Randy's Journal: Archives
Weight a minute
I've heard that the competition is complaining that Boeing is out there "grossly exaggerating" the weight differences between the A380 freighter and the new 747-8F - to make the case that the 747-8 freighter is more efficient than their A380F.
Well, okay, yes we do say their airplane is heavier. And my Airbus counterparts would have you believe this is public relations "smoke and mirrors." But it's simple arithmetic we're talking about here.
I mean, why would you want to buy an airplane that hauls 74 tonnes more weight on every trip, just so you can have the capability to carry 7 tonnes more revenue payload? That's right, every time an A380F takes off, it will be carrying 74 tonnes of extra weight. If you ask me, that's the definition of a very inefficient freighter.
Let's do the math.
The A380F tips the scales at 74 tonnes more OEW than the 747-8F.
According to Airbus' own published data, the A380F will carry 141 tonnes of revenue payload, minus tare - "tare" being the weight of the containers and pallets the freight is loaded on or in.
By comparison, the 747-8F can carry 134 tonnes, minus tare.
The difference then is 7 tonnes. Which means, the A380F can carry that much more in revenue payload. Follow me so far?
Now, the A380F's operating empty weight (OEW), as published by Airbus, is 252 tonnes, excluding tare. The 747-8F's OEW is 178 tonnes, excluding tare.
The difference here is 74 tonnes. The A380F weighs 74 tonnes more than the 747-8F. Simple, right?
Then, if you divide the revenue payload capacity for the A380F (141 tonnes) by the corresponding figure for the 747-8F (134 tonnes), you discover that the A380F carries 5% more revenue payload.
Now, divide the 252 tonnes of OEW for the A380F by the 178 tonnes of OEW for the 747-8F. The result is that the A380F carries over 40% more airplane structure weight than the 747-8F.
Bottom line: with the A380F, you're flying around over 40% more airplane structural weight for only 5% more revenue payload!
That's not a good trade-off. And it's why Boeing believes the 747-8F will consume about 30% less fuel per trip and well over 20% less fuel per tonne.
This has nothing to do with "Boeing PR." And has everything to do with simple math.