You need new ideas or you never get anywhere. The purpose of old farts is to keep pointing out the current state of the art that the new idea must beat. They can be ruthless at it....which is why innovators tend to tune them out. You can't make progress if someone is always dragging you down.
The flexi-wing concept has been popular. Look at the prior research on dynamically controlled structures. Also look at the high-flyers (HALE) multi-motor flying wings. Takes some software and some controls to keep from exciting a bunch of different structural modes. There is a video out there of an R/C version of such a thing, and you can watch the ripples and waves along the length of the wing.
Where I think the aero-heads lose it is when they branch over into structural design. A recurring goal is to try to make structures like Legos. I worked a project not too long ago with a government customer who was very proud of using a modular, "Lego-like" construction. (Their words, not mine.) However, they got all tied up in their internal marketing. A structure like that is nowhere near as structurally efficient, so you pay a price in significantly increased weight. They never seemed to acknowledge that. Just as in the summary in the news article here. So the breakthrough that you need that would make a modular wing feasible (modular in the Lego-sense that the article is describing) is a new kind of structure that pays no penalty for joints. Without it, you will have only concepts and aero developments--not a practical wing. (This modular thing is being linked by a great government push to printed parts. Printed parts is the hottest topic in every college right now.) Unfortunately, you cannot yet use the stuff for aircraft structure because there are no approved allowables for the material. Even the metals are more like composites, because the properties are not close to isotropic, and are very sensitive to process controls. Just like composites.
And while I'd strongly bet that the MITs are thinking toward using printed metal and printed plastic "bricks" as their producibility enabler, I think industry has been working for 30 years on fiber placement technologies. For sure the key to making affordable non-metallic structures is to get rid of the huge amount of touch labor.
The other thing people don't commonly understand is that in order to put a test article into a government wind tunnel, like the photo of the modular wing in the NASA Ames tunnel, is that you need something like a factor of safety of 5. This is there to protect a national asset from damage should your experiment model behave differently than you might expect. So you build it massively stiff and strong, and you don't learn anything at all about the behavior of a flexible wing. Unless you actually articulate the model. I can't tell from the photo if they did this, but I doubt it. I would welcome one of the bright and bushytailed to explain the project in more detail. In particular, the statement that the structure "...has the same stiffness, but ours has less than roughly one-thousandth of the density.” They must be comparing to an earlier version of their own bricks, else they are not comparing apples to apples.
If you want to see more about the aeroelastic structures at high speeds, go look at the X-29. Been a long time ago, but as a research vehicle, it took advantage of newer, higher strength materials.
As far as aero-heating, unless you are flying a fighter at lower altitudes, this really shouldn't be an issue. On a transport or airliner it is not a serious design driver. If this seems counter to all that you have been told, go look for the NASA aplet that lets you put in the altitude and airspeed and it calculates the stagnation temperature. You might get a ten degree rise, but at 30,000 feet the ambient temperature makes that irrelevant.
Dave
Topic: NASA's new wing design? (Read 707 times)