RealFlight Project

Hello!

The last 2 days I see a lot of people are interested and excited about what I've been working on for the past while. So I figure I'll present to the public.

I'm seeing if I can make a real airplane that obeys the forces of thrust, lift, drag and gravity. This airplane would, by nessesity, require a real runway to take off and land on. It should act fairly realisticly in the sky.

I'm not with Kazenojin or part of a group or on anyone's retainer or really looking for help ( James Miller has offered to double check my math for me since he says he knows aeronautics. ).

Due to this, like a good scientist, I am making all my research notes available to the public as I work on this. So, in lieu of an SL 'Physical Review Journal' type publication, if you are interested, stop by my office - they are on my deck by the plane. Check for updates

I won't nesseccarity make the scripts available to anyone (except James), though I'd love to see other pilots use my controlling attachment My single attachment can interface with and control (if the owner gives you permission) any craft that is using my control scripts.

Thanks for your interest

PS: with the the University going up, I think an SL 'Physical Review Journal' type publication would be a wicked thing to work on

Way to go madox!
There is some really advanced open source flight simulator project with a name like xplane or xflight or something, maybe you could steal some of the math code from them?

The name is x-plane, however, I don't think they are open source...at least, not anymore. That sim is quite advanced, and very popular among the FS community.

From developing a missile, I can tell you that one thing you will need to simulate is the bleed-off of momentum when an airfoil changes orientation. There is no wind resistance and certainly no Bernoulli effect in SL, so you will need to calculate the direction the aircraft is moving in and negate some of that momentum (i.e. apply negative thrust in that direction) at the same time as you apply thrust in the new direction.

Matter of fact here's some stuff I scrounged up a while ago...

FL = Lift Force
CL = Lift Coefficient
rho = Air Density
V = Velocity
alpha = AOA in radians
A = Cross-sectional area


FL = .5*CL*rho*V^2*alpha*A
CL = FL / (.5*ro*V^2*A)

For a thin plate with a small alpha:
CL = 2*pi*alpha

(Landau and Lifschitz.) A typical CL for a wing is about 0.5.

Do you mean FlightGear? It's not as advanced as X-Plane, but it's 100% opensource so one might be able to rip some code from that. As a flightsim nut I think this is a very interesting project - afraid I'm not quite skilled enough to contribute much in terms of aeronautics/aerodynamics though. Maybe avionics - let me know if you need any VOR towers or onboard instruments

Thanks Huns - ya I've been toying with that equation already but I didn't know what a typical CL would be. Doesn't AOA take the plane's pitch into account? Maybe not, since the airflow still ramains the same, but then that equation seems to not behave as I expect. Because pitching the plane up creates more lift doesn't it? Or is it just that a componant of thrust becomes lift when you pitch up, and lift from wings remains a constant magnitude.

Anyhow, I'm not seriously working on lift yet still doing drag and thrust.

Hehe Futt - a VOR tower that broadcasts sim name might be useful.

AOA = Angle of Attack = Pitch.

Increasing AOA does increase lift to a certain point. The plane pitches up because the raised ailerons are being pushed on by the wind, and the plane, being attached to the ailerons, angles up as the equal/opposite reaction. This causes more air to collide with the underside of the wings and fuselage, which adds lift in the same way that the angled blade of a fan adds thrust. The tradeoff involves -9.8 m/sec squared and how that interacts with the mass of the plane and the thrust being generated by the engine(s).

You can also increase lift by lowering the flaps, but this also increases drag. The landing gear adds a good amount of drag and zero lift while it is down.

> For a thin plate with a small alpha:
> CL = 2*pi*alpha

Notice that they specifically said a small alpha. The larger the AOA, the more thrust you have to develop to keep your speed constant. If your plane weighs 20,000lbs and your engines develop 15,000lbs of thrust, you cannot accelerate or keep a constant velocity while flying straight up.

Another thing to take into account is the weight of the fuel, its rate of consumption, and any ordnance that may be fired or dropped from the plane. That stuff's easy. If you want to get fancy, you can also take the ram air effect into account: the faster you go, the higher the pressure of the air in the engine intake(s).

Now, this may seem like a lot to heap on LSL, but I'll tell you something. I used to have an old Atari (cartridge-based game console, not the ST) and on that Atari I had a flight simulator. It can be done!

These days I spend a lot of time playing with A-10 and F/A-18 flight simulators. The subject is close to my heart.

Thanks for posting those forumals, Huns! So glad to see people actually like this project, and are willing to help out! If anyone else has any comments or suggestions, please reply here.