Tandem Flight Engine Demo v01

Community Forums/Showcase/Tandem Flight Engine Demo v01

Chroma(Posted 2007) [#1]
This is a small demo showing off my flight physics lib in action. You start off on the runway. A joystick is required btw. There are some external views you can access by using joystick buttons 2,3, and 4 and also the hat switch allows you to look around when in the cockpit.

As you can see this is version .01. Which means it's...basic and far from being the finished product. If you feel the need to criticize then that's ok, knock yourself out.

Here's the key controls (they're not listed in the demo):

Joystick for aircraft control (very unrealistic atm)
Plus and Minus keys (+/-) for throttle
Joystick button 2 for out of cockpit view
Joystick button 3 for cockpit (hatswitch to look left right back etc)
Joystick button 4 for fly-by view
Spacebar to reset yourself to 0,your altitude,0
F key for flaps

Here's some tips:
1. If you're easy on the controls you can get very realistic response. You can crank it until you fall out of the sky. I haven't modeled real flight controls yet.

2. For taking off, pitch the nose up to about 10 degrees AOA at around 120 knots. That'll be a nice easy take off.

3. For the most realistic flight at this point, keep your airspeed above 250ish knots. Anything lower and you need to baby the turns (no rudder physics atm).

4. For landing do a few S-turns to bleed off airspeed or you can hit F for flaps. Level off and get your airspeed to around 115 knots and about 8 AOA for a nice soft landing.

That's about it for now. I have to do some more research...I have a few bad numbers in there but it's still not bad. Btw, there's absolutely no angular velocity calculations in it atm. Keep that in mind please.

Enjoy.

http://webzoom.freewebs.com/zamagames/TandemFlightEnginev01a.zip

EDIT: Just updated to v01a which allows arrow keys by hitting C and F1,F2, and F3 for views.


Xzider(Posted 2007) [#2]
That was fun:) good job...

I can do a 360 degree turn in 2 seconds or so though


ckob(Posted 2007) [#3]
i tested it out and your off to a very good start. I noticed when I went full throttle from the start the nose lifted before I gained any speed. The other thing that was weird is during all my flying around I some how rotated the plane model about 90 degrees. But as I said your off to an awesome start and Topgun music on top of that :P nice job


Andy(Posted 2007) [#4]
I have a gravis blackhawk digital and although the throttle works in B3D in general and Windows settings, it's always on full trottle in the demo.

Any chance of power being mapped to buttons in a future demo?

It seems that you are modelling the velocity vector, but I dont see any lift being applied...

Andy


Chroma(Posted 2007) [#5]
but I dont see any lift being applied


If I was modeling just the velocity vector you'd have to have the nose almost pointed straight up to take off. The aircraft is modeled at about 25,000 pounds and gravity is modeled at 9.8m/sec (1 unit = 1 meter). The engine puts out a max of 25000 pounds of thrust so in essence, you'd have to put the nose straight up and you'd still not leave the ground or maybe ever so slightly. So you can see from the above that lift is being applied. And I'm using the actual lift formula L = Cl * blah blah blah. What's not is actual flight surfaces so you can actually keep turning out of the flight envelope if you want to, that's why I was saying at this point to baby the flight controls when you're under 200 knots. When I get actual flight controls in based on surface/airspeed/inertia and surface location from the CG, then it'll be more realistic on the controls. There's no angular anything going on atm. The turns are using TurnEntity, that's why you can do funky stuff atm.

Also, you can tell lift is being applied by turning the aircraft. If there was no lift it'd just keep going straight and only turn based on thrust(which would be hardly noticeable). Btw, MoveEntity is not being used. It's all forces and PositionEntity.

I'll map the throttle to the mousewheel and repost, give me about 10 minutes.

EDIT: Ok now the throttle is mapped to the + and - keys. Hit the plus key to increase throttle by 2500 and minus to decrease by 2500.


Andy(Posted 2007) [#6]
>So you can see from the above that lift is being applied

So where does it go? Even at 500 Kts, the aircraft is flying straight forward without lifting off. EDIT Even at 3000 kts, it's not lifting off? what gives?

>I'll map the throttle to the mousewheel and repost, give
>me about 10 minutes.
>
>EDIT: Ok now the throttle is mapped to the + and - keys.
>Hit the plus key to increase throttle by 2500 and minus to
>decrease by 2500.

The plane is still on full throttle, except now it's moving backwards.


Andy


Chroma(Posted 2007) [#7]
Do you have a joystick? In order for a plane to lift off the ground you have to raise the nose a little to increase lift. At about 125 knots, pull back on the stick slightly until you get about 8 to 10 AOA units. It will lift off.


GfK(Posted 2007) [#8]
Do you have a joystick? In order for a plane to lift off the ground you have to raise the nose a little to increase lift.
Either that or adjust the flaps to turn forward momentum into lift. But you don't seem to have added that feature yet.


Chroma(Posted 2007) [#9]
Hmm...flaps are in there. Lemme test it.

EDIT: Atm, I have most of an F-16 modeled. Weight, thrust etc. An F-16 will not lift off with just flaps fully extended (flaperon) and zero AOA. So I guess in that aspect, it's acting right hehe.

EDIT #2: Ok I lowered the weight of the aircraft to the weight of a cessna. It does lift off with flaps and no stick input! So it is working correctly. Eventually I'll put in an option to fly the F-16 or a cessna 172.


Andy(Posted 2007) [#10]
>Do you have a joystick?

Yes!

>In order for a plane to lift off
>the ground you have to raise the nose a little to increase
>lift.

That depends on the incidence of the wings, which it appears that you are not modelling.

>EDIT: Atm, I have most of an F-16 modeled. Weight, thrust
>etc. An F-16 will not lift off with just flaps fully
>extended (flaperon) and zero AOA. So I guess in that
>aspect, it's acting right hehe.

How much lift do you derive from the fuselage and how much from the wings?


Andy


Chroma(Posted 2007) [#11]
That depends on the incidence of the wings, which it appears that you are not modelling.


Hop in an F-16 and rely on wing incidence to take off. Not gonna be pretty... Again, this is modeled on an F-16

How much lift do you derive from the fuselage and how much from the wings?


The wings are modeled at 300 square feet. Plug that into the lift formula.

To quote someone properly, use [quote] and [/ quote].


Andy(Posted 2007) [#12]
>Do you have a joystick?

I even gave you the name and make of it.

>In order for a plane to lift off the ground you have to
>raise the nose a little to increase lift.

Then you lecture me.

>Hop in an F-16 and rely on wing incidence to take off. Not
>gonna be pretty... Again, this is modeled on an F-16

Then you mock me.

>The wings are modeled at 300 square feet. Plug that into
>the lift formula.

Then you patronize me.

>To quote someone properly, use [quote] and [/ quote].

And we are back to lecturing.

Chroma, except for trying your demo, making a few observations and asking questions, what is it exactly that I have done to deserve your disrespect and patronizing attitude?


Andy


Chroma(Posted 2007) [#13]
Nm...not gonna stoop lol. Just try out the demo and post your findings. That's about all the advice I can give you. Well, that and the quote advice. =P


Chroma(Posted 2007) [#14]
Gfk...lol the flaps are in but I had them so when you activated them that surfaces moved UP not down...not very effective flaps. Great speedbrakes tho!


Andy(Posted 2007) [#15]
>I've tried to explain to you what's going on in the demo
>but you're just not listening I guess.

You were not explaining what's going on, which was the reason for my prodding.

>In every one of your posts you're trying to discredit that
>I'm modeling real flight physics.

Not at all. You started out by posting about an open source flight sim, and the second you feel you have something that appears to work, you get very excited and shortly afterwards very secretive and aggressive when people ask questions.

I am very happy that someone is doing it. I'm simply trying to follow the development.

>Sorry but don't care if you believe me or not.

Good, you shouldn't care if other people believe you or not. But atleast entertain the possibility that people might ask questions out of curiosity.

Let's get back to the topic at hand. EDIT An F/A-18 intercepter remake would likely be very popular among Amigans. A few 'corrections' like the ability to destroy buildings and actual Mig models would propably be needed though...


Andy


Chroma(Posted 2007) [#16]
If I was being secretive about it I wouldn't have posted a demo. Duh! And I've been trying to do this off and on for a few years, banging my head against the wall. Up for hours staring at code that should work but didn't. So yeah, I'm a little excited it's working now...guilty as charged.

Funny you mention Migs. I saw a Mig-21 earlier and got an itch to model one. I also have an idea to mix Sky Captain/Crimson Skies/Fighter Ace 1.5 type stuff into an online game. But that's months away. Kinda like a 1920s meets new technology with giant robots attacking cities.

The latest shot of the new F-16:



Vorderman(Posted 2007) [#17]
I wish someone would do a flightsim that allows combat between the buildings in cities, like Sky Captain but also the scene between the 2 choppers at the end of Blue Thunder. Normally flight sims involve turning left or right as hard as possible while the opposition does the same, sometimes one person catches up and can shoot - it's usually pretty dull primarily because there's nothing to hide behind in the sky.


Andy(Posted 2007) [#18]
>Funny you mention Migs. I saw a Mig-21 earlier and got a
>itch to model one. I also have an idea to mix Sky
>Captain/Crimson Skies/Fighter Ace 1.5 type stuff into an
>online game. But that's months away. Kinda like a 1920s >
>meets new technology with giant robots attacking cities.

Then you absolutely need an airship-aircraft carrier as a launchpoint.

Andy


ckob(Posted 2007) [#19]
i've also been working on getting a flightsim based on ww1 style planes for some time now. I have moved on to Blitzmax using Minib3d but so far chroma's is the best i've seen so far in blitz.


IKG(Posted 2007) [#20]
Stop being such a drama queen, Andy.

Anyway I would love to try this demo out but I don't have a joystick..


Chroma(Posted 2007) [#21]
Give me about 30 min and I'll put in joystick,arrowkeys toggle.


Andy(Posted 2007) [#22]
>Stop being such a drama queen, Andy.

Stop bringing up issues that have been laid to rest, David.

Andy


Jeremy Alessi(Posted 2007) [#23]
Chroma, can you make a keybinding file so we can set the controls up ourselves? Anyway, I've been following you a bit on the flight engine and I'm not certain but it seems like somethings you've taken too low level considering Blitz's abstract capabilities but then again I've only done variations on impulse sources for my jet pack sims ... of which I have a few versions. The latest version of which lets you pitch, yaw, and roll the boosters. Angular velocity is also present but it's a hack. However, I'm sure that creating the angular velocity could also be done in an abstract manner utilizing what Blitz gives us already. Anyway, I just want to try the demo but I don't have a joystick with me atm that'll work on this, the nearest I have is an Xbox 360 controller.


Chroma(Posted 2007) [#24]
Updated with arrow keys option.

Hit "C" to change between joystick and arrow keys. I also put the views on the Function keys. Z is left rudder and X is right rudder.

F1 - cockpit view
F2 - outside view
F3 - fly by view

@Jeremy...I wish I was even close to that point. I can try to throw together a text file so you can set your own stuff up it may be a bit though.

At the moment there's no angular nothing modeled. I do understand how it works though. Each wing has an aileron that changes the angle of attack which shifts lift in the corresponding direction allowing roll. I'm hoping to have this in soon but also allow it to be adjusted so a variety of aircraft can be modeled. When I finally do get the vertical tail modeled, it will cure that nasty side slipping. =x

From what I've read about angular velocity I just have to get the position from CG that the force is acting and what direction it's acting relative to local aircraft orientation. Inertia comes into play somewhere at this point. Still sorting that one out.

Also in this version I cranked up lowered the flap drag a bit. If you set the throttle to 5000 and hit F for flaps and keep airspeed around 120 by throttling up to 7500 every now and again, you can come in pretty decent. Flare up a tad bit so aircraft mechanics like me don't have to change so many tires.

EDIT: Just threw in stabilator movement.


Jeremy Alessi(Posted 2007) [#25]
Hmmm... Interesting! I think I could help out a ton with this. As I said I don't think we need to dig to far beneath Blitz's abstraction of 3D. I haven't done jets/planes before but I think what I've done with the jet pack stuff could help out with this ... of course who knows until I try. Do you still live in Hampton? Currently, I'm in Ocean View right across the bay maybe we can meet up sometime?


Chroma(Posted 2007) [#26]
Yep I'm still here at Langley.

Here's something I whipped up.



Robert Cummings(Posted 2007) [#27]
>To quote someone properly, use [quote] and [/ quote].

And we are back to lecturing.

Seriously, begin using quotes. Otherwise I can't be bothered to follow your messy posts.