I remember sitting in a class one day and hearing that there would always be wingtip vortices on planes, and wondered if that could be solved by looping the wing around (to where it almost looks like a biplane).
I wonder how many other ideas are being sat on because people don't realize its significance or have the resources (such as time or desire).
There are still tips and vorticies, just not at these speed/size/power settings. The length of the blade is the biggest issue. These are effectively short blunted tips with a hole in the blade. Whether the improvements would translate to air, with all the associated speed of sound issues, is unclear.
Another old option for eliminating such issues is to put the prop in a case, like a jet ski or most modern military submarines. Or just eliminate the concept of tips and turn the entire case.
For small fish they’re probably about the same but they seem like they’d be superior for larger fish since they wouldn’t be able to get drawn into the middle so you’d have less strikes along the backs like you often see on whales or large sea animals.
A century ago engineer Luigi Stipa did experiments with several flying wing aircraft designs. Here is Stipa-Caproni's "intubed propeller" from the 1930s:
Ok so there is an entire subreddit dedicated to weird wings. I’m not surprised anymore but I’m still amazed at how online communities can be so specific.
This issue is an unending source of discussion. The thing is, you cannot eliminate wingtip or wake vortices by putting a finite barrier at the wing tip, no matter how large. This is because [begin hand-waving approximation] for a wing to produce lift, it is necessary for the airflow passing in close proximity to the wing to be deflected downwards (no acceleration, no force.) This unavoidably creates a region of shear at the boundary between this wake and the surrounding air mass, leading it to 'roll up' into two counter-rotating vortices (as this is a hand-waving approximation, I won't mention the circulation around the transverse axis of the wing...)
We can't banish them, but you can do things to reduce them, the simplest of which is to move the tips further apart (i.e. lengthen the wings.) Everything about airplane design is a compromise, however.
Good ideas are a dime a dozen. What's rare and precious is the very hard work of birthing an idea into existence with good execution. Unfortunately, even with a good idea, hard work, and excellent execution, innovation still usually ends in failure.
Yeah, I can say with some certainty that every aerospace engineer has this idea at some point then moves on to other things. A select few have pursued it but at least at aircraft scale it results in a number of other engineering challenges related to structures and resonance so it's usually abandoned. The brilliance here is applying it to an area where the aspect ratios are so low that the mechanical issues don't apply and you can just cast it out of a big chunk of solid metal.
I remember sitting in a class one day and hearing that there would always be wingtip vortices on planes, and wondered if that could be solved by looping the wing around (to where it almost looks like a biplane).
I wonder how many other ideas are being sat on because people don't realize its significance or have the resources (such as time or desire).