How much fuel do wifi/sat antennas burn?

[lostav8r]

I saw that the starlink antennas are a lot slimmer than the old geosat based ones. I heard from an engineering friend that there is almost no fuel burn impact at cruise because the antennas are mounted far back and the plane is slightly nose up minimizing the airflow over the antennas.

Is someone who is good at math/physics able to elaborate?

[Conflicting Traffic]

Very very rough numbers: a small, well streamlined antenna fully immersed in the boundary layer would cost you about 0.0007 gal/h at 120 knots at sea level. Maybe a little bit more because of the effect of the wake downstream if the antenna is not at the very tail of the aircraft.

A better estimate could be made with a better description of the system geometry (aircraft plus antenna), but even then, if you wanted a real number, you would need to validate the calculations with wind tunnel data. Flight test data would be better again, but given how small the number is, it likely can't be measured during flight test because of the noise in the data. In any case, your final result would likely be very close to 0.0007 gal/h.

[co-joe]

I found it surprising that the Ryan Air CEO apparently said that a Starlink antenna would cost a 2% fuel burn penalty and so wasn't worth it for their short haul flying. 2% is massive.

[rigpiggy]

I understand the Wifi antenna on the 737 negates the savings from the winglets