GEAR & TECH

There's a race going on for fastest military helicopter

Right now, the fastest military helicopter in the world is the U.S. Army's Chinook, but the Army is looking at a new family of vertical lift helicopters, and both top contenders are much faster than the Chinook. But the U.S. isn't the only major power looking for new helicopters, and Russia claims that its offering will be the fastest in the world.


Sikorsky's X2 demonstrator flew for years, allowing company engineers to gain important experience now used on the SB-1 Defiant, a prototype for the Army, pictured above.

(Robert Sullivan)

Whoever wins will be well positioned to sell their hardware to allied militaries, including those countries that fall into both countries' spheres of influence, like India or the Philippines.

America's top contenders are the SB-1 Defiant from Sikorsky and the V-280 Valor. The SB-1 Defiant is part of a fairly new breed; the compound helicopter, which features a pusher propeller at the back of the bird instead of a normal tail rotor. The V-280 Valor, while impressive and capable of extreme speed (about 70 percent faster than a Chinook), is actually a tiltrotor, so we're going to largely ignore it for the rest of this discussion.

So, on the U.S. side, that leaves the SB-1 Defiant and its projected speed of 287 mph, about 50 percent faster than the Chinook. To achieve this high rate, the Defiant will send up to 90 percent of its engine power to that pusher propeller at the back of the aircraft. Most helicopters generate forward movement by tilting their main rotor blades, requiring a lot of fuel and power for relatively little forward flight power. The Defiant would give buyers a huge advantage in speed and range.

But Russia, through the state-owned Rostec company, wants in on the action, too, but their program is nowhere near as far along as Sikorsky. They announced in February, 2018, that they would be creating an experimental helicopter that is supposed to debut in and conduct its first flight in 2019.

They have not released a name or design, but there are some recent hints as to how they might create a helicopter that could fly over 200 mph, enough to beat the Chinook.

First, in March, 2018, Rostec's United Engine-building Corporation announced that it had started work on a next-generation engine for helicopters that it hoped to make 15 percent lighter than comparable engines. If Boeing were able to trim the weight of the Chinook's engines by 15 percent, that would save the aircraft 250 pounds — that's something, but far from enough to surpass the Defiant or Valor in a race.

But Rostec found another way to potentially increase the available power and longevity of engines. UEC says their new granular nickel alloy, VV725, represents a shift in materials science. Currently, most aircraft use 0.04 percent carbon or less because lots of carbon in the alloy makes it strong, but brittle.

VV725 contains 0.12 percent carbon; three times as much as standard offerings. Rostec and UEC think they've avoided the brittle problem by adding other materials, like hafnium and tantalum. If UEC's numbers are right, the long-term strength of the aircraft will be raised 8 percent.

A Ka-52, a derivative of the Ka-50 attack helicopter, flies at Torzhok Air Base in Russia. The helicopter has stacked rotor blades like the Sikorsky SB-1 Defiant, but no pusher propeller like the one that makes the Sikorsky Raider so fast.

(Airliners.net, Alex Beltyukov, CC BY-SA 3.0)

And, with the ability to increase engine strength while also reducing weight, they might have a chance at reaching 250 mph or faster. The Ka-50 has a maximum speed in level flight of 196 mph, and it has a similar main rotor blade to the SB-1 Defiant but no pusher propeller. Add the propeller with the upgraded engine, and that thing might outrun the Chinook.

But the SB-1 Defiant is scheduled to fly within weeks or months and could be adopted in the 2030s. Typically, it takes around 15 years from first flight to an aircraft entering service, military helicopters included. Russia's Ka-50 first flew in 1982 but didn't reach combat units until 1995. But the design of the Ka-50 began in early 1977. So, 18 years from original design work to the finished product.

That means that Russia's offering will likely reach the market well after the SB-1 Defiant, so it needs to be able to outrun the Defiant — not the Chinook — to take the crown as the world's fastest military helicopter. The Defiant is expected to hit 287 mph, largely thanks to Sikorsky's more than 10 years of experience with the X2 Demonstrator, a push propeller aircraft that first flew in 2008.

Can Rostec, whose fastest helicopter is currently the Mi-35M with a top speed of about 208 mph, close the gap?

A Russian Mil Mi-35M, the country's fastest military helicopter.

(Anna Zvereva, CC BY-SA 2.0)

An important note is that the Mi-35M was originally created by the company Mil, the firm which made nearly all Soviet-era Russian helicopters. Not all of that company's expertise survived its acquisition by Rostec.

So, it's not impossible. Russia has built great helicopters in the past. But Russia is suffering from serious funding problems. And their most recent weapons acquisition programs were unimpressive. The much-hyped Su-57 created buyer's remorse in India, and that country bailed on buying the jet, mostly because it was underpowered.

And Russia's premier new tank, the T-14 Armata, might or might not be as capable as advertised, but Russia won't buy it right now because they can't afford it.

So, a new, revolutionary helicopter will be a big stretch, but not impossible. And with the high speed of the Ka-50, it's easy to imagine Russia ripping off the SB-1 Defiant's push propeller, provided they can keep their airframe stable with all that extra propulsion from the rear. The final outcome in the race will likely be apparent by the end of 2019 or 2020, but neither helicopter will be fielded by a military until 2030, if ever. So, you know, stay tuned.