screenshots and comparision of MSFS vs X-Plane philosophy

[Keith Smith]

For those who are interested, here's a collection of shots I've put together from previous flights:

http://picasaweb.google.com/keith.smith

 

Here is an excerpt from a response sent by X-Plane's author to the author of an article that was critical of Blade Element Theory (the model under which Xplane runs)

 

There's some good stuff here that just touches the tip of the iceberg and helps you realize why correctly modeled planes in XP "feels" more like a real planes in many circomestances.

 

In the REAL 172, let's say you ADD FULL POWER AT NEAR-ZERO ANGLE OF

ATTACK.

Does the propwash hit the horizontal stab and increase elevator

effectiveness? YOU BET IT DOES!

Does the MS LOOK-UP table consider this? Dunno.. BUT X-PLANE DOES!

 

In the REAL 172, let's say you ADD FULL POWER AT VERY HIGH ANGLE OF

ATTACK!

Does the propwash stream into the local wind in such a way that it no

longer hits the horizontal stab to the same degree, thus changing

elevator effectiveness? YOU BET IT DOES!

Does the MS LOOK-UP table consider this? Dunno.. BUT X-PLANE DOES!

 

In a real Beech Baron, let's say you kill an engine.

Does the prop SOAK UP ENERGY FROM THE WIND, THUS REDUCING LIFT AND

DRAG ON PART OF THE WING? YOU BET IT DOES!

Does the MS LOOK-UP table consider this reduced LIFT ON ONE SIDE OF

THE PLANE ONLY DUE TO POWER CHANGES? Dunno.. BUT X-PLANE DOES!

 

In a real Beech Baron, let's say you kill an engine, yaw and pitch

the plane severely, and wind up getting the vertical stab into propwash.

Does the real vertical stab suddenly catch wind and change speed,

angle of attack, and rudder effectiveness in this new situation? YOU

BET IT DOES!

Does the MS LOOK-UP table consider this changed rudder effectiveness

as a function of engine power, angle of attack, and sideslip? Dunno..

BUT X-PLANE DOES!

 

In a REAL Beech Baron, does ONE wing stall BEFORE the other if you

have lots of power on one side, and little in the other? YOU BET IT

DOES!

Does this result in different stall characteristics based on

asymmetric power configurations? YOU BET IT DOES!

Does the MS LOOK-UP table consider this per-side wing lift and drag

as a function of engine power, angle of attack, and sideslip? Dunno..

BUT X-PLANE DOES!

 

Obviously, this is only the tiniest tip of the iceberg.. i could ring

off cases you have not considered ALL DAY LONG. I can find a million

holes in your lookup table WHERE THE LOOKUP TABLE DID NOT CONSIDER

ALL THE POSSIBILITIES OF THE ACTUAL FLIGHT. So, the lookup table may

be 100% PERFECT FOR ONE PARTICULAR BIT OF THE FLIGHT ENVELOPE, BUT I

100% GUARANTEE THAT THE REAL AIRPLANE WILL NOT MAKE IT'S ENTIRE

FLIGHT RIGHT AT THAT CORNER OF THE ENVELOPE, HUH?

 

So, a GOOD sim needs to really UNDERSTAND WHAT IS GOING ON, so it can

interact propwash, downwash, bits of stalled wing or rotor across the

ENTIRE FLIGHT ENVELOPE, not just the few pre-planned corners of the

envelope that live in your tables.

 

Yet, you seem to forget about all these possible CRITICALLY IMPORTANT

situations that your BLIND-IMITATION-TABLES can NOT foresee because

of (wait for it) you WANT TO KNOW ABOUT THE AIRFLOW OVER THE RIVETS

OR PROP DING. In other words, the premise of your article seems to be

that you obsess over only a few pre-planned datapoints that you want

to hit PERFECTLY... to the exclusion of all common-sense and actual

real-world flying encounters, which will go beyond whatever you plan

in your tables.

 

OOPS.

 

In the event that you claim that I am wrong, then please show me

where, in the MSFSX file for a 172 and a Baron, you specify:

1: the 172 elevator increase or decrease in authority and pitch-

stability, as a function of power, air-density (which effects

propwash!), and angle of attack

2: the baron change in lift, drag, and pitch-moment, on each wing,

with resultant change in performance and stall characteristics, as a

function of asymmetric power and air density (the things that will

control propwash for a given plane)

 

"The myth that X-Plane has superior flight dynamics than FSX has been

mercilessly shattered in this comparison"

Umm.. not really. You have not begun to touch things like phugoid

oscillations, short-period response, asymmetric power handling, take-

off distances, landing distance, climb-rates, cruise speeds.. do you

even know what all of these things ARE? You never even TOUCHED on

ground-handling... the Patty Wagstaffs Extra, as simulated in MSFS:

you can slam the plane down in most any sideslip, any speed, and any

attitude that I have been able to test, and the plane just sort of

stops whatever ham-fisted maneuver you were flying and proceeds to

roll down the runway... do you know what a ground-loop IS? A

simulator that lets you get away with such horrible flying is giving

huge NEGATIVE training value since it lets you make horrible mistakes

that you could not POSSIBLY get away with in the real plane.

[Tim Krajcar]

Boy, if he toots his own horn any harder he'll be a br[Mod - Happy Thoughts] band all by himself.

Despite Mr. Meyer's ego, X-Plane is a great sim. I wish the airport areas didn't look like FS4, and that software on the PMDG level was available for it... but this does remind me to boot it up and give it another go.

[Keith Smith]

Tim,

 

Austin is a character, no doubt about it. There are times where you wish he had someone to help with his PR. Other times, I just remind myself that X-Plane was originally written by one guy, and only recently became a 3-5 person effort. Quite amazing.

 

Oh, and you're right, terminal scenery and the lack of a decent FMC are always brought up in comparison to MSFS, and X-Plane always falls short in those areas. Some of is that MSFS has more advanced capabilities, but much of it is simply because nobody has built them yet. It's worth mentioning that last point, not as an excuse, but simply because it means things could change. Freely available scenery is growing all the time and improving in quality, too.

 

There are FMC plugins on the horizon, too: http://www.xpgoodwayteam.org/site_gw-fms/Site/B353CA8F-F9F0-4876-9493-B62364A14415.html

 

And one other for a 747 that's just about finished, I just can't dig up the link right now.

[Peter Nolin 954217]

I think the link you're searching for is http://www.eadt.eu/

Edit: This link is from 2007-june-16 pointing to the x737 project instead due to a sad happening regarding copyright violations.

 

About Austin and his sim. Well, currently X-Plane is my first choice altough I only used MSFS for many, many years right up until august 2006.

The competition is good for us all. MSFS does ofcourse have a huge advantage regarding the surrounding scenery, and especially airports. X-Plane has other advantages which I prefer like *no* lag in the gauges.

This might sound like "so what" but it has to be seen, not heard of. It gives flying a new dimension which just can't be described.

 

I do, despite all that is said, think that the global scenery (which comes on 6 Dual Layer DVDs) is by far superiour to the MSFS scenery. But then, on top of all the green stuff, the mountains MS has alot more objects (houses, churches, etc) which I really miss.

 

I really hope the "fight" goes on between the sims. And if you are happy with MSFS then keep flying it. I really can't be sure either. Some day I might return but as of now X-Plane got me.

 

Austin on the other hand could need a course in PR. He just can't do everything alone. And with more and more people joining the train he will get more and more emails with questions. I've already heard some horrorstories about his responses. Apparently he is a human and all humans have moodswings.

 

And one more thing, X-Plane doesn't have a perfect flightmodel. It's ofcourse more "alive" and it really feels alot more real than MSFS but it lacks a few things. Like winglets ain't working as they should, neither can you do a real flatspinn in X-Plane.