Fello'fly transatlantic test flight

[Jeff]

5% fuel saving seems a lot!

[graham]

If six tonnes is 5%, then a regular flight would contribute 120 tonnes which is pretty frightening for one flight. Times that by the number of trans-Atlantic flights per day and the figures become enormous.

[davebasing]

It’s an interesting project which I have been following for some time with my work hat on. As winglets were designed based on observation of birds with upward sloping feathers on their wing tips, so this project derived from considering why flocks of birds fly in a V formation. Studies of aircraft wake showed that while flying directly behind disturbs the air flow and reduces lift requiring more power, the nature of the wake effect when flying in an offset position actually serves to increase lift and thus reduce power requirements. In effect the trail aircraft benefits by the equivalent of the level of drag experienced by the lead aircraft. The lead aircraft does the hard work which is why birds in a V formation constantly change the leader position (i.e. the lead bird gets knackered and moves over to get a bit of a rest, in the aircraft case fortunately the leader doesn’t get knackered, just requires a bit more thrust). Taking the conversion factor for Jet A1 as being one tonne of fuel producing 3.16 tonnes of CO2 then a 6 tonne reduction in CO2 equates to a saving of almost 2 tonnes of fuel for the following offset aircraft. The lead aircraft of course experiences no savings thus the cumulative saving by flying in combination is just under 1 tonne of fuel per aircraft on this basis. There are of course ATC & other operational issues to be overcome. Also issues of who should benefit in each flight if the two operators are not the same but this should be fairly easily resolved. Also if the aircraft are on the same track (e.g Atlantic Track C) but with different origins and/or destinations (e.g. say Montreal and New York at one end and Dublin and Frankfurt on the other) then the benefits are slightly reduced as the aircraft tracks will diverge at one or other end, but the cumulative effect in emission savings (which go beyond just CO2) is still significant. The aircraft separation in the test was some 3kms. Different types do of course produce differing wake patterns so tests will be required using different types in combination.