Be-200Altair Version: 3.1.0 (Development for FlightGear)

Repository

https://github.com/HerbyW/Be-200Altair

Introduction

FlightGear (http://www.flightgear.org) is an open source flight simulator that is even used in flight schools to train basic maneuvers, radio communication and navigation tasks. It is available for windows, mac and linux.

In this article I want to go through my latest two commits to further improve the development of the Be-200Altair, a multipurpose amphibious aircraft.

https://github.com/HerbyW/Be-200Altair/commit/fcf4a7b3f2da2a32e8cc8fa1bf7bc07d190d392d

New Features

FDM (flight dynamics model)

The main gears were not touching the ground and they had to be adjusted to compensate the compression. This was more tricky then expected. Finally I found the right switch and changed the value from -210.81 to -207.41 in the file: gear-water-ground-position.xml, located in /systems:

<switch  name="gear unit z-position1">
                <default value="-207.411023944"/>
                <test  logic="AND" value="-112">
                    simulation/terrain_sw == 0
                </test>
        <output>gear/unit[1]/z-position</output>
</switch>

simulation/terrain_sw == 0 means that we have ground below the wheels and then the value of the gears is -207, if we are in water it is -112. We can retract the gears in water and the model should then not jump to the surface but stay in the water like a boat.

The other change was adding slats to the model and adjusting the lift and drag values for the new surface. Here you see the final result in the 3D modell, which I made in Blender and animated in the /Model/Be-200Altair.xml.

<animation>
        <type>rotate</type>
        <object-name>SlatsR</object-name>
        <property>surface-positions/flap-pos-norm</property>
        <factor> -38 </factor>
        <offset-deg>0</offset-deg>
        <axis>
            <x1-m>  -5.12154 </x1-m>
            <y1-m>   2.16081 </y1-m>
            <z1-m>  -0.81393 </z1-m>
            <x2-m>  -2.75067 </x2-m>
            <y2-m>   6.54309 </y2-m>
            <z2-m>  -0.86243 </z2-m>
        </axis>
    </animation>

<animation>
        <type>translate</type>
        <object-name>SlatsR</object-name>
        <property>surface-positions/flap-pos-norm</property>
        <factor> -0.28 </factor>        
        <axis>
            <x>1</x>
            <y>0.0</y>
            <z>1</z>
        </axis>
    </animation>

The first animation rotates them with 38 degree and the second translates them for 28 cm to the front. I used the flap property as the slats are controlled with the flaps.

3D-Model

The 3D-model and the livery picture got a few make ups and took me 2 days.

Flightrecorder and Multiplayer update

All animations are recorded now and transmitted over the multiplayer protocol.

Refueling on the ground

The picture shows the menu with the new setting for two different tank configurations, the values of the tanks are changed to fit the real aircraft. A truck is animated to make it more fun.

Some smaller updates

• The engine smoke, touchdown effects and water effects got some small adjustments to make it more realistic.
• Autopilot functions now in much more stable conditions
• Stall warning adjusted with the new slats
• Slats instrument in the cockpit added

New version number

The new number is 3.1.0, it is transmitted over the multiplayer layout, so that I know what version my colleges are flying. It is set as property in Be-200Altair-set.xml:

<aircraft-version>3.1.0</aircraft-version>

and is then transmitted as string[1] over the multiplayer protocol via

<string n="1" type="string" alias="/sim/model/Be-200Altair/version"/>

Fuel instruments in the cockpit

https://github.com/HerbyW/Be-200Altair/commit/8135cb854b82669d6bcd961f4f66285deaf9390b

We see all 4 instrument showing now the right values:

• On top we see the actual fuel flow in gallons per hour have a value of 972.5 per engine, the two instruments on the right show 3050 kg per hour, as 1 gallon has a weight of ~3kg. The small vectors show ~3000kg fuel per engine left.
• The instrument on the left shows ~6000kg total fuel.
• The second from the left shows also 6000kg plus 48% filled tanks.
  This corresponds with the menue and the values there! Maximum fuel is: 26630 lbs for a 3850 km long flight without cargo.

Roadmap

Next will be the further improvement of the FDM. The pitched turbines have some strange effects and there should be a flight system to compensate that.

How to contribute?

Pull request to my github repository or direct contact via Mumble FlightGear Chat.

GitHub Account

https://github.com/HerbyW
It contains my real name, my git username, my steemit username and my callsign in the multiplayer.