Sound As A Weapon Pt.2 – M25- Hell Reaper

This is the second post of the series ‘Sound As A Weapon’. If you have missed the previous post, you can read it here.

In my previous post, I talked about how the Nazis used sound as a psychological weapon. Now, we’re going a step further.

Between 1969 and 1972, the Soviets were experimenting with a brand new concept, a weapon that could kill without technically firing a weapon in another nations territory.

Supersonic Flight.

Before talking about this weapon, we need to make sure that we know how sonic booms work. (don’t worry I won’t bore you a lot with all the super nerdy physics, just enough to effectively explain this insane soviet project).

When a plane is flying through the air, it produces vibrations- vibrations produce noise. Everything is pretty normal as long as the plane is moving slower than the speed of sound.

The noise produced by the plane moves away from it in all directions forming circular waves. But, since the plane is moving forward, these circles get squashed in the front and pulled apart behind the plane.

Diagram of Sonic Boom
A Sonic boom

When the plane breaks the sound barrier, i.e. when it goes faster than sound, the soundwaves going out towards the front of the plane get squashed so hard that they just form a single shockwave. This shockwave travels right behind the plane in a conical shape.

When the shockwave hits you, you can hear two loud bangs (usually, but sometimes there may even be just one).

The first bang is from the shockwave hitting you, and the second one is caused when it passes you and the pressure falls back to normal.

Contrary to popular belief, the ‘Sonic Boom’ isn’t a one-time occurrence that happens when the plane breaks the sound barrier but is a constant sound.

The Hell Reaper

The Hell Reaper
The Hell Reaper

The ‘M25 Hell Reaper’, was the idea that the Soviets came up with.

V. V. Struminsky, with the help of V. M. Masishchev, began the process of designing a plane that could collapse buildings, destroy tanks and kill men, by merely flying over them at supersonic speeds.

It was designed to kill using sonic booms.

The Aircraft had the appearance and the aerodynamics of a flying brick. It may seem counter intuitive for an aircraft, but it was actually intentional.

To maximize the intensity of the sonic boom, the designers had to maximize drag. The Brick Shaped body helped to increase drag, but it wasn’t enough. To increase the drag even more, they added a deployable ‘ledge’ that would increase the drag by up to 60%.

The Hell Reaper was meant to use four massive jet engines to propel its brick-shaped body to speeds of up to Mach 1.4.

Reality Check!

Planes, use control surfaces like Ailerons, Elevators and Rudders. The control provided by them, is largely dependent upon the flow of air around them.

When the plane is flying at super sonic speeds, the slightest adjustments made by the pilot can completely flip the plane, because of the high airflow at such speeds.

In layman’s terms, the faster a plane goes, the harder it is to control it.

The problem with this is, the Hell reaper needed to fly very low to the ground to effectively use its sonic boom as a weapon…. that is not a good idea😅.

Apart from this, the plane had to be extremely sturdy, as it had to withstand a LOT of drag. As a result, production cost would be very high.

Oh yeah, and Jet engine technology wasn’t advanced enough in the USSR to make it go fast enough.

After realizing that their weird, brick shaped plane that defied the principles of aviation, could not go fast enough, was too expensive, and too hard to fly, the soviets gave up on this concept.

There was also the question of ethics. This plane would not have been able to target specific enemies. It would simply kill anything and everything close enough, even animals.

This disaster of an idea came up because of a loophole in the international treatises. A supersonic passage of an aircraft is not considered as firing weapons and hence is not an act of war🙄.

Supersonic flybys are used today as an intimidation tactic because if you know a flying war machine that can level a few city blocks, is keeping an eye on you, you would probably try not to provoke it.


This post was part 2 of this series, exploring the weird ways militaries have tried to weaponize sound. Sound has been used as a psychological as well as a literal weapon. Stay tuned for part 3, it has probably the weirdest weapon idea of all time, it’s quite funny.

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