Can a feather shuttle match a nylon shuttle? Researchers at IIT might have an answer. Sanjay Mittal, 55, was always thinking about the suffering done to birds whenever he held a feathered badminton shuttlecock.
The professor of aerospace engineering at IIT Kanpur started to consider this. Could a nylon substitute mimic the way a duck or goose feather shuttle, which is utilised at the top levels of the sport, flies?
A research study by Mittal and two other Indian scientists, Darshankumar Zala and Harish Dechiraju, examined the aerodynamic performance of nylon shuttles at various flight speeds and was published last week in the Physics of Fluids journal published by the American Institute of Physics. Their paper, “Computational analysis of the fluid–structure interactions of a synthetic badminton shuttlecock,” examined the ways in which air movement and velocity can cause the shuttle’s flared skirt to deform.
This makes better designs possible, which could help the nylon shuttle more closely resemble the aerodynamic performance of a feather shuttle by making it stiffer. According to Mittal, “this could be a game-changer.”
Mittal began playing badminton at IIT Kanpur campus clubs. He has a strong interest in aerodynamic studies in sports. Co-researcher Zala is a BTech student from Ahmedabad, and Dechiraju is a product application engineer working for a semiconductor company in Chennai. Mittal was Dechiraju’s classmate at IIT.
The main distinctions between shuttles made of duck or goose feathers and those made of nylon or synthetic materials are explained by Mittal. A feather shuttle is typically fragile and unusable after a few shots. However, it is more shape-retaining than nylon. Additionally, there is the problem of animal abuse. A push is underway to introduce nylon shuttles from an eco-friendly perspective. However, the nylon one’s aerodynamics are drastically different because it deforms in shape more quickly and becomes too unstable to play with. In order to keep the nylon stiff where it should be and behave just like the duck one, our study has set out to redistribute the nylon in a shuttle design.
Typically, a shuttle weighs 5 grammes, of which 1.5 grammes are made up of the cork and 3.5 grammes are the skirt. A nylon shuttle that is subjected to pressure at speeds greater than 40 mps, or 89 mph, loses shape and changes how it flies as the vortex structure weakens. In light of this, shuttle speeds can easily exceed 300 mph.
“A nylon shuttle becomes unstable as it deforms because there is significantly less air resistance. The opponents have very little time to react when the speed increases that much. Such inconsistent play is disliked by elite players. Duck shuttles have a constant coefficient of drag, so they remain stiff regardless of the speed they are subjected to, according to Mittal.
After comparing the two types of shuttles’ relative trajectories and analysing the aerodynamic forces acting on the shuttlecock and its deformations at different flight speeds, Mittal and his colleagues discovered patterns in nylon that differ from those found in natural feathers. The outermost skirt of nylon shuttles is often fragile and asymmetrically deforms inward by up to 9 mm. Reduced air resistance causes the speed to become uncontrollable and crazy.
A pressure difference causes high drag in synthetic shuttles. The outer skirt is responsible for 75% of the drag. In contrast to a duck shuttle, where the centre of pressure is directed towards the feathers, the nylon shuttle’s distribution of pressure is more towards the cork.
The study also showed a process of buckling, where the shuttle sways vertically after 40 mps and the skirting starts getting rumpled. At 40 mps, nylon shuttles give way and take on an unstable square shape. After that, they begin to vibrate radially and eventually move in the shape of a wave. It’s shaky and difficult to play, says Mittal.
He makes an analogy between this and batters facing an uneven cricket pitch. Players prefer uniformity over a struggle for survival because they are accustomed to a particular type of shuttle where they can demonstrate their skills. Duck is currently the gold standard. Thus, the goal of our research is to determine how to reconfigure 3.5 grammes of nylon in a shuttle skirt to mimic the behaviour of a duck shuttle.
According to Mittal, top producer Yonex releases two nylon shuttles each year that have larger holes in the skirt and thicker walls. Although it is outside his area of expertise, he believes that other composite materials, such as nylon, which is inexpensive and malleable compared to carbon fibres, but still light and elastic, can be tested. Redistributing nylon structure to resemble duck shuttle trajectories is the aim. Hiring designers to work on it is the next step, he says.
Even though he claims his research can assist designers in fine-tuning the structure, Mittal thinks Indian coaches are knowledgeable about shuttle flights despite lacking precise scientific information. He believes there is a greater purpose because he is a fan of Chinese legend Lin Dan. The badminton community in India is quite large. But we import all equipment, including shuttles and racquets. What if we could use science to create our own designs and then export machinery?
