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SAF - Stealing From Nature

SAF - Stealing From Nature

The heart of the SURU concept is efficiency.  Of all the people, technologies and events that have inspired me in my design education, the one aspect that has always had the deepest impact was efficient use of materials.  Bashing a problem over the head with vast resources, be they money, advanced technologies or exotic solutions, is always exciting, but the simple solutions are always the most powerful.

The best vehicles in history, particularly those that raised expectations and created new markets, all benefit from efficiency in design.  They use the forces of nature to be lighter, stronger, and easier to use rather than fighting physics.  

In aerospace this is seen particularly clearly.  Flying vehicles that balance forces always handle best, and display remarkable levels of performance.  Everyone knows about exotic planes like the F-22 Raptor, SR-71 Blackbird or Airbus A380 Superjumbo, but I find so much more intelligence in the design of a DeHavilland Mosquito, Douglas DC-3 or Rutan Ezee.  The latter group are exceptional handling and high performance (for their intended mission) vehicles that also have the virtue of economy.  

In other words, they do a lot with very little.

Good design means using every element carefully, and making sure a design emphasizes a material or shape's strength, rather than depending on some exotic or complicated technology to compensate.  Of course, every designer would love to begin each project with a limitless toolbar of materials and budget, but that is not reality.  And often, those projects just end up being mediocre. 

From what I have read about the F-22 and A380, the benefits don't really match the costs, when compared to simpler and more elegant solutions like the F-16 or Boeing 777.  It is not a direct comparison of missions or capability, but a comparison of how much (or how little) cost and technology was needed to achieve an outcome.


Making Less Do More

The Amarok P1 was an experiment designed to push the limits of minimal material application in an electric motorcycle.  At the time of that project's birth in 2010, all electric motorcycles were constructed as conventional fossil-fuel bikes, the only innovation being that they had batteries and electronics located where motors and fuel tanks normally were.  As a result they were hugely inefficient.

The whole point of moving towards battery-powered vehicles is to reduce wasted energy. All combustion-based propulsion systems lose 75% of the energy contained in the fuel to friction. Think about it. Three quarters of the fuel is lost as waste heat.  By contrast, battery-electric drive converts 90-95% of the energy stored in the batteries into propulsion.  

That is a terrific improvement but the effectiveness is significantly reduced when the overall design adds 30-40% more mass.  Batteries are very heavy fuel storage units compared to equivalent liquid fuels.  They are also bulky, which means that a large volume needs to be freed up.  Stuffing square batteries and electric motors into a conventional motorcycle design was almost the worst design solution possible.

The Amarok experiment was not about batteries or electronics, but about material economy.  What was the least amount of material, and the simplest simple, an electric propulsion motorcycle could get away with.  The answer came in the form of the Amarok Structural Aluminum Fuselage (SAF).


Learning from Nature


Back in the 1920's, a young aerospace engineer named Jack Northrup built an airplane using thin sheets of aluminum that were riveted together.  The resulting design was stronger, lighter and performed batter than any of the wood and canvas airplanes made at the time.  


The secret to it's power was not the material, but its employment. The sheets were fabricated into hundreds of hollow boxes, which were individually weak and fragile, but when stacked together and combined using a common outer skin formed a multi-cellular structure that was orders of magnitude stronger than its component elements.  

Like a honeycomb or a cardboard wine crate, the material was not strong at all. But once formed into interlocking hollow spaces and linked together, a superstructure was created. The stressed-skin, multi-cellular aerostructure has been the basis of nearly all aircraft and road vehicles ever since. The advent of advanced composites like carbon fibre is slowly supplanting it, but on a cost-for-performance level, it is untouchable.

The Amarok SAF weighed less than 4 kgs (compared to an equivalent motorcycle frame weighing 10-12 kgs), and that mass included all of the following functions  : vehicle frame, battery storage container, aerodynamic exterior skin, and support for all of the secondary components. The best part? It cost less than $300 to fabricate (as a one-off, meaning that at scale that cost would be even lower) and could be made using hand tools and wooden tooling.

SAF means the high performance does not have to have large capital investment, or require complicated manufacturing technology.  This was the golden egg that Amarok gave us, and is the basis of SURU.



Unlike Amarok, the performance needs of SURU cycles is modest.  However, that does not mean that SURU does not enjoy all of the same benefits.  A SURU frame contains batteries, control electronics, and forms the core onto which all of the bike is affixed.  It is also immensely strong and durable, without the need for exotic materials and is assembled without expensive jigs.

What all of this translates into is a frame that we can confidently provide a lifetime warrantee for and produce in Canada at a cost that is competitive with anything from low cost countries in the Far East.

Good design is about finding appropriate solutions to product problems.  There are many ways to make an electric cycle that is lighter and stronger still than a SURU, but can they deliver with the same cost and value?

Not that we can tell.