Recently I had an exchange with Australian Flying magazine editor, Steve Hitchen. He asked some great questions and after giving my responses I realized some of his question were common ones I hear being discussed. So why not share our give-and-take? Steve’s questions are in blue. I’d like to talk about power. With LSA restricted to 120 KIAS, it seems unlikely we’ll get much engine development to increase power unless regulations change to either allow an increase in speed or gross weight. LSA are getting more power, to wit, Rotax’s new 915iS with 135-horsepower and the Continental Titan line with 180 horsepower. I do not think this is the end of the horsepower boosts …plus LSA speed and/or weight changes could conceivably follow in the USA but are currently not limitations in other countries that accept the ASTM standards as a basis for approval or certification.
Aviation Future Shock? Questions & Answers with a Australian Editor
LSA are getting more power, to wit, Rotax’s new 915iS with 135-horsepower and the Continental Titan line with 180 horsepower. I do not think this is the end of the horsepower boosts …plus LSA speed and/or weight changes could conceivably follow in the USA but are currently not limitations in other countries that accept the ASTM standards as a basis for approval or certification.
I'd like to talk about power. With LSA restricted to 120 KIAS, it seems unlikely we'll get much engine development to increase power unless regulations change to either allow an increase in speed or gross weight.
What would be the point of more powerful engines on LSA?
Well, that topic could take us down quite a lengthy path. Let me offer a somewhat shorter reply. You are right about many tech developments — and on that I point you to an article published recently in General Aviation News' "The Pulse of Aviation." Two thoughts: (1) I believe the LSA sector has reached an interesting level of maturity. The pace of major innovations may have slowed but the most important developments are now common on most LSA (and light kits). This situation is not so different than smartphones that totally upended mobile a decade ago with the introduction of the iPhone. In a similar time period, that industry has also matured and development has lost its torrid pace. (2) The funny thing about innovation is you often don’t know how or when it might emerge. Electric propulsion is one possibility and then we are seeing the first glimmer of a new class of aircraft with a collection of spinning blades or rotating wings. Who can guess where precisely that is headed? Whatever the coming changes, they will work first on lighter aircraft. My article referenced above tries to speculate a bit.
There's already a lot of technology in LSA thanks to the need to save weight, which has me wondering where the sector is going. Can you provide me with some thoughts?
One definition of composite is "made of various materials." In the past "composite" implied fiberglass. LSA already rely on fiberglass, aluminum, and steel but add high-tech materials such as Kevlar, carbon fiber, and titanium. Today, the most advanced designs have significantly carbon fiber airframes, partly for weight but also strength as well as aerodynamic efficiency and design beauty.
Composite versus metal. Is there something else? What type of composites are in common use and what types are under development? What drives composite development? Does metal still have a future in LSA? Is mix-and-match of both the way to go?
That's one beauty of fiberglass and carbon. You can have beautiful shapes and strength with weigh savings. Assembly ease is a factor, too. Those materials will surely persist for those reasons and for future production efficiencies. However, since nearly all airplanes are low-production — essentially hand-built with modest use of robotics, even at the Boeing or Airbus level — prospects for genuine mass production seem distant.
What are the major construction methods? Is there room for the construction method to contribute to the aircraft performance in terms of weight saving? Aircraft like the Ekolot Topaz have fuselages formed in two halves then adhered together like a Revell P-51 model. Is this the way of the future? Is there room for mass production?
Avionics development has seen technology cascade down from GA, but there is some that has been designed from scratch for the LSA sector, such as AoA Indicators. Which way will the technology flow in the future? Is EFIS going to become standard for LSAs or do the traditional clocks still have a place? Have we reached a pinnacle in LSA simply because the sector can operate without technology such as HUDs?
Perhaps we are pushing some boundaries if new ideas and materials are not forthcoming. However, they are forthcoming. I’m not too worried about it. For example, crush zone technology in cars did not add weight — in fact removed it compared to other methods — and this greatly added to safety.
Weight-saving is always an issue for manufacturers. In Australia a land-based LSA can lift no more than 600 kg (1,320 pounds), so what can manufacturers do to increase their useful load? Are we reaching a dangerous situation where the aircraft are getting too light or are too heavy to include some desirable safety features, such as parachutes?
Are regulations stifling LSAs? Should LSAs be able to fly at up to 750 kg MTOW (1,650 pounds gross) to give manufacturers more design freedom? Is there anything that has to change to enable more technology to be used in LSA, and if so, what is it?
You are right that LSA is leading the innovation charge in many ways. Where can the industry go from here? We (LAMA) have spoken to FAA a lot in the last three years as we seek new opportunities within the present regulatory framework. It is perfectly clear that LSA were a significant reason why FAA went ahead with the Part 23 rewrite and use of industry consensus standards. To answer the future question, I again refer you to this recent article. The freshest new tech in aviation may come from outside aviation but I would never discount the passionate, imaginative, and motivated designers and developers operating in light aviation today.
There's a lot there, but there's also a lot to think about. Until the rewrite of FAR23, the LSA sector led general aviation in technology, especially in the use of composites. The new FAR23 is sort of like catch-up regulation for GA, but where does the technology leader, LSA, go to from here?