A love of model airplanes has inspired a unique photography project capturing one of China's disappearing shantytowns. Gao Fei and Li Xiang report from Tianjin.

The transformation of shantytowns is a project that is rapidly changing the living environment of tens of millions of Chinese. Now, a unique aerial photography project has captured the destruction of one of these run-down areas.

Model airplane enthusiast Li Xinyang, 41, is recording the changes in his hometown, Xiyu-zhuang - the largest shantytown in Tianjin - by using cameras strapped to model helicopters.

The photos became popular after Li posted them online, with many netizens saying they brought back childhood memories.

Most of the houses in Xiyuzhuang were built in the 1950s. Left in disrepair for many years, the houses are in sharp contrast to the surrounding modern buildings. At the end of 2013, the Xiyuzhuang shanty town transformation project was officially launched.

Li was born in Beijing but his family moved to Tianjin where he started primary school. He grew up around Xiyuzhuang in Hongqiao district.

Li recently passed by Xiyuzhuang and heard that it would soon be pulled down. He decided to take photos of the place - his childhood paradise - to remember its history and compare its past and future.

As an experienced model airplane operator and aerial photographer, Li had all the equipment needed.

Since 2006, when Li became interested in model airplanes, he has assembled more than 300 fixed wings and a dozen mini unmanned aerial vehicles by himself, spending about 700,000 yuan ($11,300).

When asked why he is so obsessed with model airplanes, Li laughs and says it is because he is a playful person.

Li got top marks on his college entrance examination, and in 1995 he was working for a foreign company in Beijing, earning a good salary. But he was unwilling to be constrained. Li quit his job when he was 23 and spent two years backpacking all over China.

When he ran out of money, he returned to Beijing and set up an advertising company. Several years later he had accumulated enough money to support himself to continue "playing".

"I like playing the ancient lute, guitar and flute. I also like painting and calligraphy, riding, archery and shooting," says Li.

Several years ago, he gave his friend's son a model toy ship as a birthday present. When playing with it, he found himself falling deeply in love with model toys, and started to develop model airplanes and ships.

Within a year, he had bought model vehicles for air, land and sea, and studied how to assemble and operate them by himself.

Li founded a folk association with some 40 members, who often play with model airplanes. It is called Xiangyu Club. On weekends, club members get together and play with their models - practicing taking off, landing and simple pattern movements in the air.

Li was unsatisfied, finding the activities too simple. "How about fighting?" he suggested. "We can fly our model planes to fight against each other, the one who crashes the other's plane down is the winner!"

The model planes flew and crashed into each other in the air, and the people on the ground cheered. Several crashed to Earth. "Exciting!" says Li. "Although we destroyed seven or eight planes, we still enjoyed it very much, everyone from the 70-year-old grandfathers to the 15-year-old boys."

Li then got the idea to photograph the planes fighting, and put cameras on the model planes and flew them high, to take pictures of the "airplane battles" in mid-flight.

"But the model planes were so fast that the camera could not follow them," says Li. "So I began to use a helicopter, then DSLR, then big planes. From photo to video, my technology developed step-by-step, until the images were not only clear, but also steady."

"I do everything very efficiently," Li says proudly. "And my parents both support me. That's why I have spent most of my time playing. In my opinion, a person with freedom to choose what he wants to do is a truly happy one."

Aerial photography is gradually becoming a part of Li's career. He now has a team to help him with aerial photography.

This year, Li and his team will focus on various photography projects, including "Beautiful Tianjin" and "The 1,100 ancient towns of China", holding large image exhibitions. The latter one will take three years.

"I will talk to the local people, because I want to record not only the images of the towns, but also their local customs and feelings, as well as their memories," Li says.