View Full Version : Sonic Cruiser time advantage

11th Dec 2001, 13:55
I have lately been looking at Boeing's proposed Sonic Cruiser design and the time advantages that aircraft might or might not bring. I would be interested to hear from anyone who felt inclined out of intellectual curiosity to run through some typical figures and see how they come out - either on the back of an envelope or better still in any nav computer that could cope with the parameters. So for example, what would be the real-world time savings on LHR-JFK, FRA-LAX, CDG-SYD assuming M0.95 cruise (but with realistic TMA speeds at each end) and stratospheric flight levels, versus big twin, A340 or 744 as desired? I'd be happy to hear from you offline or on the forum if it seems sufficiently interesting.

(All offline replies treated as unattributable)

casual observer
12th Dec 2001, 08:13
IMHO, if you are talking about city pairs like LHR-JFK, FRA-LAX, the proposed .98M Sonic Cruiser doesn't provide much added value to the passengers. When you include the time one needs to travel to the airport, check-in time, time to clear the customs, and time to travel from the airport to your hotel or home, the time saving in the air really is not that significant.

However, if your travel on the Sonic Cruiser involves intinary that bypasses hubs, for example, DEN-CPH nonstop instead of DEN-JFK-LHR-CPH, then the time saving could be significant.

I firmly believe the biggest selling point for the Sonic Cruiser is not the appeal of travelling slight faster for the passengers. A member of Yahoo's Orders group has tried to come up a one-week schedule of an LHR-based airline and showSonic Cruiser time saving (http://groups.yahoo.com/group/orders/files/Sonic%20Cruiser/) which translated into 46% increase in distance travelled. I did a simple two-aircraft rotation for a HKG-based airline supporting a daily flight each to Europe and to Australia. The same two daily flights would require three 0.85M airplanes. Once again, it means each aircraft would have a 50% increase in productivity. The 15% increase in speed has surprisingly opened up many more windows of "sensible" schedule which in turn allows airlines not to idle their long-haul planes on the ground. This is the beauty of Boeing's 0.98M aircraft proposal. The hype of travelling faster for passengers is nowhere as valuable as the potential to increase productivity for airlines.

13th Dec 2001, 03:20
Also, everyone has harped on the higher fuel burns.

What no one considers is that fuel has far lagged behind inflation in price, while salaries have not.

As that trend continues it becomes more and more profitable to burn more fuel to reduce flight times.

Crew productivity is already at its limit. You aren't going to get below two pilots or 1 flight attendant per 50 pax so the only way to reduce salaries is to go faster, even incremental improvements in speed could help the airline's bottom line.


casual observer
13th Dec 2001, 04:29
Exactly. Let's assume that Airbus is right that a .98M aircraft will burn 40% more fuel than a .80-.85M aircraft. Typically, 20% of an airline's unit cost is spent on fuel. A 40% increase in fuel cost translates into an 8% increase in unit cost. However, the 15% reduction in crew cost, and more importantly, the 30-50% increase in aircraft productivity will more than likely reduce the overall unit cost. If I were an airline executive, I would ask Boeing to give me a B747-sized SC, too. Driving down the cost is what most airlines are looking for. Having bigger planes is one way to drive down the cost, but it's effective only if you can fill the planes. The bigger the plane is, the fewer the number of routes it can be used. The SC should be able to offer airlines more flexibility and more opportunities. If Boeing's claim is true, that is, it will only burn 20% more fuel, then it means even more saving.

I have come up with the following simple example from HKG to LHR, LAX, and SYD. The schedule is a bit tight, but you can get a rough idea of the value of 15% increase in speed. Theoretically, I can use only three planes to provide daily service to the above three cities from HKG.

Times in parenthesis are SC flight time vs current flight time.

HKG-LHR 19:00 - 21:20 (11h20m vs 13h25m)
LHR-HKG 23:45 - 18:00 (10h15m vs 11h55m)
HKG-SYD 20:30 - 07:00 ( 7h30m vs 8h50m)
SYD-HKG 09:00 - 13:40 ( 7h40m vs 9h00m)
HKG-LAX 15:20 - 10:00 (10h40m vs 12h25m)
LAX-HKG 12:00 - 17:00 (13h00m vs 15h15m)

That's a whopping 20:08 of daily untilization rate with three planes. More realistically, with four planes (and perhaps an additional trip to Tokyo), I can still get about 16+ hours of utilization rate. It's simply impossible to get that kind of utilization rate with a .85M aircraft.

(I can have another early afternoon departure to LHR so that the 9:00 SYD passengers can transfer to.)

The SC does make midnight departure to Europe from the Far East infeasible. But anytime between 06:00 to 19:00 should work fine. That means airlines might be able to use busy airports, such as LHR, when they are less busy.

To the US West Coast, I can come up with quite a few possibilities, e.g.:

HKG 1200d 0640a LAX 0900d 1400a HKG
HKG 1600d 1040a LAX 1230d 1730a HKG
HKG 2000d 1440a LAX 1700d 2300a HKG
HKG 0100d 1940a LAX 0100d 0600a HKG

The more I look at it, the more I think the SC has a great potential.