The authors of the airship-glider believe that it will be able to move a large amount of cargo over great distances without spending a single gram of fuel.
Airships can lift large loads effortlessly, but they need engines to move horizontally. Gliders, on the other hand, make long non-motorized flights, but they need energy for the initial ascent to altitude. What happens if you cross two types of devices?
The American corporation Hunt Aviation is designing a new type of aircraft, which, according to the main author of the idea, engineer Robert Hunt, will be able to cover great distances without using any fuel.
The device is called Gravity Plane or even more frighteningly - Gravity-powered aircraft, but there is no talk of any anti-gravity in the project.
This is a hybrid of a balloon with a glider, the principle of which resembles witchcraft - the car does not violate conservation laws, but it flies without using fuel.
So, before us is a double-hull catamaran balloon, with large variable sweep wings.
At the beginning of the flight, the average density of the car is less than the density of air. Helium in cylinders lifts the apparatus into the air.
By the way, a fun fact - the engineer assumes that his brainchild will achieve even better results using not helium for lifting, but a vacuum.
In the superstructure located in the middle part of the hull there are wind turbines that can store energy when gliding down and, on the contrary, create jet thrust when climbing
It's funny, because for a long time hot heads have been fighting over the idea of a vacuum airship, but they are shattered by the fact that the necessary in this case, a strong (read - heavy) shell will eat up all the gain in Archimedean force, which, in fact, in comparison with helium at all small.
Hunt, on the other hand, believes that with modern materials (such as carbon composites) he will be able to provide adequate shell strength at a low mass.
Let's leave such calculations on his conscience and return to a more plausible version with helium.
In Gravity Plane, an innovation is applied that radically distinguishes the device from conventional airships.
When the car with the cargo and passengers has reached the desired height, a transformation takes place with it - the compressors begin to pump atmospheric air into the gap between the catamaran hulls and the flexible helium cylinders inside them.
The cylinders are compressed, the density of helium increases, and the total weight of the machine is also supplemented by the weight of the received air - everything is like that of a submarine, which pumps seawater into the gap between the durable and outer hull for descent.
Let us add, in the case of the vacuum version, air is simply admitted inside the case, and in subsequent cycles it will be pumped out by pumps. The implementation of such an idea is doubtful, but now this is not the main thing.
One way or another, the plane becomes heavier than air and begins to fall. This is where the wings come into play - the car works like a glider, transforming the fall into sliding and horizontal motion.
The wind turbine that Hunt intends to use in his car. The horizontal disc has "shutters" that open when pushed by the air stream and close on the opposite side of the disc when they go against the stream
At the same time, the windmills built into the body (the original design, again, by Hunt; with vertical axes of rotation) also store energy. Again, in the form of compressed air stored in separate cylinders.
It would later be used to speed up horizontal movement, or facilitate lifting.
These windmills are reversible. When needed, they turn into propellers. And as engines, Hunt decided to use reversible machines as well - compressors and pneumatic motors in one person.
So, our glider picked up high speed and switched to level flight. Soon, his kinetic energy dries up. The pumps then evacuate air from the cavity adjacent to the helium cylinders.
The helium bags are expanding again. The glider turns into a balloon - gains altitude to start the cycle again.
When the gravity plane will fly, the authors of the project do not report, but they talk about the imminent testing of individual units on small prototypes and models.
Weaknesses are visible in the project with the naked eye.
Helium bags inflate and shrink inside rigid cigar-shaped bodies, which, since they are impressive in size (this is still a balloon), have a noticeable resistance to air.
This fact cannot affect the aerodynamic quality of the vehicle, no matter how perfect its wings are. And changing the sweep angle depending on the flight mode will not help much.
Helium cylinders squeezed, wings folded and stone down
But it is precisely the high aerodynamic quality that helps ordinary gliders to make amazing flights.
So the world record for planning a free route is 2.1745 thousand kilometers.
It was installed on the German Schempp-Hirth Nimbus 4 DM in 2003 in Argentina by German Klaus Ohlmann and French Herve Lefranc.
The aerodynamic quality of this glider is 60, which is perhaps the best indicator among all the winged aircraft in the world.
By the way, if you divide two thousand kilometers by 60, then you get an unrealistic initial altitude for the start, but here you need to take into account - the glider flies along a "sawtooth" trajectory, periodically making up for the loss of altitude due to the rise in the ascending air currents existing over the heated land areas, under cumulus clouds or near mountain slopes.
In addition to doubts about the aerodynamics of the revolutionary hybrid from Hunt Aviation, it should be noted that the simultaneous use of the gliding properties of the machine and the charging of air accumulators with compressors driven by wind turbines, which, in turn, work from the oncoming flow, clearly contradict each other.
In general, the balance of energy (the set of the required speed and the cost of air pump drives, and so on) is another issue.
Yet Mr. Hunt's train of thought is noteworthy. Let us recall, by the way, that the idea of combining the aerostatic principles of support and the lift of the wings in one machine is far from new.
But no one, it seems, has yet come up with the idea of using these forces in one apparatus, not in parallel, but sequentially.
Can gravity-fed aircraft overturn traditional aviation concepts and become a symbol of the second century of motorized flying, as the creators of this hybrid claim? Hardly.
Here's how an exotic device with specific areas of application, such as patrolling forests or recreational flights … Perhaps the idea of an American company will make sense.
