China's transport, tanker & heavy lift aircraft - esp. Y-20/YY-20
- Thread starter Totoro
- Start date
That post had been removed by the mods there. Any other source for the video?
For what again? It's not low quality...?
I wonder if there would be a winglet added in the future. Would definitely help with the fuel burn reduction, ability to carry a slightly higher payload, climbing faster, and lastly, with the aesthetics too. After all, it's not a high aspect ratio wing to begin with. So, winglets must offer those benefits.
It's an extension to the wing, if it offered any advantage then they would have done it.
Things can change in the future like with clipped wings on later P-51 to make it more maneuverable.
lcloo
Major
Winglet is not the only design to go for. There can be other wingtip design or the whole wing design (as in Y20) that may be more superior for the role the aircraft is designed for.
The Xi'an Y-20 transport aircraft does not have winglets because its wing design is already optimized for aerodynamic efficiency.
Span Efficiency Over Winglets: Instead of using winglets, the Y-20 features a high aspect ratio wing that naturally reduces drag. Winglets are often used when increasing wingspan is impractical due to airport space constraints, but the Y-20 does not face such limitations.
Y20 employs a supercritical airfoil, which enhances lift and reduces drag without needing winglets. This design improves fuel efficiency and performance at high speeds.
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Is that true? The Y-20 aspect ratio seems similar to large airliners by eye at least (, ). It actually has a smaller wingspan than the 747 (50m vs 60-70m), so the space constraint argument doesn't make any sense...
Correct me if I'm wrong but aren't supercritical airfoils also only advantageous at transonic speeds? Which isn't relevant for the Y-20 travelling at maximum 0.75 Mach.
Why are you even comparing Y-20 and B747? The latest B747-8 has a MTOW 450t compared to ~220t for Y-20, they aren't even remotely in the same class of aircrafts. Ridiculously high aspect ratio wings come with it's own can of worms that it brings mostly structural considerations, also tactical military transports have to consider the fact it'll be operating off unprepped runways and small airports, B747 requires airport rating of 4E due to it's long wingspan and long take off roll, such airports are relatively rare. This is why C-17 required winglets due to airfield limitations since the optimal wing design would exceed the limitations while this wouldn't be a issue for Y-20 as Y-20 is a smaller aircraft and hence the optimal wing for Y-20 would be small enough to be within those limitations.
Supercritical wing works by delaying where the shock forms on the wing as long as part the airflow over the wing is supersonic, it'll benefit from the added efficiency however exactly when that happens is slightly different for each specific wing design but it if I'm not mistaken the onset of this effect happens at lower airspeeds for lowly swept wing such as the ones on military transports.
Thanks for explaining. B747 was a poor choice for an example, careless on my part. I must've misunderstood the original post, I thought they meant that the Y-20 did not have to obey airport size limits, so it could have a higher aspect ratio. Didn't consider that it was a small enough plane to stay under those limits either way.