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The F14b JSBsim by Richard Harrison

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Re: The F14b JSBsim by Richard Harrison

Postby Johan G » Wed Dec 24, 2014 11:44 pm

Richard wrote in Wed Dec 24, 2014 1:01 pm:...providing the HUD is in AA mode (:AHa key sequence or use the buttons)...

Neat! I have not though of that one could make aircraft specific multi-key commands. 8)

I am about to document on the wiki how one could add it to ones aircraft following the examples in the base package F-14.

Edit: Done! Howto:Add multi-key commands to an aircraft :)
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Re: The F14b JSBsim by Richard Harrison

Postby Richard » Fri Oct 16, 2015 8:06 pm

I figured that I should probably list the recent changes to the F-14. This is in r1020 of FGAddon in my git repository and will be on my site soon.

We now have F-14A and F-14B. The YASim version has been remove to make way for the F-14A TF-30-P414. The TF-30 engine has a configurable compressor stall model.

The VSI, ASI, Altimeter, G-Load are redrawn, oxygen quantity and cabin altitude (RIO) are new
Image

ALS Panel backlighting and interior shadows.

Image

ALS canopy glass effects, frosting, caustic effects.
Image

New panels on the side console (Ext Environment, Air Condition)
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This is the redrawn altimeter. I'm quite pleased with the way this one turned out. This is also modelled as per the aircraft in that it will fall back to pressure altitude when there is no power; otherwise the altitude value displayed will come from the CADC.
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New ALS flames
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The F-14A with the TF-30 engine has a configurable compressor stall.

Image

The compressor stall configuration is less likely as the slider is on the left and inevitable on the right.

The stall is modelled using internal engine pressure differential (based on the LPC and HPC rotor speeds) and inlet turbulence based on angle of attack and sideslip.

MBC (mid compression bypass) failure is also simulated; although in reality this will do pretty much the same as moving the slider, however it does mean you can configure the parameter slider about right and then add an extra failure.

The slider in the middle is in theory the "normal" mode. In the aircraft you'd expect each engine to have a different compressor stall point, depending on maintenance etc, so I'd usually set the parameters to slightly different values. Experimentation will be required to set these to reasonable values.

You will hear a pop coming from the engine when it stalls; it is possible to miss this, so the pilot must monitor the engine gauges to detect a compressor stall. If you get a compressor stall below 130kts there may not be enough rudder authority to correct the yaw from the afterburner. If you do get a compressor stall whilst on carrier approach the correct recovery procedure is to abort the approach, maintain airspeed and increase thrust whilst being careful not to get too much yaw and keeping your alpha under control. If alpha gets too high or yaw rate builds then departing the aircraft before hot steel and metal hits water is advised. This can all be over in about 20 seconds so be careful out there.

To clear a compressor stall pull the throttle for that engine back to idle and wait for N1 to recover. The longer the engine has been stalled the more time this will take. You will also see higher temps when the compressor is stalled.

The engine is much less likely to stall above 80%, and generally never stalls above 85% (although it is still theoretically possible just unlikely with that amount of hot stuff coming out of the back of the engine). I've not (yet) modelled afterburner blowout as this is based on a different set of parameters that I haven't yet managed to discover.
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Re: The F14b JSBsim by Richard Harrison

Postby wkitty42 » Fri Oct 16, 2015 9:14 pm

i got the frost on the windows earlier when i was playing with it arounf 17000 ASL headed north out of KJFK... it took me a few minutes to figure out where the heat was...

the only other thing i ran into was not being able to control my flight path via the F11 autopilot control... i could turn the AP on on the bottom left and it would go into wings level mode but i was unable to make the craft turn by changing the heading bug... i was somewhat able to control the altitude but the heading bug and true heading options just never did kick in for me... yeah, i made sure to 'X' the selection boxes and not while trying...

over all, though, it is a nice easy flying craft... i was able to chase down a few AI craft... i just need to play around a little more to figure out how better to control my speed so i can stalk AIs or pull up beside them for a photo op by their passengers ;)
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: The F14b JSBsim by Richard Harrison

Postby legoboyvdlp » Fri Oct 16, 2015 9:47 pm

You need to use the 3d cockpit AP for best results, wkitty. ;)
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Re: The F14b JSBsim by Richard Harrison

Postby Richard » Sat Oct 17, 2015 12:53 am

wkitty42 wrote in Fri Oct 16, 2015 9:14 pm:i got the frost on the windows earlier when i was playing with it arounf 17000 ASL headed north out of KJFK... it took me a few minutes to figure out where the heat was...

the only other thing i ran into was not being able to control my flight path via the F11 autopilot control...


The frosting is neat; and always wise to brush up on your NATOPS before you jump into the cockpit -)

Heading bug AP should work; although I might have broken it when I added the route manager following autopilot - I'll look into this.

The APC (throttle panel, next to the throttles) set to auto will hold your speed; I've allowed it to operate in flight (whereas the aircraft has interlocks to prevent this).
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Re: The F14b JSBsim by Richard Harrison

Postby abassign » Sat Oct 17, 2015 3:47 pm

I found this little problem highlighted in (A) and (B):
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Re: The F14b JSBsim by Richard Harrison

Postby Richard » Sat Oct 17, 2015 5:39 pm

abassign wrote in Sat Oct 17, 2015 3:47 pm:I found this little problem highlighted in (A) and (B):


Thanks for the report; I'll have to redo the glass mesh.
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Re: The F14b JSBsim by Richard Harrison

Postby wkitty42 » Sun Oct 18, 2015 2:29 pm

Richard wrote in Sat Oct 17, 2015 12:53 am:and always wise to brush up on your NATOPS before you jump into the cockpit -)

what/where is that??
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: The F14b JSBsim by Richard Harrison

Postby Richard » Sun Oct 18, 2015 2:38 pm

wkitty42 wrote in Sun Oct 18, 2015 2:29 pm:
Richard wrote in Sat Oct 17, 2015 12:53 am:and always wise to brush up on your NATOPS before you jump into the cockpit -)

what/where is that??


Naval Air Training and Operating Procedures Standardization. It's generally what they call the flight manual.

If you search for NATOPS F-14A (aka NAVAIR 01-F14A-1) you might find a PDF like this NAVAIR 01-F14A-1
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Re: The F14b JSBsim by Richard Harrison

Postby wkitty42 » Sun Oct 18, 2015 3:08 pm

oh! i was looking for something in flightgear accessible from the menus... thanks for the links :)

[edit: wow! 458 pages? i guess i won't be printing that out for reading while in the ""library""... ]
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: The F14b JSBsim by Richard Harrison

Postby Johan G » Sun Oct 18, 2015 8:50 pm

Richard wrote in Sat Oct 17, 2015 12:53 am:...and always wise to brush up on your NATOPS before you jump into the cockpit -)

wkitty42 wrote in Sun Oct 18, 2015 2:29 pm:what/where is that??

Richard wrote in Sun Oct 18, 2015 2:38 pm:Naval Air Training and Operating Procedures Standardization. It's generally what they call the flight manual.

If you search for NATOPS F-14A (aka NAVAIR 01-F14A-1) you might find a PDF like this...

While the NATOPS often can be flight manuals (usually ending with "-1", hence colloquially called "dash one"), they can also be more general, like regarding carrier operations or be really general and cover flight planning procedures and the like.

If you want to be ultra-realistic when planning, NATOPS General Flight and Operating Instructions: OPNAV Instruction 3710.7T (2.9 MB pdf) is the one to read. It is more or less the US naval aviator's equivalent to the Aeronautical Information Manual (AIM) and Aeronautical Information Publication (AIP) combo.
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Re: The F14b JSBsim by Richard Harrison

Postby wkitty42 » Sun Oct 18, 2015 11:53 pm

thanks for the additional information!

the real problem, such as it is, it the availability of information in the sim for pilots to read and study without having to go outside the sim...

remembering back to the IBM PCjr days when the original M$ Flight Simulator came out, one simply loaded up and was easily able to take off and go flying... granted, a lot of time has passed but the thought is still the same... hit the starter button and go... maybe with a little more research and understanding of airport takeoff and landing paths... but overall basically a newbie's actions to jump in and go... yeah, in single pilot mode with no thoughts of MP at all ;)
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: The F14b JSBsim by Richard Harrison

Postby Thorsten » Mon Oct 19, 2015 5:22 am

oh! i was looking for something in flightgear accessible from the menus.. (...) the real problem, such as it is, it the availability of information in the sim for pilots to read and study without having to go outside the sim.


The amount of information that we can make accessible in-sim is quite limited. If you have a more complex aircraft, even the procedures operating it nominally are usually 30+ pages - to deal with problems is much more.

For the Shuttle for instance, to be able to read this status display

Image

you need a lot of context. You can, for instance, perhaps deduce that there's a nitrogen tank pressure value displayed - but that doesn't tell you what it's for. You need to understand what the role of the nitrogen system in operating the OMS engines is to understand what to expect if nitrogen pressure is shown low.

So if the sim would report a nitrogen failure, of course the procedure to deal with it could be in the in-sim help. Except that would make the in-sim help hundreds of pages of texts dealing with every possible failure mode, which in turn would make it bloody useless.

Similarly, maneuvering targets are entered as PEG-4 or PEG-7 guidance targets. If you don't know what PEG-4 or PEG-7 is, that can't be easily explained (the guidance scheme is some 30+ pages paper).

I think the message is clear - whenever the simulation approaches the real thing in complexity, you will need the real documentation to fly it.
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Re: The F14b JSBsim by Richard Harrison

Postby wkitty42 » Tue Oct 20, 2015 6:30 pm

i was thinking more of links in the menu kinda like the link to the equipment map that opens in one's web browser... either link to a local file in the craft's docs directory or a link to an external document on the web...

of course, that's just more reason for a MP player to spawn on the runway and spend time blocking traffic while they read the docs ;) :lol: :halo:
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: The F14b JSBsim by Richard Harrison

Postby Richard » Tue Oct 20, 2015 8:27 pm

wkitty42 wrote in Sun Oct 18, 2015 11:53 pm:the real problem, such as it is, it the availability of information in the sim for pilots to read and study without having to go outside the sim...


Competent pilots should do their ground school learning before getting into the Aircraft -)

The FG Wiki will be updated by the time of the next release to explain these things;

wkitty42 wrote in Sun Oct 18, 2015 11:53 pm:...M$ Flight Simulator came out, one simply loaded up and was easily able to take off and go flying...


Maybe a link in the menus to open the wiki page would be useful. *but* you can just jump in the F-14, maybe read the aircraft help, then quickstart and fly.

I might add failures in the same way as Thorsten's (excellent) failure modelling in the shuttle, but at the moment even when you have a compressor stall it will always be clearable, and the BiDi hydraulic pump is unbreakable; and this isn't realistic - but it takes a lot of effort to get realistic failure modelling that will cascade across systems.
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