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:
- 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.
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.
- 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.
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.