Pilot Report - reprinted with permission from Private Pilot® Magazine Daring Derringer Doubles the Fun Wing’s Mini-Twin has Outstanding Speed and Safety by Shirley Clark

SOME REALLY weird, wild but not necessarily wonderful little airplanes have tested the twin-engine market. Any pilot knows what these light twin designers were thinking of that is, any pilot who has been tooling along with one fan as his sole visible means of support, flying over the mountains, or at night, or out over the water, only to have that engine go into automatic rough or, worse yet, to quit cold.

It would have been nice if some of these designers had been able to double the safety factor by having two engines instead of one, but the only thing they usually accomplished was to double the potential trouble. When one engine fades, controllability is a critical factor because of the unequal thrust, an extremely white-knuckle situation at takeoff time. It's about as much fun as flying into a box canyon. Usually, the best procedure is to chop the other engine, which puts the pilot right, back where he was before he paid for two engines instead of one, started using appreciably more fuel and began carrying around the extra weight of both, which further deteriorates the performance characteristics expected of a normal single-engine aircraft

Here, in the almost-80s, modern twins have improved somewhat in engine-out performance and controllability. But the amazing thing is that none of the light, medium or heavy twin-engine airplanes with reciprocating engines on the market today can measure up to the lightest of the new light twins the Wing Derringer. Single-engine performance of the Derringer is superior and the plane is a veritable pussycat to fly, with both or either of the engines.

The Derringer is a sleek, fast, little low-winger with an empty weight of only 2100 pounds, with an 850-pound useful load, for a full gross weight of 3050. Cockpit height from the ground is only 5 feet, 8 inches, giving the Derringer a low-slung profile which is pleasing from an esthetic standpoint, with the plus factor that the low wing makes it casually easy to climb aboard.

Cockpit height is four feet even, and width is 3 feet, 8 inches. Snug but ample, compatible with the Derringer mystique of being a nice, tight little ship. If you like to climb into something and spread out, you should buy an SM8-A or an Otter instead.

Original design of the Derringer incorporated a slab tail a "stabilator" which is a one-piece horizontal stabilizer and elevator combination. Current Derringer configuration, FAA-certificated, has a conventional tail with adjustable stabilizer and elevators.

Wingspan is 29 feet 2 inches, length is 23 feet, and tread is 10 feet, 10 inches, for nice, stable ground handling. Engines are two Lycoming IO-320s, 160 horsepower each and fuel-injected. Props are Hartzell two-blade, constant-speed, and full feathering.

Fuel aboard totals 88 gallons, carried in the George Wing-patented wet wings.

Last but not least, Derringer specs are: max speed - 238 mph, cruise at 75% power - 227 mph, 65% power - 221 mph, and at 55% - 208 mph. Range at high speed cruise is 920 statute miles, with a possible 1000+ miles at 65% power.

Over-the-wires speed is 90 mph. Stall speed in landing configuration is 67 mph. Stall speed with gear and flaps up, hopefully at some altitude, is 76 mph. Rate of climb with two engines, maximum gross weight at sea level, is 1900 feet per minute.

The trump card, ace-up-your-sleeve is, of course, the fact that the Derringer still will climb at 500 fpm on one engine, at maximum gross weight, sea level. Twin-engine service ceiling is 19,600 feet, single-engine ceiling is 10,000 ft.

Salient features are the Derringer's inherent stability and beautiful feel of the controls.

Although the Derringer was fully FAA-certificated some years ago, first one difficulty and then another, none of them germane to the present, hampered full-scale production.

The Derringer was all set for mass production by Wing Aircraft Company some years ago, when corporate struggles, big business hassles, and federal finagling made it impossible to proceed. In George Wing's words, it was "the blackest day of my life" when the program was called to a halt. "It's a long, complicated story." In brief, Wing Aircraft separated from its parent HiShear Corporation. Wing, who founded both companies, now is in control of WAC and the Derringer, and, separately, still a director of Hi-Shear.

In the year since Wing's true enthusiasm for the Derringer kindled the restart of production, work has progressed steadily in lining up subcontractors, outside processing and purchasing materials. Inventory at press-time was extensive, listing pages and pages of small, fabricated parts, finished components and subassemblies completed and ready for final assembly.

Significant new development is that Wing Aircraft has moved into a spacious new manufacturing facility and George has pulled out all the stops for production of the Derringer.

With the head start of a healthy inventory of components ready to go, major new material purchase was metal for an initial run of 90 wrap-around wing skins. Each wing skin is a single sheet of .063 70/75 T6 aluminum measuring 148 inches in length by 96 inches in width

John Anderson, Wing Aircraft production manager, explains that the first step for the bare metal wing skins is heat-treating, softening the material to a workable condition.

After heat-treating, the sheets will be packed in dry ice and transported to McDonnell-Douglas at Long Beach where they will be stretch-formed to the Derringer die, creating the entire wing shape. Derringer tooling is designed around the McDonnell-Douglas equipment, a Pacific hydraulic brake which has been converted to a stretch press for wing skins.

Unique feature of the Derringer is the chemical milling of the skins for the wings, fuselage and empennage. The one-piece wrap-around wing skin starts out at a thickness of .064, but is chem-milled down in thickness where strength is not needed. Fuselage skins start out at .040 thickness. Maximum thickness is retained where strength is needed, and in areas of rivet patterns allowing countersinking and flush riveting.

Chem-milling was part of the program to reduce the number of parts with the twin advantage of reducing weight. The resultant parts are a little expensive to make, but there are considerably fewer of them and they require fewer fasteners, thereby achieving cost-offsetting production economies.

End effect on the Derringer is a beautifully smooth surface on the overall aircraft, with no ugly laps or rivet heads to mar its sleekness.

Harry Moss, another long-time Wing standby, explains that the full leading edge of both Derringer wings, from the main chord line into the nacelle, also serve as fuel tanks. Ribs are located down the length of the leading edge for strength with the inboard baffle rib inside the nacelle: the removable fuel tank inspection rib is on the outboard end.

Contrary to some other manufacturers problems with sealing a wet wing, the Derringers have never had any fuel leakage after many years of service.

The Wing marketing philosophy on the Derringer is that people buy airplanes with a sense of pride of ownership. He tells of a new model aircraft he was considering buying in 1946. "I remembered the beautiful airplanes the company had produced before the war, with walnut panels, gorgeous upholstery and perfectly finished. But here was this darned flannel-like upholstery and a gray-painted instrument panel. It wasn't something to make you reach into your wallet. You might have bought it if you truly needed it but not because of pride of ownership.

"If they had put two more grand into it, beautiful interior and so forth. I would have bought it. You'll stretch your budget if you really want something. The way you make people want an airplane is to make it unique, and do it nicely. You may not be the Ford Motor Company (although they build some desirable merchandise), but you'll fill your slot in the market.

"That's what I want to do. The market for a light, two-place twin-engine airplane of quality was there when we started, and it's here now."

There have been thousands of inquiries about the Derringer, all cataloged by name, state and country and cross-referenced. Although exact figures are not revealed, there are a significant number of orders with cash deposits.

Ernie Gann, the illustrious aviation writer, has put his money on the line for a Derringer, and because George Wing is Gann fan number one, he may have a corner on the market.

Delivery price of the Derringer is undetermined at this point, with inflation advancing faster than magazine deadlines. One thing about it, the Derringer isn't increasing in price any more rapidly than anything else. In fact, buying something real with your money instead of letting the greenbacks lie around and deflate may be the only way to get ahead.

Joe Lynch, long-time Wing standby, summed up company attitude of the Derringer production, "I've worked on the airplane right from the beginning. I think we have a pretty good head start right now. We have a lot of things going for us. and I believe it will work."

George Wing
Pursuing the Elusive Dream

WHILE HE WAS an engineer at North American Aviation during World War II, George Wing invented the Hi-Shear rivet which was used initially on the P-51 Mustang, significantly cutting the weight of structural fasteners and simplifying its war-time production.

After leaving NAA, he founded Hi-Shear Rivet Tool Company which later became Hi-Shear Corporation. Named "Inventor of the Year'' by the Torrance, California, Chamber of Commerce. He holds a number of patents, among them the Hi-Lok fastener.

He also is founder of Wing Aircraft Company which developed the Derringer, now going into production. In all restraint, it must be said that only a man of George Wing's basic brilliance and multi-talents as a designer, inventor, developer, engineer, pilot, businessman and financier could have carried a project of such magnitude as the Derringer from his first wishful thinking in the 1930s, down the long road of FAA-certification, to a restart after incredible setbacks. Also, Wing is a truly likeable Southern gentleman and fosters the loyalty of a great number of people, some of whom have been with the Derringer program since John Thorp turned over the preliminary design to him some years ago. George's tenacity to finally deliver the little two-place twins to the flying public has been expensive. He has poured cubic cash into the dream of the Derringer. And still is.

The Derringer

by George S. Wing

I STARTED LAYING out a light twin engine airplane way back in the Thirties just as a hobby project, with the dream I would some day build it. I went through five or six designs and always had the dream to ultimately get into the airplane manufacturing business. We started using an airplane to make sales calls for Hi-Shear Rivet Tool Company in the 194Os. The first airplane I bought was a Culver Cadet, then a Cessna 140, then a 182. It became obvious to me, for our business purposes, that those two back seats could be sacrificed in exchange for another engine. If a company is going to really use a business airplane it would be mighty helpful if that plane had true multiengine capability.

I had become acquainted with John Thorp when I had purchased one of his Sky Skooters. I was one of the first persons ever to own one. I had tremendous respect for that little airplane and bought another one. I had not been recently active on a design program except for the Ag-2, but was busier than the proverbial feline on the roof with my responsibilities at Hi-Shear. Furthermore. I did not feel really current: although I had been a working airplane designer at North American in the confidential design group previously, by this time I was no longer current.

I had a high regard for John Thorp' s ability as a designer, and he was much more current than I. I asked him if he would be interested in doing a study for me. He had previously done studies on what he called a "Twin Skooter." but it was a very different design than the one we ultimately wound up with. As newcomers in the airplane manufacturing business, I figured we would have to do a lot better than the big guys or drop the program.

Every airplane has to be designed around a propulsion system. At the time we first drew up the Derringer, there were no constant speed, feathering propellers for light airplanes. The most interesting engine was a proposed 245-cubic inch that did not transpire successfully.

First engine we used was a 200-cubic inch fuel-injected Continental without feathering props. We flew the prototype with a fixed pitch propeller and it performed amazingly well. It proved that having an extra engine was nice; it really would fly on one engine. Later. Lycoming flattened up their 320-cubic inch engine, and Hartzell came along with constant-speed, full-feathering, lightweight props.

It had become apparent that we had a new breed of aircraft users in the general aviation field. Price was a consideration, but they were willing to pay more for performance. They required more IFR-.type operation. After John Thorp had completed his design studies, I put a crew to work on the process of developing the structure. I came up with a new design for wing structure' that had lots of advantages - a very reliable fuel system, a very trouble-free wet wing.

It was more than a design - it was an invention which I succeeded in patenting. There are no splices in the wing skin or spar web. It made it possible to use very thick material through the rivet patterns, to countersink and dimple and to make a very fine joint with no laps as there might have been.

Beginning with the prototype, until today, no Derringer has ever leaked a drop of gas. Everything we did at the start is the way we will be doing it for all of the Derringers. It can't be simulated. We have proof positive that the wing works. Our two aircraft are more than ten years old, and have flown hundreds of hours throughout the United States, across the Atlantic and back over Canada, in all kinds of weather conditions.

The fuselage skins are stretch-formed and butt-joined with no laps. The results are superior. Every Derringer will have tinted glass, all stainless steel control cables, (and) all structures will be zinc-chromated before assembly, and so forth.

In my work for Hi-Shear, I had to design for the fighter pilot. If my customer was making a fighter airplane, I had to go to them and convince them that was what the fighter pilot needed. Because, if you win a skirmish, and you win enough of those, you're going to win a war. It's that plus margin.

We never went to the customer and said, "What do you Want?" We always went to them and said, "Here' s what you need." That's what we're doing with the Derringer. We think there are enough customers, enough people who need this kind of machine.

The little Derringer won t do everything. You have to have other airplanes to do other things. But there are people who need this kind of equipment, and when you can do a really fine job and make that guy really happy and proud, then I think you build up customer loyalty, and build up all the good things for the next models, and so on - a good reputation.

The Derringer will be the first time I've been able to sell to the end customer, the user. That's the great part. I'm sure there will be headaches connected with it. But, to be able to deliver the product to the guy who will use it himself, that's the magic.

John Thorp

The Designer for Designers

JOHN W. THORP is a leading father-figure in aviation circles by virtue of his time-proved expertise in aeronautical engineering and design. His many design accomplishments for major aircraft manufacturers as consulting engineer have been exceeded only by triumphs through his own Sky Skooter and the build-it-yourself movement.

The current Experimental Aircraft Association favorite is his Thorp 1-18 home-built design, because it is fun to fly and comparatively easy to build - both hard-won Thorp goals. It took a lot of Thorp complexity for all that resultant simplicity. Approximately 300 of the T-18s have been built from a total of 1350 sets of plans sold. There may well be another 1000 T-18s on the way or in the dream stage.

Thorp worked with George Wing in drawing up the Derringer so PRIVATE PILOT asked him a few questions.

Why is the Derringer designed as a two-place, twin-engine airplane?

JWT - Because a traveling salesman, or someone using the airplane in his business, would be glad to give up an empty rear seat that he didn't use for another engine he might have need for some time. It has been proved that the market is there by all the interest.

How about your general design philosophy? How did the Derringer turn out looking the way it does?

JWT - There's a lot to be said there. Particularly on low wing airplanes, there is usually a problem of interference drag between the wing and the fuselage. The wing is lifting a certain amount, so many pounds per square inch, and the fuselage is lifting, either