From the archives: Wolfgang Langewiesche on quiet airplanes

Editor’s note: In this prescient article from 50 years ago, legendary pilot and writer Wolfgang Langewiesche considered the role of general aviation airports in a world of ever-expanding suburban communities. He saw the need for a quieter breed of airplanes in order to prevent a public backlash. Now, with electric airplanes tentatively finding a foothold, this article seems as relevant as ever.

Quiet, Please: A new approach to our airport problem

So now we’re getting it in the neck for making so much noise. Airports are closing right and left, and no new ones open. Suburban communities do not want them.

Between the tax assessor and the zoning board, our general aviation airports are being abolished.

At the same time, more and more people move into the metropolitan areas. A few years hence, if nothing is done, most people will live so far from their airplanes that flying becomes impractical.

What can be done? I see one thing: create now a legal class of Noiseless Airplanes, and give zoning boards and home-owners something they can admit while barring what they are determined to bar. By “now” I mean now. It will take years for such a step to take effect. The legal class has to exist before a noiseless airplane is worth building. The airplane has to be demonstrated before the communities will believe it is possible. The communities have to admit them before they can be built in numbers. So ― we need lead time, and we had better make a start.

Langewiesche by Cub
When Langewiesche began writing, airports were little more than open fields.

By “noiseless” I mean ― well, the “Noiseless” typewriter is not noiseless, but when it first came, its silence was incredible and marvelous, compared to the clacking kind. In airplanes we need a similar drop in noise-level; a drop that is dramatic and astonishing. No mere improvement would make the difference that needs to be made.

By “class” I mean that some very strict standard should be set, preferably by FAA, and airplanes should be certified as Noiseless if they meet those standards. It would be similar to the (as yet non-existing) STOL class. But there’s one difference. Airworthiness is not involved. Hence, no international agreement would have to have moved out. We could just start. But if the FAA can’t set this up there are lots of other people who could. There is no law against saying ― “I find this airplane noiseless.” The trick is to have people believe you. An industry association would perhaps be believed. A great air town such as Wichita, might set Noise standards for the downtown airport it ought to build ― and its standards might be accepted by other communities. A State Aeronautics commission might make itself useful.

What privileges would such a certificate confer on an airplane? None. The privileges would come from the airport owners, the Zoning Boards and Planning Commissions.

The real estate developers, the big lending institutions ― Life Insurance Companies, Building-and-Loan Associations. Those are the people who determine what gets built.

They would allow a Noiseless airport to exist where they will certainly bar a standard airport, or get rid of it if they can. For one thing, if the traffic is “noiseless” they would have no legally valid reason to bar it. The ruling could not be made to stick.

For another thing, their people are keenly aware of the role aviation could play in their affairs. I don’t mean for transportation of their executives, I mean how it would affect their localities and their projects and their customers ― the people who will live there: better accessibility, better community facilities, higher property values, a better tax-base: those are the things that matter. But there is always that noise ― and they know that the public has now become allergic to aircraft noise. Right now, those people are keenly interested in STOL’s and STOL-ports; more so, perhaps, than most aviation people, but STOL means noise, lots of it. But if such a thing as a Noiseless Airport were possible, they would say ― “by all means let’s have one.”

As suburban sprawl has continued, airports like Van Nuys have been totally surrounded by houses.

Can a “noiseless” airplane be built? Certainly, and within the existing technology ― the only question is what it would cost extra in weight and performance, and therefore ultimately in money. But the history of the airplane (and of the automobile) shows that this question is not important. By now, when we buy an airplane, the basic flying machine is the least of what we buy. Most of the money goes for comfort and convenience features, from tricycle landing gear to electronics; plus the extra power and extra wing necessary to carry the extra comfort and convenience. We all know how this has paid off in increased utility. It would do so again. To be able to go into a suburban airport, instead of some field an hour’s drive away, could raise your block-to-block speed by 50 or 100 mph! But that’s dream stuff. The grim reality is, I believe, that just to keep the airports we have, we shall have to cut our noise way down.

The airplane makes noise in three ways. First, the exhaust. This can be muffled down a lot more. What about tandem mufflers? Unlike the automobile, the airplane has lots of space. The exhaust could also be tamed by cooling it. What comes out of an engine is no more, in volume, than what went in ― provided it is cooled down to the temperature at which it went in. We have available, on the airplane, enormous cooling surfaces and a constant cooling airstream. Why not use them?

A third way to lessen exhaust noise is to megaphone it up into the sky, away from people. The place where it is barking now ― by the pilot’s feet ― is wrong both for the pilot and the man on the ground. You know those Super-Cub Patrol airplanes which carry a loudspeaker in the side of fuselage, for talking to the ground: Why not use a similar arrangement to throw the exhaust-noise upward? All it would take is a megaphone, funnel-like, buried in the fuselage and directed upward. Into the proper zone of this funnel the exhaust pipe would have to leak. You can “fold” a megaphone ― make it go around corners — and thus store a pretty big one in a relatively small space. How effective would a megaphone be? A factory could build one for about 1000 dollars and find out.

All this involves getting the exhaust past the cabin, and that poses problems — doors, fire-proofing considerations, drag, appearance. But how about that place up front where the Cherokee Six carries those suitcases? It could take a big second muffler or a megaphone, or an inter-cooler.

Or, another variation: This is the 50th anniversary of the granddaddy of modern airplanes (all-metal cantilever low-wing monoplane with enclosed cabin and a regular door), the Junkers F13. Hugo Junkers, the millionaire professor who commuted to his factory on a bicycle, had not been afraid to make his airplane look extremely odd: that tippy-looking low-wing configuration; those unsupported wings. And imagine an airplane built of metal, when everybody knows airplanes must be light! Twenty years later, most airplanes looked that way and they still do. The F13 ranks with Fred Weick’s Ercoupe and the early jets among the designs that really moved the airplane forward a notch. But in one respect it was never imitated and maybe we should pick that up now. The exhaust system was a sort of smoke stack that rose up from the top of the engine cowl, then bent back and ran above the cabin roof to a point well aft of the cabin. (Later, the aft-running pipe was cut, and only the upward stack remained). Could we use that? It would be one way to get the exhaust past the cabin, clear of possible fuel leaks, to a place where there might be a second muffler or a megaphone, or an inter-cooler. Or we might get a big noise-reduction simply by discharging the exhaust above the cabin, so that the wing could act as a noise shield. It would be pretty visible. But for a noiseless airplane it might be good policy to carry a highly visible something that is for noise reduction.

The second way airplanes make noise is the propeller — and our kind of airplane mostly in takeoff and initial climb. I believe a shorter propeller with more blades would be quieter. And the electric-fan people have blade designs that suppress noise by lessening the vortices that form at the blade tip. Anything useable in that? But the problem might be solved mostly by operating procedures. We still take off as if there were some doubt about it. Will the Curtiss Jenny clear yonder trees? Will the intrepid aviator survive one more aerial flight? But there is no doubt, and there rarely are trees. If the field is long enough to land on, it is long enough for the same ships to go out with climb power — at the top of the green. Most training flights go out lightly loaded. To restrict takeoff weight might be part of noiseless operating. It might be enough simply to restrict throttle and prop control by an elastic stop, to hold them just out of the snarling range. Then, if a pilot did need full power, he could push against the stop and get it. He could then also get a ticket.

NASA design
Could electric motors and distributed propulsion make airplanes dramatically quieter?

The third way we make noise is by drumming: all those surfaces which we rattle with our engine and with the pulsating prop-blast. I believe this effect is rather strong. Hold your fingernail or your forehead against the doorpost and feel the buzz. You know very well that anything which buzzes like that must make a lot of noise. We only don’t hear it because other noises drown it out, but for people on the ground this may be a big part of the noise. On outboard motorboats, a remarkable quieting job was done some years ago for the same reason that applies to us now: the public was fed up, real-estate values were suffering, and outboard motor boats were going to be banned on many lakes. This quieting job was done in part by better engine mounts: keeping the boat itself from vibrating and becoming a noise source in its own right. In airplanes we already have very fine engine mounts, and further improvements along that line may not pay off. It may be more productive next to damp or muffle the surfaces themselves. If automobile designers can take a tinny door and give it that nice dull thud we should be able to do the same job on an airframe

All this would cost payload, speed, and money. But there would also be some advantages — quite apart from the main thing, which is to keep our airports from melting away under us. In treating our fellow citizens so they won’t kick us out, we incidentally would treat ourselves a little more kindly. Despite all we say, our airplanes are not quiet, inside. They are merely tolerable. Children don’t like to fly, and women not very much. Noise is the main reason. Voices still get shrill and irritated. Conversation still is not worth the effort, except as between two pilots who more-or-less know that’s going to be said. To anyone who thinks airplanes are quiet enough inside I recommend a 3-hour flight with wax earplugs. You can hear the radio perfectly, and monitor the engine better than usual. But what peace! Then, after 3 hours, still at cruise power, take the plugs out. You won’t believe your ears. “That?” you will say, “That I have claimed is an acceptable environment?

“Dirt,” someone has said, “is matter in the wrong place.” Noise is sound in the wrong place, and for millions of people on the ground, that’s us. Noise is also nature’s alarm signal — the sign of danger, violence and distress. For lots of people that’s us again. A sharp reduction in noise would change the whole mental image people have of the airplane, and would enormously broaden its public acceptance.

So there’s a big step to be taken, and we had better take it soon.

To me, the sound of an airplane is the most poetic sound in the world, better than the cooing of the doves in Middle Western fields, better than the whistle of the old steam trains, better than the tooting of a ship in New York harbor, better than the monastery bells ringing in some Bavarian valley. Especially a big piston-engine, when its sound is filtered through a mile of air: When you listen to that, all sorts of musical notes swell and fade inside that sound. This is the sound of one of man’s great adventures. But it’s got to stop now, that’s quite clear.

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