September 27, 2021

Another flight in this series, we explore some of the most interesting fractured "chaotic" terrain on Mars as we fly the same route we did in the last video with the basic flight simulator included with Google Earth.

Google Earth's flight simulator illustrates Mars better visually, while X-Plane illustrates the physics involved, rendering the terrain from 1/64th degree Mars Orbiter Laser Altimeter (MOLA) data and a single texture.

Approximate -- and it's important to stress *approximate* numbers for this simulated fixed-wing aircraft concept are below. Producing a real Mars airplane with this kind of performance would be a big engineering challenge. Keeping the basic airframe dimensions, there is margin for compromise in mass, power, range, design limit, and atmospheric density requirements as the air pressure and temperature on Mars vary widely depending on altitude, time of day, and time of Mars-year -- [ Ссылка ]

Earth-indications for airspeed pressure readouts are carried over from X-Plane's Earth flight model and are visible on the PFD and HUD, so an analog and digital airspeed indicator has been calibrated arbitrarily for 0' MOLA and 6.000mb of pressure.

There are various handles, knobs, switches, LED readouts, etc. on the panel which control various simulator parameters and allow simulation at various masses.

Not illustrated in this video, JATO functionality can be simulated, with a toggle switch for forward thrust to allow for pushback, and a thrust handle (which a solid JATO would not have), as well as a burn duration. No mass is simulated automatically, as this design would not have it innately, but it is here for experimentation.

Similarly, no mass is accounted for for the Ballistic-Recovery-Chute solution which can be simulated (not featured in this video), with the main chute area adjustable logarithmically to giant unrealistic proportions for a gentle touchdown. An actual ballistic parachute solution that would result in a slow enough descent for even an unmanned scientific or cargo payload would almost certainly require additional controlled propulsive thrust to arrest the descent rate, and could quickly grow to be mass prohibitive.

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Specifications:

Empty mass: 850lbs (tailwheel) / 900lbs (tri-gear) or more, i.e. whatever you wish to simulate
Design Gross: 1150lbs (tailwheel) / 1200lbs (tri-gear)
Design payload: 300lbs
Design Limit +/- 6.0G (tailwheel), +/- 5.7G (tri-gear) [+/- 2.25 Earth-G (tailwheel), +/- 2.14 Earth-G (tri-gear)]
Airfoil: NACA 20016 (16% thick)
Washout: 0.5 degrees
Dihedral: 1.2 degrees
Span: 69.5'
Average chord: 25.0'
Aspect Ratio: 2.78:1
Wing Loading: 1.51 lbs/ft^2
Propulsion: Electric, 125hp peak
Prop: 5-blade, constant speed, 14.5' dia
Landing Gear: Fixed, tailwheel or tricycle
Steering: Tailwheel/nosewheel via rudder link
Battery: 50 kWH, internal
Battery: 37.5 kWH, external drop (125lbs) (up to 3)
Flapperons: 0-18 degrees
Spoilers: 0-60 degrees

Control (realtime UAV, autonomous UAV, or theoretical crew-capable):
Undefined

Construction:
Undefined

Performance (1200lbs):
KIAS = Knots Indicated Airspeed at 0' MOLA, 6.000mb

Vso: 67 KIAS
Vs1: 75 KIAS
Vx: 120 KIAS
Vy: 180 KIAS
Vfe: 140 KIAS
Vno: 265 KIAS
Vne: 330 KIAS

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[Mars Basics, from another video description]

For those unfamiliar, Mars's radius is 53% Earth's, gravity is 37%, and average surface pressure is a mere 0.65%, ranging typically 5mb-10mb at altitudes aircraft might operate in. Excluding Earth's oceans, Mars has more land area than Earth. Google's default Earth flight-model is used regardless of planetary setting.

As real Mars lacks landing facilities, fixed-wing Mars UAV technology demonstrators that do not have VTOL capability present significant mission limitations without proven operations from areas found to be large enough, smooth enough, and free of obstacles such as boulders or small craters. For scientific missions designed to last months or years, more small VTOL multi-rotor UAV's with limited endurance are expected to be most viable in the near future. Much is unknown, however, and it is an exciting new frontier of experimental aircraft design.

While there is increasing evidence Mars may have had oceans in the past, there is no liquid surface water at present, so average elevation is often considered "sea level". Actual surface elevation varies widely, from below -26,000' in Hellas Chasma to over +70,000' atop Olympus Mons, the giant shield volcano. Correspondingly, average surface pressure varies widely, and is affected significantly from day to night (diurnally) and seasonally.

Actual Mars weather has been observed from both surface and orbit to vary from calm to turbulent at times and subject to unpredictable high winds, dust storms and dust devils. Much remains to be studied, particularly at the relatively low altitudes subsonic aircraft might be expected to operate.

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