Flight Modeling vs. Flight Handling.

[jimbop]

I don't see what can be done about it short of actually flying RL versions of each modelled aircraft. And even then you are limited to a single instance which could differ markedly from other individuals. Pilot experience and style would also have a strong impact on what is essentially a subjective interpretation anyway.

In short, I don't see where this can go... Interesting topic though.

Fully agree with the gunsight handling comment! I am still struggling with this myself and tinkering with the response to try and get it 'just right'. Problem is that the sweet spot differs for each aircraft for me so I am finding myself changing it quite often. You certainly don't want ultra-responsive controls when flying the Blenheim for instance!

[CaptainDoggles]

Interesting topic indeed!

I don't buy it though, or perhaps just not the car analogy.

To put it in a context that I can relate to being someone involved in motorsport of the 4 wheeled variety...

You can have two cars with identical performance numbers across the board, top speed, braking, acceleration, lateral Gs, etc... Yet one will have to be bullied into doing it and the other will behave as if connected directly to your brain.

If two cars have identical accelerations then they'll hit the same speed at the same time. Period. If the driver of one feels like he has to "bully" the car into doing it then that's his problem. Just a problem with his perception - because we already know the car is doing it just as well as the other car. If it didn't, then the accelerations would not be identical.

As far as this can relate to aircraft, well, I'm not sure what ElAurens is advocating exactly, but it does raise the issue of how to simulate what basically boils down to a pilot's opinion.

Being an engineer, my belief is that the nebulous qualities that we call "handling" or "feel" will show up when we consider things such as the aircraft's stability. For example the Spitfire was widely considered to be a forgiving aircraft but (test) pilots complained that the early versions "did not have enough elevator authority" and that it was difficult to control the aircraft, pitch-wise. When the issue was investigated it was found that the aircraft had a very narrow longitudinal stability margin.

I struggle to imagine a concept that can't be quantified, or related to some measurable quantity in some way.

[BP_Tailspin]

Here we go .....

[Blackdog_kt]

I think everyone that posted so far is correct in some way and touches upon all the main aspects of the topic.

I can certainly feel what ElAurens says, but that's through years of perception under controlled conditions (same control profiles, peripherals, software used, etc): in the previous IL2 series it didn't feel the same doing 500km/h in a 109 and doing the same in a 190, but it took quite some time to notice it.

In a similar fashion, when i first took up a 111 in CoD it felt much heavier and full of inertia than whatever bomber i had ever tried in IL2, but in a way that didn't feel uncanny. To the contrary, it felt just right and i had the feeling that the extra weight and size really showed.

I think the variables are too many and while it's true that i can't think of something that can't be quantified and measured (like Doggle says), maybe we don't have the technology to take advantage of it yet. Of course it's mostly fundamental newtonian mechanics at the speeds and masses we are talking about, but how many consecutive higher order derivatives of a certain function can a current PC compute per second and at how many instances and points across the aircraft's surface before melting?

It's also difficult to quantify objectively because of the same reasons: few or no surviving aircraft, probably different in handling than when they came off the line after all these years (refurbishments, weight changes due to modern avionics installed per ATC rules, removal of guns, etc), a dwindling amount of veterans who all have their subjective opinion (depending on their flying habits) and a multitude of sim fliers with millions of combinations of different controllers and input curves.

It's a nightmare


I think that technology-wise Xplane is probably the closest one can get to having a wind tunnel emulator running on a PC (as long as the individual flyable is also done to a high standard to take advantage of the sim's engine in full), but sadly it will be some time before we see such technology in combat sims: it's so taxing that with full multi-core support in Xplane 10, a current PC can not run more than 4-6 AI aircraft with the same FM accuracy at the same time without noticeable performance loss. In fact, there are people who take Xplane flyables, simplify their FMs and reissue them as AI-only aircraft to populate the game world.

P.S. Very interesting topic

[CaptainDoggles]

Originally Posted by Blackdog_kt

in the previous IL2 series it didn't feel the same doing 500km/h in a 109 and doing the same in a 190, but it took quite some time to notice it.

I agree with this, but it comes back to perception/opinion. Maybe I feel the 109 "feels faster" and you have the opposite impression.

Is that even possible to quantify, let alone model?

My gut says no, because it's probably not an actual difference in the aircraft, just a perceived difference.

[mazex]

Originally Posted by Blackdog_kt

I think that technology-wise Xplane is probably the closest one can get to having a wind tunnel emulator running on a PC (as long as the individual flyable is also done to a high standard to take advantage of the sim's engine in full), but sadly it will be some time before we see such technology in combat sims: it's so taxing that with full multi-core support in Xplane 10, a current PC can not run more than 4-6 AI aircraft with the same FM accuracy at the same time without noticeable performance loss. In fact, there are people who take Xplane flyables, simplify their FMs and reissue them as AI-only aircraft to populate the game world.

P.S. Very interesting topic

I don't understand why X-Plane is so "hyped" - or have I missed to un-tick some default "arcade" setting?

Look at the clip below where I do my regular test of the FM in X-Plane (latest version 10). Some barrel rolls right after take off.

http://www.youtube.com/watch?v=ciJCTBW7zGc&hd=1

I'm sorry for being a bit evil in my comments

[ElAurens]

Originally Posted by CaptainDoggles

Interesting topic indeed!

I don't buy it though, or perhaps just not the car analogy.



If two cars have identical accelerations then they'll hit the same speed at the same time. Period. If the driver of one feels like he has to "bully" the car into doing it then that's his problem. Just a problem with his perception - because we already know the car is doing it just as well as the other car. If it didn't, then the accelerations would not be identical.

As far as this can relate to aircraft, well, I'm not sure what ElAurens is advocating exactly, but it does raise the issue of how to simulate what basically boils down to a pilot's opinion.

Being an engineer, my belief is that the nebulous qualities that we call "handling" or "feel" will show up when we consider things such as the aircraft's stability. For example the Spitfire was widely considered to be a forgiving aircraft but (test) pilots complained that the early versions "did not have enough elevator authority" and that it was difficult to control the aircraft, pitch-wise. When the issue was investigated it was found that the aircraft had a very narrow longitudinal stability margin.

I struggle to imagine a concept that can't be quantified, or related to some measurable quantity in some way.

Nothing personal Doggles, but I suspect you have never driven on a race track (road course). Two vehicles of similar performance can behave very differently and one can indeed be easy to extract it's performance from while the other is a workout to drive.

In a sim there is none of this.

They are all easy. And if they are not (rare) then players tweak thier joysticks or put trim on a slider, or what have you, to make them easy.

[CaptainDoggles]

Originally Posted by ElAurens

Nothing personal Doggles, but I suspect you have never driven on a race track (road course).

No offense taken. You're somewhat correct, I've only been out on a track twice ever.

Two vehicles of similar performance can behave very differently and one can indeed be easy to extract it's performance from while the other is a workout to drive.

Similar performance, or identical performance? First of all that's different terminology than you were using before and secondly I'd agree that two similar vehicles can behave differently.

But two identical vehicles cannot behave differently. If they behaved differently then they are either not identical or are not receiving the same inputs.

They are all easy. And if they are not (rare) then players tweak thier joysticks or put trim on a slider, or what have you, to make them easy.

I'm sure that driving sim players are tweaking their steering response curves too.

[TomcatViP]

For those that are convinced that two aircraft performing the same are behaving in the same manner, pls take a look at january issue of Air Force Monthly. There is an interview of an ex F-16 pilot flying now F-15C in Hawaï...

You'll change your mind in a single page of reading

What we lack in CoD is inertia (mainly in rotation) and external perturbation of flows around our aircraft.

[ElAurens]

Originally Posted by CaptainDoggles

No offense taken. You're somewhat correct, I've only been out on a track twice ever.

Similar performance, or identical performance? First of all that's different terminology than you were using before and secondly I'd agree that two similar vehicles can behave differently.

But two identical vehicles cannot behave differently. If they behaved differently then they are either not identical or are not receiving the same inputs.

I'm sure that driving sim players are tweaking their steering response curves too.

Doggles, two different cars can have identical (as close as possible in the real world) measured performance, but can handle and feel very differently.

I suspect it will take another 5 to 10 years of computer development to enable the kind of nuance I'm getting at here.