David Megginson wrote:
2. At manifold pressures below 20 in hg, the AC has much too much power
compared to the real AC. I normally use 16 in of manifold pressure in
procedure turns and then with the gear down and 15 deg. of flaps, the
descent and airspeed fall in place at the outer marker. I can't even
carry 10 in MP in the model in an approach.
Part of the problem, I think, is that you've specified an
unrealistically high performance in the "approach" section of the
YASim config file. A 16 degree angle of attack is basically at the
stall, so the airspeed shouldn't be 71 knots. Start with something
like 14 degrees and 55 knots, then play around until both landing
performance and in-air stalls are realistic. Remember that the
aircraft model is specified a fair bit below maximum gross weight, so
the stall speed should be slower than the published one
Hi David,
I took your advice this evening and tried the 55 knots with 14 degrees.
Yasim did not want to converge at first (insufficient elevator trim) but
after I increased the hstab effectiveness to 2 (was 1.5) it converged.
I also took the hstab incidence to 0 (was 0.6 I believe). The stall
speeds are still correct and the landings are much smoother, more like
the real ac. I also refined the MP gage interpolation as it was off at
the low end such that it made the problem seem worse. 10 on the MP gage
is now 10 in hg in the property list and 15 is now 15, etc.
I have made two OT changes. First, I shot some touch-n-goes in the real
N7764P and observed my field of view and panel view. This made me
decide to move the view point back and slightly to the right. Now the
ADF gage and the DME display are in the natural scan w/o moving the
"hat". Still have to look to the right to note the tach and MP as in
the real ac. Second, I added the c172p ADF radio to the radio stack
above the nav/com 1, adding a bus voltage condition to the text layer in
the adf-radio.xml file. After several instrument approaches with the
model in fgfs, I can now use 10 in MP in my approach setup where I would
use 15 or 16 in MP in the real ac. This still allows me to practice
with a set procedure for the power which is much better than it was. If
after a few more evenings of approaches, I am satisfied with the setup,
I will have you submit these patches.
I still think yasim could use more prop drag at low MP. It still allows
the RPM to creep towards 1800 sitting on the ramp with the throttle
closed and the prop forward. The real ac would be at about 700 RPM for
this case.
Thanks for the suggestions,
Dave P.
-------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc. Do you grep through log files
for problems? Stop! Download the new AJAX search engine that makes
searching your log files as easy as surfing the web. DOWNLOAD SPLUNK!
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=103432&bid=230486&dat=121642
_______________________________________________
Flightgear-devel mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/flightgear-devel
