Leaving aside the sonic boom problem for a moment, would a faster cargo plane be more economical? As I understand it, bigger is better with respect to cargo planes. Is that accurate? If we could build a cargo plane that could go faster than Mach 1, would there be any economic advantage? Would the shape of the airframe as necessitated by aerodynamics prevent large quantities of cargo from being carried? I assume we don’t have supersonic cargo planes for a reason, but I don’t know what that reason is.
In practical terms, no. With current engine technology, it takes more fuel to move something from A to B at 1200mph than it does to move it at 600mph, even taking into account the longer flight times.
Because such planes would cost a whole lot of money both to develop and to operate, and there’s no significant cargo business which is so time-sensitive that reducing the flight time is worth the additional cost.
It’s worth noting that although the Concorde made an operating profit it never came close to paying back its development costs, and once the planes wore out no-one was prepared to invest the billions necessary to develop new ones. If it’s not worth the investment to allow cash-rich time-poor businessmen to spend 4 hours in the plane rather than 8, it’s certainly not worth it for any inanimate cargo.
It depends. Larger planes are good if you have a lot of gear going to the same place, and in such a case, a larger plane is generally more economical than many smaller planes. Larger planes require longer, more heavy-duty runways, though.
No, unless there was some huge advantage to getting the cargo to its destination marginally faster. Supersonic planes are generally very fuel-inefficient.
Yes.
Supersonic cargo planes would be fantastically expensive.
There’s also the problem that flight time isn’t the only source of delays. I don’t know what the actual numbers are, but if it takes 8 hours for your package to arrive at the first airport and another 12 for it to get from the second airport to its destination, it doesn’t make much difference whether it’s on the plane for 3 hours or 7, does it?
The only cargo for which extremely high-speed flight makes sense is the kind that the recipient would likely object to receiving. This could be for a number of reasons - “Oh, you shouldn’t have!” or “I’m so sorry, but this isn’t my size” - but it’ll usually be because it’s the sort of cargo that goes boom.
The Concorde burns something like 6800 gallons/hour, and flew at 2100 kilometers/hour. That works out to something like 3.2 gallons of fuel burned per kilometer. A conventional jet like the 737 (which has similar range and capacity in some variants) burns around 800 gallons/hour, traveling at 670 km/hr giving 1.2 gallons/km. So for fuel costs alone you have to pay 3x as much, though it does travel 3x as fast. (Data from, er, this PBS classroom assignment…)
Bigger cargo planes are far more efficient and not any slower than a 737. A big cargo plane will be an order of magnitude cheaper than the Concorde, especially once you consider all the operating costs (supersonic jets are expensive and require lots of maintenance).
Say you’ve got to move cargo 10000 km. Are you willing to pay ten times as much to get it in 5 hours instead of 15 hours? It’ll probably be cheaper to hire lots of people to make sure that extra 10 hours isn’t a problem in the first place…
If the supersonic cargo plane had the same cargo capacity as the regular plane, then in theory it could complete more deliveries per day and allow the delivery company to reduce its overall fleet. Of course, the advantages of reducing the number of planes would be offset by the higher fuel costs of the supersonic planes and by their presumably higher initial costs.
In the early 80’s, the Soviets used the Tu-144 as a cargo plane. Total number of flights 47. If the Russkies couldn’t make it work at the height of the Cold War, then no one with a real world grasp of economics would touch it with a ten foot pole.
If you are in New York, go to the Intrepid carrier and walk through a used Concorde. The thing is TINY yet the tickets were $7000 or thereabouts for what you can find as cheap as $600 on a normal plane.
The amount of power required to punch through the sound barrier is very high. I also recall an aeronauical discussion once that said to double an aircraft’s speed you would need 8 times the power.
Where supersonic would really excel would be in transpacific flight - turn a 14-hour flight into 5 or 6. However, the technology does not warrant the cost. Now that we are used to paying $1000 to $1500 to get to Australia, Shanghai or Hong Kong - how many will pay 10 times as much to get there in half the time?
As for cargo - what cargo is worth the extra money? People are generally more precious, pound for pound, than international cargo; and most places that use cargo services have an acceptable delay time already built into their processes.
How about 1/4th to 1/5th of the time? It’s likely the plane in question will never be built (tho I hope they do), but go fast enough and I think the demand would be there.
I have heard that what makes the cost of typical flight possible was the fact that passenger airliners were also stuffed with cargo, at least on some flights. Profits reaped from shipping fares helped subsidize the cost of a seat. Is this true?
I believe that you are essentially correct. However, the only cargo worth the weight penalty to put on a commerical flight are things like express mail and high-cost and/or perishable items (like lobsters or pharmaceuticals). U.S. Air Mail used to be a distinct service until 1975; today, all first-class domestic intercity mail is routinely transported by air. Commerical airlines have transported U.S. mail under contract for decades.
I suppose the only cargo that really need transporting that far that fast are humans or human organs, or perhaps biological samples, and for the last two I’m sure the military would be glad to use a F15 or something.
The biggest problem with a supersonic or hypersonic jet is that fuel burn and heat dissipation requirements are not linear, but rather exponential.
The amount of fuel it takes to go twice as fast is much more than twice as much, the amount of heat generated going Mach 3 vs Mach .7 is not 4 times as much, but more like 8 times as much.
Get what I’m saying? It’s just diminishing returns for effort.
Assuming you get past the other points made in this thread, more deliveries per day means more flight hours and flight cycles (one takeoff and one landing per cycle), which means more maintenance, more frequent checks and inspections and more time on the ground rather than in the air. Add that to the fact that you’d need a flight crew for all those flights, and existing regulations have limits on the length of a duty day and there is a push to limit the number of legs pilots can do (it is more fatiguing to conduct take offs and landings than it is to fly in a cruise), you have much higher operational costs than existing planes do. And reducing the fleet means you reduce the destinations you fly to, which would have a cascading effect on delivery costs on the ground as well.
