> No U.S airlines currently fly into any Russian cities, and those that flew over Russia's vast airspace to Asia had already been rerouting out of an abundance of caution. That adds time and burns a lot more fuel, increasing costs.
Yes and no. If you add a refueling stop to a long-haul flight, it can save enough fuel to make up for the rerouting. (Long-haul flying is really inefficient because you have to take-off/carry all the fuel needed to make it to your destination).
e.g. a flight from NYC-Paris-Delhi is only 5.5% longer distance than direct, even though it now routes over europe instead of a direct polar route over Russia
(This isn't perfect, it still shows a bit of routing over Russia, but you get the idea). And you still have staffing costs, landing costs, etc. Weather related routings, night-time landing restrictions, etc.
> Yes and no. If you add a refueling stop to a long-haul flight, it can save enough fuel to make up for the rerouting. (Long-haul flying is really inefficient because you have to take-off/carry all the fuel needed to make it to your destination).
It seems obvious, but I always forget that the rocket equation applies in aviation as well. The massive difference in fuel efficiencies when you get your oxidizer for free tends to overshadow it.
The rocket equation doesn't apply here, because planes don't just get their oxidizer for free, they get the whole reaction mass as well. So they generate forward momentum in a different way. Additionally, once a plane reaches cruising altitude, the only energy losses are due to air resistance, because the lift vector from the wings and the gravitational pull are antiparallel to each other and perpendicular to the direction of motion. The commenter above is still correct though, because the energy needed during ascent is proportional to mass times height. So if you can cut the fuel in half by limiting the total range, you can save a huge amount of energy (i.e. fuel) during ascent.
A plane is not a satellite. You need to constantly expend energy to keep it in the air. The more weight is on the plane, the more lift you need. To get a bigger lift, you need to angle the control surfaces steeper, which increases drag.
Therefore transporting heavy things by air (like fuel) is extremely inefficient.
That's a common misconception. In level flight, when you align the lift and gravity vectors correctly, they do not expend energy as work. Only 100% symmetric wings (as seen e.g. on acrobatic planes) require a constant positive angle of attack to generate lift. By using "normal" flat-bottomed wings and minimizing air resistance from forward motion, you can effectively glide huge distances using only the energy you get from slightly lowering your altitude in the gravitational field (downward motion component parallel to the gravitational vector equals work done on the plane to keep its forward velocity constant and balance losses from drag). Mass gets cancelled out there, because forward drag doesn't act on it and you also get more energy back from the gravitational field while descending. With an infinitely thin frame (=zero air resistance) or by using thermal updrafts, you could even stay in the air indefinitely. That's how glider planes work without any engine and why commercial jets at cruising altitude (very low drag up there) have some of the best fuel economy per person of all forms of travel. That's also how airlines can offer tickets at prices from which you wouldn't even be able to pay for gas when you drive the trip by car. Ryanair for example can fly you from Rome to London and back for ~40€. You'd be hard pressed to find a car that uses less than 40€ worth of fuel for just one leg of this trip, even if it could drive in a straight line. Flying itself is really cheap - it's everything else around aviation that's expensive.
Edit: I should probably add that this is different for cars. Cars don't just have aerodynamic drag, they also have rolling drag, mostly from small displacements of the tires where they contact the ground. If you ever tried to ride a bike with low tire pressure you'll know what I'm talking about. A heavy car that has the same aerodynamic cross section as a lighter car (think two cars of the same make/model, but one fully loaded and one empty) will have more rolling drag and thus use more energy/fuel. Two planes of the same model but with different mass will roughly consume the same fuel during level flight (there are slight higher order effects that I've glanced over here, but they are neglectable in the big picture).
Your explanation is misguided and half-truth at best.
Every airplane needs wings that generate lift to support its weight, and heavier airplanes need more lift. That lift does not come for free, except (if I'm not mistaken) in the theoretical case of infinitely long wings. To generate lift, a wing necessarily bends the stream of air downwards; that's it reaction mass.
Different references are used for angle of attack: some say zero angle of attack corresponds to zero coefficient of lift (called the absolute angle of attack), others try to align the reference with the chord line of the wing (geometric angle of attack). Obviously for symmetric wings the two are the same. In the case of geometric angle of attack, you could say a wing generates lift even with zero angle of attack. That doesn't mean that that lift comes for free! To generate more lift, the wing still needs a higher angle of attack (or more airspeed).
Higher angle of attack means more drag. There's just no way around it.
Gliders can stay in the air for very long times because they have very large lift-to-drag ratios, and hence very shallow glideslopes. They descend slowly, and the pilot tries to find rising air (thermals, ridge lift, lee waves) that rises faster than the plane descends. But make no mistake, even it those cases the plane still descends compared to its surrounding air.
So no, two identical planes but with different mass will most certainly not consume the same amount of fuel during level flight. The heavier plane will consume much more than the lighter one (depending of course on the difference in weight between the two), and the difference will be much larger than the difference between to identical cars carrying different loads.
See "See How It Flies" (https://www.av8n.com/how/) for a relatively gentle introduction to the physics of flight.
>a wing necessarily bends the stream of air downwards
This is only true for control surfaces and perfectly symmetric wings, but not for zero angle of attack wings as I explained above. Normal, cambered wings work because of the Bernoulli effect, where pressure is lower above the wing because of the way airflow is designed. Lift is not generated by pushing air down, the wing is literally getting sucked upwards. There are some mass dependent losses due to turbulence on the outer wing edges (which is, incidentally, why you see winglets on all jets nowadays), but those are higher order corrections as I also mentioned above. For an actually gentle introduction regarding how wings work, see e.g. this student level explanation here: https://www.grc.nasa.gov/www/k-12/UEET/StudentSite/dynamicso... -> Note that for the shown wingtype, no part of the airflow gets pushed down during level flight.
If you still don't believe me and instead want a realistic, highly technical argument, I suggest you take a look at literally any plane's operating handbook - especially the performance section. Here's one for the Cessna172 as an example: https://www.cpaviation.com/images/downloads/Cessna%20172M.pd... -> Note that under Cruise Performance, fuel consumption in terms of gallons per hour is calculated using pressure altitude and outside air temperature. You do not need to take aircraft mass into consideration for this part of trip planning. It is only important during takeoff and climb.
>Gliders can stay in the air for very long times because they have very large lift-to-drag ratios
You should look up how gliders sometimes carry extra weight in special water tanks to improve speed without sacrificing performance. Their optimal lift-to-drag stays the same, but the speed at which they achieve it becomes higher. How do you explain that? And of course they descend with regards to the surrounding air, I never said anything like that. But in terms of basic physics, updrafts are just a way of getting potential energy back that was lost due to drag lowering the kinetic energy.
Also: You are confusing angle of attack and angle of incidence. These things are not a matter of reference, the latter being inherent to any airplane's design. But they are irrelevant to this discussion.
> Normal, cambered wings work because of the Bernoulli effect, where pressure is lower above the wing because of the way airflow is designed.
Wait a minute. I thought this was debunked quite some time ago?
> Lift is not generated by pushing air down, the wing is literally getting sucked upwards.
Lift must be generated by pushing something down because otherwise you'd have a violation of Newton's laws. And the only way that pushing something down doesn't move that something is when that something is a solid support (like for example the chair I'm sitting on right now), which is not the case of an airplane in flight.
> This is only true for control surfaces and perfectly symmetric wings, but not for zero angle of attack wings as I explained above. Normal, cambered wings work because of the Bernoulli effect, where pressure is lower above the wing because of the way airflow is designed. Lift is not generated by pushing air down, the wing is literally getting sucked upwards
Bernouilli is one of the ways to describe the pressure differences around an aircraft wing in an airstream. But the popular Bernoulli-explanation where wings don't deflect the airstream is utterly wrong. Think about it, and consider for a moment the airplane as a black box, or a spherical cow for all I care. How does it stay in the air? Because the air exerts an upward force on it. Therefore, according to Newton's third law, the airplane exerts a downward force on the air. That force deflects the airstream down; there simply is no other way.
> Lift is not generated by pushing air down, the wing is literally getting sucked upwards.
By which force, exerted by which object? The air! If the air pushes/pulls the aircraft upwards, the aircraft pushes/pulls the air down.
> Note that under Cruise Performance, fuel consumption in terms of gallons per hour is calculated using pressure altitude and outside air temperature. You do not need to take aircraft mass into consideration for this part of trip planning. It is only important during takeoff and climb.
The tables and charts used for the calculations clearly indicate the conditions for which they're valid, one of which is a weight of 2300 pounds. I don't know how you're supposed to make calculations for other takeoff weights, but the fact that the weight is clearly stated as a condition shows that it's important.
> You should look up how gliders sometimes carry extra weight in special water tanks to improve speed without sacrificing performance. Their optimal lift-to-drag stays the same, but the speed at which they achieve it becomes higher. How do you explain that?
As you say, it doesn't change their lift-to-drag ratio. When they go faster they also meet more rising air in the same time. What matters is that they can only stay aloft when they find sufficient rising currents, which is completely impractical for most kinds of airplane. Airliners for example can glide to an extent and they sometimes do, but they can not "effectively glide huge distances using only the energy you get from slightly lowering your altitude in the gravitational field" as you originally stated.
> Also: You are confusing angle of attack and angle of incidence
Angle of incidence is the angle at which the wing is mounted to the airplane. It is not in itself relevant to the lift the wing produces, which is why I didn't mention it. I'm not confusing anything.
For more practical considerations, see e.g. this video: "How much does it cost to FUEL an airliner?!" by Mentour Pilot (https://www.youtube.com/watch?v=dU8Ah1VC2Wg). Some excerpts:
At 1:47:
> The cost of fuel is one of the single biggest costs any airline out there has. My airline that I work for spent about 11 billion dollars in fuel last year. And this is why keeping a check on the costs, as in both the price of the fuel and also how much fuel is being used is extremely important. It is the difference between being profitable and non-profitable in the airline world.
At 4:26
> The total cost of fuel for the airline is about 40% of the cost of the whole flight.
At 10:01:
> We only carry as much fuel as we need for the flight that we need to do with [(couldn't understand this word)] reserves and diversion fuel. The reason we don't carry more fuel than that is because it costs fuel to carry fuel. The weight of the fuel is going to make the aircraft burn more fuel.
So the cost of fuel is very important to the airline industry, and carrying fuel costs fuel and hence money, because of the weight of that fuel.
Yes, flying is still relatively cheap because the fuel cost is shared by all passengers, and because airlines for reasons that I don't quite understand pay no or almost no taxes on their fuel; certainly much less than what you pay to fill up your car.
Two equal airplanes but with different weight can glide the same distance, same glide angle, but the heavier plane will have higher airspeed to give the extra lift needed for the extra weight.
This is mostly true, but due to a small Reynolds effect the heavier plane should actually perform a little bit better.
What you describe is why gliders sometimes carry water as ballast in their wings. It enables the same lift/drag ratio at a higher speed, at the cost of a higher stall speed.
This is one of the higher order corrections I was referring to. Note how the article describes that this is not a dominant factor under normal conditions and actually gets lower the faster the plane flies. So if you can keep parasitic drag down by designing your aircraft nicely, you can get pretty far to the right in the plot at the end of the page.
As gruez says, a heavier car needs more fuel to accelerate and has more rolling resistance. It also needs more fuel to drive up a slope. Some of these can be regained in a car with regenerative braking, but even than only partially because there are always losses.
But the difference is not nearly as large as it is for airplanes. Having your fuel tank only half full means more trips to the gas station, which might even negate all gains you try to make.
It seems a good idea though not to drive around with things live heavy tools all the time when you don't need them.
For general cars it’s negligible, but for formula 1 it matters: I think it’s in the order of 1/10th a second per lap or something - the car get multiple seconds per lap faster over the course of a race (despite the lower grip as tires wear)
Sure, it takes less fuel to move a car that moves less, but fuel is an nearly irrelevant fraction of total weight in most cars. A gallon of petrol weighs about 6 lbs.
A heavy car takes more energy to get up to speed. The extra weight also "stores" more energy once you get up to speed, but that's useless when you don't have regenerative braking. Also I'd imagine that rolling resistance would be higher when the car is heavier.
And using smaller airframes (because you can run smaller/lighter fuel tanks, along with lower drag) can add to those efficiency gains:
> the total fuel consumption of a 7,200 NM flight can be reduced by up to 15% by making an intermediate stop half way, while using conventional existing long-haul aircraft. When the aircraft is specifically designed for medium-range operations (such as e.g. the Airbus A300), the total fuel savings could increase to 27%.
From: "Evaluation of intermediate stop operations in long-haul flights"
This is a Russian government Ilyushin currently en route from St. Petersburg to Washington. As the United States has a Russia flight ban, assumptions are that the airplane has special authorization.
Lost on the news cycle but rich in the subtle language of diplomacy was that notice of the expulsion was delivered while the Russian senior diplomat was conducting a press conference.
https://youtu.be/yLaX-035hOo?t=161
They were informed beforehand. He took that call from one of his cronies in order to make a point that the US is the one violating international norms, etc. by PNGing those Russian diplomats. (Which is nonsense, given the context.)
odd that this is downvoted. it’s an unpopular, but necessary, perspective to hear presented (mostly) rationally. i disagree with a few of its foundational premises, but then, it disagrees with some of mine (e.g. Nato intransigence on its “open door policy”) and that’s ok. i appreciate the read and is a good corrective to the putin-as-hitler madman narrative.
It seems that the plane had to go all the way around the closed airspaces of Finland and Norway (well, Scandinavia) to reach the Atlantic. Or maybe it's the projection.
The usual route from Moscow and St. Petersburg to the Eastern seaboard is over Norway and Greenland, but since the EU airspace is closed to Russian flights, the routes to e.g Cancun, Punta Cana, Porlamar, etc. have to take a detour over Kola Peninsula and the fly over the Atlantic parallel to the North American coast. The detour adds maybe 30 minutes to the flight time.
The reciprocal closure of Russian airspace over Siberia to European and US airlines has a bigger impact on cross-continental flights. The London-Tokyo has been trending in the news, since it's now 3 hours longer and has to go over Alaska, [but I think the bigger impact is on nonstop flights like Washington, DC - New Delhi. These must be completely non-viable now for US carriers.]
Most aircrafts traveling west from Asia or Eurasia on a direct flight take a polar route to get to North America. If not over the north pole, at least as close to artic circle as possible.
The US has the same setup in Moscow too though. Among "non-friendly countries" it's common that close to half of embassy staff are actually spies or at least 'intelligence analysts'.
Pretty much all diplomats are spies, whether officially or unofficially. Their work involves learning and understanding things about the counterpart, openly or otherwise, and reporting their findings. The main difference is that the official spooks take more risks and carry out more direct action.
> Among "non-friendly countries"
Among all countries. Any embassy of note (say, US in Germany, or French in Algeria, etc) hosts at least a few actual spooks at any given time.
The spy world isn't opaque. Each country knows who most of the spies are. They generally operate out of special sections of the primary embassy in each country.
Almost all spies act under diplomatic cover so that they have immunity when they get caught. Operating without that cover is a risky mission which normally means your host country can't save you and will deny you.
Each country just allows the spies to pretty much go about their business, follows them from the embassy when they can, and then uses them as pawns when necessary, like this.
Edit: seems people misread my intention, I am challenging the parent response because it reads like something out of a spy novel with nothing to back it up.
This discussion has gone poorly but I think it's a totally fair question to ask for a source. I can't find anything to corroborate the "close to half" number but here's a couple of articles about diplomatic staff being spies.
Not OP, but I read about this in a book by an ex-CIA guy a long time ago. I think even friendly nations do it to each other too. It's like an unwritten rule to have spies in embassies. Of course, I don't know how much was sensationalized, but it somewhat makes sense to keep tabs on everyone else if everyone is doing it.
Also, this is why counter-intelligence exists in every nation. Watching embassies is part of what they do.
‘... spies?' I thought we were chums with the Low King!’
'Of course we are,’ said Vetinari. ‘And the more we know about each other, the friendlier we shall remain. We’d hardly bother to spy on our enemies. What would be the point?’
Not really. If they would not act criminally they would not need diplomatic cover. Most of the "spies" there are actually agent handlers, i.e. handling native agents, infiltrating unions, press, police, army, government. Spying is mostly not passively writing reports of intelligence matters, it's mostly actively pursuing criminal acts. Writing wrong press articles, social media posts, paying natives to do something illegal, killing union folks, torturing students.
The passive agents writing the innocent intelligence reports are usually not under diplomatic cover. They are under some commercial cover mostly. As with Israel also arts and students.
Your comment is valid- it’s likely unreasonable to expect evidence for this claim in particular to be furnishable.
That said, if OP can’t provide evidence for the percentages they mention, perhaps the bigger problem is that they shouldn’t have made the claim in the first place.
A CIA employee working at listening station based at an RAF base in the UK (presumably listening into transmissions from e.g. Russia) is rather different from spies based at the Russian embassy in Washington.
FlightRadar24, FlightAware, etc. are actually heavily censored. As a recipient of FAA radar data they have to agree to remove planes owned by rich people and corporations that don't want to be publicly visible. https://www.faa.gov/nextgen/equipadsb/privacy/
ADSBExchange.com does not accept FAA data or process any removal requests.
That's not how ADSB works.. FlightRadar/FlightAware do not have an "FAA Radar feed", they have a network of rtlSDRs listening for ADSB traffic. They offer the removal of the public display of flights, you can still purchase a commercial account to view them..
Depending on the company they use three sources of data: community feeders, FAA radar feeds, and the most recent addition is satellite based ADSB receivers.
The latter two are how they get coverage in places where people don't live, like polar or oceanic flights.
The US says: "You're not welcome, you have XX hours to leave the country". The diplomatic personnel have to figure out their own ride home. Normally that's fine (private charter flight, commercial, whatever), but in this case there are few (no?) flights to Russia, and the Russian's can't fly there due to airspace restrictions.
So in this case, Russia asked for a special exemption to the US airspace restriction so it could get its personnel out. The US said "fine", and the Russians are flying the IL-96 in to pick up its personnel
The FAA ban has an exception for diplomatic flights: "EXCEPT ... STATE AIRCRAFT OPERATIONS GRANTED A DIPLOMATIC CLEARANCE BY THE U.S. DEPARTMENT OF STATE"
There are commercial options, e.g. flying to Turkey, the Middle East, China, India etc and taking a connecting flight to Moscow. But Russia probably doesn't want a large group of their spies and families travelling together on a commercial flight.
Yes and no. If you add a refueling stop to a long-haul flight, it can save enough fuel to make up for the rerouting. (Long-haul flying is really inefficient because you have to take-off/carry all the fuel needed to make it to your destination).
e.g. a flight from NYC-Paris-Delhi is only 5.5% longer distance than direct, even though it now routes over europe instead of a direct polar route over Russia
http://www.gcmap.com/mapui?P=nyc-del,+nyc-cdg-del
(This isn't perfect, it still shows a bit of routing over Russia, but you get the idea). And you still have staffing costs, landing costs, etc. Weather related routings, night-time landing restrictions, etc.