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The dumbed down nature of flight simulation add ons
PostPosted: Sun Dec 23, 2018 16:24 Reply with quote
voronezh
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Joined: 22 Jul 2015
Posts: 30




Flight simulation add ons take some getting used to. They are a purchase of unknown quality/accuracy. Usually the lavish product descriptions come with the following at some point:

"Realistic and accurate flight dynamics based on real-world performance and handling data with input from real-world pilots."
The above text forgets to mention a very common policy that many (but not all) add-on developers adopt: the 'hot rod', 'souped up' add-on. These are aircraft whose performance parameters are way above the real aircraft. These caricatures of real aeroplanes bolt off the runway and climb like jet fighters fully loaded with fuel and passengers. I first noticed this with a Captain Sim Boeing 727 for FS2004, shortly after take off at full load I was hitting 380 knots. Then there was the Boeing 747 of Ready for Pushback that I could climb with full fuel and some payload to 40,000 ft without any inconvenience of a stall or a step climb or a dwindling air speed. So some add-on companies adopt this approach while charging the full rate for a supposedly accurate/purist product and then delivering the dumbed down product. The way that these incorrect values are implemented is quite interesting. Almost invariably they don't put a grossly uprated engine thrust figure (say 30,000 lbs of thrust for an engine known to deliver 12,000 lbs) to achieve their aim. This is because it's not a very effective way of messing up the aircraft. People will look into the aircraft.cfg and then compare it to the differing values for engines thrust they find on the internet and change it back if they suspect the aircraft is too high performance. So no a more subtle and much deeper approach is taken. Invariably you find on even the most grossly overpowered aircraft that the thrust is about right. Usually it's multiple parameters across the aircraft.cfg and the .air file that contribute to the super performance. So you might have an aircraft with an empty weight of 0 lbs or a negative skin friction co-efficient. Another commonly used technique is to reduce the inlet area of the engine, meaning you retain the engine performance of a large diameter engine but suffer none of the drag penalty that the larger diameter should incur. Mach drag is an area routinely meddled with, in reality its a steep S shaped curve that levels off. These souped up add ons have just a spike of Mach drag, pretty much negating the build up of air resistance that occurs, enabling greater climb rates and easy attainment of the mach cruise speed. The fact that there are not only variables that make up the flight models but also graphs makes correcting the aircraft handling a specialist skill requiring a lot of knowledge about engineering as well as Microsoft flight simulator. Problems of course occur if you start altering variables/graphs etc, the flight model might be wrong, might give unrealistic performance to the aircraft but it will be 'balanced' to produce a flyable plane. The user that then puts in correct data for say inlet area, a proper Mach drag curve and some other drag variables might come across a built in deterrent that trips up people who want to experiment. Of course the plane has been given exaggerated performance in some areas but these will be toned down with other multipliers. So you might miss the parasitic drag thats been bumped up to 1.6. Consequently after you've toned down a few values and go for a test flight you might might find the aircraft struggling to climb or stuck on full power at Mach 0.7, when its cruise was M0.82. So now you've created the inverse of the 'hot rod' commercial airliner with something that has less performance than the real aircraft. Another hazard or altering variables is that even with the incorrect exaggerated values the designers had configured these values to give a certain 'feel' to the aircraft that might be quite accurate. In altering these values to something more realistic you may well lose this 'feel', so the aircraft now performs less spectacularly but because of the nature of the adjustments its behaviour is unlike the real aircraft.
So why do aircraft developers sell aircraft with deliberately wrong values ? Primarily to serve the casual simulation user. These users fly with the default full fuel and expect the aircraft to just fly. They don't want to end up running off the runway with an aircraft that doesn't jump into flight. They don't want an aircraft that will stall at 4000 ft/min. or that would object to being turned at high climb rates or that rolls alot due to aerodynamic forces. So aircraft come with massive yaw dampers, exaggerated elevator areas, bumped up forces for control surfaces meaning whatever the stage of flight the user can turn, climb or accelerate. These unrealistic contortions make the plane easy to fly.
Another reason is to profit by selling the customer something of relatively low value. A bit like selling a compressed music file we've saved time on development by just putting default values and standard curves from other aircraft and tweaked them. One significant benefit for the flight simulation industry of dumbing down add-on aircraft is that these aircraft because of this policy are still open to development. So rather than having an environment where the majority of aircraft have been captured with high fidelity designs leaving developers only less popular, obscure aircraft that will accrue lower income there are still plenty of openings. Developers could even upgrade their existing aircraft saving on the cost of the internal/external model. So blindingly obviously money is a factor when considering why developers make aircraft of these type, money also drives the large number of little GA aircraft because they're small, easy to make and systems limited. I recently have been looking at the aircraft.cfg and air file for some CLS (Commercial Level Simulations) aircraft notably their Mcdonnell Douglas DC-10. This aircraft is part of the Flite range which means reduced system depth, however CLS seem to have taken this also to mean incorrect flight dynamics also as virtually none of the aircraft parameters are correct. The 'heavy' versions do not even have the correct fuel capacity, all versions 'jump' off the deck, even the heavies take off without any elevator input with full fuel and payload. I think of aircraft like these as 'can do' aircraft, whatever the user requires the aircraft obeys whether on the ground or at 40,000 ft. In order to do this, serious distortion of the flight parameters must take place. Lift forces are much higher than real, wing areas, stabiliser areas will all be greater than the real aircraft. One thing I've repeatedly encountered is incorrect fuel flow rates - many add-ons are much more frugal than in reality, giving them ranges way over what could be achieved. So a purchase of this aircraft is really only buying the 3D external and internal models and little else of value, making this a somewhat expensive product. The thing is when you read reviews about all these faulty flight model aeroplanes these sort of glaring defects aren't mentioned. CLS also made a jumbo in the same style as the DC-10 but presumably because they thought this might be a popular aircraft they killed the frame rate on the FSX version. I get 60 fps on the FS9 version but am struggling to get more than 20 fps in FSX. Another little gem that reviewers forgot to mention. Another area of dumbing down that most flight simmers will have noticed is the flap extension and retraction being far too quick. Of course the casual simmer doesn't want to wait a few minutes for the flaps to come out. There can be unfortunate consequences when full flaps are suddenly applied and the airspeed falls and the inevitable stall occurs. The stall speed will be lower than realistic anyway due to the lack of drag and other favourable parameters. FSX and FS2004 are in some ways dumbed down and therefore an aircraft with correct values for everything will still encounter a lack of realism because of the way trim or some other aspect is dealt with. A truly well simulated aircraft will have 'incorrect' values in some areas to try to alleviate the problems the platform has as well as huge amounts of custom coding to cover the requirements of all the elements the simulation doesn't bother with. Ironically some freeware aircraft will have accurate flight models. But many enthusiasts will have their hard drives full of 'professional' versions full of incorrect values and graphs that are much higher performance than in reality and consequently much easier to fly.
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"Realism"
PostPosted: Tue Dec 25, 2018 13:50 Reply with quote
WalterLeo
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Joined: 10 Feb 2009
Posts: 1660
Location: Viena Austria




Hi friends:

Besides best whishes to everybody for the holidays starting now, we should congratulate ourselves for having PT simulations at hand. Other freeware developers who try to present decent flightdynamics are at HJG. Their DC-10s (10,15,30,40) have superb flightdynamics and tuned to every version of the DC-10 family. Other payware developers have not done that.

see that:

http://simviation.com//hjg/

I myself am posting often on their forum.

Kind regards

and best whishes

Walter Новогодний drink

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PostPosted: Tue Dec 25, 2018 14:53 Reply with quote
voronezh
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Joined: 22 Jul 2015
Posts: 30




Hi Walter, seasons greetings. I'll have a look at HJG, it'll be interesting to see how that compares with what I have. Project Tupolev aircraft I doubt (but don't know for a fact) suffer from any of the above difficulties. One other thing that's now irritating me is payware aircraft that utilised Inertial Navigation Systems that either have a non functional one in the VC (or not) that need to be patched to make the INS work or even worse you need to manually add files and setup the panel.cfg with all the hazards involved. How lazy is that ?
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Flightdynamics FS and real
PostPosted: Thu Dec 27, 2018 01:00 Reply with quote
WalterLeo
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Joined: 10 Feb 2009
Posts: 1660
Location: Viena Austria




Hi Voronesh:

The criticall test is always the AOM of the real airplane. I have tried that with the Tu-104 and Tu-114, for the Tu-124 I could not find the AOM, my versions of that simulations should fly as real as its possible in FS9, means climb, descent, range and speed as the real thing. If take off and landing distances are near the real thing better so.

Kind regards

Walter

Rem: Under that criteries the PT Tu-154s and IL 62M are not far from real.

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PostPosted: Thu Dec 27, 2018 19:47 Reply with quote
shc_04
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Joined: 13 Apr 2007
Posts: 177
Location: Turkey




I agree about HJG, they put a lot of effort in their addons and their presentation (site, forums etc.) and i can also add Calclassic and David Maltby as well. For fs9 there are many freeware addons far better than most of the payware ones.

But i truly think PT-154 is in an another level, because of its unmatched standarts i never fly any other addon.

Happy new year to everyone!

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Hi Mehmet
PostPosted: Fri Dec 28, 2018 01:17 Reply with quote
WalterLeo
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Posts: 1660
Location: Viena Austria




Nice to read something from you:

It was my fault not mentioning David Malthby. By his own opinion and of real pilots accord his BAC 111 is one of the best flying FS9 simulations.

Season greetings from Austria

Walter

P.S.:

The wonderful thing with freeware simulations is, that you are free to find better solutions (like flightdynamics) for a good simulation and you can publish it. With payware you can not do that, authors rights are against it and nobody wants to be sued.

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The dumbed down nature of flight simulation add ons
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