# How does a V formation save fuel for the lead plane?

I'm watching an episode of Mythbusters where they show aircraft saving 3-5% fuel when flying in a tight V formation. Interestingly, this also applies for the lead airplane.

How is that possible for the lead plane, too? Does the same apply for cars as well, or is it a flying phenomenon?

• have u seen birds flying in V formation?? They also save their fuel by doing this.. The lead plane cause a disturbance wave on which the others ride..en.wikipedia.org/wiki/V_formation – Vineet Menon Dec 9 '11 at 10:21
• en.wikipedia.org/wiki/Wingtip_vortices – Vineet Menon Dec 9 '11 at 15:59
• @Vineet: Thanks for the links; however my question relates specifically to the frontmost bird, plane, etc: though it wasn't in a wingtip vortex, it still showed improved efficiency in flight, and I'm wondering why that is the case? – fbrereto Dec 9 '11 at 17:16
• ook...my bad... – Vineet Menon Dec 10 '11 at 5:48

The lead bird does gain something from the V - it's the same principle as the spoiler on the back of a car.

The vortices from the wings of the bird would create a low pressure region immediately behind it, which in simple terms sucks the bird back. The following bird prevents this vortex by splitting the upper and lower air flows with it's wings and so on - until it reaches the last trailing bird.

Although the front bird still does the most work, it does save a few % of it's energy, and similarly the last bird, although it benefits from the birds in front does pay an extra few % for the vortex behind it.

• So then I would imagine this benefit would also apply to cars (assuming they are shaped to produce such vertices, are in the right relative positions, etc.)? – fbrereto Dec 11 '11 at 22:35
• Possibly physics.stackexchange.com/questions/5504/… but I suspect the cars would have to be very close (< 0.5 m?) to have an effect – Martin Beckett Dec 11 '11 at 22:51