Re: [Flightgear-devel] MSFS2k2 MDL file format documented?
Interesting.
I have looked into the EULA, but not yet the docu iteself.
The EULA says:
1. GRANT OF LICENSE. This EULA grants you the following rights:
Software Product. You may install and use the SOFTWARE PRODUCT on an
unlimited number of computers, including workstations, terminals or
other digital electronic devices ("COMPUTERS") to design, develop, and
test software application products that are designed to operate in
conjunction with Microsoft Flight Simulator 2002 and subsequent
versions thereof, ("Application").
[...]
All rights not expressly granted are reserved by Microsoft.
Bye bye,
Wolfram.
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[Flightgear-devel] Boeing 747 preview
The moon looked so good tonight, I couldn't help posting a shot. This is the 747-400 model still quite rough. You can't tell yet but I've got the flaps (10 of them, did I miss any?) done. The engine is done, just waiting to hang 'em on the wings last. You also can't tell that I haven't done the hstabs yet :-) http://www.spiderbark.com/fgfs/747rough.png Anyone know how big the gear wheels are? Got some nice close pictures of gear...and I'd guess about 1m diameter...but it'd be nice if someone happened to know. Best, Jim P.S. any other 747-400 trivia, measurements would be appreciated also...been "winging it" (pardon the pun) for a lot of this. ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] MSFS2k2 MDL file format documented?
I haven't looked at this yet, but thought any plib guys might be interested in this AVSim.com news item: The Microsoft Flight Simulator 2002 Development Team has released yet another SDK component, this time the MDL SDK.Among the documents in the SDK are the MDLFMT.doc. This file is described as "An introductory document that describes the file format details (including file layout, the standard parameter block, and the parameter dictionary GUIDs) for aircraft model files used by Microsoft Flight Simulator 2002." Link: http://zone.msn.com/flightsim/FS02DevDeskSDK09.asp The download is a .EXE, so I haven't downloaded it yet (I'm a linux guy). If you look at it, feel free to report back any findings. Thanks -- Cameron Moore [ If a word in the dictionary were misspelled, how would we know? ] ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] DC-3 takeoff roll: partial solution
At 02:47 PM 5/22/2002 -0700, you wrote: >David Megginson wrote: > > 1. According to the author, at least, differential braking is bad form > >while taxiing the DC-3; you should use differential power instead > >except for very tight turns. > >I'll buy that. But working dual throttles during the takeoff and >landing rolls can't possibly be a good idea, right? In that regime, >you're still stuck with rudder and braking only. During the landing >roll (with no significant prop wash), you're stuck with braking only. > > > 2. Maintaining a straight heading is hard during the early part of the > >takeoff roll, but the text describes S-curves rather than violent > >spinning as the problem for inexperienced pilots. > >Is that with or without braking being applied? I can confirm that I >execute lots of S curves during takeoff in the DC-3 when using the >brakes method. It only spins violently when you try to correct yaw >divergence with a flapping rudder. > >Just to clarify what I said earlier: the reason that it looks like a >rudder problem is that turning the plane a "little bit" with the >rudder is possible. But once it is pointed little bit away from the >velocity vector, it begins turning *farther* away very rapidly. If >you don't correct this immediately, the aircraft will rapidly be so >far out of whack that the rudder is incapable of correcting the yaw. >Thus, what started out as a tiny rudder input diverges into a ground >loop. But it's caused by a *lack* of rudder authority to correct the >problem, not by too much authority causing it. Does that make more >sense? [snip] Differential braking should be kept to a minimum in any airplane, for two reasons: (1) An airplane is a really lousy automobile. It has about as little undercarriage as it can get away with (one has only to look at pictures of an airplane and a truck scaled to the same size to realize this), and every brake application is hard on its pitiful little brakes. (2) Differential braking tends to scrub rubber off some very expensive tires. So differential power becomes the steering method of choice in airplanes that have it available. Light taildraggers generally have steerable tailwheels, and being single-engined, they always have some prop blast over the tail; consequently they're not very hard to steer in the takeoff roll. Larger taildraggers don't have steerable tailwheels because the steering forces would require powered controls which were not in use when they were designed. In the Gooney Bird one must line up on the runway, lock the tailwheel, and hold the wheel firmly back until there is full tail surface control. Prior to that point, you aren't really steering a heading: you're just holding yaw rate to a minimum. The airplane will turn somewhat in a crosswind; this can be dealt with to some extent by judiciously positioning and aiming the airplane before starting the roll. The divergence you mention is present in a real taildragger; it's just a basic instability in the yaw axis resulting from most of the weight being supported in front of the cg. When the fuselage is misaligned with the direction of motion, the side force on the wheels is destabilizing. I don't know exactly how the tailwheel lock is implemented in the DC-3; in the AT-6, the last couple of inches of aft stick travel center and lock the wheel. It's an ideal arrangement, because if you don't have the stick back the tailwheel won't do you any good anyway. rj ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] DC-3 ground handling. Fixed?
Andy, I'm really just exploring near stall modeling issues so that our simulation can be improved. Anyway you can get a bird in the air is reasonable, especially if it shows up weaknesses in modeling. So, just for discussion's sake and noting that nobody with detailed knowledge of and experience with this aircraft has weighed in, I have questions. Isn't the L/D ratio at high angles of attack different (poorer) when in ground effect? If you can accelerate to above stall speed rolling on all three wheels, what happens when you start to lift. Wouldn't you expect the aircraft tend to nose up into stall? Regards, Charlie H. Cameron Moore wrote: > * [EMAIL PROTECTED] (David Megginson) [2002.05.23 13:59]: > > Andy Ross writes: > > The tech drawings at > > > > http://www.douglasdc3.com/dc3tec/dc3tec.htm > > > > (especially the big one at the bottom) suggest to me an angle of > > incidence of 2-3 degrees, but I haven't printed them out and measured. > > As far as measuring aircraft dimensions and such, I use Gimp's measuring > tool to measure things. Measure a known distance and record the length > in pixels, then you can measure whatever else you want and do the pixel > to feet conversions without haven't to print anything out. Pythagoras > is your friend. :-) > -- > Cameron Moore > [ Why is the man who invests all your money called a broker? ] > > ___ > Flightgear-devel mailing list > [EMAIL PROTECTED] > http://mail.flightgear.org/mailman/listinfo/flightgear-devel -- "C makes it easy to shoot yourself in the foot; C++ makes it harder, but when you do, it blows away your whole leg." - Bjarne Stroustrup ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] DC-3 ground handling. Fixed?
* [EMAIL PROTECTED] (David Megginson) [2002.05.23 13:59]: > Andy Ross writes: > The tech drawings at > > http://www.douglasdc3.com/dc3tec/dc3tec.htm > > (especially the big one at the bottom) suggest to me an angle of > incidence of 2-3 degrees, but I haven't printed them out and measured. As far as measuring aircraft dimensions and such, I use Gimp's measuring tool to measure things. Measure a known distance and record the length in pixels, then you can measure whatever else you want and do the pixel to feet conversions without haven't to print anything out. Pythagoras is your friend. :-) -- Cameron Moore [ Why is the man who invests all your money called a broker? ] ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] DC-3 ground handling. Fixed?
Andy Ross writes: > Now, that number comes ruler and protractor work on a 3-view diagram. > It's possible that I missed a measurement, and that the ground AoA > should be much larger. It also assumes a build in wing incidence of > 0, which may not be true on the real aircraft (I couldn't find data on > this stuff). But if it's really 10 degrees, then the behavior is > pretty much correct. The tech drawings at http://www.douglasdc3.com/dc3tec/dc3tec.htm (especially the big one at the bottom) suggest to me an angle of incidence of 2-3 degrees, but I haven't printed them out and measured. All the best, David -- David Megginson, [EMAIL PROTECTED], http://www.megginson.com/ ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] DC-3 ground handling. Fixed?
> OK, I found an explosion case in the propeller code which could be > triggered by a propeller turning backwards very slowly. That's pretty > much consistent with a aircraft with a stopped engine, so I'm > hopefully this is it. It's been checked in (this was obvious enough > to check in based on code inspection only), so see if this fixes your > problem. It does. > I make no promises about actually getting off the ground successfully > on one engine, however. :) I managed to do it (once), but I wouldn't like to be a passenger on that plane. Also, I can't reproduce the spinning problem, seems like your prop patch did the job. Thanks a lot! Andras === Major Andras e-mail: [EMAIL PROTECTED] www:http://andras.webhop.org/ === ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] DC-3 flies again (thanks, Andy)
With today's changes from Andy, the YASim DC-3 now flies, beautifully. Rudder corrections do work during the later part of the takeoff roll (after you've lifted the tailwheel), but they have to be small and anticipatory -- i.e. if you hold the correction until you see its effect, you've held it too long (I stole that from a writeup by a real DC-3 pilot, but it seems to apply here as well). I let the plane weave a bit, but it wasn't too bad. The real challenge will be taking off in a crosswind, but I haven't tried that yet. I flew a circuit around KSFO at 1000ft ASL, and the plane handled beautifully. I extended the crosswind and downwind slightly, but otherwise flew the circuit exactly as I would in a C172 except that I kept my inputs small and started them well in advance. I was amazed at how easy the plane was to handle and at how smooth and graceful its responses were -- either Andy's model is too simple, I'm a better pilot than I think (unlikely), or the DC-3 really deserves all the affection it gets from fliers. On final, I was so busy worrying about flaps, MP, RPM, gear, etc. that I didn't notice the plane climb back up to circuit altitude until I was fairly close to the runway. I pulled the throttle to idle, applied full flaps, and lowered the gear, and the plane practically flew itself down. The flare was beautiful -- the plane seemed to glide forever just above the surface, and it was still easy to control after the mains made contact (thank god for long jet runways). Nice work, Andy. For anyone else who wants to try this, the tailwheel is now locked by default, and you'll have to use 'l' (small L) to unlock it for taxiing. I'll have to start work on the 3D interior. All the best, David -- David Megginson, [EMAIL PROTECTED], http://www.megginson.com/ ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] DC-3 ground handling. Fixed?
Charlie Hotchkiss wrote: > Perhaps I'm showing some ignorance here (I'm certainly not a pilot, > much less an expert), but isn't the induced drag in that situation so > large as to preclude reaching flying speed? The wings acting at that > angle much like a drag brake? I read somewhere that pilots > deliberately pushed forward on the column to lift the tail at a > specific speed in order to reduce drag and allow speed to build up. In the DC-3 as modelled, the pitch angle of the wings while resting on the ground is only something like 10 degrees. That's high, but significantly lower than the stall angle of 14 degrees*. If the aircraft can fly at that AoA under its own power, it can certainly accelerate to that speed. It won't get there very quickly, and will use more runway doing it (a big problem, unless you happen to be at SFO), but it definitely works. Now, that number comes ruler and protractor work on a 3-view diagram. It's possible that I missed a measurement, and that the ground AoA should be much larger. It also assumes a build in wing incidence of 0, which may not be true on the real aircraft (I couldn't find data on this stuff). But if it's really 10 degrees, then the behavior is pretty much correct. I suspect the real reason that this isn't done in practice is the runway length issue, along with the fact that the tail wheel isn't as strong as the mains and probably doesn't like being dragged along as much. Anyone have a good reference? * This number is a guess, too. Andy -- Andrew J. RossNextBus Information Systems Senior Software Engineer Emeryville, CA [EMAIL PROTECTED] http://www.nextbus.com "Men go crazy in conflagrations. They only get better one by one." - Sting (misquoted) ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] DC-3 ground handling. Fixed?
Andy Ross wrote: > [I combined a bunch of responses... > > Once the tailwheel leaves the ground, it's squirrely but controllable. > This is not doubt bad form, but I found that holding the stick back to > keep the wheel firmly on the ground during the takeoff roll until the > aircraft took off on its own was the safest way to take off. Andy, Perhaps I'm showing some ignorance here (I'm certainly not a pilot, much less an expert), but isn't the induced drag in that situation so large as to preclude reaching flying speed? The wings acting at that angle much like a drag brake? I read somewhere that pilots deliberately pushed forward on the column to lift the tail at a specific speed in order to reduce drag and allow speed to build up. Regards, Charlie H. - "C makes it easy to shoot yourself in the foot; C++ makes it harder, but when you do, it blows away your whole leg." - Bjarne Stroustrup ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] DC-3 ground handling. Fixed?
I wrote: > Major A wrote: > > I think the main problem really is the rapid increase in airspeed, > > which is unnatural, and doesn't occur if both engines are used. > > Bingo. This is a bug in the propeller code [...] (I'm pretty sure it > used to work -- I remember doing hammerhead stalls in the A-4 when > testing). Don't say it. I know. The A-4 doesn't have a propeller. OK, I found an explosion case in the propeller code which could be triggered by a propeller turning backwards very slowly. That's pretty much consistent with a aircraft with a stopped engine, so I'm hopefully this is it. It's been checked in (this was obvious enough to check in based on code inspection only), so see if this fixes your problem. I make no promises about actually getting off the ground successfully on one engine, however. :) Andy -- Andrew J. RossNextBus Information Systems Senior Software Engineer Emeryville, CA [EMAIL PROTECTED] http://www.nextbus.com "Men go crazy in conflagrations. They only get better one by one." - Sting (misquoted) ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] DC-3 takeoff roll: partial solution
I wrote: > Attached is the DC-3 file I was using last night, which maps the > castering bit to /controls/tailwheel-castering. I lied again. Now it's attached. Andy -- Andrew J. RossNextBus Information Systems Senior Software Engineer Emeryville, CA [EMAIL PROTECTED] http://www.nextbus.com "Men go crazy in conflagrations. They only get better one by one." - Sting (misquoted)
Re: [Flightgear-devel] DC-3 takeoff roll: partial solution
David Megginson wrote: >> Note that I set castering="0" rather than removing the attribute >> completely. > > I saw it in a slow, taxiing turn at around 10kt or less, but I had > done the modification myself before you posted yours. I'll try it > with exactly your suggestion. Ah; this is my fault. You got faked out by the dumb YASim parser. It looks (well, looked, it uses the more robust mechanism now) only for the *presence* of the castering attribute, not its value. So specifying castering="0" told YASim that the wheel *is* castering. Like I said, it's fixed now; don't yell at me. :) Attached is the DC-3 file I was using last night, which maps the castering bit to /controls/tailwheel-castering. I'm going to check the patch in right now, so give it whirl and see if it works for you. > For now, perhaps locking the tailwheel could automatically snap it > to 0 deg steering angle. We could even handle that in the input > bindings, if there were a pseudo-steering property for the > tailwheel. Sorry, I wasn't clear. That's exactly what happens right now. The way it works is that "castering" causes the gear to ignore the whole issue of steering direction and simply ignore all force along the ground plane. This is nice and simple, and generally has the right effect (even for the DC-3 tail wheel, excluding the "falling into place" feature). But it makes the falling-into-place feature harder to implement. Andy -- Andrew J. RossNextBus Information Systems Senior Software Engineer Emeryville, CA [EMAIL PROTECTED] http://www.nextbus.com "Men go crazy in conflagrations. They only get better one by one." - Sting (misquoted) ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] DC-3 ground handling. Fixed?
Andy, > Bingo. This is a bug in the propeller code; I apparently introduced a > FPU explosion when the thing is going backwards. It has nothing to do > with the aero or ground modelling, so I was looking in the wrong > place. I'll get this fixed. (I'm pretty sure it used to work -- I > remember doing hammerhead stalls in the A-4 when testing). Sorry I only realized this just before I actually mentioned it. I used to test in a from-the-back view, in which the window goes black when the divergence happens, I had to test it again with the normal out-of-the-cockpit view to see the 1000kt+. > Really? When I tried it, I couldn't turn against the tail wheel at > all, even with full braking applied. The tail wheel didn't move until > 50 kts or so when it lifted; then the plane became squirrely, as might > be expected. Under what conditions did you see that behavior? If > it's sliding at speed, are you absolutely sure that's wrong? I can confirm this, the plane moves straight whatever you do as long as the tailwheel stays on the ground. This is definitely far closer to reality than the free swinging we had before. Modeling skidding and sliding friction would be more realistic, but not that important. Thanks for sorting this out so quickly, I will investigate the problems more thoroughly next time... Andras === Major Andras e-mail: [EMAIL PROTECTED] www:http://andras.webhop.org/ === ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
re: [Flightgear-devel] DC-3 ground handling. Fixed?
Andy Ross writes: > > I tried that, and it's an improvement, but the tailwheel seems to > > slide sideways too easily. > > Really? When I tried it, I couldn't turn against the tail wheel at > all, even with full braking applied. The tail wheel didn't move until > 50 kts or so when it lifted; then the plane became squirrely, as might > be expected. Under what conditions did you see that behavior? If > it's sliding at speed, are you absolutely sure that's wrong? I saw it in a slow, taxiing turn at around 10kt or less, but I had done the modification myself before you posted yours. I'll try it with exactly your suggestion. > I noticed that too -- this will be harder to implement. There's no > "feedback" for the steering direction right now -- castering is > implemented by simply assuming that steer == velocity. The code would > need to calculate a steer angle, test for "forward", and set the > castering bit to false only if that is true *and* the wheel lock is > on. That ties a bunch of code sections together in a kinda messy way. For now, perhaps locking the tailwheel could automatically snap it to 0 deg steering angle. We could even handle that in the input bindings, if there were a pseudo-steering property for the tailwheel. All the best, David -- David Megginson, [EMAIL PROTECTED], http://www.megginson.com/ ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] DC-3 ground handling. Fixed?
[I combined a bunch of responses to avoid repeating myself.] Just for an "I told you so" moment: the gear and aero modelling (but sadly not the propeller, see below) in YASim was doing everything properly. The plane was being modelled perfectly,and (almost) all the effects reported were physically justified and quantitatively correct. Thbbt! I was just modelling a plane that doesn't exist. :) The tail wheel lock, to me, seems to fix all the problems with DC-3 runway handling. David still has an outstanding complaint that I haven't reproduced yet (I'm hopeful it's a miscommunication and not another bug), but everything else seems to be working great. I did about 5 pattern circuits last night in it. My flying wasn't pretty, but the plane stayed on pavement the whole time. Once the tailwheel leaves the ground, it's squirrely but controllable. This is not doubt bad form, but I found that holding the stick back to keep the wheel firmly on the ground during the takeoff roll until the aircraft took off on its own was the safest way to take off. Likewise, 3-point landings worked better than trying to get the mains down first. YMMV. OK, on to the responses: Alex Perry wrote: > Andy Ross wrote: > > You started up the engines, firewalled the throttle, let the RPMs > > stablize, released the brakes, and the aircraft pitched *up*??? > > That's clearly unphysical. > > Why ? The nose pitches down with power and brake application. So, > releasing the brakes makes the nose pitch up. Touche. I should have qualified. :) The bug report was of a pitch up strong enough to force the tailwheel into the ground and cause a crash. That's far stronger than the mild pitch effects you get from engine/gear forces causing a torque about the CG. Actually, the DC-3 doesn't show this effect very well -- the tricycle planes have nosewheels with light spring constants that can compress a lot. The DC-3 tail gear barely compresses at all, and the mains have much higher spring constants and compress less for the same torque. Major A wrote: > Not immediately, the aircraft pitches up after rolling for a few > seconds. I think the main problem really is the rapid increase in > airspeed, which is unnatural, and doesn't occur if both engines are > used. Bingo. This is a bug in the propeller code; I apparently introduced a FPU explosion when the thing is going backwards. It has nothing to do with the aero or ground modelling, so I was looking in the wrong place. I'll get this fixed. (I'm pretty sure it used to work -- I remember doing hammerhead stalls in the A-4 when testing). Just a hint for everyone's future bug reporting: if you see a problem like "accelerated to 1000 kts", the please YELL ABOUT THIS VERY LOUDLY. I was chasing a "pitch up", which is a rather milder condition that I thought was due to a gear configuration weirdness. Radically unphysical behavior just Shouldn't Happen. David Megginson wrote: > Andy Ross wrote: > > You can lock the tailwheel by simply removing the castering="1" bit > > from the gear definition. This could be pretty easily made settable > > at runtime via a property. > > I tried that, and it's an improvement, but the tailwheel seems to > slide sideways too easily. Really? When I tried it, I couldn't turn against the tail wheel at all, even with full braking applied. The tail wheel didn't move until 50 kts or so when it lifted; then the plane became squirrely, as might be expected. Under what conditions did you see that behavior? If it's sliding at speed, are you absolutely sure that's wrong? > One peculiar property of the DC-3 tailwheel I read about is that it > can be locked only when aligned with the longitudinal axis of the > plane. I noticed that too -- this will be harder to implement. There's no "feedback" for the steering direction right now -- castering is implemented by simply assuming that steer == velocity. The code would need to calculate a steer angle, test for "forward", and set the castering bit to false only if that is true *and* the wheel lock is on. That ties a bunch of code sections together in a kinda messy way. Andy -- Andrew J. RossNextBus Information Systems Senior Software Engineer Emeryville, CA [EMAIL PROTECTED] http://www.nextbus.com "Men go crazy in conflagrations. They only get better one by one." - Sting (misquoted) ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] DC-3 takeoff roll: partial solution
Andy Ross writes: > OK, if anyone wants to try it before I get home, the following 5-line > patch adds support for a settable "castering" attribute for gear > objects. Apply it to the YASim directory, and then replace the tail > wheel definition in dc3.xml with this: > > > > > > > Then bind a key to toggle it, and we're set. Hopefully I haven't > broken anything. I'll test it this evening. That sounds like an excellent start. One peculiar property of the DC-3 tailwheel I read about is that it can be locked only when aligned with the longitudinal axis of the plane. If you activate the lock when the tailwheel is turned, it will not engage until the wheel passes through the longitudinal axis, at which point it will snap on. That way, there's no risk of locking the wheel at an oblique angle, but you can engage the lock early while turning onto the runway. If that's too fancy, we could just have the lock instantly snap the wheel to position for now. All the best, David -- David Megginson, [EMAIL PROTECTED], http://www.megginson.com/ ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] DC-3 takeoff roll: partial solution
Andy Ross writes: > > 2. Maintaining a straight heading is hard during the early part of the > >takeoff roll, but the text describes S-curves rather than violent > >spinning as the problem for inexperienced pilots. > > Is that with or without braking being applied? I can confirm that I > execute lots of S curves during takeoff in the DC-3 when using the > brakes method. It only spins violently when you try to correct yaw > divergence with a flapping rudder. As far as I can tell, that's without braking. Braking during a takeoff roll would be so unusual for typical pilots that stories about flying the DC-3 aimed at a modern audience would be sure to mention it. One of the narratives specifically mentioned just tapping the rudder pedals rather than making large rudder inputs during the early part of the takeoff roll (i.e. at slower speeds) to avoid the s-curves. > Hey, now that's really good information. This would *definitely* > help with directional stability. You can lock the tailwheel by > simply removing the castering="1" bit from the gear definition. > This could be pretty easily made settable at runtime via a > property. I tried that, and it's an improvement, but the tailwheel seems to slide sideways too easily. You can see it most clearly from external view, where applying only a light differential brake causes the tail to rotate sharply. Could there not be enough weight on the wheel? Note that I set castering="0" rather than removing the attribute completely. All the best, David -- David Megginson, [EMAIL PROTECTED], http://www.megginson.com/ ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] DC-3 takeoff roll: partial solution
> > You started up the engines, firewalled the throttle, let the RPMs > > stablize, released the brakes, and the aircraft pitched *up*??? > > That's clearly unphysical. > > Why ? The nose pitches down with power and brake application. > So, releasing the brakes makes the nose pitch up. Not immediately, the aircraft pitches up after rolling for a few seconds. I think the main problem really is the rapid increase in airspeed, which is unnatural, and doesn't occur if both engines are used. Actually, it diverges for some reason, I just made another test and ended up with an aircraft at 35 deg, some roll to the right, and 1346kt! This is a few seconds after turning one engine on, running it at full speed, and releasing the brakes. No flaps, all controls centred. Andras === Major Andras e-mail: [EMAIL PROTECTED] www:http://andras.webhop.org/ === ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
