homepage Forums Read Only Forums Read Only Forums Knights Over Europe (Read Only) Weight of the argument.............KOE's models!

I thought I'd highlight a section of the SimHQ interview on KOE in regards to what JP4 had to say about creating the flight models for the sim:

Faithfully recreating the flight characteristics of each plane has been one of our fundamental goals for the project. We take our hats off to the way our flight model accomplishes this. It starts with fundamental data that has little ambiguity like: weight, physical dimensions, airfoil, etc. That data is then processed by the flight model using very sophisticated aerodynamic and physics formulae. This allows each aircraft’s characteristics to “fall out” naturally without forcing each to conform to sometimes-contradictory performance plots. This also means that aerodynamic fidelity extends beyond the normal flight envelope and into departure realms.

Those familiar with physics-based flight engines probably can recognize in the discussion above some of the parameters that might go into making the KOE flight models functional. Of course one of the hardest things about creating a WWI sim, is determining the actual flight characteristics of these long gone aircraft. A good starting point is historical research and flight tests of still existing aircraft, as well as authentic replicas. Still, no foundation or museum wants to push their remaining treasures to the limits, and of the hundreds of models that no longer exist in the world, well we're just plain out of luck for ever securing modern testing information on these lost relics!

So what to do, or specifically what can be done to "fill in the blanks" on the unknown quantity that represents the exacting flying characteristics of the Siemens-Schuckert D.III for example?

Well take a look here at the Aspect's D.H.4 modeling:

[img]http://groups.msn.com/_Secure/0UQDdAkkZp...441929172230526[/img]

In another post on this forum, I surmised how the extensive modeling of KOE's 3D aircraft skeletons seemed to indicate Aspect's approach to integrating damage modeling along with other things like multi-skin swapping, and allowing for authentic interiors to be rendered in-game. However, perhaps there's another reason for the extensive modeling we see being done for KOE's aircraft..................perhaps the 3D aircraft skeletons themselves serve as models to generate the initial flight modeling data!

Again, just doing a little detective work here and some extrapolation, but how better to recreate the flying characteristics of aircraft from a by-gone era, than to create them in exacting form so that they may be tested by a physics program for component weight, CG bias, etc. etc.!

Are we seeing evidence of the "bare bones" approach Aspect is taking to recreate, as closely as possible the authentic flying characteristics of WWI's warbirds?

It's just guesswork at this point in time, but thus far KOE looks to be one unique flying sim experience........make no "bones" about it!

FxW,

The internal framing approach taken by Aspect looks quite good. IIRC, SDOE featured a similar approach. If this is properly incorporated into the DM, I anticipate good things.

As regards FM's, KOE is by no means first flight sim to claim the use of "sophisticated aerodynamic and physics formulae" to generate FM on the fly so to speak. Laudable as the basic concept is, no one has yet been able to make it work properly within an entertainment sim. I will wait to see the actual results.


LB

Indeed physics modeling is tricky...

One. You are limited by the CPU of your computer systems. (And others)

Two. You are then limited by the extent of your physics engine.

And Three. You are limited by the ammount of data you can get for an aircraft.

Comming from SDOE (Physics-based) you have to be really careful of weight distibution, inertia sizes, airfoil properties (Such as wing efficiency, aspect-ratio, area, chord, built in incidence angle, wash, points at which airfoil data is gathered and computed, and of course then the actual airfoil shape which would give you drag calculations at certain AoA, low speed lift and so on...)

Of course after that there are the other affects on your flight model such as your engine (R.P.M., fuel consumption, H.P., gyroscopic affects with rotaries, torque, gear-ratio) and then the propeller (Pitch and shape, length, weight, angle of incidence...)

Thats a lot of stuff!!! Now you know why it takes so long to make an aircraft for SDOE.

Hopefully the modelling techniques used will also highlight such effects as aileron induced adverse yaw and what happens when some swine decides to punch a series of small holes through the aircraft.

Exerpts from Flying The Bristol Fighter by Trevor Roche
Trevor is flying D8096 from the Shuttleworth Collection. The plane was built in 1918.

"The field of view is much better than most of the biplanes I have previously flown. This is due to the fact that the fuselage is actually raised up above the lower wing. Hence, without reducing the gap between the wings (which would cause unacceptable interference between the upper and lower wings), the pilot's head is almost level with the upper wing."

"As the throttle is opened, the Brisfit accelerates rapidly. Initially I keep the stick back to ensure that I have some weight on the tail skid to counteract any swing caused by engine torque as I smoothly open the throttle and ignition advance lever. Actually there is very little swing and as I raise the tail and use the rudder to keep straight the aircraft leaps into the air at 45mph."

"During the climb to 2000ft, I begin to have a look at the lateral and directional handling characteristics of the aircraft. The ailerons feel fairly heavy, and as expected, they produce large amounts of adverse aileron yaw. This means that in a roll to the right, the aircraft actually yaws to the left due to the increased drag of the downgoing aileron. (...)for the Brisfit it means that the pilot must balance turns carefully with the rudder. Infact, I have been told that it is easier to lead turns with the rudder, and then follow up with aileron. I try this and find that it works well. The aircraft has a slip bubble to measure yaw, which works in the opposite direction to a modern slip ball. Thus, I am able to turn with the rudder and then move the stick in the direction of the bubble to balance the turn. (...)it is hard to keep the aircraft totally in balance and I note that accurate gun sighting during combat must have been extremely difficult in this machine."

"During steep wing overs the nose does not drop down naturally and align itself with the relative airflow as in a more conventional aircraft, and continual use of the rudder is required to push the nose in the direction intended."

"I fly straight stalls with power on and off (...) The stall is easily identified as a mild buffet felt through the stick and airframe with no significant wing drop. I experiment with applications of rudder and elevator at the stall and find no serious adverse effects."

"I accelerate the aircraft to about 100mph. The trim change with speed is easily matched by the rate at which pitch trim can be adjusted by the large lever on the side of the cockpit. The aircraft performs well (...) with enough pitch force change with speed to give the pilot a good feel of speed when manoeuvring without the need for constant retrimming to relieve excess forces. However as the speed increases the ailerons feel exceptionally heavy and I find I need to use two hands on the stick at 120mph."

Trevor also noted that the rudder and elevators were light on the controls, with the elevators a little oversensitive at the landing speed of 55mph.

All that is needed is to model it.

Excellent excerpts SunScream!

You would probably enjoy this discussion that we're having on the Aerodrome forum presently concerning the flying characteristics of the Fokker Dr.I (albeit derived from experience flying nearly authentic replicas of the triplane).

Aerodrome forum link

Gee, this guy can fly around in Warbirds just as he pleases? Darn lucky basturd . What kinda pilot is he? A normal GA one who had the right connections to get into Warbird or is he a professional WarBird (ex airline) pilot who hops around from one airshow to another?

Perhaps lucky, but certainly insightful.......and a nice guy at that.