X-6D Titanium Dart

The fastest jet on Droo! Mach 9.66

this craft is NOT mobile friendly

This thing completely suprised me. As X-6C was limited to Mach 6.1 due overheating I startet to change critical parts with struts and shielded the wings with flat struts, as struts are more heat resistant. I expected something like Mach 6.5 or maybe Mach 7, but the limit is now just the atmosphere, as it is still a jet.

It's now looking a little weird, but it works! Nav lights were also removed, but it's an X-Plane not an airliner, so I'm fine with this.

Action Groups

AG1 - Open/Close Canopy
AG2 - Open/Close Air Breaks
AG3 - 80% Afterburner CutOff. Sets thrust to 80%. Useful for fuel efficient flight.
AG4 - Warning Sound for Overheating ON/OFF (default = ON)
AG5 - Cockpit Lights ON/OFF (default OFF)
AG6 - Flight Log ON/OFF (default OFF, logs every minute to flight log - see screenshot)
AG7 - Flight Program (made for a start from DSC Eastward Runway)
AG8 - Landing Gear
... and there is still a camera between the Droods for cockpit view without switching to the Droods.

How to fly and AG7 Flight Program

• The plane still is not neutral by default. At low altitudes you should set trim/slider1 to around -20%
• The plane is build for high altitude flight! At sea level it will overheat at Mach4 and above.
• So gaining altitude and speed in a good relation to each other is the key for speed records.
• A bad climb can lead to heat issues or to "slow" speeds, where the plane seems to get stuck at Mach 6.
• Getting to Mach 9+ will take hours. I changed my fast fordward setting to 4x. Be patient and keep that in mind. You won't reach such speeds in minutes.
• From Mach 9.5 the craft will start building up an orbit within the atmosphere. With Mach 9.63 it's going to be impossible to keep the apoapsis within the atmosphere. As the X-6D was never build for space and has no gyros, this will lead into an uncontrolled reentry. So don't go to space, except you like fireworks.

The Flight Progam AG7

This program is build for a start standing on DSC Eastward Runway and not tested for any other start!
It will run for somewhat around 45mins of flight time with stats like this:
21mins to Mach 5
40mins to Mach 6
1h 3mins to Mach 7 without any interaction
2h to Mach 8 without any interaction
2h 51mins to Mach 8.5 without any interaction.
When getting up to 50km ASL I started slowly lowering Trim to 0 and pitch lock degrees one by one, to reduce drag. Dont set both instantly to 0! Keep an eye on altitude an stay above 50km.
4h25mins to Mach 9
5h45mins to Mach 9.5

This will be a very long flight. You can achieve flight times of 10 hours and cover a ground distance of up to 100,000km.

Test results of X-6D

Struts with a heat resistnace of 1500K are a quite good choice, while fuel tanks and nose cones with a heat resistance of 1000K are not. So tinkering is not necessary.

Parts seem to transfer heat. So there is a small gap between wings and wing shield. When directly attached I always run into heat issues.

I elongated the nose from 4.7m to 6m. While the nose is now heavier, it's better for drag. So long and spikey designs seem to be a good choice for high speeds.

Long time i wondered why this plane reached such altitudes. When calculating the forces on the craft it was not the lift by the wings, but the centrifugal force caused by speed and the small planet Droo. For example at 60km ASL with around Mach 9 the upward force by wing lift is aorund 5kN, while the upward centrifugal force is above 170kN. This means every craft going to Mach 4 and above will get significant lift by centrifugal force.
This also means, this craft would not perform like this on an earth sized planet, as the centrifugal force will be only 10%.