The Skinny on Airplane Painting

In the world of aerodynamics, every little improvement can add up to big savings. One of the areas that airlines are constantly experimenting with is paint. Now, easyJet has announced it will start using a new kind of paint that might save some gas for the airline. But why do they even use paint at all? Keep reading.

This new paint is supposed to do a couple of things better than existing paint. First of all, it weighs less than traditional paint, and even a couple of pounds less can add up to big savings when looked at per year across an entire fleet of aircraft.

Airbus

This magic paint also creates a smoother surface on the skin. That can help reduce drag, if ever so slightly, but it also prevents debris from stacking up in the small crevices that exist with traditional paint. Apparently, easyJet thinks it can improve fuel consumption by 2 percent. If that pays for the cost of the paint, then it’s a worthwhile move.

But it does beg the age-old question . . . why use paint at all? People will often look at American Airlines and think it has an advantage because it just uses a bare metal skin instead of one that’s painted. As you’ve probably guessed, the suggested benefit isn’t really clear or everyone else would be doing this as well.

First of all, while paint does weigh something, it also provides excellent protection for the skin of the airplane. It’s a buffer to keep the elements from eating away, as has been known to happen over time.

To combat this, airlines with bare metal finish can use other materials to protect the skin, but that then takes away from the cost advantage of going without paint. They also have to polish the skin to keep it from looking awful and that adds more cost.

Another issue with bare metal is that fewer and fewer airplanes are actually made with metal. The newest ones down the pipe use composites and that means you can’t get that shiny metal finish. This isn’t a performance issue but it does make your airplanes look really bad.

That’s why when American took delivery of its A300 aircraft long ago, it painted them gray. In later years, they were put into the metal scheme, but as you can see above, the entire rear of the airplane remained gray because of the composites. The A300 doesn’t have nearly as much composite as the newer airplanes like the 787 so it’s only going to become more of a problem.

If you’re still skeptical that paint is a good idea, you can look no further than the airlines that actually have tried to go with a bare metal scheme to see if it saved any money. Notably, Air Canada stripped the paint off a 767. (See a picture of this ugly bird) The benefit wasn’t there and the paint returned.

So paint is here to stay, but what kind of paint? If easyJet can really get 2 percent better fuel consumption, then others will likely follow.

[Photo via Flickr user egmTacahopeful/CC 2.0]

27 Responses to The Skinny on Airplane Painting

  1. Ted says:

    Southwest used to have a specialty livery to celebrate their 25th anniversary, called “Silver One” that was in the bare metal scheme similar to American. A few years ago, Southwest said that it was too expensive to polish it, and so they painted it gray. As the employees started referring to it as “Gray One” and it got looking pretty bad, they finally just repainted it to the normal blue scheme. So, I think you are right that the bare metal doesn’t generate the cost savings that people say it does.

  2. Jason H says:

    I’m not sold on the smoothness factor. You said, “This magic paint also creates a smoother surface on the skin. That can help reduce drag, if ever so slightly, but it also prevents debris from stacking up in the small crevices that exist with traditional paint. ” However, studies on marine mammals have shown that their skin is not smooth, yet they have a smaller hydrodynamic drag than a similar metal object with a polished smooth skin.

    Research has found that “a bit of roughness breaks up the boundary layer and improves efficiency.” http://www.avweb.com/avwebflash/news/SharkSkinResearch_ReduceAirplaneDrag_196715-1.html

    We are obsessed with smooth, but I do remember my super smooth pinewood derby car didn’t win, but the next year when I left it much rougher it was wicked fast, even though the basic cutout was identical.

    • CF says:

      I can’t say I know much about the aerodynamics in this particular case, but any example using pinewood derby cars is good enough for me. (Mine never did well.) I was just using the justification being given. If it does save 2% in fuel as easyJet thinks it does, then it sounds great to me, however it works.

  3. Brian says:

    Two things:

    1. This is not replacing the paint on the aircraft. It is a thin coating that bonds with the paint. We are talking mere grams of extra weight here.
    2. This is not new technology, just a new application. Military aircraft have used this coating before.

  4. When it comes to airlines they really need to think more of what makes a better impression in the publics eye. Bare metal doesn’t look as nice as a real nice paint job and can give some people the impression that there is something wrong with the plane. A nice photo-op look a plane has the better.

    If you ask controlers at any airport they will tell you they like light painted airplanes as they are easier to see on the runways at night, but darker planes are easier to see on the ground when its snowing.

    Maybe paint manufactures need to think of a paint that can ‘glow’ at night (reflect light), but turns darker when it’s cold like with snow. Like those coffee mugs that when you add hot liquid the dark area goes away and reveals a picture of something and then when the mug cools it turns dark again.

    • Hunter says:

      I agree with your first point in principle, but would add the caveat “a real nice paint job THAT IS WELL MAINTAINED.” There’s nothing that strikes fear in a cautious (or infrequent) flier’s heart than stepping aboard a bird with chipped and peeling paint. While it may not have anything to do with safety, one can’t help but wonder about the airline’s attention to detail and maintenance of their fleet when they can’t even keep their aircraft looking nice.

    • K Van says:

      Sherwin Williams has a paint that “glows in the dark”. They use it on high risk areas to be seen at night.

  5. Sanjeev M says:

    Think about why golf balls have lots of dimples in them. Same concept in theory should go for bare metal fuselages.

    Seemingly the paint issue has been tried and tested over years. At some point you just have to look for savings elsewhere like RNP (and NextGen whenever that comes out)

  6. NEIL SACKS says:

    tHIS IS NOTHING NEW. Eastern airlines did this during the early 1970′s. The logo and hockey stick were decals and the aluminum skin was polished at regular intervals. Removing the first coat of paint lowered the weight on an L-1011 by over 500 pounds. The polishing of the skin reduced drag on the fusilage. Both of these factors improved fuel efficiency.

  7. Califken says:

    American actually paid more for the metal in their planes so they could leave it bare

  8. John says:

    Golf balls have dimples to achieve spin, thus loft. The more the spin, the higher the trajectory. It has nothing to do with aerodynamics of straight flight.

  9. They should just make the planes look nice and then they can charge a ‘visual appeal’ fee. I’m wondering now why Ryanair and Spirit haven’t done that yet…lol

  10. Matt says:

    Golf ball dimples reduce drag because of boundary layer separation issues, and so they are very important for aerodynamics. The dimples also induce some spin, but “straight flight” does not exist for golf balls or any free-falling body.

    Comparing a plane to a golf ball is a different issue entirely.

  11. CP says:

    I don’t know enough about physics and the forces of flight to comment on whether a painted versus non-painted plane is more efficient. I do have to say, though, that I’ve always liked American’s silver birds, and I think they always look polished (I say that with some authority as an AA Platinum). It’s nice to fly a U.S. airline that doesn’t basically have a white fuselage with a colored tail (as CO, US, and DL now all have). And AA’s look has certainly stood the test of time!

  12. Bobber says:

    I always assumed that American left theirs unpainted because their maintenance was so shocking they needed to see where the holes were (allegedly).

    • US Airways left some of their 737-300s mostly unpainted in a “usairways.com” scheme so it’d be easier to inspect them for cracks and the like.. (Or maybe that is the 737-200s?)

      • CF says:

        Actually, US Airways was forced to do that on some airplanes because of corrosion issues. It was not a voluntary thing, IIRC. They tried to spin it as a special usairways.com livery as you said, but it just looked awful.

  13. Demo says:

    How much does a typical paint job cost? can’t be cheap after taking off the old coat, painting and then of course the cost of having it out of service.

  14. No fair. You compare a picture of Air Canada under a dull gray sky with no sun and a gloomy gray/white background, and the American under bright blue sky without a cloud in sight. Of course the AC is an “ugly bird” by comparison.

    CP is right, the Silver Birds are not only beautiful in their own right, but a pleasant change from boring white tubes. Southwest is the only other domestic carrier that comes close – although I have seen some WN where the blue is starting to look faded.

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