Composite Airframes vs. Aluminum

DAYTON, Ohio -- Beech VC-6A at the National Museum of the United States Air Force. (U.S. Air Force photo)
DAYTON, Ohio — Beech VC-6A at the National Museum of the United States Air Force. (U.S. Air Force photo)

If you are interested in aviation, even on the most casual level, then you’ve no doubt heard time and again that composite materials are both lighter and more flexible than aluminum, with a much higher elasticity.

Yet, people still build airframes using aluminum, don’t they? So it can’t be all that bad, right? The truth is that each serve their own purpose, one isn’t “better” than the other, just better depending on your goals. For instance, aluminum still tends to be cheaper than composite alloy. That is shifting, with the cost of composite materials coming down all the time, but as it stands, here and now, aluminum is still the choice for many budget-minded aviators around the world.

Here are a few points that you need to know when it comes to comparing aluminum and composite airframes:

Composite Advantages

  • Ease of Construction

Not all aviators are professionals. That means that not all aviators have access to professional workshops to build their aircraft. Composite airframes for home-builts are put together right in the pilot’s garage. While aluminum may be the cheaper material, it only stays cheap if you have access to a fully-loaded metal shop, if you know how to weld aluminum, if you have all the tools, etc. Many composite airframe kits can be put together with the same tools you use on your car.

  • Smooth Surfaces

Not only can composite make for a smoother, more aerodynamic surface, you can also keep your antennas inside the body of a composite plane without worrying about loss of reception, thanks to composite’s electronic transparency. Aluminum is a strong conductor which can interfere with radio signals.

  • Weight

This is the big one: it’s lighter. So much lighter in fact that the Epic E1000 wouldn’t really be possible without it. The E1000 carries a 1,120 pound fuel payload, takes off with 1,600 feet of runway, boasts a roomy 15 foot long cabin, and hits a max cruise speed of 325+ knots, all with a weight of just 4,400 pounds.

Aluminum Advantages

  • Mass Production Pricing

If you’re mass producing and looking to save money, aluminum still has some advantages. It’s not so great for one-off projects and hobbyists, but it’s still technically the cheaper metal.

  • UV Degradation

In some cases, aluminum does tend to stand up better to the elements. It takes aluminum longer to see significant signs of UV degradation, for instance, whereas a composite plane will generally need to be kept in the hangar or under cover.

  • Certification

The FAA is still wrapping their heads around composite aircraft. Eventually, it will be easy to get certified with a composite aircraft. Right now, aluminum airframes will streamline the process and get you into the sky a little sooner.

If you have access to the tools and equipment, you may just be able to save money on an aluminum airframe. Be that as it may, it’s not hard to see why many aviators are choosing composite over aluminum when building kit-based aircraft, and why many manufacturers are doing the same.

3 thoughts on “Composite Airframes vs. Aluminum

  1. I still prefer aluminum. You can see damage, can be quickly repaired, and easier to work with. CFRP is “plastic”. When damaged, the damage is below the skin and not prevalent to the eye. Requires NDT inspection. Also cannot repair on flightline. Lastly, depending upon when damage occurs, the damage requires a countersunk repair spreading out .3″ of an inch for every layer of Carbon filler. Not cheap either.

  2. The whole issue of Aluminium alloys versus Composites is about weight, weight has commercial implications greater use provides for greater savings.

    The engineering infrastructure has the problem of being able to identify and repair damage and composites need a controlled environment. I see early that someone mentioned the welding of Aluminium this has never been done in my world on any type of aircraft firstly it is aluminium alloy we are discussing ie 2024 and 7075 type material all of which are used in an application that benefits from the properties of such materials. Nobody has spoken of the toxicity issues associated with composites when exposed to heat or the ability of damage that travels in such structure. This is a big issue. Ultimately I see commercial airliners being made of composite and private aircraft ie GV type machines being built from aluminium alloys, there again could be wrong.

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