On Sun, 2002-04-14 at 11:28, Andy Ross wrote: > David Megginson wrote: > > Andy Ross writes: > > > All that being said, did the configuration patch for the takeoff RPMs > > > do what you want? It was better justified than the idle hack. :) > > > > The plane seems to take off OK, but there are handling problems -- in > > a 72kt climb at full power, the nose pulls so strongly to the left > > that even full right rudder deflection cannot compensate. > > This effect must be independant of the recent patch, no? None of that > would have affected trim conditions. It seems like this comes up > again and again (in JSBSim too) as a consistent bug report. It's > really not a bug. It's just that real aircraft correct for the effect > in ways that the simulator doesn't.
The 172 does have dihedral and it should only require a relatively small amount of rudder to correct for engine torque. To be fair, however, what many people call "unflyable" around here isn't anywhere near the case. The most recent JSBSim complaint, for example, only took two clicks of keyboard aileron to correct at climbout speeds. Not too many test pilot types around here ... > > In this case, the pull you are seeing is the engine torque. It is a > rolling moment, not a yaw, and thus you want to be correcting against > it with aileron trim, not rudder. The 172 has very little (zero, in > the current model) dihedral, and therefore there is almost no coupling > between yaw and roll. On a real aircraft, this is compensated for by > asymmetry to the wings, control surfaces, a can't to the engine, or > all three. That is, it has a "baked in" trim. > > One option would be to experiment to acheive a value for aileron trim > that worked well at cruise, and set that in the aircraft xml file. A > cooler option would be to make the solver do it, but that requires > code. > > Andy > > -- > Andrew J. Ross NextBus 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 -- Tony Peden [EMAIL PROTECTED] We all know Linux is great ... it does infinite loops in 5 seconds. -- attributed to Linus Torvalds _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
