Or at least enough more to make a big difference.

Key point: Between sanctions and budget cuts, Moscow cannot afford more incomplete Su-57s.

But buying into the Su-57 program won’t magically solve the program’s problems. The Su-57 is an immature design whose production line is small and inefficient. That won’t quickly or cheaply change.

Russian president Vladimir Putin made a big show on May 14, 2019 of visiting the 929th Chkalov State Flight-Test Center in Russia's Astrakhan region.

Six Sukhoi Su-57 stealth fighters -- fully half of the Su-57s that Sukhoi has built since the type first flew in 2010 -- escorted Putin’s Il-96 VIP plane on the trip from Moscow to Astrakhan.

Speaking on May 15, 2019, Putin said the Kremlin would buy scores of Su-57s over the next eight years. If Putin is serious and the Russian defense ministry follows through on the pledge, Russia soon could possess a meaningful number of stealth fighters.

But there are good reasons to be skeptical. The Su-57 still isn’t a mature design. It lacks key combat systems. Sukhoi hasn’t set up a big, efficient production line for the type. And Moscow almost certainly doesn’t have the money to buy a large number of stealth fighters.

After years of slow development, one engine fire and a theatrical “deployment” of apparently non-combat-capable jets to Syria, in 2018 the Kremlin announced it would all but suspend production of the Su-57 in favor of upgraded versions of the venerable, non-stealthy Su-27. Moscow would buy just 16 new Su-57s through 2027, resulting in an overall force of no more than 28 stealth fighters.

Economics surely motivated the change in plans. Russia in 2016 spent $70 billion on its armed forces. But an economic downturn that shaved nearly four percent off of GDP in 2015 forced Moscow to reconsider its spending priorities. "In preparing the 2016 budget, there was clearly awareness that this level of spending could not be sustained," the International Institute for Strategic Studies explained.

The government tried to spin the decision to curtail Su-57 production. “You know that today the Su-57 is considered to be one of the best aircraft produced in the world,” Yuri Borisov, Russia’s deputy defense minister, told a television audience. “Consequently, it does not make sense to speed up work on mass-producing the fifth-generation aircraft.”

The 2018 decision meant the Russian air force for the foreseeable future would not operate meaningful numbers of stealth fighters. The United States and China, meanwhile, both are mass-producing stealth fighters and developing new stealth bombers.

Putin in May 2019 promised to address the imbalance. Claiming that Sukhoi had driven down the cost of an Su-57 by 20 percent, Putin announced the Kremlin by 2027 would buy 76 Su-57s instead of just 16. “I hope that the adjusted plans will be executed,” Putin said.

Sukhoi has not said how much an Su-57 costs, but it’s worth noting that Lockheed Martin’s F-35 stealth fighter costs around $100 million per copy on a mature, fully modern assembly line that annually produces dozens of planes.

The U.S. military in recent years has bought between 60 and 70 F-35s a year as part of an overall $700-billion annual defense budget. The F-35 accounts for one percent of U.S. military spending. If Moscow spends one percent of its own military budget on Su-57s, it might be able annually to afford six of the planes for a total of 54 new stealth fighters by 2027.

But that’s an optimistic assessment. Before it can mass-produce Su-57s that the Russian air force actually can use in combat, Sukhoi must complete development of the type’s combat systems, integrate weapons on the planes, expand the assembly line that builds the stealth fighters and train workers actually to make them.

All of these things are easier said than done. And simply throwing money at them won’t necessarily work. The F-35 program has experienced no shortage of technical, industrial and logistical setbacks while also enjoying nearly 20 years of sustained funding.

Of course, it’s possible that Putin’s six-plane Su-57 escort and subsequent announcement of a possible big new order for the type both weren’t really related to any serious effort to equip the Russian air force. It’s possible they’re part of a marketing campaign for prospective international buyers.

It’s no coincidence that Russia’s initial plan to acquire Su-57s for its own use coincided with India’s decision to quit co-development and co-financing of a variant of the Russian stealth fighter for the Indian air force.

Russia might be hoping to entice Turkey into joining the Su-57 program and taking over India’s role as a major financier. The Turkish air force has ordered F-35s, but the U.S. government has threatened to block the order owing to Ankara’s decision also to buy Russian-made air-defense systems whose sensors could gather sensitive data on the F-35’s stealth profile.

A big display of Putin’s supposed confidence in the Su-57 could be just the thing to convince Turkish officials to gamble on the Russian stealth fighter.

But buying into the Su-57 program won’t magically solve the program’s problems. The Su-57 is an immature design whose production line is small and inefficient. That won’t quickly or cheaply change.

David Axe serves as Defense Editor of the National Interest. He is the author of the graphic novels War Fix, War Is Boring and Machete Squad. This first appeared in May 2019.

Image: YouTube Screenshot.