The world's first collapsible soft-top scissor door sports car that broke 100 in 3.2 seconds, these traffic tags have gained great exposure for the MG CyberSter. But as China's first real sports car, the MG CyberSter deserves much more than a few cool traffic tags. Therefore, SAIC Motor carried out a dismantling activity in the Anting Automobile City factory to show us the charm of this car at the technical level.
In the world of sports cars, foldable soft tops and scissor doors are not uncommon, but there has never been a product that combines the two. Even a multi-million-class supercar such as the Lamborghini Murcielago Roadster usually offers a canvas roof that can be removed by hand.
For MG, this meant that the design needed to be completed from scratch, with no vendor to provide a complete solution and no established precedent to refer to. While satisfying safety, convenience, and sealing, the roof and door also need to take into account a large number of special scene factors and design complex control logic.
The end result was satisfying. The MG CyberSter's soft top opens and closes fully automatically in just 8 seconds when stationary, eliminating the need for manual operation. It is worth mentioning that as long as the speed does not exceed 50 km/h, it does not affect the opening and closing of the roof, but the whole process needs to be slowed down by 2 seconds. In terms of doors, the maximum opening angle is 61°, the lateral opening width is only 457mm, and it can hover at any angle, and there are ultrasonic radars on the upper and outer sides of the doors to achieve obstacle avoidance and anti-pinch functions.
In total, there are 3 electric motors, 9 sensors to drive and control the folding of the roof. Two of the three motors are mounted at the bottom of the soft roof on the left and right sides and are responsible for driving the opening and closing of the entire roof, and the other motor is responsible for controlling the roof lock. Most of the nine sensors are located on the soft top to monitor the position of the roof folding, and one in the middle of the roof to monitor the locking status.
The situation with the doors is more complicated, and the difficulty is mainly in the design of the hinges. To put it simply, a regular swing door only needs to consider one direction, while a scissor door moves in both directions. As a result, the door will encounter the problem of difficult to control the size and surface difference from the beginning of assembly. In the daily use of consumers, the body may also be slightly deformed due to factors such as parking on ramps, resulting in doors that cannot be closed perfectly or have problems with the neutralization of the lock.
To solve these problems, MG has specially designed a patented 6-way DOF adjustable single-axis hinge that gives it 2 mm latitude in both directions of motion. Thanks to this, CyberSter's scissor doors can open and close normally on 11-degree uphill and 7-degree sideslopes, while being able to cope with extreme temperatures ranging from -30 degrees Celsius to -80 degrees Celsius. Before going to market, the engineering team tested more than 2,000 test-cases for scissor doors in different application scenarios, covering a variety of extreme working conditions and failure scenarios.
Even for a normal coupé, tightness is a special concern, especially for the CyberSter, which has a folding coup and scissor doors. However, SAIC has completely mastered the simulation capabilities of the sealing strip design, and chose the circular bubble sealing strip solution for the CyberSter from a performance perspective.
For the choice of soft top material, the CyberSter opted for a structure of two layers of 100% woven fabric sandwiched with butyl rubber in between, and a drainage channel around the roof. As a result, the CyberSter can withstand the most intense rain tests, with 230 times the standard precipitation of the national standard for heavy rainfall.
A friend at SAIC told me that at the same time as the teardown was being showcased, a freighter was heading for the UK with 153 MG CyberSters, scheduled to be delivered to the first owners at the GoodWood Festival of Speed in the near future.
The author of this article is He Qiao, a kicking car gang