John Wojnaroski wrote:
> On the 747 YASim model, have not been able to slow to a resonable
> approach speed < 150kts and maintain altitude, run out of elevator
> authority around 184 kts and flap settings seem to have no effect. The
> numbers I have in my 747 flight manual don't match up with what I'm
> seeing in the sim. For example, for 450k lbs, landing speed at full
> flap/slat setting is 128kts. It won't fly at that speed!
Certainly not, when it's gross weight is 800k lbs. :)
The weight you quote is close to the zero-fuel weight, which is
typical for landing. By default, YASim will top your tanks off at
startup. The plane in this condition will indeed have a very high
approach speed. Try setting the /sim/fuel-fraction property to
something like 0.2 for a reasonable approach configuration.
Your problems with the lack of elevator authority seem real, though.
You could try tuning the "effectiveness" property of the hstab
definition, like so:
<hstab ... effectiveness="2"> <!-- Give it 2x as much force
per surface area -->
I'm not sure what the AoA produced by max back-yoke in a 747 is. It
looks like the YASim model tops out at around 16 degrees, which is
probably not enough.
> Or any of the reference landing speeds for that matter. Realize the
> model is not intended to be *right-on*, but closer would be
> nice. (Using the 0.7.9 official release)
Undeniably. Unfortunately, the only way to get it closer is to have
people work on and provide feedback for the models. I'll freely admit
that I don't spend much time in the 747 model, because big jets don't
push my buttons.
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)
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