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angrathias t1_j5gkvvm wrote

Don’t normal aeroplanes already cruise at like 900kmh? What’s the big difference ?

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lughnasadh OP t1_j5gmdtm wrote

>>Don’t normal aeroplanes already cruise at like 900kmh? What’s the big difference ?

Jet airliners (Boeing, Airbus, etc) are about the same speed, but this engine isn't competing with those.

This design only works on smaller planes. So this is faster than most of those, and it seems quieter, more fuel efficient and cheaper to maintain.

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gerkletoss t1_j5i5yxt wrote

How small are we talking here? Also, can that thing glide?

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caspy7 t1_j5iaqxi wrote

Most things can glide given the right conditions. 😁

More seriously, I'm no aviation guy but gliders tend to have longer wings and are light particularly because of their lack of engines. So while traditional planes can glide some, the compactness of this design makes me think it would be especially poor at gliding.

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polar_pilot t1_j5id2p3 wrote

Yeah the glide range of this thing would be abysmal, and the speed with which it would achieve best glide distance would probably make an emergency landing/ crash far less survivable. Perhaps it’ll come with a parachute system?

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caspy7 t1_j5ieffe wrote

Traditional planes can glide some and hit the ground at a more gentle angle and do I recall that helicopters do some slow rotator spin to make landings more survivable?

That was something that came to mind, if these are an improvement on helicopters that'd be great, but if they became known as deathtraps when the engine fails it could tank the tech forthwith.

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theBytemeister t1_j5ifvau wrote

Autorotation. If you really want a better understanding of what is happening, read up on autogyros. They are essentially a helicopter in auto-rotation that is pushed around with a propeller.

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gerkletoss t1_j5ifcyc wrote

>and do I recall that helicopters do some slow rotator spin to make landings more survivable?

Aurorotation. The airflow through the rotor reverses and the spinning creates a ton of drag.

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polar_pilot t1_j5ifmvd wrote

Yeah the more wing you have the better you can glide- more or less. An airliner can glide a LOT better than an f-16. Helicopters can do what’s called an auto-rotation, the airflow over the blades creates lift and spins them- same principle as a gyrocopter- thus slowing descent. A parachute would be the only way this thing makes sense. I imagine it would be installed considering they’re not hard at all to put on a composite frame aircraft

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gerkletoss t1_j5if6wl wrote

I was wondering about emergency landings, not gliding as plan A

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NotShey t1_j5k3lys wrote

>So while traditional planes can glide some,

Glide ratio of a typical airliner is around 17-20:1 (17 miles horizontal for every 1 mile vertical). Highly maneuverable aircraft are where you tend to see abysmal glide ratios. I don't believe it's publicized anywhere, but I suspect your typical F-35 glides about as well as a brick.

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im_thatoneguy t1_j5krfc9 wrote

Their first RC plane scale prototype was on a glider.

It's just an alternative to turboprops or turbofans, so sure you could attach it to anything. You could attach a turbofan to a "glider".

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Renovateandremodel t1_j5i8n9x wrote

I’m curious as to the sound of it, and wondering if the sound can be dampened down to a point of 80 db?

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im_thatoneguy t1_j5knwfo wrote

This can take off like a helicopter: VTOL. So imagine a medivac chopper that can then cruise at the speed of an airliner. You could fly direct from the front lines of a military conflict to a field hospital. In other words, you could get to a hospital 3x faster or 3x further in the same time.

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ExedoreWrex t1_j5njoy5 wrote

The difference here is how the thrust is delivered. Instead of having the engine directly attached to the propulsion mechanism in the same nacelle (as we see in airliners with turbo fans and turbo props) the propulsion mechanisms can be attached via simple ducted vents. The thrust is also generated from cold ducted air unlike the heated exhaust of most turbojets. Unlike turboprops there are also no external blades to pose a moving hazard. This system should also allow for much quieter aircraft as the gas turbine could be placed inside the airframe and soundproofed much more easily than an externally mounted engine.

The lack of centrifugal force or mechanical drive mechanism in the thrust generators also allows them to be easily rotated without the usual mechanical issues in more traditional designs, making this especially useful for VTOL. The rotation can also allow for the thrust to be used for lift as well as a forward driving force, eliminating the need for lengthy wings. Use cases with multiple gas turbines used for additional thrust should also eliminate problems of a thrust imbalance if a gas turbine failed. The ducted high pressure air should be able to be sent to all thrust generators from any and all gas turbines.

Look up all the difficulties the Osprey has thanks to the complexity of it’s rotating turboprops. This system eliminates all those complexity issues and can provide the exact same functionality more efficiently.

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