Flight Simulation - How do I know...

[Peter Tsang]

I have this questions in mind for years now.

Many hard core flight simulations focus on the avionics, flight models, missile systems and perhaps atmospheric conditions. I have noticed however that many of them are putting less emphasis on the speed of the aircraft that they are trying to model!

I was playing Falcon 4 on the other day and it's really great experience again, to play around with the panel buttons and the various different instruments. Watching a LGB homing in on a target from the MFD is really exciting. And then I fired up another one LOCKON on the 2nd LCD and incidentally found out that riding in the cockpit of a F-15 is way faster than the F-16 I was flying specially when you are comparing them side-by-side.

My question is: how "true" is the true speed that a simulator like the Falcon 4 is trying to model, is 450 knots really that "fast" visually in Falcon 4 or the same speed in LOCKON is the "true" speed in the real world??

 

[Peter Tsang]

What were the fps you were getting? An industrial military synthetic trainer has to run to the standard of 60Hz or in gaming terms 60 fps. This is based on the scientific theory that a human eye views images at 60Hz.

The second question to look at is the fidelity of the database - ground features, etc. Are there buildings and trees which help to give a sense of scale at low level? The database does not have to be complex, but must have enough detail to give a decent representation of an area.

For example, MS Combat Sim 3 incorporated Autogen buildings and trees, which randomnly draws them over less detailed areas. This was good for low flying as the features do give some scale to your height and speed. Razorworks' Commanche V Havok used generic buildings for cities and polygon-shaped forests for its low level detail. Again, this provided decent emmersion for the player as he knew how to use those features for 'bobbing' attacks.

If you fly a jet in ArmA 2, the overblown features on the landscape can reduce the fast speed experience significantly, especially if the refresh rate struggles.

For high altitude, it is regarded that the human eye can see as far as 80nm (nautical miles) on an exceptional, clear day. A typical day would have reduced horizon to 50nm at high altitude.

Hi shaggyd,

It's truly resourceful.

I've also learnt that 60Hz theory over the years reading forums here and there, so it's quite clear to me. One of the titles which I'm slightly addicted to is the Thirdwire series. There're a number of titles from WWI, Vietnam War, Cold War through to the modern era so it's pretty comprehensive in terms of the varieties of aircrafts which you could play around with. Surely, the number of war theatre is equally diverse not to mention add-ons. The theatre can be moved between titles. Amongst all, the WWI theatre is the smallest yet with more densely populated trees and buildings. The frame rate when in the air is like 100+ and back to 40+ when in very low level flying like 100 feet above ground. Still it is the only terrain which I can feel that sense of speed when flying in a F-86 Sabre at speed in excess of 500 knots though I'm not sure of that is the 500 knots in the real world.

Having said all that, a drawback which is holding it back is as you mentioned, the scaling of objects. Out of sheer co-incidence, I found that the size of a F-86 Sabre is of the same height as a building in other theatre which I reckon is not properly scaled. There is also a file which control the "Horizon Distance" expressed in meters. Different level of details gives different Horizon Distances, the higher the level is, the greater the distance is and that bleeds the frame rate.

Would the size of the theatre being one of the factors which affect the frame rate I'm still not very sure. But I am just wondering which flight simulator is the best representing a true, real world speed?

 

[Peter Tsang]

I remember from playing Flight Simulator that there was never an appreciable sense of speed. Even in the accelartion pack where you got the fighter jet, I still found it "slow".

Maybe it's just me.

Well there're some which is "fast", HAWX, JetFighter V just o name a few, but all these are arcadish.

 

[Peter Tsang]

Back to the original question - To know what your perception of speed is, you would have to experience it in real life. Training and excellent eye/hand co-ordinations play major factors in perceptions of speed, especially when you require precise movement reactions in short time (and under g-force stress). Or google Youtube videos on low-level flights.

How do you know I've already done the youtube search. The trouble is the youtube clip doesnt tell what airspeed is that. So despite it looks very fast, I can't tell if that is 500 knots or 450 knots or 600 knots.

The thirdwire series is very good because there are so many aircrafts to fly, the thing is there are not many real world objects.

 

[Peter Tsang]

Does your sim work on actual speed relative to Earth or on indicated airspeed?

For LOMAC I look at the indicated speed on the HUD
For the Thirdwire series it has a speed indicator on the bottom left corner of teh screen which I believe is the actual speed relative to earth.

The field of view will also make a big difference, a wider field of view will seem quicker than a narrow one.
by the way fsx and real life match pretty closely

http://www.youtube.com/watch?v=uiKuCzcgCRA
http://www.youtube.com/watch?v=fzuybuk97tU

Thanks I heard that fsx is good.