Aircraft

Pegasus hybrid-electric VTOL promises massive range, no redundancy

Pegasus hybrid-electric VTOL p...
The Pegasus adds electric propulsion to a twin tilt-rotor design similar to the V-22 Osprey
The Pegasus adds electric propulsion to a twin tilt-rotor design similar to the V-22 Osprey
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The Pegasus adds electric propulsion to a twin tilt-rotor design similar to the V-22 Osprey
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The Pegasus adds electric propulsion to a twin tilt-rotor design similar to the V-22 Osprey
The Pegasus runs a large turboprop generator, powering two electric tilt-rotors on the wings
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The Pegasus runs a large turboprop generator, powering two electric tilt-rotors on the wings
Range and speed promises far outstrip any all-electric VTOL aircraft, as you'd expect
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Range and speed promises far outstrip any all-electric VTOL aircraft, as you'd expect
All hail the mighty Pegasus!
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All hail the mighty Pegasus!
Four-seat cabin looks like fun to get into
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Four-seat cabin looks like fun to get into
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Superyacht designer Steve Kozloff has turned his hand to next-gen aviation with a twin-prop VTOL aircraft that promises a monster 1,380-mile (2,222-km) range, as well as the ability to take off and land conventionally where there's a runway.

The Pegasus concept adorns a very helicopterish four-seat cabin with a set of fat wings, each fitted with a large tilt-capable propeller, 11 ft (3.3 m) in diameter. These props are driven by electric motors, each making around 700 horsepower, and together, says Kozloff, they'd make around 7,500 lb of thrust. The aircraft would weigh 3,300 lb (1,497 kg) dry and 6,000 lb (2,722 kg) fully loaded, leaving plenty of room in the weight budget for cargo.

The propulsion system would be powered by a generator, spun by a Pratt & Whitney PT6A-67R turboprop engine capable of making 1,424 shaft horsepower. The aircraft would carry some 250 gal (946 L) of fuel, giving you that colossal range estimate.

With retractable landing gear, it's capable of conventional takeoff and landing, and Kozloff says it's capable of reaching takeoff speed within 400 ft (122 m) of runway. It'd pull up quickly upon landing, too, reversing its props to get it stopped in a short distance.

The Pegasus runs a large turboprop generator, powering two electric tilt-rotors on the wings
The Pegasus runs a large turboprop generator, powering two electric tilt-rotors on the wings

It promises a very quick cruise speed over 345 mph (556 km/h), and a top speed of (checks spec sheet) ... "Impractically fast," which I'm sure is some kind of aviation term. Kozloff says the aircraft's "stunning looks" help the Pegasus live up to its nomenclature as a "mythical white stallion."

Mythical indeed. The eagle-eyed reader will have noticed, possibly in the headline above, that two props deliver approximately zero redundancy. Damage one of those suckers on takeoff, and if you're not clear of your superyacht, it's going to get a new deck ornament, maybe a pyrotechnics show or a new Pollock for the bar, depending on how many passengers were on board.

The configuration is not unprecedented, of course; it's similar to the first tilt-rotor aircraft, the V-22 Osprey, and its civilian equivalent, the AgustaWestland AW609. But both of these have proven extremely expensive, and AgustaWestland has found the AW609 a tough sell at two to three times the cost of a helicopter – even if it does fly twice as far, twice as fast. Presumably it's been an even tougher sell since a prototype crashed in 2015, killing both long-time test pilots after more than 1,200 flight hours.

Four-seat cabin looks like fun to get into
Four-seat cabin looks like fun to get into

So the Pegasus might work in a physics sense, and it might be certifiable, and its design might thrash the pants off the eVTOL class for range, speed and payload, but it's a notoriously difficult and expensive design to produce, it offers no propulsion redundancy, and it runs on fossil fuel.

And it's been designed by a superyacht guy, not one of whose many fine-looking Goliath Series boat designs appear to be under construction at this point either. So yes, not one we're likely to see flying any time soon, but it's fun to think about, and it does give Kozloff a neat little futuristic jigger to add to the cinematic universe of his many superyacht renders. Phwoar, this one looks like a giant pirate ship with its face painted.

Source: The Goliath Series

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14 comments
14 comments
dan
Pegasus has understood that a million costly aircraft must offer a decent range and payload. its hybrid system with bio fuel/fossile fuel energy source outperforms by 10 to 15 any battery technology. Osprey uses a crankshaft in between both turbines for redundancy. it is to prove that the Pegasus solution is safer, lighter and more efficient. In case of failure, at least this concept could glide and land safely (at very high speed?), eliminating a major problem of eVTOLs. Good luck Pegasus!
Towerman
There is No Major problem with Evtols EVTOLS have redundency, they have reliable motors ICE fans can only dream about, they have less complexity too. A 4 rotor quad EVTOL can still fly with one motor out so there is no redundency issue whatsoever.

Loz i see Joby just made an announcement, perhaps you can add it on NewAtlas ?
jerryd
I don't understand why more are not using tilt wings as so much easier, safer and one can have cross shafting to 1 prop going out doesn't cause the plane to break up at speed or flip into the ground low down.
Since there is a 1 engine out requirement it'll never pass FAA.
David
In the event of failure of either motor, if the failsafe position for the nacelles were to be for the rotors to be horizontal, could both rotors then be allowed to autorotate to help bring the aircraft down reasonably safely.
vince

At least they should have made it green by using hydrogen as the fuel for a generator to provide the electrical power for the 750 hp motors. But they need 4 rotors not 2 for practicality and safety. Just a stupid design all around for speed nothing more.
kenneth53
How does one determine the mass of an aircraft's flight range? Do you measure the entire volume of the space encompassed by the distance it can fly and calculate the mass of the air contained in it, or just the airspace through which the vehicle travels? I imagine it is the same sort of calculation they apply to massive sinkholes. Or maybe, just maybe, using the word massive in referring to things which do not have mass is an error. ;)
Nelson Hyde Chick
Looks like another toy for the wealthy as the rest of humanity is left to rot.
Nelson Hyde Chick
jerryd. If the props stop spinning on this design the plane could glide to a landing, with the wing tilted they couldn't, so this way is safer.
Aermaco
The rotating wings with props are so much better than this particularly bad geometry that is blasting its wing downward as it tries to lift upward. The face area of prop wash has what appears to be maybe 30% of it lost in forcing the wing down. If the flaps were not dropped it would be 50% lost lift. The nacelles that extend beyond wings for rotated props are much better if wings don't rotate.
Gabor Pauler
One has not to be aircraft engineer, just use some common sense, to recognize that wings will block large portion of propeller downwash, making the whole design unworkable. Another nice product of "photoshop aircraft industry".
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