Roskam Airplane Design
Caleb Nelands
Born in The Hague on February 22, 1930,[2] Roskam received his engineer's degree in aeronautical engineering in 1954 from the Delft University of Technology followed by a Ph.D. degree from the University of Washington in aeronautics and astronautics in 1965.
Roskam has been involved in the design and development of 36 aircraft programs, including 12 which made it to flight, while working for three major aircraft companies.[3] He was actively involved in design and development of the Boeing SST, Cessna Citation I, and Learjet 35. He also acted as a consultant on the Boeing 747.[4] He was particularly proud of his work on the Piaggio P-180 Avanti.[citation needed]
In 1967 he became a Professor of Aerospace Engineering at the University of Kansas. He served as chairman of the department from 1972 to 1976 and was recognized as the Ackers Distinguished Professor of Aerospace Engineering from 1974 until his retirement in 2003. During his time at the university he continued to serve as a member of various advisory committees to NASA and was a member of the X-29 future applications committee. He was involved in founding the Aerospace Short Course program at the University of Kansas in 1977, which has grown into a center for aerospace professional development and training, and he still teaches for the program.[citation needed]
In 1991, Roskam co-founded the Design, Analysis and Research Corporation (DARcorporation) with Willem Anemaat in Lawrence, Kansas. He served as the company's president until 2004.[3][5] The main focus of the company is design consultation, software and textbooks in the aviation field. The company developed its own aircraft design software, Advanced Aircraft Analysis (AAA), as well as a second design program for a NASA Small Business Innovative Research contract.[5]
In 2002 he published Roskam's Airplane War Stories a collection of stories about airplane design and analysis and engineering mistakes that were made. Many of the stories are based on his own experiences and have previously been used to demonstrate to young engineers that "when we make mistakes, we kill people". Roskam has written eleven books on airplane design and flight dynamics.
Shortly before his retirement in 2003, Roskam received the Chancellor's Club Award for his career in teaching, recognizing his exceptional teaching history.[4] His former students include Alan Mulally, former president and CEO of Boeing Commercial Airplanes.[6] Mulally calls Roskam one of his heroes and notes that he learned important skills such as team-building during Roskam's courses.[7] Roskam is also credited with helping Mulally get his first job at Boeing.[8]
The American Institute of Aeronautics and Astronautics honored him with the AIAA Aircraft Design Award in 2007. The award is given each year for advancements in the area of aircraft design, in Roskam's case the award was to recognize his lifetime contribution to the fields of airplane and configuration design and education.[9][10]
The impact and influence that Dr. Jan Roskam has had on theory and practice in airplane and configuration design, on the promotion of the field through his research and service, and on education and mentoring, is profound. With this history in mind,
the Dr. Jan Roskam Faculty Opportunity Fund has been established to honor him.
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However, coming from a more mechanical than pure aeronautical background, I feel that even now, doing a masters in what is essentially conceptual airplane design, I am lacking a certain foundation in the methodology of airplane design.
My question is: In the modern age of airplane design, where we are starting to get interested in more novel and radical configurations, are the approaches presented by Roskam and Raymer (and I am sure there are others authors) still valid?
Many studies and presentations you will encounter about radically different configurations with much higher performance are the aviation equivalent of car commercials. Someone tries to get attention in order to get published, or she/he needs to convince investors to fork over their money.
Trust me, the aircraft designers of the last century were no idiots. They had the luck of living in a time when it took only a few years for aircraft designs to become obsolete, so they could go through the whole design process many times and apply what they had learned before.
Someone graduating from university today will be lucky if she/he gets the chance to go through every step of a major design process even once. I myself have brought three aircraft into the air and consider myself very lucky. I had colleagues who retired without ever having seen one of their many projects take off (literally).
The consequence of this is a very mature industry which has found an optimum configuration for most purposes already and is only tinkering with the details. Add to this an ever increasing thicket of regulations which have grown on the experience from existing designs. Sure, the progress in computer control is impressive, and engines get better all the time. Manufacturing precision is ever increasing, and materials still become better and more consistent. But overall, we still build aircraft like we did a generation ago, and I do not expect this to change radically in the future.
What impacts the design process most is certainly the incredible precision of simulation software, which allows to see details which remained hidden in a wind tunnel or a strength test. Things which had to be done consecutively can now be done in parallel, and the precision of knowledge at an early stage of a design is much higher than before. But at the same time aircraft become ever more complex, so the advantage of better simulation is eaten up by the increase in complexity. Add to that the fact that mostly beancounters will have the last word, where before engineers could determine how the work was done, and you will understand that the level of preparatory work is shockingly inadequate in modern aircraft companies. Many of the avoidable early mistakes will require late, expensive fixes (but by that time the stingy beancounter has left the company with a huge bonus for the money he bragged to have saved).
The design process is still the same, and where before the experience of a few people helped to find an overall optimum, large, integrated teams will together determine this optimum. The inexperience of the participants will only show up in delays, when the iterative design cycle needs to be repeated more often than anticipated, but the result will be of high quality - really bad designs are a thing of the past. But cutting corners will still have consequences, so small annoyances will still plague new designs. Consequently, most of the engineering work will involve ironing out these annoyances or retrofitting new systems to existing airframes.
To answer your specific question: Yes, the relation between OEW and MTOW will still hold in the future, and radically new configurations will show an advantage only on paper, before they have been thoroughly designed and test-flown. Better materials and methodologies will help to improve the ratio between OEW and MTOW, but this advantage risks to be eaten up by the desire to add bells and whistles everywhere.
To add to @PeterKmpf's answer: the basic design methodology will be unchanged so long as the laws of physics remain unchanged. But the method of application of the methodology is changing very fast, and will continue to do so.
As a mech eng student, the OP is unlikely to have any real-world experience of the engineering environment in which Roskam's 8-volume set of books were first published, in 1985-1990 (according to Wikipedia). That is 25 to 30 years ago. As just one example, the fastest computer in the world back then (the Cray-2) had a clock speed slower than any modern PC except for cheap laptops or tablets, and less RAM than an top-of-the range modern cellphone. And with a price tag of around $20m, that computing resource would be shared between hundreds or perhaps thousands of users, not sitting on an engineer's desk for his or her exclusive personal use.
Today you don't need to "estimate fuel fractions for different mission segments from historical correlations". You can look at the accurate real-time data being collected automatically by every modern aircraft that your company has built, and look at it for negligible marginal cost. You don't need to approximate from a "historical log-lin correlation" - again, you can look at the actual data, in as much detail as you need.
This accelerating rate of change presents educators with some serious challenges. The university engineering departments don't have access to all that real-time data, and even if they did they are (correctly, IMO) trying to teach some general principles, not the specifics of what Company X does this week. But the danger is that the students work through the case studies in an excellent collection of 25-year-old books, and without any other input, they get the wrong idea that those case studies still represent the current state of the art.
Dr. Jan Roskam led numerous webinars on airplane design during his years teaching for the KU Aerospace Short Course program. Sadly, Dr. Roskam passed away in 2022, but recordings of his webinars are still available to view for free using the links below. Each one-hour webinar focuses on specific companies and their contributions to the commercial, military and transport aircraft industries. Learn from a legend in aircraft design how some of today's best known companies got started, persevered or went bankrupt, merged or made it on their own.
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