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In regards to this article on BBC, which discusses the use of streaming technology to allow passengers to watch films/TV shows etc. on their portable devices, the following statement caught my eye:

It would increase the drag of our aircraft by 2%, which equates to 20 million euros [$23.6m; £15.5m] in extra fuel.

Is this cost increase purely to do with an increase in weight and additional drag owing to the new equipment required or is there any other factors at play here?

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  • $\begingroup$ An antenna produces parasitic drag but also the weight of the equipment add to the induced drag a wing produces (the more weight the wing has to lift, the more drag the wing itself creates). But it's hard to believe even both make up 2% $\endgroup$
    – Steve H
    Commented Jan 16, 2015 at 13:51
  • $\begingroup$ @SteveH you might be surprised at how much difference a small aero change can make. $\endgroup$
    – fooot
    Commented Jan 16, 2015 at 17:44

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Because it says "drag", my guess is that implies an external antenna.

For example (which I found using a Google search),

Commercial and Large VIP Aircraft Broadband Internet Solutions

HR6400 Antenna System

The HR6400 antenna system for commercial and large VIP aircraft provides passengers and crew true wireless broadband Internet access. No matter where you fly - over land or water in any region of the world - you can browse the Internet, send and receive emails in real-time, use Voice-Over-IP (VoIP) telephony, access your VPN, conduct video conferencing, and watch IP television.

The emerging standard for Ku-band systems with the most efficient Ku-band antenna available, the HR6400 is mounted on the aircraft's fuselage, providing all the performance you need in the smallest possible footprint. The easy-to-install HR6400 comes complete with antenna, antenna control unit, high power transceiver, radome, and radome attachment ring. It covers everything from the energy coming from the satellite to the modem connection.

For example, here is a typical antenna installation (not necessarily the one mentioned above) on a 737:

Installation on aircraft

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It is important to distinguish the streaming of media from the on-board server, and an internet connection to the outside world.

The first is just a matter of setting up an access point inside the cabin that wouldn't have any impact on the drag.

The latter requires some sort of antenna that probably needs to be placed outside to achieve a decent connection. There are many proposal for those, one for instance is here). Note that in the background section it says:

Current aeronautical antenna solutions have drawbacks in terms of cost (active phased arrays) or drag (dish antennas).

I guess that in the interview Mr Hurley was referring to those dishes, as other projects seems to have a definitely minor impact on an aircraft cross section.

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  • $\begingroup$ The one's I have seen are dome shaped and don't produce much drag. $\endgroup$
    – Engineer2021
    Commented Jan 16, 2015 at 15:07
  • $\begingroup$ Does the antenna need to be placed outside the fuselage simply because they're usually aluminum? In other words, with a composite aircraft (like a 787) could you add this antenna without cutting a hole in the fuselage? $\endgroup$
    – Gabe
    Commented Jan 16, 2015 at 23:32
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    $\begingroup$ @Gabe: Skin of composite aircraft is still conductive to provide adequate protection from lightning (made so by embedding a wire mesh in the top layer). The antenna needs to go outside this. It could possibly go in the radome in the nose or another antenna bay with non-conductive cover could be designed somewhere, but that is only possible as part of the design, not as after-market addition. $\endgroup$
    – Jan Hudec
    Commented Jan 19, 2015 at 10:27

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