9 questions for Harry Clements

From time to time, we ask a particular aviation personality to answer some random questions. Harry Clements (a former Air Facts contributor) was an aeronautical engineer for many years with his hand in the design of some well-known airplanes. Now retired, we posed these questions to Harry to delve into the mind of an engineer.

1. Everyone has a favorite airplane. What’s yours?

Favorite airplanes come in different flavors – those you designed and developed, those you design that other people like, and those you like to fly. My design favorites, in descending order, are the Cessna 620, T-37 and 310. The 172 gave me a measure of celebrity (other people loved it) but my contributions were not threshold breaking and the airplane was a business success, not a technical success.

Cessna 310 prototype
Clements helped design the Cessna 310, and it remains his favorite airplane.

I loved to fly the 195, but had nothing to do with its development, but really loved to fly the 310. The limitation was that the models of it I flew were greatly different than the prototype 310 I helped certificate and somebody else made those improvements. And the winner is, still–the Cessna 310, for being good in two categories. A lot of other people liked it, too, and it’s been featured in TV series and movies.

2. What is your proudest moment as an engineer?

I think there are two moments, or really ends to continuing events, that tie. The first is when my innovations, like a new type of stall warning spoiler but more importantly the forward fuselage strakes, were successful, saved the T-37 program from cancellation, and earned me a commendation from the Air Force. That got me some celebrity, too.

The second is when my (aerodynamic) design of the 620 went through wind tunnel test and flight test without change – and 620 project manager Ralph Harmon, designer of the Bonanza and other good Beech airplanes, said it was the most trouble-free airplane he had ever worked on and the test pilots said it ranked as one of the best airplanes they ever flew. The downside is that nobody remembers that I designed the 620, and even some of my colleagues of the time didn’t know that I, one year out of college, was the interim project manager for the airplane while we waited for Ralph Harmon to join us from Beech. I mostly made sure our “new” detail designers had enough information to do their work. Of course the 620 flight test confirmation of the design followed long after that mostly ceremonial short term assignment.

3. What do you think has changed the most about Wichita from your days as an engineer to now?

I must start by saying that after attending Wichita University (now Wichita State University) and overlapping that some with nearly ten years as an engineer at Cessna, we left Wichita and spent almost thirty years on the West and East coasts before returning to the area because of elderly parents.

Wichita had grown and matured greatly during this time and the aviation industry had too. Emphasis was on business jets and not general aviation, to the extent that Cessna had moved that part of their business to another Kansas town. Even Boeing Wichita had switched from military airplanes to major assemblies for their commercial airliners. In the 50s, the aircraft companies (Beech, Cessna, Boeing) were indeed part of the community, sponsoring teams and events and providing recreational facilities for their employees. They represented “us.”

On return I was unfavorably impressed by these companies going on TV to say they were part of the community. If you’re really part of the community, people know it and don’t have to be told. My feelings were confirmed when a county commissioner divulged to me that one of them, seeking a benefit (probably a loan and tax breaks) to modify one of their facilities told the local politicians that other cities were offering inducements and if our city and county didn’t come through with as good a deal they would move that operation out of town. The city and county naturally complied. These were not the companies, and industry, that I had worked in before.

4. What airplane that you didn’t work on do you wish you had?

This category comes in two types. I admire airplanes with longevity, especially longevity in production, which means they are really, practically good. And then there are airplanes whose great looks differentiate them from the ordinary–or even the good and sporty looking–ones that have come out over the years. The T-37 was in production 20 years, and in service for over 50, and the 172 is the most produced airplane in aviation history but neither comes close to the C-130 or Bonanza which have been in (sometimes intermittent) continuous production for well over half a century. Those are two great airplanes.

Staggerwing Beech
The Staggerwing Beech, another favorite airplane.

I have two reasons for selecting the C-130 as the one I wish I had something to do with, because I have. I had a manufacturing department at Rohr Industries and before, during, and after my time there the company produced the nacelles for the C-130. And my grandson, who missed being trained in the T-37 by one year, is now an Air Force C-130 pilot.

The classiest looking airplanes in history, in my view, are the stately Spartan Executive and the sleek Staggerwing Beech–guess I like the looks of old American general aviation airplanes the most, and I wish had conceived both of these. They both, however, are somewhat stout representatives of the class. I also like the looks of old American general aviation pilots (but I’m not very stout).

5. What personal characteristics do you feel are necessary to be a successful engineer? What technical  skill or ability was your best asset?

I think the best characteristic is the determination and dedication to learn the basics of technology, physics and engineering (and a little chemistry), such as related math, strength of materials, fluid flow, dynamics of motion and at least an introduction to systems (of which there are many to become familiar with). With this foundation, expanding into other areas or specialties is facilitated. I am on the higher end of education myself, but as a manager and defining the engineering department’s function in a company as “getting a good product out the door” I have found that some of my best employees have been those with only two years of engineering education – during which time they learned those basics. They might be more useful for achieving that departmental goal than a PhD who has gravitated into an isolated specialty.

If I had a specialty myself, it was what was known as rigid body dynamics – involving somewhat complex, mostly multi-axis airplane motions such as “dutch” roll, periodic longitudinal motions of different frequencies, and spiral divergence. The contributing disciplines are aerodynamics and math. The rigid body limitation is that structural flexure is not considered in the analysis, a pretty good assumption for pretty stiff aircraft like general aviation and business aviation models, most airliners, and many military airplanes. That nobody will know what I am talking about is why I had to become a specialist in it, because somebody had to do it. I’m probably better known for innovations, especially aerodynamic innovations. I developed this skill by always thinking about ways to improve something, even things not aviation or aerodynamics related.

6. Thinking about safety, if there were a pie chart to divide the safety pie, what part would be the pilot and what part would be the airplane?

I’d give 80 percent of the pie to the pilot, and maybe a small percentage of things other than the airplane in the remaining 20 percent. Things do go wrong mechanically – I’ve had 1) the fuel flow clog up and on another flight 2) a rod from the throttle disintegrate in the carburetor and stick in the full power on position while I was a “sky diving” pilot, which were both scary but didn’t result in an accident. And that’s why there is a per cent attributable to a sequence of failures or errors, while no single error or failure in the sequence would have caused an accident. The other small per cent is related to isolated incidents of weather that you just couldn’t avoid.

I’m going to cite a trio of easily avoidable fatal accidents that occurred in a short period of time while I was at Cessna to demonstrate various aspects of “pilot” error. This was before mechanical control locks and, in this case, an experienced pilot took off with the control wheel on the empty “co-pilot” side tied  with a seatbelt in the full back position to avoid control surface flapping when the airplane was tied down in the turbulent Kansas wind. The airplane stalled right at takeoff and the pilot was killed. In another case the experienced pilot let a passenger out to walk to an office and left the engine running. The passenger walked into the prop and was killed. The pilot should have known to shut off the engine. Then a new pilot in our flying club took his family on his first trip after getting his license, flew into weather I’m sure his instructor had taught him to avoid, and killed all four aboard.

Harry Clements
Harry Clements was an engineer at Cessna during the development of some iconic airplanes.

7. This is the season of commencement speakers. If you were speaking to a class of graduating aeronautical engineers, what advice would you give them?

I would tell them not to think that just having a degree makes them a competent engineer – and that they must continue to learn as a practicing engineer in order to earn the title. As they progress, they should be open to opportunities that will give them additional learning in engineering or even another discipline that pertains to their business. And not to ignore the economics of what they are doing – as one of my mentors said a successful airplane is one that sustains itself in the air economically. That sometimes means subjugating the engineering fascination with efficiency in order to give the customer what he wants.

8. We’re going to ask you the same question we asked Richard Collins, Mac McClellan and Hal Shevers: are general aviation’s best days behind it?

I’m afraid that I believe that they are, and have felt so for some time. As I’ve described in comments I noted that some time ago the field exhibited the economic nature of a saturated market, meaning that – for whatever reason – nearly every potential buyer has been reached and the market then will primarily consist of replacement sales. Someone pointed out that it could have been caused by the disappearance of the WWII contingent of pilots, and that has some merit, but I believe we had developed airplanes that made general aviation flying available to people who wanted them for transportation, probably both for personal and business travel.

And while there will always be those that want to be pilots and fly, just for the satisfaction, the deregulation of the airlines made commercial air travel more affordable, siphoning off some of the general aviation trade, and the resulting explosion of airline travel saturated the airways making personal flying more difficult, and expensive. Together these things have discouraged those who just want to fly around for the fun involved. Somehow the industry has not found a good way to provide the flying experience for this group.

9. What did you get out of engineering that you couldn’t have gotten from any other kind of work?

It got me other kinds of work. Having an engineering and technical background gives others the belief that you have capabilities that others do not have – and that may be true – but in any case they will give you opportunities that probably wouldn’t have otherwise come up. And you likely will find those opportunities stimulating and rewarding. First in my cases the Rohr Corporation, till that time making airplane assemblies, started a division to manufacture components for space launches and since the product and its manufacturing methods were highly technical, management felt its general manager ought to be an engineer. That got me my first general manager’s job.

Later, in part because I was a fairly rare executive with an engineering degree, I was selected for the program of the President’s Commission for Executive Exchange, and with it my first Federal government job with what seemed to require a technical orientation in the newly founded Occupational Safety and Health Administration. Following that, the Treasury Department wanted a Director for the Bureau of Engraving and Printing who had private sector manufacturing experience but have a technical background in order to manage  the work of developing anti-counterfeiting means to offset coming color copiers. They found me, and it was possibly my best job. But I left it to get back and close out my career in my first love, the aviation industry.

To read all of Harry’s Air Facts articles, click here.


  • Another interesting piece Harry -thanks.

    It seems Cessna was a happy place to work at during your time.

    Was there any basis in fact about the rumour that the 180 was designed to be quite roomy and as a result (reasonably) comfortable for tall pilots due to the fact that Dwane Wallace and the Chief Test Pilot Mort Brown were fairly tall guys?

    • I decided early on not to get involved in cabin and instrumental panel arrangements on our commercial models because this was an area of interest, and conflict, within Cessna’s senior management. To me the main combatants were VP’s tall Del Roskam and short Tom Salter, either of whom would have overruled me in any case.

  • Thanks for the great article! I am starting college in a few months for aeronautical engineering and it was nice to read this article!

    • Good for you. I have a grandson who got an engineering degree from RPI, but he broke the chain and majored in Mechanical. I also returned to school after retirement, in Aero, taking a few courses that weren’t even offered when I first attended. Best of luck in your schooling.

      • Thanks! I am going to go to the University of Idaho for Mechanical Engineering and then probably get a master’s in aero. I hope to work for Scaled Composites when I finish school!

        • I like your ambition and the specificity of it, and I told my grandson if you want to be an engineer and not sure in which field, Mechanical gives you the broadest exposure which can then be used in any of them.

      • Harry, congratulations for your grandsons achievement at RPI, but I’ll wager only you, he and I on this forum know of RPI 😉

        Thanks for your contributions here.

        • I was very proud when he got a scholarship to that prestigious institution – but I think it would not be so impressive if you didn’t already know what RPI was the acronym for! He is now a C-130 pilot, maybe leading in my footsteps.

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