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airforce2

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Posts posted by airforce2

  1. Dennis;

    There's an important point you are missing here. I haven't attached Steve Small's work to Lago's product. I look at it as enabling others to attach Steve Small's publicly released freeware work to Lago's unfinished payware product in the privacy of *their* own homes... And if you closely inspect the aircraft.cfg file I have provided, much of the parameterization is either default or original work on MY part, which I offer for free as a bridge between the two components.

    Again, you can't make this work unless you go and get Barry Blaisdell and Steve Small's work from them. Not from me. Not from Lago. From them. It'd be a far different matter if I wrapped up their stuff in my zip file and sent it to you.

    A merge enables compatibility between two pieces of an aircraft simulation...panels, sounds, visual models, flight dynamics, scenery, etc. I agree that Steve spent a considerable anount of time developing this...and out of the kindness of his heart has released it for free use to the public. But where does it end? Do I need to ask Aaron Swindle if it's OK every time I install one of his freeware sound packages with a different airplane? Do I need to ask him before I post on a bulletin board "hey guys, I just tried Aaron's sounds with Charlie's new aeromafliggity panel and they rock...here's how I did it..."? I say no. Do I need to ask him before I publish a panel with instructions that that say "now go get Aaron's sounds from avsim and put 'em here to make his good stuff work with my good stuff?" No, I don't. The interoperabilty of all these pieces is what makes flight simming.

    Ultimately, an author has an undeniable right to control how his/her work is distributed...if he wants, he can sell it, or he can release it to the world, or he can limit the release in a variety of ways. I just can't see a problem with telling people how to use an author's work once they have gone to the trouble of acquiring a valid license from the author to use it.

    As long as we are only using (or facilitating use by others)...not redistributing...a freeware product, I think it's in the realm of fair play.

    Cheers

  2. Dennis;

    Do we need some kind of special permission to download a freeware product and use it?

    There is no redistribution occurring here...the file used is in a freely distributed package on the major sim sites. You will find that there are a number of such merge packages out there, like Lee Hetherington's merge of the Project Opensky visual models with Wilco's PIC 767 panel, for example. As long as nobody is taking the copyright owner's work and redistributing it without his permission, or worse, making a profit from it, I fail to see an issue here. You have to go get Steve's airfile from a place where Steve has made it publicly available...if he doesn't want that to happen, then he can remove it from the distribution sites, as is his right.

    I still believe Lago would be $$ ahead to pay Steve to distribute his flight dynamics with the Lago package...they are very good.

    Bob

  3. Folks;

    I have written an aircraft.cfg file that merges the Lago panel and visual model together with a freeware flight dynamics model for the Twin Otter written by Steve Small and packaged in Barry Blaisdell's DHC6 model.

    You will need to download and install Barry's Twin Otter first. It is file dh6exe22.zip located at both avsim.com and flightsim.com. The rest of the instructions are in the comments at the top of the config file attached here.

    Steve has a reputation for solid work in FS flight dynamics, and this one is no exception.

    Cheers

  4. You can resize the overhead panel to your liking by opening it, then right-click on the window and undock it, then resize the undocked window by dragging the borders as desired.

    Next time you open it, it will be as you resized it. If you save a flight subsequent to doing that, the window should retain its properties when the flight is selected at FS startup, I think.

    Cheers

  5. Geez, you're right, the weights are 60% too high...another unbelievable gross error.

    However, reducing the weight to where it should be puts all the performance out of whack again.

    The gent who called this a "fantasy aircraft" appears to have hit the nail on the head. What a disappointment this is becoming.

    Lago...might I suggest you find someone like Steve Small or Johan Dees and entice them to help you FIX this flight dynamics mess before your reputation suffers any more from this debacle?

  6. In general, once the flaps go all the way down, you need a considerably higher power setting because you have added a great deal of drag. In the case of the Twotter, the flaperons extend nearly the entire wingspan. But...the plus side of having all that drag is that the airplane will decelerate quickly when you retard the throttles to idle, making the roundout and flare from a steep approach possible.

    In a C-130, when flying assault landings (usually steep and to a short field), you have to carry a *lot* of power because you're on the "back side" of the power curve coming down. If you look at a speed-lift curve it's shaped kind of like the Nike trademark...a "hook" shape on the low end. Once speed gets below L/D max (the bottom of the curve where lift-to-drag is optimum, aka best glide speed) it takes *more* power to hold level flight as you get slower. This is also generally marked by a pronounced increase in deck angle.

    Cheers

    Bob Scott

    Chief Pilot and practicing amateur aerodynamicist

    The Not Quite Ready for Prime Time Beta Test Team

    "In relentless pursuit of mediocrity"

  7. When you push up the prop levers, the props increase their "bite" into the air (blade angles rotate from idle to full forward), which puts a load on them, slowing them down. Think of it like letting out the clutch on a car.

    The "mixture" levers are really "condition" levers. Lago is in error calling them "mixture" levers in their manual. The FS2002 internal functions use the mixture controls to do the condition lever functions...my guess is that's where the mix-up happened, probably on the part of the programmer(s).

    Cheers

    Bob Scott

    Chief Pilot and practicing amateur aerodynamicist

    The Not Quite Ready for Prime Time Beta Test Team

    "In relentless pursuit of mediocrity"

  8. Yes, Virginia, there IS a problem here.

    As I mentioned in a previous post in the "A new (better) set of flight dynamic tweaks" thread, this problem is due to the Lago Twotter's yaw damper.

    If you open the AP panel and turn the yaw damper off (press YAW ENG, light should go out), you can now get full 30 deg rudder deflection. Verify this by looking at rudder travel in a spot-plane view before/after turning off the yaw damper. With the YD on, you're lucky to get 5 deg of travel. The yaw damper, as implemented in this flight model, prevents intentional uncoordinated rudder inputs, making a forward slip or a cross-control x-wind landing nearly impossible.

    I recommend increasing the yaw_stability factor in the aircraft.cfg file to ~1.5 and leaving the yaw damper on the AP turned off...the effect will be the same as if you had a properly functioning yaw damper, but without effectively cancelling out all of your rudder input.

    Lago...please add this one to your "aw $#!$%" list.

    Bob Scott

    Chief Pilot and practicing amateur aerodynamicist

    The Not Quite Ready for Prime Time Beta Test Team

  9. Igor says that the engine readings are already fixed in the next release.

    There's something strange going on with the vertical speed. I have also noticed the fact that the indicated vertical speed is always ~300 fpm higher than the selected vertical speed.

    Last night I noticed that with 1000 fpm selected in the vertical speed target, the aircraft indicated a 1300 fpm climb. But the airplane was in a 1000 fpm climb...the second hand on the clock and the altimeter needle were spinning at the same rate...I timed it and sure enough, we were climbing at 1000 fpm.

    So...Lago...there's a problem with the indicated vertical speed.

    Regards from your dedicated beta test team

    Bob

  10. Folks;

    The engines on the Twin Otter are turboprops, not reciprocating engines. There is no such thing as a "mixture" control on a turbine engine. The two levers erroneously identified as mixture levers in the manual are actually condition levers, which should have three positions...idle/cutoff (all the way back, kills the engine), ground idle (a slower prop speed used for ground/taxi ops, and flight/max increase (normal mode for flight).

    You should be flying with the condition levers full forward...and if pulling them back somehow results in a) still flying, and b) better fuel economy...well that's a sim-ism and not how it works for real.

    Cheers

    Bob

  11. One thing I've discovered is that the yaw damper pretty much kills your ability to cross-control the airplane (for foward slips or x-wind landings. If you pull up the AP page and deselect the yaw damper, x-wind landings get a lot easier.

    My personal thought is that pushing up the yaw_stability parameter will do what a yaw damper *should* do...leave the AP yaw damper off, as it kills legitimate uncoordinated rudder inputs.

    Cheerio

    Bob

  12. To fix stall speeds:

    [Reference Speeds]

    flaps_up_stall_speed= 74.000 //was 63.000

    full_flaps_stall_speed= 58.000 //was 50.000

    I don't have the overcontrol problem as I can set progressive damping in my PFC yoke thanks to another great utility from Pete Dowson. For those experiencing elevator oversensitivity, try reducing the elevator_effectiveness parameter in the [flight_tuning] section to 0.8-1.2 range. Start at 1.0 and experiment up/down from there. Believe it'll depend a bit on your joystick or yoke as well.

    Cheers

    Bob

  13. Folks;

    Here are my latest tweaks to the Twotter flight dynamics. The performance is more at par with what's in the manuals, i.e. 80 KIAS final approach speed, touchdown at 70 KIAS in a proper attitude. Steep approach performance looks more like I would expect, too.

    Caveat up-front: I am not a Twotter pilot, but I do have well over 4,000 hours real-world flying experience in many classes of flyin' machines from sailplanes to C-141 heavy transport jets. I've got a few hours in a DHC-3 Otter (single-engine) that I use as a basis for what I would expect DHC-6 performance to look like.

    Use or don't use as you wish. This model flies like an airplane should...can't say for sure it flies exactly like *this* airplane should.

    Cheers

    Bob

    _____

    [flight_tuning]

    cruise_lift_scalar=1.000 //was 1.621

    elevator_effectiveness=1.400 //was 1.394

    aileron_effectiveness=1.000 //was 1.240

    rudder_effectiveness=2.000 //was 1.240

    pitch_stability=1.750 //was 1.416

    roll_stability=1.100 //was 0.972

    [propeller]

    propeller_moi= 15.000 //was 17.00

    [turboprop_engine]

    idle_rpm_mechanical_efficiency_scalar=0.300 //was 0.508

    [airplane_geometry]

    oswald_efficiency_factor= 0.880 //was 0.700

    [Flaps.0]

    extending-time= 6.000 //was 5.000

    lift_scalar= 1.000 //was 0.990

    drag_scalar= 3.750 //was 1.350

    pitch_scalar= 1.000 //was 0.600

  14. Igor;

    On the A/P panel, the far right says VS HLD and shows a 4-digit target VS value to its right. When I increase the climb rate (in ALT mode) to 1000 fpm, the aircraft climbs at 1300 fpm. If I increase it to 1200 fpm, the aircraft climbs at 1500 fpm. It seems to me that if I show 1000 fpm in the VS HLD window, I should get a 1000 fpm climb, not a 1300 fpm climb.

    Also, on a Collins AP, when you press VS, you will *initially* set a vertical speed hold equal to whatever vertical rate you were in at time of engagement, but the up/dn controller still should allow you to change the target vertical speed. It is "held" at the selected value, not "fixed".

    The implementation of the ALT and ALT SEL do not match any Collins AP logic that I know of (I have type ratings in both the Gulfstream II and III, which use a similar older Collins AP). The Collins boxes use ALT button to engage altitude hold (if you press it, the acft holds the altitude it was at when entering ALT HLD mode. The ALT SEL is used to arm the altitude capture function. For example, if you are level at 8000 in ALT HLD mode and wish to climb to 10000, you would push the ALT button to deselect ALT hold, dial in 10000 in the altitude target window, engage either VS or IAS hold, and initiate a climb (with VS by toggling the up/dn switch to select a climb rate, or with IAS by adding power) and engage the ALT SEL button (you should get an ALT SEL light on the top line of the controller). The acft will climb in the selected mode until reaching the new alt, then it will level off at the selected altitude and enter ALT HLD mode (the ALT SEL light goes out and ALT HLD comes on).

    If you forget to press ALT SEL to arm the altitude capture, the plane will continue to climb/descend right through the selected altitude. Also, if you change the selected Vert Spd within 200-300 ft of level off, it will automatically deselect the ALT SEL mode. More than a few pilots have busted checkrides because of this gotcha in the early Collins AP controllers.

    Regards

    Bob

  15. I bumped up the drag_scalar value in the flaps section to 3.75...improves steep approach performance a bit.

    I don't know about the real Twotter, but this model is "in the groove" at approach speeds of 65 KIAS (40 flaps) and 75 KIAS (Flaps 20). Fly these speeds and I think you'll agree the approach/flare/landing work well.

    Cheers

    Bob

  16. Aaron Swindle and Skysong Soundworks have a freeware sound package written specifically for a Twin Otter that works very well. The stock Lago sounds are OK...but these are better...more throaty, and with a good sound system the rumble comes through well.

    Look for files prosnd-1.zip and prosnd-2.zip at flightsim.com or avsim.com

    Cheers

    Bob

  17. Folks;

    I have changed the following parameters in the wheeled version 1.01 of the Twotter aircraft.cfg file. This allows more normal landing attitudes and an on-speed 5 degree full-flap approach, the kind of flying this aircraft was designed for.

    Cheers

    Bob

    [flight_tuning]

    elevator_effectiveness=1.400 //was 1.394

    aileron_effectiveness=1.000 //was 1.240

    rudder_effectiveness=2.000 //was 1.240

    pitch_stability=1.750 //was 1.416

    roll_stability=1.100 //was 0.972

    [propeller]

    propeller_moi= 15.000 //was 17.000

    [turboprop_engine]

    idle_rpm_mechanical_efficiency_scalar=0.300 //was 0.508

    [airplane_geometry]

    oswald_efficiency_factor= 0.880 //was 0.700

    rudder_limit= 45.000 //was 30.000

    [Flaps.0]

    extending-time= 10.000 //was 5.000

    lift_scalar= 0.990 //was 1.000

    drag_scalar= 3.000 //was 1.350

  18. Igor;

    I understand that the flight dynamics are not exactly the same once the dynamics in the airfile are modified by the parameterizations in the aircrft.cfg file. But...and it is a BIG but...the air file has a great deal of parameterization that cannot be replaced in the aircraft.cfg file, for example the thrust curves for the engines, a number of various aerodynamic performance and response curves etc. These are not generic to all aircraft...so taking a B350 airfile and applying some parameter changes in the aircraft.cfg is never the same as writing a flight dynamics model--an .air file--specifically for the acft in question. Since the Twotter and the King Air use different engines, for example, the power response curves are different. The power response curves are not modified in the aircraft.cfg file...so we have a Twotter with King Air engine characteristics.

    Re-naming someone else's airfile is a huge foul...if you intend to use the MS airfile, it's quite simple to reference it in the sim= line of the aircraft.cfg file. I am hoping that was a grievous error and not an intentional act.

    I have tried...for several hours...to get this model to flare without ballooning. The acft does not lose energy in the flare...it floats incessantly with the props at idle, despite an on-speed approach on a good glidepath, and it (the wheeled version) is very difficult to land without porpoising on the nose gear first. Your manual (p. 14) says on-speed landing is 70 knots, BTW.

    From the DeHavilland in-house white paper: "There is very little float, and the aircraft sits down in a satisfactorily squashy manner." My experience is that so far there is terrific amount of float, and acft is very difficult to put down on the mains.

    Regards

    Bob

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