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Post by alex94 on Dec 17, 2019 11:07:29 GMT
Something I see a lot of when it comes to fs2004 aircraft, is the fdes dont simulate performance in relation to temperature.
Are there any addon aircraft out there that is able to properly simulate this due to a special gauge setup or special codes in the fde?
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Post by Mike Monce - HJG on Dec 17, 2019 13:59:43 GMT
Alex, There's nothing in the cfg or air file (I just looked through the air file to makes sure I hadn't missed anything!) that specifically relates to temperature. There are a lot of aerodynamic entities in the air file that relate those quantities to the mach value. So, it really comes down to how FS models the mach value with regard to pressure and temperature; and we have no control over that. I have the impression that there is a difference in TO performance with regard to temperature, but I've never really tested it. So, now that I'm retired you just gave me a project for today  We do see an obvious decrease in lift at higher altitudes, but how much MS has coded that with regard to both temperature and pressure I have no idea. I suspect, given the advanced details, that MSFS 2020 may do that a lot better as a major claim is the interaction of the flight surfaces with a much better atmospheric model. Mike |
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Post by Mike Monce - HJG on Dec 17, 2019 15:36:44 GMT
Ok, now that was surprising!  I did a test using the default C172 (which I know doesn't have the best FDE but it's not totally bad). I did the test starting from the end of the runway, max weight, full throttle, 0 flaps, 5 up clicks on trim. Did the first test at 0F, and then at 90F. The density altitude difference was about 2000 ft. From the C172 tables I could find, all indicated a net takeoff roll difference of about 400ft. Even more, the manual listed the clearance distance for a 50ft obstacle to be about 1400ft and 1730ft. Well I did my test using the C172 and then noting exactly where the wheels left the ground and using a scaled map of the airport showed a difference in takeoff roll of just about 400ft and the 50 ft obstacle clearance of close to what the manuals also list! I guess MSFS models density altitude fairly close. In fact, much better than I would have guessed! Mike |
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Post by alex94 on Dec 17, 2019 16:16:42 GMT
oh wow, thats actually really cool, and im glad it does a better job then once thought.
main reason I ask, is some russian addons claim to have a gauge system that replicates temp, runway conditions etc
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Post by walterleo on Dec 17, 2019 16:54:11 GMT
Hi:
The PT 154 M in her last Version simulates the influence of temp and altitude on Performance es Well braking coefficients. But they have donee that by calculations outside the FS.
Kind regards
Walter
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Post by aerofoto - HJG Admin on Dec 17, 2019 17:46:17 GMT
I'd be guided by Mike's judgement in regard to this .... beacause as a Physics Professor (retired) and an FDE specialist too he (like me ) he never offers bad advice  I can confirm Mike's assessment re T/O and ambient air temperature/s. This (at least) is simulated "reasonably" well in FS .... and such performance influence/s are equally noticeable in regard to airport elevtion too. Using our, or most other, simulations .... perform a MGW T/O at SL .... THEN .... perform the same at the like of SKBO/Bogota, Colombia (which has a airport elevation of some 8.360 FT ASL or SLLP/La Paz. Bolivia, whixh has ab airport elevation of some 13,325 FT) and note the difference/s. Similiar applies too (so I've noted in FS2004) in regard to ambient air temperature/s and ROC too. Set a "very cold" air temperature as SL and one can expect to be able to achieve a slightly higher ROC climb (following T/O) for standard power settings. Altitude and ambient air temperature (in particular) "do" seem to influence the performance/s of any simulation. I wouldn't go so far as to say that FS replicates the real world in all aspects though .... because it simply "doesn't". FS only has a finite number of parameters that can be "easily" manipulated for starters. There "are" manners and means though by which to fudge data, and in doing so fool FS into performing and presenting the infications we want (it's panels and gauges primarily I'm talking about here) and from which we then further manipulate a number of other flight tunings accordingly (those "calculations" Walter hints at) in order to achieve the final and overall performance/s "we want". At best .... and due to the "limitations" of FS itself .... we can get "close" to R/W performance (well within the ball park at least), but, for reasons of these same "limitations" (of the host program .... and other FS idiosyncracies too), FS performance/s can never be spot-on .... as we've mentioned here many times in the past. Mark C AKL/NZ |
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Post by aerofoto - HJG Admin on Dec 17, 2019 18:08:04 GMT
Wouldn't surprise me in the least .... since some of the Russian programmers are "VERY CLEVER DUDES" Just as a matter of curiosity .... What's the name of the gauge/program and where's it located ? Care to post "all" the details here ? Mark C AJKL/NZ |
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Post by walterleo on Dec 18, 2019 9:54:32 GMT
Hi Mark:
As I understand in the PT-Tu 154 M these calculations are coded into the panel I suspect into the systems gauges, the Tu-154 M has two of them.
gauge00=PVA_Tu154_0_018!logic, 63,2,10,10
gauge01=es_154m_3_105!Logic, 67,3,10,10
The source code is not known to me.
Kind regards
Walter
P.S.:
As Russian winters are long, cold and dark seems that is a good condition for FS development and the brains behind Project Tupolev have a good university preparation as some of the brains of HJG also have.
But joke aside: The PT-Tu-154s must be "flown" with the PT-Panels.
With the last versión of the TU-154M came a function which simulates the real behavioiur of its engines regarding cold tempratures:
There are limits to apply, to avoid over-reving the engines.
But also other simulations like "my" Tu-114 shows behaviour like the real thing, taking off from MUHA at full wheight at 25 deg C. It flies away at the last meters of its 4000 m Runway.
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Post by aerofoto - HJG Admin on Dec 18, 2019 17:18:36 GMT
"A story" (not necessarily the story though) I heard is due to major changes within Russia over the past 30, or so, years there has been a fair number of suddenly "out of work" aviation development specialist-ski's  .... some of whom have since unleashed their talent/s on FS-ski Mark C AKL/NZ |
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Post by alex94 on Dec 18, 2019 21:52:19 GMT
When i was playing an old car racing game, a developer had developed a special external program that made feeatures not possible in the original game.
I wonder if this dll or some other external programming is possible? I mean, even if itwas i doubt itd be done, as even developers arent even making stuff for fsx anymore (only 2 years younger than fs9)
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We do see an obvious decrease in lift at higher altitudes, but how much MS has coded that with regard to both temperature and pressure I have no idea. 
.... some of whom have since unleashed their talent/s on FS-ski