We don’t know much about the FC-31, China’s other stealth fighter prototype. But a non-flying model of the FC-31 that appeared at the Zhuhai air show in southern China in early November offers some compelling new clues.

That’s because the model is different than the flying FC-31 prototype—which also attended the Zhuhai show. Comparing the model and the plane could reveal Shenyang Aircraft Corporation’s ambitions for its new stealth jet.

The model boasts better stealth features, new engines and a wider range of sensors. If Shenyang adds all these enhancements to the FC-31, the resulting fighter could more closely match the American F-35.

Here’s what we know for sure. The FC-31 first appeared in September 2012 at Shenyang’s factory airfield and took off on its inaugural test flight on Oct. 31 that year. Early on, observers called the new plane the J-31. Shenyang confirmed the FC-31 designation at Zhuhai this year.

There has only ever been one FC-31 prototype—and for good reason. Unlike Chengdu’s J-20 stealth fighter—four copies of which are flying—the FC-31 is a strictly private venture. The Chinese military has not yet ordered the plane … and may never. The J-20 is set to become China’s first, and likely main, front-line stealth fighter.

That’s not unusual. Chinese industry currently produces several warplane designs solely for export—most notably the JF-17, a hugely upgraded MiG-21 variant that forms the backbone of the Pakistani air force.

Indeed, there are rumors that Pakistan is interested in buying FC-31s.

The FC-31 is roughly 55 feet long, sports a one-man, two-piece cockpit and two Russian-made RD-93 engines. Its belly bay can accommodate four medium-range PL-12 air-to-air missiles—assuming artwork on display at Zhuhai is accurate.

The F-35 can also carry four medium-range air-to-air missiles in its internal bays.

The new Chinese plane has side-by-side twin nose wheels, a feature often associated with carrier-launched naval fighters. Blurry photos in the summer of 2014 seemed to depict a non-flying FC-31 model on the deck of a land-based mock-up version of Liaoning, China’s sole aircraft carrier—a possible hint at a future role for the FC-31 in Chinese service.

To be fair, some observers say the shape on the carrier mock-up is not an FC-31, rather a shrouded J-15—an older fighter model. In any event, there’s definitely a carrier version of the U.S. F-35.

The FC-31 prototype seems to have limited sensor capabilities. Its nose can surely contain a multi-mode radar. And at least one antenna on its wing could be part of a passive receiver for detecting enemy radar emissions. But unlike many other fighters including the F-35, the FC-31 doesn’t have fittings for a long-range camera.

But if the non-flying model at Zhuhai is any indication, the FC-31 could get a host of improvements. The model has a bigger nose, possibly to indicate carriage of a high-tech electronically-scanned-array radar. The model also includes an under-nose fairing for a camera, similar to the fairing on the F-35.