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Create Alternate Static Source knob and static system
Create Alternate Static Source knob and static system. This will involve:
- creating the 3D knob on the right side of the panel lightning knob (see: https://github.com/Juanvvc/c172p-detailed/issues/728 )
- rework the panel textures around the position where the ALT STATIC AIR knob will go, since there are some labels on that place
- implement the static system (which will help with https://github.com/Juanvvc/c172p-detailed/issues/538 )
@Juanvvc wrote:
The alternate air intake takes the static pressure from the cabin, as onox says. It is used when the pitot tube is blocked, normally due to icing. The alternate air intake uses the cabin air as static pressure, and this air is usually much warmer (i.e.: less dense) than the external air. This means readings will be skewed: the altimeter will show an altitude higher than real, for example. In some cases, there is not any alternate air valve and you must break the glass of the VSI. Check: http://www.aviationgroundschool.com/sample_pages/airspeed3.html and http://studentpilot.com/interact/forum/archive/index.php/t-37253.html
video with alternate static source knob: https://goo.gl/photos/rApgjAdzfuSsEUcw6
@algefaen was this video shot by you? If so, can I use as source for the sound for the static knob?
@algefaen was this video shot by you? If so, can I use as source for the sound for the static knob?
Yes, yes. Sorry for the potato quality, my gopro ran out of steam. (=
alge
@algefaen Thanks, so I will prepare the sound and add to a new branch bug-741. Would anyone else be up for implementing the static system?
I created a branch named bug-741 with two new sounds from the video by @algefaen: alt-static-push.wav and alt-static-pull.wav. So once we have the 3D model for the alt static source lever, we can implement the static source system and use these sounds for the lever.
@onox would you maybe be interested in helping with the programming?
The error in the alternate static system's pressure is not induced by the different temperature. There are two items: the selector valve works like a piston during switching which introduces an short term error. An during flight the cabin pressure is different to the static port's pressure because the air streams differently around and through the cabin. Open windows, pressure drops. Close them, open cabin air vent and pressure is increased. Side slip also affects the pressure in a non-trivial way
Found some data in the POH of the 172R-NAVIII, which has the same static system (more or less). It gives detailed figures for the IAS with having the cabin vent and/or the windows open.
@okroth Great, could you please post what you have found here? If you can upload images only of the parts of the POH that are relevant that will make our job much easier! Or is it a long section? Thanks a lot!
172R_NavIII-IM-p164-165.pdf One can easily find such a POH using "172RPHBUS-00" as search term. Take the ones from Cessna support...
I found the momentary hops the VSI and altimeter make when alternate static is selected in a movie "Cessna C172R Pre-Flight". The VSI jumps momentarily to +250fpm when knob is pulled out, and -150 when pushed in. The altimeter jumps from 790ft to 800ft when knob is pulled, and back to 790ft when knob is pushed in again. In another movie "How to preflight a Cessna 172", the VSI jumps +400fpm and -300fpm.
We have a branch named bug-741 which contains two sounds I created for the alternate static source knob. @wlbragg should I close that branch and re-push those files to whatever branch we will continue with the interior work or would you like to tackle this on that very branch?
@gilbertohasnofb good question, how much other mesh/modeling work is there? I ask because it may make more sense to open a new, more generic, branch/PR encompassing multiple mesh issues and attach this, the sound, etc. to the new "generic" branch with "Fixes #XX" in the first comment. If not then I think we should use the sound branch and finish this entire issue before proceeding to any other mesh work.
I think it's very little mesh work so maybe it makes sense to simply do everything together. I will close that branch then and then merge the sounds when we tackle this in the next mega PR. Sounds good?
Who wants to do the system? Graphics are almost ready.
@gilbertohasnofb maybe you want to push your sounds now?
vertically same height as radio dimmer horizontally half way between throttle and mixture
@wlbragg I will fix the textures later, just put the knob in the correct position and I will fix the rest
Who wants to do the system? Graphics are almost ready.
Maybe let's just work on the 3D object and textures and leave the system for some other PR, this is already way more massive than it should be. I really want that mammoth getting merged asap. Would that be fine with you?
@gilbertohasnofb maybe you want to push your sounds now?
What sounds?
@wlbragg Do let me know once you have the knob in the correct place and I will fix the panel textures, ok?
Done the texture for the knob, see:
Will fix the panel once you have the position of the knob defined.
@wlbragg just one thing, this is only applied to 4X-CHV for now. If you like the textures I will sync it to all other liveries so you can make it livery dependent. Also, that new courtesy light has been applied to all textures and so it can also be made livery dependent.
I created a branch named bug-741 with two new sounds from the video by @algefaen: alt-static-push.wav and alt-static-pull.wav. So once we have the 3D model for the alt static source lever, we can implement the static source system and use these sounds for the lever.
I really want that mammoth getting merged asap. Would that be fine with you?
Sure, but only if we can get this PR cleaned up, finalized and merge asap so I can continue. I don't even have to push this model yet if you would rather wait for the system to go along with it.
I think everything else is appropriate for the PR (new key, master bat and alt logic, radio and panel light mesh edits).
So I will freeze after one more push of some miscellaneous stuff I have. Then we can clean-up and get this merged and start over.
Sound good!
Let me know if you want me to push the the Alt Static Source Knob now or wait!
Do let me know once you have the knob in the correct place and I will fix the panel textures, ok?
It is in place, you want me to push it then with my last commits or take a picture or both?
Just pull my last commits and push whatever you have. I will take a look at the sim later today and work from there.
By freeze you mean feature freeze, right? As we still need to fix some stuff:
- sync all textures among different liveries
- fix panel textures due to new alt static knob
- UV-map this knob
- decide and implement a solution for the integral lights dilema
- make the transponder backlit
- possibly other bug fixes