spillone' (big needle) as we used to call here in italy.
    From what the 339 flight manual says you just wait the vr at 85 knots, pull the nose up 7 degrees and wait the lift off.

  • Roccio you are an outstanding star of the fan group community.* Did you ever encounter the (!) remarkable Lockeed F-104 starfighter which seemed to have been more widely adopted in European NATO countries than in the USAF?* It's wing loading must have caused field length limitations and therefore take-off speed consideration. Was it handled differently from the 339 or did it just assume a pitch attitude and wait for lift-off?


    http://www.avialogs.com/en/air…f-104g-flight-manual.html


    Starfighter has a V1 on which is rotated and usually immediaty climbs, also w heavy load.

  • I noticed a little misalignment of the trim gauge



    The plane image shoule be horizontally aligned with the 0 reference, while it's a bit lower.

    • Official Post

    I noticed a little misalignment of the trim gauge



    The plane image shoule be horizontally aligned with the 0 reference, while it's a bit lower.


    But for which trim setting is the question? If you put the aircraft on the runway, you will get a takeoff trim, if you put it up in the air you will get a trim setting that makes the aircraft fly level with the current speed. So that image could be anything, how do you know its the zero trim setting?

  • I found this on the real flight manual:



    The instrument shows, with a miniature airplane, the amount of correction given by the trim.


    The longitudinal trim, with flaps on UP position is limited at the first reference line of the instrument in NOSE UP and DOWN.



    With flaps extended (T/O and DOWN) the correction is possible within the second reference in the NOSE UP direction.



    TRIM INDICATORS:


    You have an instrument with a needle (the aircraft image) and a gauge with some references. In relation of the movement of the trim the plane image will be "nose up" or "nose down" reflecting the trim position.


    There are also two indicators for neutral position or the yaw and roll trim



    that illuminate o green light when the corresponding trim is in neutral position. This indication is only displayed if the plane is on ground.

    • Official Post

    bump.

    Noticed that the too high speedbrake extension angle with gear down has been reported more than a year ago!

    Same goes for the reversed engine acceleration and the question if ground effect is generally not modelled in Aerofly FS2 or if it's just missing in the MB339.

    Thank you for bumping up this thread. I wrote it all down but since there is so much to do I can't promise a quick fix.

    There are enough things on my todo list, e.g. Learjet 45 and Airbus A320 tutorial and the FBW fixes, I'm going to be busy for quite some time :)

    Some of the reported bugs are easy to fix and they will probably be removed with the next update or the one after that. Things like the engine acceleration aren't as easy to fix.