252
edits
YASim: Difference between revisions
Jump to navigation
Jump to search
Add section Variable tail incidence / elevator trim
mNo edit summary |
(Add section Variable tail incidence / elevator trim) |
||
| Line 71: | Line 71: | ||
Wing section support to define variable geometry (geometry parameters per section) | Wing section support to define variable geometry (geometry parameters per section) | ||
* '''append="1"''' | * More than one <wing>-element is allowed now. | ||
* x, y, z, chord and incidence attribute shall be specifed only for the first <wing> in the XML file. They will be overriden for subsequent <wing>-elements. | |||
* Use '''append="1"''' for additional '''wing''' elements to skip x, y, z, chord and incidence attribute as the will be calculated from previous '''wing''' element tip chord. This workaround is currently needed due to limitations in the XML parser. | |||
==== hstab ==== | ==== hstab ==== | ||
| Line 77: | Line 79: | ||
You are allowed only one hstab object; the solver needs to know which wing's incidence to play with to get the aircraft trimmed correctly. | You are allowed only one hstab object; the solver needs to know which wing's incidence to play with to get the aircraft trimmed correctly. | ||
'''New in 2018.1:''' '''hstab''' supports sections in the same way '''wing''' does, but it is still considered as /the/ (only) hstab used by the solver. | '''New in 2018.1:''' | ||
* '''hstab''' supports sections in the same way '''wing''' does, but it is still considered as /the/ (only) hstab used by the solver. | |||
* '''incidence-max-deg''' and '''incidence-max-deg''': optional attributes to limit valid result range fore the solver. | |||
==== vstab ==== | ==== vstab ==== | ||
| Line 548: | Line 552: | ||
15426, 60, 91592 | 15426, 60, 91592 | ||
</pre> | </pre> | ||
=== Variable tail incidence / elevator trim === | |||
Small GA aircrafts usually trim with a trim tab on the elevator. For efficiency, airliners normally do not trim the elevator ("flap") | |||
but rotate the whole stabilizer (=tail) wing, e.g. they change the incidence for this wing. While this feature was somehow foreseen, | |||
it was not implemented yet, most likely because the "tail incidence" is one of the free variables used by the YASim solver. | |||
However, it is possible now to use the control="INCIDENCE" within the <hstab>. | |||
<pre> | |||
<hstab ... incidence-min-deg="-13.0" incidence-max-deg="2.0"> | |||
... | |||
<control-input axis="/controls/flight/hstab-trim" control="INCIDENCE" /> | |||
<control-speed control="INCIDENCE" transition-time="20.0" /> | |||
<control-output control="INCIDENCE" prop="/surface-positions/hstab-rad" /> | |||
</hstab> | |||
</pre> | |||
{{Note|The control output of INCIDENCE is the angle in radians, not in degree, as that is the unit internally used by YASim.}} | |||
{{warning|The OPTIONAL incidence-min-deg and incidence-max-deg set the limits for the solver. You must make sure to select a sufficiently large range or solver will fail. }} | |||
First experiments with this feature were successful in that the aircraft pitch could be changed as expected but fine tuning will be necessary. | |||
== Related content == | == Related content == | ||
* [[Howto:Make a helicopter#XML Elements]] – Rotor and rotorgear YASim elements | * [[Howto:Make a helicopter#XML Elements]] – Rotor and rotorgear YASim elements | ||