SE aeronautics claims tri-wing aircraft could revolutionize commercial aviation
designboom.com
designboom.com
"I’m highly skeptical. Drag is already very low on modern jetliners. You’re not going to achieve 70% fuel reduction without a miraculous improvement in engine efficiency. A “once-through” air supply system would be inherently less efficient than current recirculating systems. No fuel in the wing? Then fuel weight is not distributed and the wing must be stronger.. thus heavier. I would love to be wrong about this, but with the information given, this design looks like vaporware."
It's so low that they have to add a bit of drag in the right place to prevent stalling (the small fins on top of wings).
> No fuel in the wing? Then fuel weight is not distributed and the wing must be stronger.. thus heavier.
It's also less secure in cases of emergencies, as far as I know.
I forgot why but I think there where also some really good reasons (beside closeness to fuel) why turbines are now mostly below the wings.
Aslo wouldn't building 3 wings more expensive even if they are smaller?
And then I have very little experience with aero dynamics, but my intuition tells me that there are some tricky parts around the (forget name: movable parts at the back of wings) and additional failure cases as you now (likely??) have to have 3 sets off them on each side.
With 3 sets of wings, the plane would have much more flexibility with the center of gravity. With two wings this needs to be where the wings are. This is why fuel is put in the wings in such configurations. It's a good design if you only have two wings. With 6 of them and the engines mounted on the back, you can play around a bit with different weight distribution.
I'm guessing that using fuel bladders on top of the roof would allow for flexible placement anywhere between the first and last set of wings. Also, you can pump fuel around as well to change the weight distribution (and possibly even trim the airplane's pitch).
Drag of modern planes is quite optimized for their current designs. However putting the fuel in the wings and mounting the engines on them probably adds a fair bit of drag regardless. Also such wings have to be bigger and stronger. I've had a window seat next to the wings of an A380; they are massive. So, I can see how changing that configuration that could eliminate some drag. And using modern composite materials without seams is also going to help with both weight and drag. Less weight means more fuel savings. If it adds up to 70-80% will be interesting. IMHO the real issue is going to be getting rid of kerosene as a fuel. Synthesized fuels like hydrogen or methane could potentially be a lot more sustainable.
Many of the advantages they list would also apply to conventional designs, including fully-composite construction. The only advantage of multiple wings I can see is that the horizontal stabilizers on most planes generate downforce, which a multiple wing system could avoid. On the other hand, canard designs also avoid that and it seems the gains aren't so important as to get them adopted.
https://www.seaeronautics.com/about-us
Their address is in a residential area, and the lot there (Mathews Manor) seems to be cursorily chosen.
9997 OLD SPRINGVILLE RD, TRUSSVILLE, AL
Actually, two of their team have the last name Mathews.
Few things:
> the patent-pending ‘SE200′ concept features a lightweight tri-wing layout to enhance lift over drag
Weird statement. Generating lift is the extremely easy. You don't need 3 wings to do this. Doing so while minimizing drag as much as possible is what's hard, as more lift results in more drag. Looking at all that extra wing surface tells me the parasite drag is going way up. You'd be much better off placing that same surface to extend the wing length, which would reduce tip vorticity drag.
Also having three-wings in a horizontal line like this is going to dramatically reduce the effectiveness of the rear wings. Wings produce downwash in the airstream that negatively impacts performance of any surface downstream. This is why canard designs have to be designed VERY carefully. So right away the "will minimize drag" claim is pure fantasy.
> Fuel is stored on top of the fuselage in self-sealing bladders, and not in the wings.
This really reminds me of something an undergraduate would put in their capstone project borne out of their lack of knowledge. Fuel stored in the wing is a good thing, as it alleviates bending stress due to lift and helps dampen aero-elastic phenomena. Also, this way the fuel mass (which changes during flight) doesn't significantly move the center of gravity, thus changing the stability and control characteristics of the aircraft, and not creating more trim drag.
Just a first pass analysis to distract me from work. I hope some more people here can pick this apart more. With a bit more time, I'd like to examine the stall characteristics on this vehicle (which I imagine are just atrocious) .
Someone looked at the drag on an airliner and thought "sailplanes have thin wings for low drag, airliners have thick wings for fuel storage and have high drag, we'll just put a few thinner wings and revolutionize the industry! Oh, and I hate stale, recycled cabin air, and the pandemic showed how bad that can be, so let's not do that. We'll build it in one piece, like a plastic injection molded part, instead of a bunch of riveting, and save more money that way too."
They took Chesterton's fence and threw it in the woodchipper...
The new developments are:
1. Aerogel thermal insulation, enabling airborne tankage of liquified hydrogen, LH2.
2. LH2 to be synthesized on-site at airports using electrical power delivered by regional high-voltage DC transmission lines, and later by low-voltage underground superconducting transmission lines.
3. Cheap, abundant, intermittent renewable power, to be banked as LH2 during price minima at mid-day from solar, and at night from wind.
4. Direct, fuel-cell conversion of LH2 to power lightweight electrically-driven turbines.
Fully exploiting the opportunity will need whole new airframes to accommodate much larger but lightweight LH2 tankage that would not fit in current wings; and enabling advance investment in airport infrastructure to synthesize, store, and deliver LH2 to aircraft, starting at certain high-traffic intercontinental airports, to support the new fueling model.
The efficiency gains available, and reduction of CO2 delivered directly to the stratosphere, are enough to justify the massive upheaval. But the current blinkered economic structure of air transport mean it cannot happen without active, international government support.
Fortunately, the cost structure may be made transparent enough to leave little scope for the legalized corruption that plagues typical big infrastructure projects.
Intermediate rollout stages are plausible, such as conversion of existing turbojets to burn hydrogen; and of existing airframes to carry LH2 in under-wing tanks alongside engines.
I'd like to see a dual (twin) fuselage version of this.