Rainflaps Modular System
"Rainflaps" is a modular system designed to maximize rainwater collection in commercial buildings.


The Rainflaps concept is a modular system designed to maximize collection of rain water in commercial buildings for various uses. The name Rainflaps was inspired by aircraft wing flaps which only extend during takeoff and landing to increase lift and drag respectively. Rainflaps are deployed automatically during rainy days and retract when the rain stops.

When deployed, Rainflaps provide the following three benefits:
(1) they increase the projected area of a building for  rainwater collection,
(2) they collect rainwater that runs down from vertical surfaces of the building and
(3) they provide a temporary rain shelter for pedestrians.
The system can be triggered by a rain gauge installed on the rooftop of the building.

The Rainflaps system consists of ten unique components (excluding the motor to drive the system) that are reused multiple times to construct one or more water collection modules.The modules are installed in a building at a 10-degree angle to facilitate the collection and channeling of rain water. The modular approach minimizes tooling cost and maximizes installation flexibility. The concept is geared towards commercial buildings with flat walls as they are more common and it also simplifies the design of the modular components.

One may question why a dynamic system as opposed to a permanent canopy structure? A dynamic system allows the collection system to be concealed when not in use, thus it will not affect the building architecture. Furthermore, there are other environmental factors such as wind, snow and pests which make a permanent structure undesirable.

Although the Rainflaps system allows for infinite number of modules to be chained together to form a single assembly, realistically the maximum number of modules that can be driven by a single motor is no more than three due to the weight of the components and tolerance stack-up.

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