Real Engineering
Уровень B2· 1288 слов
It is close to midnight when the emergency is called in. Dark and rainy night on an aircraft carrier.
An MV-22 sits on the deck of the carrier folded up. Alarm bells and sirens erupt. An F-15 has just crashed in the Libyan desert, and its pilot is running for his life. Every passing second gets him further from being a survivor to being a geopolitical bargaining chip.
The Arab Spring arrived in Libya in February 2011. What started as small sprouts of localized protests soon erupted into a violent civil war.
The population was finally rising against the 42 year rule of Gaddafi, but the dictator's counter-offensive was brutal. With radio warnings echoing across the Libyan desert “We are coming tonight... we will find you in your closets. We will show no mercy and no pity.”
Gaddafi unleashed the country's advanced fighter jets on its own people. And NATO drew a red line there. Moving to impose a no fly zone over the country with the combined airforce of NATO.
Amidst the chaos, this American pilot crash landed behind enemy lines after a mechanical failure. His life now depends on this. The V-22 Osprey.
For thirty years, this machine has been plagued by accidents and criticized as a technological Frankenstein. Too complex to fly. A controversial hybrid of a plane and helicopter, but tonight only it could be the hero.
Slowly unfurling its massive composite blades, the wings rotate ninety degrees and lock into place. Twin halos appear overhead, as its blades thrash the air into submission. The V-22 now has to make its most difficult transformation.
This aircraft has to operate in two modes. Vertical and horizontal flight. Two completely different flight modes, using the very same controls. This is the Thrust Control Lever. It controls both the collective pitch in vertical flight, allowing the V-22 to
control altitude in hover, but in forward flight it controls speed by controlling the engines thrust, and altitude is controlled by the elevator, which is controlled by the stick.
A fly by wire system was the only option to allow the control logic to flip like this, and things get even more complicated in the transition.
With the turn of this wheel the pilot effortlessly controls the nacelles. Tipping them forward, trading vertical rotor wash for forward thrust. As this transition happens the V-22 is neither helicopter or plane, and the computer has to gradually blend both control logics together until the transition is complete.