What are 'Tradeoffs'?
“At its core, all engineering comes down to making tradeoffs between the perfect and the workable.”
In 2001, the Pentagon commissioned Lockheed-Martin to create a multipurpose aircraft that would fulfil the different needs of the Air Force, Navy, and Marines.
The result was the F-35 Lightning, the most advanced fighter jet in the world.
By building one plane instead of three, they hoped to save taxpayers money.
Expect things didn’t quite go as planned.
The project ran over budget, and the plane had numerous problems.
The reason?
Ironically, they were asking too much of the plane.
The brief called for a ‘jack of all trades‘ aircraft, but achieving this objective would mean grappling with the central challenge of all engineering problems: trade-offs.
So what exactly is a ‘trade-off’?
It refers to the scenario where improving one aspect of a product, system, or process may result in a corresponding disadvantage or compromise in another aspect.
The term ‘trade-off’ has many alternative names, such as compromise, balance, negative correlation, optimisation, etc.
To give a relatable example, consider your smartphone.
You want it to have a good battery life, but you also want it to be compact and easily portable.
Let’s say you wanted your phone to last a week without charging.
How big would it need to be to have sufficient battery power?
You’d probably have to carry it in a travel bag instead of your pocket!
In this case, the trade-off is between the battery capacity and the device's size.
Until battery technology improves, a handheld phone can’t have a super long battery life.
Anyway, back to the fighter jet.
As you can imagine, there were multiple trade-offs to consider, which compromised the overall plane’s design.
The engineers simply couldn’t balance the various competing objectives.
Like engineering, tradeoffs are a significant factor in natural selection and evolution.
This is because compromises must be made when a system is under pressure to improve.
Common trade-offs include the following:
1. Speed vs Accuracy
Example from the man-made world: Hitting a golf ball
Example from the natural world: Archerfish
2. Speed vs Energy
Example from the man-made world: Formula One racing car
Example from the natural world: Cheetah
3. Cost vs Benefit
Example from the man-made world: Fighter Jet
Example from the natural world: Praying mantis
4. Load vs Strength
Example from the man-made world: Bridge
Example from the natural world: Shells
5. Resolution vs Sensitivity
Example from the man-made world: Camera
Example from the natural world: House fly eye
6. Safety vs Efficiency
Example from the man-made world: Commercial aeroplane
Example from the natural world: Desert snake (hunting at night)
As the above examples illustrate, the simplest trade-off is two-dimensional, defined by [A] versus [B]. e.g. strength vs. weight
1. If the trade-off is [A] or [B], it can be a preference and we might speak of a choice;
2. Both [A] and [B] may be preferred, but at different times under different circumstances, so the trade-off becomes subject to external conditions and can be an adaptation mechanism;
3. [A] and [B] may be antagonistic, in which case we might speak of a compromise or optimisation.
Trade-off number three tends to be the only option.
In the case of the F-35, the trade-offs were multi-dimensional, making it impossible for the aircraft to meet its intended purpose.
To summarise, engineers and innovators encounter situations where improving one aspect comes at the expense of another, and the challenge lies in finding the best trade-off that meets the overall goals and constraints of the project.
Found the above interesting? Then register for our upcoming Biomimicry course. It’s full of amazing case studies of lessons you can learn from the natural world to improve your innovation efforts.
