Grounded? Russia's answer to US next-gen fighter hits the skids.

Russia's ambitious T-50 fighter plane project was meant to develop a rival to two futuristic US jetfighters, the F-22 Raptor and the planned F-35 Lightning-II.

But now, the T-50 appears to be rivaling the F-35 another way: in development troubles. The Kremlin is slamming the brakes on its "fifth generation" fighter program and cutting its initial rollout to a quarter of those originally planned.

The decision seems a setback for Vladimir Putin's sweeping $800 billion rearmament program, a vital component of the wider effort to restore Russia to its Soviet-era status as a major global superpower. However, the sharp slowdown in plans to procure the sophisticated new jet may represent an outbreak of wisdom on the part of Russian military chiefs, who will remember how the USSR was driven into bankruptcy by engaging in an all-out arms race with the US.

Financial constraints are the key reason cited for cutting the military order from 52 to 12 of the planes over the next few years, according to the Moscow daily Kommersant.

"Given the new economic conditions, the original plans may have to be adjusted," the paper quotes Deputy Defense Minister Yuriy Borisov as saying. The project to build a cutting-edge fighter plane, which is partly financed by India, will not be canceled, but held in abeyance while the Russian Air Force makes the most of its existing "fourth generation" MiG and Sukhoi combat aircraft, he added.

No one knows whether technical problems may also have played a role in the decision to shelve the fighter.

"We may suppose there are problems, but hard information is lacking," says Alexander Golts, an independent military expert. "For instance, the prototypes of this plane have been using an old engine, pending the development of the engine it needs. Has that been developed yet? We have no idea."

The only operational "fifth generation" fighter in the world is the US F-22. Its production was canceled in 2009, after fewer than 200 of the hyper-expensive planes had been built. American military services are now awaiting the arrival of the newer and also hugely overpriced F-35, also known as the Joint Strike Fighter, but that program has been dogged with serious delays and technical failures.

The T-50, an advanced stealth plane with many capabilities lacking in previous fighters, has prompted some alarm in the West. The Russians have presented the project as an example of how they are able to leapfrog over the lost years, after Russia's military-industrial complex collapsed along with the Soviet Union, and field 21st century weapons that can rival the best the US has to offer.

Most of the weaponry that's currently in Russia's military inventory are Soviet-era designs that have evolved to incorporate new technology. Only three projects currently in the testing phase have been entirely developed by post-Soviet Russia. They are the T-50, the recently unveiled T-14 Armata tank, and the Bulava submarine-launched ballistic missile.

Recent reports suggest that Russian military brass have also decided to slash orders for the new Armata tank, and instead continue using older, Soviet-designed models for a few more years.

There is no word on the fate of other grand projects that Russian military leaders have claimed to have on the drawing boards. These include plans for a super-sized aircraft carrier that would dwarf the US Nimitz class, and a fleet of enormous supersonic transport planes that could deliver up to 400 tanks anywhere in the world. [Editor's note: The original version mischaracterized the carrying capacity of the transport planes.]

"Despite all these soaring plans, I think we see a bit of reason taking hold in the Russian military establishment," says Mr. Golts. "Even if there were no economic crisis, and no sanctions, this massively expensive rearmament program would not be what Russia needs right now. Scaling it back is a wise move."