Constructal Law and High Speed Helicopters
Recent research seems to suggest that Constructal Law may govern the design of aircrafts and other flow-systems.
If these laws do apply, then they may be used as design inputs. Such an approach can be a powerful way to:
- Determine whether a company is dealing with innovation or optimization, and manage the project accordingly.
Should we organize this project with a flat hierarchy and mission orientation, or a traditional hierarchy, planning and control? - Inform, early-on, a serious market strategy.
Do we look to answer a market demand or to create a currently inexistent or unclear market need? - Make high-level architecture decisions and arbitrate among a plethora of design possibilities.
Should we discard the suggestion to include 3 engines on this particular helicopter type? - Assess, early-on, whether the necessary technology is available and mature for the success of the project.
Do we know how to manufacture a resistant airframe material that is this light?
The following is an example to illustrate the power of such an approach.
Developing the X-next #
Using the Constructal Law framework, we find that high-speed vertical-take-off rotorcrafts–such as the Sikorksy X2, Airbus Helicopters X3 or Boeing V-22–are a genus of their own, which is clearly distinguishable from classical helicopters.
On the graph above, we have positioned an arbitrary example of a high-speed helicopter. Indeed, an imaginary Company X is looking to develop this new product. And the project is given the code name X-next.
Since X-next is meant to become a new species in an emerging genus, Company X is best advised to run this project as an innovative endeavor–using a flat hierarchy and a flexible strategy.
And in looking for market opportunities, Company X ought not to neglect unexpected or uncommon mission profiles. Instead of limiting the marketing scope to classical helicopter segments–such as oil & gas and law enforcement–Company X should explore new markets.
Its marketing people should not discard even the craziest of ideas from the outset. Can there be a market for urban package delivery: essentially replacing trucks by airborne merchandise delivery to a down-town office building?
But how about X-next’s System Architecture? #
Company X is targeting a certain load capability for the aircraft, and the Constructal Law gives it an estimated top speed target as shown in the graph above.
From there, Company X may go on to size the actual dimensions of the aircraft as in the following example. The fuselage length may be deduced from the aircraft’s weight.
And the size of the blades may be deduced from the fuselage length.
We can note that in the two last vertical-lift criteria–blades and fuselage characteristics–classical and high-speed rotorcrafts are in the same genus, as one may expect.
The same laws also govern the engine mass–and hence power–of both classical and high-speed rotorcrafts, which is to be expected because the engines have to be scaled for the vertical take-off phase. In that phase, the X-next essentially behaves like a helicopter.
Note that the X-next, which is considerably larger than the Airbus Helicopters X3, should have similar motorization as its smaller sibling. In other words, the X3 seems to be equipped with oversized engines.
Such an approach may also be applied to other characteristics such as range, fuel, size, weight… at aircraft and component level, in order to inform design decisions.
And given the set of targeted characteristics, Company X can determine, early-on in the design phase, whether the available technology can ensure the success of the project. Do we have the necessary know-how to manufacture blades of that size? Are the needed engines available on the market?
Of course, this framework is not a substitute for aircraft design handbooks. However, since it deals with design problems on a macro-level, through the lens of flow, it offers a useful tool set for new product development.
By definition, there can be no design handbooks for truly innovative products–because those products, or aspects thereof, have not yet been created.
The framework presented in this paper overcomes this obstacle by leveraging the fact that flow systems, old or new, technological or biological, are all part of the economy of nature and must all obey the laws thereof.
The truth in this remark is indeed shown by that old canon in natural history of “Natura non facit saltum.” … or, as Milne Edwards has well expressed it, nature is prodigal in variety, but niggard in innovation.
Charles Darwin
To Sum it Up #
Constructal Law offers a framework that has the potential to greatly improve product development: all the way from project setup and culture, to market positioning, to product architecture and technology.
Author: E. Dib #
References #
- A. Bejan, J. D. Charles, S. Lorente, The Evolution of Airplanes
- E. Dib, Constructal Law and Increasing Returns: The Evolution of Machines and Catching the Next Wave
- C. Darwin, On the Origin of Species