Page 1 of 2 12 LastLast
Results 1 to 10 of 16
  1. #1
    500+ This must be a daytime job
    Join Date
    Feb 2006
    Location
    N/A
    Posts
    511
    Contribute If you enjoy reading the
    content here, click the below
    image to support MyCockpit site.
    Click Here To Contribute To Our Site

    PMDG, FSX & Throttle Movement

    Okay, another small issue I need some help with. When I'm using PMDG 737-700 in FSX, the throttle advancement and movement of aircraft dont match.

    It's at idle 19.6% N1 roughly and if I move the throttles to like 23% it'll go from GS 0 to GS 10 pretty quick, and if I dont back the throttles down to idle it'll continue to speed up in GS. I do have all weights, fuel, CG and etc set.

    The funny part of this is, when using FSX default B737-800, the throttles work as they should. About 40% N1 before in any movement, so I know I have the throttles, FSUIPC, PM and all that good stuff right. I think it's a part of the Aircraft.cfg file, but I'm not sure which part it is...

    John

  2. #2
    500+ This must be a daytime job
    Join Date
    Jan 2007
    Posts
    564
    Contribute If you enjoy reading the
    content here, click the below
    image to support MyCockpit site.
    Click Here To Contribute To Our Site

    Quote Originally Posted by jkcombs View Post
    The funny part of this is, when using FSX default B737-800, the throttles work as they should. About 40% N1 before in any movement, so I know I have the throttles, FSUIPC, PM and all that good stuff right. I think it's a part of the Aircraft.cfg file, but I'm not sure which part it is...
    I've never taxied a real 737, but I would have thought that the PMDG modelling would be a lot more realistic than the default. 40% N1 before any movement sounds a helluvalot -- very noisy too. I've never noticed that, as a passenger, on real aircraft?

    Pete

  3. #3
    500+ This must be a daytime job
    Join Date
    Feb 2006
    Location
    N/A
    Posts
    511
    Contribute If you enjoy reading the
    content here, click the below
    image to support MyCockpit site.
    Click Here To Contribute To Our Site

    Taxiing Speed

    Peter,

    Maybe I'm little high on the N1 of 40%, but it seems more natural with the default B737-700 in FSX because the engines have that delayed kinda feel, like the way it would be expected.

    However, with PMDG 737-700, it seems like I'm on ice, from 20% to 23% N1 the plane just goes to fast. Also, the steering is way to sensitive. Yet, with the default it's nice and smooth.

    I know this all sounds weird, but I have not changed anything and just to be sure I went back and recalibrated my throttles. I still get the same effect. You're using PMDG 737-700 right?

    Can you copy/paste your Aircraft.cfg in a reply here in my MYC, this way I can verify mine against yours to make sure I have the correct data...

    John

  4. #4
    300+ Forum Addict AchillesP's Avatar
    Join Date
    Sep 2007
    Location
    Greece, Thessaloniki
    Posts
    381
    Contribute If you enjoy reading the
    content here, click the below
    image to support MyCockpit site.
    Click Here To Contribute To Our Site

    Quote Originally Posted by jkcombs View Post
    However, with PMDG 737-700, it seems like I'm on ice, from 20% to 23% N1 the plane just goes to fast. Also, the steering is way to sensitive. Yet, with the default it's nice and smooth.
    John
    Hi,

    This is the way the pmdg model works. It is true that from n1 20% to 23% it is not so real. The 737-900 seems to be more real at N1 conditions perhaps of the biggest weight.

    The comments from real pilot (737-400) at my cockpit for PMDG 737-700 are:

    1.) N1 is not so real but comparing with real 737-400.
    2.) Nose looks much more heavy at turns

    All other thinks looks very realistic.
    With best regards,
    Achilles
    http://www.thefsps.com

  5. #5
    500+ This must be a daytime job
    Join Date
    Jan 2007
    Posts
    564
    Contribute If you enjoy reading the
    content here, click the below
    image to support MyCockpit site.
    Click Here To Contribute To Our Site

    Quote Originally Posted by jkcombs View Post
    Can you copy/paste your Aircraft.cfg in a reply here in my MYC, this way I can verify mine against yours to make sure I have the correct data...
    It's just the PMDG one with a couple of changes to suit pmSystems which Thomas advised -- to do with numbers of pumps and the elevtrical levels I think. Certainly no changes in power or anything that I recall.

    If you still need it after December 29th, remind me then. I've not got that system on and at present I'm busy trying to wrap things up for a break here -- we're off from tomorrow till the 29th.

    Best Regards

    Pete

  6. #6
    25+ Posting Member
    Join Date
    Jan 2008
    Location
    uk
    Posts
    45
    Contribute If you enjoy reading the
    content here, click the below
    image to support MyCockpit site.
    Click Here To Contribute To Our Site

    Taxi Thrust

    Info via relay from a commercial pilot for you.

    737-800.
    To move 737-800 full of pax, initially need 35% - 40% to move, then mid to high twenties to keep 10 - 15 knots.

    Hope this helps,
    ID.

  7. #7
    500+ This must be a daytime job
    Join Date
    Jan 2007
    Posts
    564
    Contribute If you enjoy reading the
    content here, click the below
    image to support MyCockpit site.
    Click Here To Contribute To Our Site

    Quote Originally Posted by Induced_Drag View Post
    Info via relay from a commercial pilot for you.

    737-800.
    To move 737-800 full of pax, initially need 35% - 40% to move, then mid to high twenties to keep 10 - 15 knots.
    So which parameter needs changing in the Aircraft.CFG file? Presumably something to do with inertia?

    Of course I never have many passengers when I fly -- makes the flights longer!

    Pete

  8. #8
    500+ This must be a daytime job
    Join Date
    Feb 2006
    Location
    N/A
    Posts
    511
    Contribute If you enjoy reading the
    content here, click the below
    image to support MyCockpit site.
    Click Here To Contribute To Our Site

    Inertia

    Peter thank you for looking into this and yes, after the 29th I'd like to get a copy of your Aicraft.cfg for PMDG 737-700 because I do have the Overhead Hardware from FlightDeck Solutions, as well as PMSystems. So, your copy will help me get into that a little more down the road.

    If the throttle issue is the Inertia, I wouldn't know what to change. I was looking at the the default 700 Aircraft.cfg (comparing) right next to the PMDG 700 Aircraft.cfg, and honestly I'm not to keen on what to change...

    @ Acilles, thanks for checking yours and knowing that this is not just my system causing this alone.

    @ ID, thanks for getting info from real pilot. It does help us all to be closer to reality by knowing what it should really be like.

    Please let me know if you come up with something for this Peter.

    John

  9. #9
    500+ This must be a daytime job
    Join Date
    Jan 2007
    Posts
    564
    Contribute If you enjoy reading the
    content here, click the below
    image to support MyCockpit site.
    Click Here To Contribute To Our Site

    Quote Originally Posted by jkcombs View Post
    Peter thank you for looking into this and yes, after the 29th I'd like to get a copy of your Aicraft.cfg for PMDG 737-700
    Actually I think it's the one in the attached ZIP, which contains the bits I uploaded here a while back for someone else.

    If the throttle issue is the Inertia, I wouldn't know what to change. I was looking at the the default 700 Aircraft.cfg (comparing) right next to the PMDG 700 Aircraft.cfg, and honestly I'm not to keen on what to change...
    I've no idea either. The "Flight Tuning" data would affect the flying characteristics and you don't want to wreck those. I don't see any Ground "friction" or "inertia" values. Maybe this sort of thing can only be modified in the AIR file.

    A visit to one of the aircraft designer forums looks to be needed!

    Regards

    Pete
    Attached Files Attached Files

  10. #10
    75+ Posting Member Daveanne's Avatar
    Join Date
    Sep 2007
    Location
    Ellesmere Port, Cheshire
    Posts
    137
    Contribute If you enjoy reading the
    content here, click the below
    image to support MyCockpit site.
    Click Here To Contribute To Our Site

    Getting a 737 moving

    The commercial pilot is correct, but the name of the problem getting the aircraft to move is: 'Form Drag', basically its weight, rolling restistance, its shape (actually it isnt very aerodynamic when its stood still and no airflow over the wings), so it does take about 40% N1 to get it moving.

    Sorry to bore, but as the aircraft gets moving then it accumulates intertia, lets imagane a supertanker on the seas, its only moving about 15-20 knots, but it has so much intertia, which is proportional to density (weight x Gravity) it take many miles for it to stop it.

    Theretically if a large ship and or aircraft is stood still one man could keep it moving, once it is moving, its all the "form drag" that stops you starting off that movement.

    To take it a step further, once the aircraft is moving, then it takes far less force (engine thrust, expressed as N1%) to keep it rolling.

    So how does the aircraft actually get airbourne with all that weight and rolling restistance: as we gather speed the form drag reduces and the wings start generating lift, if the forces were to be shown as a graph, then the line of "form Drag" would be very high and very quickly reduce as the speed increases.

    However for every action etc. the other problem is "lift induced drag", this is in opposition to the form drag and intially as we gather speed to the point of 'take off' is very low, compartively. However as the speed is increased the induced drag increases slowly, but at a pre-determined speed (dependant on shape size construction angle of attack etc), the induced drag gets to a level where the 'total drag' overcomes the power applied to keep it moving forward.

    These are some of the factors that limit an aircrafts "flight envelope", which is the magic graphs that give the various limits that the aircraft can opperate, for instance, you wont get a 737 to fly at .77M at 1000ft, the engines can't supply enough power to overcome the drag produced by the relatively dense air at that altitude, however take the same situation at 38,000ft the air in much thinner and the aircraft can travel faster for the same power setting, thats a very simple explanation by the way, but it should give all an idea of Why?

    To answer the original question, yes 10-15%N1 is far to low to move 737 6/7/8 series from standstill to taxi speeds, if someone does finnd the tweek, please let us know?

    Daveanne

Page 1 of 2 12 LastLast

Similar Threads

  1. pmdg 737/fs9/saitek throttle idle possition issue!
    By johncor in forum General Builder Questions All Aircraft Types
    Replies: 6
    Last Post: 01-23-2012, 02:15 PM
  2. PMDG MD-11 Throttle Quadrant
    By jfjoubert in forum I/O Interfacing and Hardware
    Replies: 0
    Last Post: 09-28-2010, 07:38 AM
  3. Alternative to Air Core Movement
    By smendlik in forum Cockpit Parts and Motion Platforms
    Replies: 4
    Last Post: 02-08-2010, 09:18 PM
  4. Re: CDI movement in PMRJ demo
    By Enrico Schiratti in forum PM General Q & A
    Replies: 0
    Last Post: 01-21-2006, 09:38 AM
  5. CDI movement in PMRJ demo
    By Mark Wisted in forum PM General Q & A
    Replies: 1
    Last Post: 01-18-2006, 12:56 PM