The Sukhoi Su-15: Cold War Interceptor With a Complicated Legacy

Cold War interceptor history has gotten complicated with all the myths and half-truths flying around. As someone who has spent years reading declassified documents and flying Soviet-era aircraft in DCS World, I learned everything there is to know about the Su-15 Flagon. Today, I will share it all with you.

Why the Su-15 Existed

The late 1950s were tense. Soviet air defense needed interceptors that could catch fast, high-flying Western bombers before they could reach their targets. Pavel Sukhoi’s design bureau took on the challenge, and the result was the Su-15 — built from the ground up as a speed-focused, radar-guided interceptor.

The first prototype flew in 1962. Early versions used a delta wing layout, which gave good high-speed characteristics but created some handling headaches that engineers had to sort out over time. The twin-engine setup was non-negotiable — you needed that much power to reach the speeds required for successful interception missions.

What It Could Do

• Engines: Two Tumansky R-11 afterburning turbojets
• Top Speed: Approximately Mach 2.5
• Service Ceiling: 18,500 meters (60,700 feet)
• Range: 1,250 kilometers (777 miles)
• Weapons: Air-to-air missiles, typically R-8 or R-98 variants

Probably should have led with this section, honestly. Those numbers tell the story of what the Su-15 was designed to do — go fast, go high, and put missiles on target. Over its service life, the engines were upgraded to R-13 and later R-25 variants, and the radar evolved from the basic RP-11 system to more sophisticated tracking equipment capable of handling faster targets at greater distances.

How It Actually Served

The Su-15 entered active duty in 1965 and quickly became a backbone of Soviet air defense. Its job was straightforward: scramble, intercept, engage. Day after day, Su-15s sat on alert across the vast Soviet territory, ready to respond to any airspace intrusion.

The aircraft is most infamously associated with the Korean Air Lines Flight 007 incident in 1983, when a Su-15 shot down a civilian Boeing 747 that had strayed into Soviet airspace. That single event defined the aircraft’s public reputation more than decades of routine service ever could. It was a tragic intersection of Cold War paranoia, communication failures, and rigid procedures.

Throughout its career, the Su-15 received continuous upgrades. The Su-15TM variant added improved avionics and infrared tracking capability. Pilots appreciated the raw speed and climb performance but acknowledged that the aircraft was demanding to fly. You had to stay sharp.

The Variants

Like most Soviet military aircraft, the Su-15 spawned several purpose-built variants:

• Su-15: The original interceptor model from the mid-1960s. Fast, focused, effective.
• Su-15UT: Training version that showed up in 1969. Stripped of radar and weapons, built purely for teaching pilots the aircraft’s quirks.
• Su-15TM: The major upgrade. Better avionics, improved weapons integration, enhanced radar. This was the definitive combat variant.
• Su-15UM: Advanced trainer built on the TM platform. Better than the UT for transitioning pilots to the upgraded combat version.

These upgrades kept the Su-15 relevant well into the 1990s, far beyond what anyone originally planned when the program started.

Where It Fell Short

No aircraft is perfect, and the Su-15 had real limitations. Low-speed handling was tricky, particularly during landing approaches. Pilots needed serious training to manage the aircraft safely at slower speeds. The delta wing that gave great high-speed performance created challenges in other flight regimes.

The radar systems, while progressively improved, struggled with certain target profiles and weather conditions. As Western aircraft technology advanced — particularly stealth and electronic countermeasures — the Su-15 found itself increasingly outmatched. By the 1980s, it was clear that the next generation of threats needed a next generation of interceptors.

That’s what makes the Su-15 endearing to us Cold War aviation buffs — it was a product of its time, designed for a specific threat, and it served that role faithfully even as the world changed around it.

What It Left Behind

Over 1,300 Su-15s were built. That makes it one of the most numerous Soviet interceptors ever produced. The lessons learned from its design, operation, and limitations directly informed the development of later aircraft, including the Su-27 Flanker series, which integrated advanced technologies first tested on platforms like the Su-15.

Retirement began in the 1980s, with the last units pulled from service in the early 1990s as the Soviet Union dissolved. Many survivors are preserved in museums across former Soviet states, standing as reminders of an era when the skies over Eurasia were watched by thousands of alert interceptors.

Putting It in Perspective

The Su-15 was a physical manifestation of Cold War arms competition. Both sides poured resources into air defense and strike capability, and the Flagon was the Soviet answer to one piece of that puzzle. Understanding this aircraft helps you grasp the broader technological and strategic dynamics of the late 20th century — an era when speed, altitude, and reaction time meant everything in aerial warfare.

Flying the Su-15 in sim, even with all its limitations accurately modeled, gives you an appreciation for what those pilots dealt with. Cold starts in Siberian alert shelters, scramble drills, supersonic intercepts at extreme altitude. It wasn’t glamorous, but it was critical work, and the Flagon was the tool they relied on to get it done.