What makes Putin hesitant to use the Su-57 in Ukraine?

The Su-57 has been met with a lot of skepticism due to its lack of combat validity. While it possesses some stealth properties, it is not as stealthy as other aircraft in production. Additionally, the engines used on the plane are less stealthy than those used by other aircraft in development. The Su-57 is not a true stealth aircraft, and its cheek-mounted radars allow it to guide missiles to targets at far more extreme angles than American counterparts.

However, this capability is only useful if expected to fight at close ranges or defend against enemy missiles while guiding its own. There is no evidence that the Russian aircraft has been used in combat to successfully carry out air-to-ground attacks. As for why the Su-57 isn't being deployed in Ukraine, there are several reasons. Firstly, there's a shortage of these aircraft, making it impractical to use them in this conflict.

Russia had set ambitious goals of acquiring just under a hundred of these fighters by 2027, but this appears to be completely unfeasible due to the severe sanctions imposed by Western nations. When your military is compelled to scavenge for components like microchips from everyday appliances, the idea of fielding a hundred stealth fighters within five years becomes highly unlikely. Secondly, there are doubts surrounding the actual capabilities of the Su-57.

Despite Russia's claims about its advanced features, it may not be as capable as they assert. Consequently, Russia is wary of the potential embarrassment that could arise if a Su-57 were to be shot down by Ukrainian forces. In the ongoing conflict, Russia has already lost an estimated 144 aircraft, including two dozen front-line manned fighters and ground attack aircraft. Given the challenging threat environment, Russia is reluctant to risk the public relations disaster that would follow if a Su-57 were downed by Ukrainian forces. Regarding a hypothetical face-off between the US F-35 and the Russian Su-57, it's important to understand that this would depend on various factors, including the specific attributes of each aircraft, the strategies employed, and the skills of the pilots. Both planes are designed for different purposes and possess their unique strengths and weaknesses. An assessment of their relative combat capabilities is complex and often debated among military analysts. However, actual combat deployments of such advanced aircraft are rare due to the associated risks and costs.

Russia was holding back with Su-57s because it was "avoiding the reputational damage, reduced export prospects, and the compromise of sensitive technology which would come from any loss" of the craft. And the SU-57 'Felon' lacks advanced stealth features, making it less stealthy and giving it a disadvantage compared to other planes like the J-20, F-22, and F-35. The SU57 'Felon' has poor build quality and lacks radar absorbent material, making it ineffective in reducing its radar signature. Having said that the Su-57 possesses a significant advantage over the American F-16 when operating in a head-on interception mode. In this scenario, coordinated combat missions involving Su-57s and ground-based radars are particularly effective. These radars can readily support the Su-57s by carrying long-range and medium-range missiles on the aircraft's wings.

But the the Russia's SU-57 in comparison to F-22 is slower as F-22 raptor has a higher top speed, capable of reaching speeds over Mach 2. The Su-57 is also supersonic but has a slightly lower top speed. The range of both aircraft can vary depending on mission profiles and fuel load, but the F-22 generally has a longer combat radius

And one of the many reason's of why Russian's are not deploying the SU-57's is that there are just not that many of them, as multiple public reports say there are currently somewhere between four and 15 operational Su-57 aircraft, and Russia's TASS news agency has reported plans for the country to acquire 76 Su-57s over the next five years.