NASA to tear the wings off plane in the name of sustainability NASA has named the MD-90 jetliner it will rebuild with a radical new type of wing support in an effort to develop technology that reduces CO2 emissions. The MD-90, like the 737s and A320s that dominate the world's commercial airline fleets, is a single-aisle twinjet. NASA thinks planes of that sort can be made more efficient …
That 'support' is of course under tension in flight, transferring some of the lift from the wing to the fuselage. I'd love to see the structure where it's attached. But I wonder where they're going to keep the fuel... isn't most of the wing space fuel tanks on most aircraft? That long thin wing is good for lift and drag but it looks like a rather smaller volume.
Mind you, if the efficiency increase matches the fuel tank size change...
less fuel, less weight and less lift so smaller volume wings makes sense. The wing struts will produce lift so it is close to a bi-plane At one extreme it could become a bi-plane glider with maximum lift and little forward velocity, at the other a dart shaped projectile with minimal lift but high speed ... neither would need much fuel while in the air. In fact I saw a documentary once where a runner on the road competed against a elastic-band-powered flyer. Spoiler alert, the road runner won, Wile E Coyote ran out of power and lost ...
Long thin wings will give similar lift, but (hopefully) reduced drag. Reducing drag will lower fuel consumption, which will mean a lower percentage of an aircraft's take off mass has to be fuel to achieve a given range.
The structure attaching the thin wings to the aircraft will probably be of a similar mass to a conventional design, because the forces passing through it into the fuselage will be similar if the jet is carrying the same number of passengers and / or cargo. Any gains in efficiency from reduced wing mass are likely to be small compared to gains from reducing drag.
The structure attaching the thin wings to the aircraft will probably be of a similar mass to a conventional design
Not necessarily - non-supported wings need to be fairly substantial to resist the bending forces acting on them, whereas a supporting truss mainly experiences stretching forces so can be much less robust, and therefore lighter. Think of a piece of wire that coat hangers are made of - very easy for anyone to bend with their bare hands, but I challenge anyone who isn't a Mr. Universe contender to stretch it.
There's a reason for putting fuel in the wings. Fuel == weight. The wings produce the lift needed to counteract this weight. The shorter the path beween the lift and the weight, the less structure that will be needed to transfer the load. So, less "parasitic" structural weight.
@Paul Hovnanian
When they are strong enough with full tanks to taxi on ground and take off I am sure they are strong enough in the air too.
Also it's easier to put fuel in the wings instead of passengers and luggage. But there was indeed a plane with passengers in the wing once.
Well the MD80 can take about 18 tonnes of fuel, nearly a third of the 64 tonne MTOW.
Half of that fuel is in the wing tanks, and the other half is in the centre tank.
https://www.hilmerby.com/md80/md_fuel.html
"Max usable tank capacity 4 200 kg in each main tank and 9 340 kg in center at 0.803 kg/l in spec weight."
Not sure if the modified wings actually affect the centre tank structure (which might still be part of the wings)
"Mentour Pilot did a good video covering this in pretty much layman’s terms back in February. Worth a watch."
I love his channel and common language explanations of aircraft. He didn't spend a lot of time on it, but he did touch on the issue of getting around with such long wing spans at airports. I don't fly anymore, but I'm not all that thrilled with an aircraft with folding wings. I know that navy aircraft do it for carrier work, but many of those also have a way for the pilot/RIO to eject if something goes wrong. The first Space Ship Two crashed due to the copilot unlocking the wings prematurely causing the craft to backflip at near supersonic speed and tear itself apart. While the commercial aircraft would only lock/unlock on the ground, I'd also hate it if there were an issue with folding while taxiing in to the terminal causing a big delay while the assignment was changed to a larger gate. It's just one more thing (or several really) that can go wrong when you want something to be very simple. What I'd like to see if how the added costs play against the savings in fuel.
If you gave the job to Derek Meddings, the wings would be at one end of the airfield being refuelled and so on, the engines would be at the side of the airfield being sent out from the service and test hangar, the luggage would be loaded into a module that comes up from an underground railway at the end of the runway and the passengers would board into two bus-like hemi-structures at the side of the airport terminal, which fold together to form the aircraft body. The various components would then be assembled out at the end of the runway where there's plenty of room a few seconds prior to take off!
This is a converted MD-50, which is a low-wing design. So the new internal bit is the roof join which transfers the rest of the lift to the fuselage.
This is also an X-plane, strictly for research purposes only. There will be plenty of room in the old passenger cabin for all the fuel tanks you need to fly a circuit or two round Area 51.
There's always in-flight refuelling!
"When Cobham was developing his system, he saw the need as purely for long-range transoceanic commercial aircraft flights, but today aerial refueling is used exclusively by military aircraft."
they are making the fuselage shorter so it'll likely weigh less.
would be interesting to understand what that 30% claim relates to because lighter plane plus more efficient modern engines is likely most of that 30%.
would be good to see a comparison of a modern 737-8 / a320 vs the md-90 its likely ~ 20+% already without spending a billion dollars on new wings.
Depending upon how efficient it winds up being, combined with battery advances (graphene aluminum-iok, anyone?) they might be able to make it work as an electric plane. Even if they only ever manage regional jet service and still need kerosene for long haul flights, that's still a considerable fuel savings.
Of course, that requires a nuclear reactor at every airport to produce enough juice if you don't want carbon fuels used.
Breaking the speed of sound and landing the aircraft is the key part. Piston engined aircraft like the Spitfire and Mustang could reach the speed of sound in a dive, but they would be dangerously out of control if/when they did.
(Not that they'd know how fast they were going, a simple airspeed indicator isn't useable once you go that fast)
"Until Musky appeared and changed the entire industry, mach-lots, dump in the sea was how most rocketry worked."
It takes nearly 50% more capability to re-land a booster so the ROI didn't work out when you also consider needing to add margin to the components so they can be used several more times. Whether SpaceX makes a profit or not with reusing boosters is anybody's guess. They're private so the financial reports aren't out there to dissect. They do seem to need an awful lot of private funding rounds every year in any case. Landing rockets has been done for ages. The Surveyor missions sent to the moon in the 1960's landed successfully and sent back data. Even John Carmack, author of Doom and Quake was landing rockets before SpaceX with his company Armadillo Aerospace.
Sound barrier was broken in 1945 by Hans Guido Mutke
On 9 April 1945, Fähnrich Mutke, in his Messerschmitt Me 262.
Mutke went into a steep 40° dive with full engine power. While passing through the altitude of 12,000 m, his Me 262 started to vibrate and began swinging from side to side. The airspeed indicator was stuck against its limit of 1,100 km/h (684 mph) (the maximum speed of the Me 262 is 870 km/h). The speed of sound is 1,062 km/h (660 mph) at an altitude of 12,000 m, depending on the environmental variables. The shaking intensified, and Mutke temporarily lost control of his plane. He reported that with the airspeed indicator still off the scale he attempted to recover from the uncontrollable dive by adjusting the main tailplane incidence angle. Rather than just having a hinged elevator, the Me 262 could change the angle of incidence of the whole tailplane, a design feature that was later added to the Bell X1. Suddenly, the buffeting stopped, and control resumed for a few seconds. Mutke throttled back and his engines flamed out, and after the short period of smooth flight, the buffeting resumed and the aircraft began shaking violently again. He fought to regain control and re-light the engines eventually reducing the speed below 500 km/h. After a difficult landing, it was found that his plane was missing many rivets and also had distorted wings
(A computer-based performance analysis of the Me 262 carried out in 1999 at the Technische Universität München concluded that the Me 262 could indeed exceed Mach 1)
Sounds like another Wunderwaffen myth to me. The Me 262 had a critical Mach number well below Mach 1 and these effects, with accompanying drag, would have built up while still barely above that critical speed. The same applied to piston types in power dives, such as the Spit and Mustang mentioned earlier. The Spit had the highest critical mac number of any piston type and, I have seen it said, possibly of any WW II type including the jets.
The acid test for going supersonic is whether the shockwave breaks free and gets heard on the ground as a "sonic boom". DH.108 Swallow VW120 achieved this on 6 Sept 1947 and lived to tell the tale (though later on it was not so lucky); it was the first British plane to go supersonic (if totally out of control at the time), and some claim it was the first in the world (but I don't know how true that is).
They all were in those days. Transonic shock waves bugger up the calibration something frightful, and the effect is dependent on altitude, so it took many years to get an instrument calibrated to a useful level of (in)accuracy. Typically, you had to install the thing in a given aircraft type and then calibrate the whole installation for a matrix of different speeds altitudes. Even today you still have to carry out all those flight tests.
Moreover the indicated airspeed differs from the true airspeed by a varying amount according to altitude anyway, and it is actually more useful to the pilot to keep it that way. So even an accurate ASI needs its numbers recalculating to correct for that altitude offset.
Back in the middle of a never-done-this-before-but-no-time-to-stop war, the whole transonic thing was just a mess.
There is what you aspire to, and who you turn to in order to achieve what you aspire to. One of these things is not like the other. The words Boeing, Budget, and Decade' sort of hang there, in much the same way a brick doesn't.
High aspect ratio, trussed wings have been floating around a long time - literally, floating around the skies - because they were actually built, and flown succesfully more than half a century ago, with many iterative designs knocked out annually since.
This particular 'modern' take on the concept has been knocking around Boeing's desk for a decade already but getting around to actually building one? Beancounters have already said "No, wait 'til someone else ponies up, and use something that's knocking about the back of the cupboard - there's an old, pimped DC9, use that"
This project may well be obsolete the day it's rolled out, it's not like there isn't a hulking great precedent for that somewhere, and if you have been exploring this for a decade already, and talking another *decade for delivery, then that's the past, not the future. (*7years at the latest, honest guv', we pinky swear)
Ahh, you know what, I'm tired of being cynical, good luck to all, and I'll cheer for a brave new dawn of aviation - now I'm off to practice getting the the right inflection on that sentiment in front of a mirror.
Net Zero is a joke and unachievable, but governments will push a lot of money around and grant some very big contracts to 'meet' those pointless targets. The truth is, the vast majority of carbon is generated as part of the planets natural carbon lifecycle, and the oceans and plants soak up most if it, and only 0.4% of the atmosphere is CO2 anyway (and if it drops below 0.2% we all die). 'Climate Change' has been politicized and weaponized to make sweeping changes that aren't really needed, but will hit the poorest the hardest (as usual) and implement controls and restrictions on a scale never seen before. Thought C19 was bad - how about 'climate lockdowns'!
The planet has survived way worse than man can throw at it - it's humanity that are screwed.
The only bit of this that I'll agree with is that "Net Zero" and "Carbon Reduction" have become politicised and that it's mankind/society as we know it that's screwed. The planet is indeed likely to 'auto-correct' and it's only microbes, simple plant-like life and cockroaches likely to survive.
Climate Change is the new moniker for Global Warming because a lot of people misunderstood what Global Warming referred to - it was a bit too physics... Warmth having been used as a semantic equivalent to Thermal Energy. Thermal Energy that translates in part to Kinetic Energy within the atmospheric shell, which results in increased atmospheric churn and thus change in the climate. CO2 has been fingered as ONE of the greenhouse gasses responsible for holding that thermal energy caught by the ground, but there are others, such as water vapour and gaseous hydrocarbons.
Let's be fair... if a rise in CO2 in the order of a fraction of a part per million can produce such dramatic effects as have been observed, then it's very worrying indeed! As for the targets being pointless... they do seem rather arbitrary, having been set by what's realistically achievable with effort rather than on the basis of what's realistically going to be effective.
"Climate Change is the new moniker for Global Warming because a lot of people misunderstood what Global Warming referred to "
That's rewriting history to fit modern agenda: What it means is literal global warming. Then it didn't happen and hockey stick curve was proven to be BS, but there was too much money to be made from taxing CO2, so they couldn't just give up and renamed it as climate change, which is literally meaningless term as climate has never been stable. Pure legalized theft.
It's not even related to pollution as avoiding CO2 increases a lot of other forms of pollution, it's just about money. Always follow the money.
" if a rise in CO2 in the order of a fraction of a part per million can produce such dramatic effects as have been observed"
It can't, obviously. First: CO2 is *weak* greenhouse gas, even common and simple stuff like water vapour is 100* nore efficient. (IPCC tries to revert this right now, BTW:They do not like reality)
Second: There's >100* more water vapour in air than CO2, so the ratio in effectiveness is at least 1:10 000. IPCC doesn't say a word about water vapour: Can't tax it.
But now barely measurable changes in CO2 are causing percentage -level of changes to global average, according to IPCC. Fummy thing is that they've zero proof for it. Or formula. Ot eve actually correct climate model aftger 30 years of trying.
Where's the slowly vanishing ice age? Universal warming in 1995-2005 which didn't happen on Earth? Greenland and VIkings? (Don't exist in any IPCC material).
As a hard scientist (do 100 lab tests, analyze, repeat if results don't match) these guys are only world class thieves with zero actual science behind the claims. Most obvious is lack of formula: Temp versus CO2 concentration. A correct one I mean, with precitable results, every time.
Trussed wings are flying all over the place (it is the scale that is changing here) so how about going one step further back and adding some strength by using guy cables?
Probably a bad idea (drag and all that) but it just seemed an opportunity to let the pylon be used as a support for wing walking: who wants to be the first to stand the whole way on top of a transatlantic flight?[1]
[1] don't think RyanAir wouldn't if they could make it work: although to reduce drag they'd advertise that you are one of the lucky few passengers who gets to lie down during the flight. Be warned: in an emergency situation, you would be required to pull-start the engines.
Unlike the posters here.
Everything in airliner design is geared towards reducing total lifetime cost of the passenger mile. As engine designs develop, and the market changes, aircraft design also must change.
There is a complex optimisation between aircraft cruising speed (= more passenger miles per yer) , aircraft drag (=more fuel per passenger mile), wingspan (=less terminals can accomodate giant planes) and wing aspect ratio, (long thin wings have less drag - sailplanes) (=greater structural issues, needing more weight to bring strength).
Adding a strut creates lift, and reduces the need for wing root strength, but adds drag.
One assumes the overall equation is marginally positive, or they wouldn't be doing it.
"Everything in airliner design is geared towards reducing total lifetime cost of the passenger mile."
NASA is concerned mainly with science and not engineering. They aren't doing applied research where the goal at the end is a viable product that aircraft makers will sell and that's a bigger and subtler difference than most people understand. Not everything can be simulated in a computer and some simulations can't be written until there is some practical experiments done to back up a hypothesis even if the math looks pretty clean (not getting infinities all over the place). NASA does design and build some things, but it's often to have a craft or custom device to be able to go out and collect data.
When I was working on rockets, we'd use the words "science project" to disparage the work it would take to come up with something on our own. It was always a goal to look for COTS (commercial off the shelf) products rather than design from scratch. We'd often modify that gear, but would know a lot about how it works going in. A good portion of a rocket can be sourced from a well stocked commercial supply company.
"Everything in airliner design is geared towards reducing total lifetime cost of the passenger mile."
Irrelevant when it's NASA. Almost sure this a pure pork project for Boeing and NASA is only middleman, getting like 10% to themselves.
Commenter is really an amateur in this business.
This is of course just ripping off the French designed and built Hurel-Dubois HD.31 family of aircraft. I'm fairly sure if they asked nicely there are some surviving examples NASA could get airworthy to allow Boeing to concentrate on unf**king the rest of their business.
"Remember much of the worlds fleet of 747s has been replaced by smaller more (per passenger) fuel efficient aircraft."
The 747 is hugely efficient per passenger mile........... provided you are running routes where there are full loads of passengers that are willing to fly that route and on a far less frequent schedule. The other factor is distance. Taxiing and take off are expensive. Look up what the A-380 can consume getting from a gate to the end of the runway and realize the Concorde was much worse than even that. On a very long flight though, that expense will amortize quite nicely.
This is an experimental X-plane, not a production prototype.
They presumably have their reasons for the cut-and-shut. I'd guess it is because they can't re-use the old wing attachment point, so easier to just cut that section out and bolt some new reinforcements in. But I have not been following it in that much detail.
It may also be for balance reasons. They're taking an aircraft with tail-mounted engines and turning it into an aircraft with wing-mounted engines. That's a major relocation of the heaviest single component of the aircraft. Taking out a plug forward of the wings would help reduce the need for ballast in the tail.
"I'll happily take 30% more leg room."
Good luck with that, mate. They've built seats 75mm less thick so they can squeeze in yet one or two more rows of seats over what used to be the norm back when I would get on a passenger jet. If they could just require everybody to stand and only provide a strap to hang on to, I could name a few airlines that would go with that.
"Need supersized Parking bays or everyone ion the busses to get to the terminal"
I'm old enough to remember walking out on the apron and climbing the stairs to get on a plane. A big reason jetways became the norm is time to get people on and off. Just one person in a wheelchair could blow a schedule the old way. It's also safer for the people servicing the aircraft not to have stray idiots wandering about under the plane where they shouldn't be.
Aren't the US against other people subsidising their aircraft manufactures?
"While NASA has committed to contributing $425 million over the next seven years, Boeing has committed to around $725 million for the program, NASA said. "
Sounds like a massive R&D subsidy to me, not just in cash terms but in "free" use of NASA resources.
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