Lightweight engines are a crucial ingredient for any UAV. Despite the sanctions, Iran has demonstrated that it can get the materials it needs to build small motors to power its drones.

“There is credible evidence to suggest that Iran is capable of producing the engines used by the majority of their UAVs,” says Galen Wright, an analyst who analyzes Iranian military capabilities at The Arkenstone.

Wright notes that much of Iran’s drone fleet tends towards smaller, shorter-ranged tactical models. “None of these are particularly rare, complicated, or expensive, which makes them attractive to Iran. There’s no need to reinvent the wheel if you can buy one off the shelf.”

The generally lower-tech components that power Iran’s fleet of smaller, tactical drones often don’t attract the same kind of scrutiny as other, more ominous dual-use materials. Thus, drone parts can slip through the web of national and international controls, sometimes with the help of a little extra cash.

Tom Cooper, an aviation analyst who has written extensively about Iran’s air forces, says his sources in Iran generally aren’t fazed by the impact of sanctions targeting the UAV industry. “Everything necessary we do not manufacture at home is easily available by means of arms brokers and middlemen, just three times more expensive than normal,” Cooper says one of his sources told him.

European engines, particularly from Germany’s Limbach Flugmotoren, frequently appear on Iran’s drone shopping list. U.S. State Department cables from the late 2000s—published by WikiLeaks—reveal that American diplomats warned their foreign counterparts about Iranian front companies trying to obtain Limbach 550E engines, among other models, and ship them to Iran Aircraft Manufacturing Industrial Company with faking shipping labels.

More recently, prosecutors in Germany have charged two men—Iman L. and Davood A.—with seeking to buy Limbach engines for Iran’s Ababil-3 drones. The Missile Technology Control regime, which restricts member country sales of certain missile and UAV technologies, doesn’t cover the engines. But Iman and Davood allegedly ran afoul of Germany’s national restrictions on trade with Iran, which requires government approval.

In public, though, Iran prefers to assert an indigenous ability to develop its drones. In 2009, Iranian media began running claims that MADO, a domestic company, was now capable of making indigenous UAV engines comparable to those Iran has imported from Europe, including a 25-horsepower model similar to one Limbach maks.

MADO’s Website, now defunct, later advertised engines with descriptions seemingly copied and pasted from Limbach’s product line, from the specifications down to the model numbers. Iran-watchers have noted that the engine from an Ababil-3 crashed in Syria bears a strong resemblance to one advertised by MADO.

Iran’s engine-development claims are hard to evaluate, but the IRGC appeared to mark a milestone in its drone production when it rolled out the Shahed-129 drone in late 2012.

Up until then, Iran’s drone fleet mostly included smaller aircraft with short range and endurance. IRGC minders claimed—but experts have been unable to independently verify—that the larger Shahed can fly for 24 hours straight.

For future drone production, the IRGC has signaled that it’s interested in building more powerful drone engines at home. In 2012 Iran’s Aviation Industries Organization claimed to be capable of producing turbofan engines. And last year, Iran’s defense minister emphasized the need to shift to jet engines from the simple piston engines Tehran’s agents have been sneaking from Europe.

Wright notes that Iran likely has a turbojet capability, as evident in its longer-range Karrar UAV. But Iran’s ability to make turbofans is less clear. “There’s been talk since at least 2012 about producing turbofans, but there’s not a whole lot of evidence one way or another yet,” Wright says.

Making drones that can fire guided missiles appears to be a more difficult feat for Iran’s aviation industry. During the Iran-Iraq war, Iranian forces equipped early versions of the Mohajer UAV with RPG-7s rocket-propelled grenades. More recently, Iran claimed that its turbojet-powered Karrar drone could drop bombs as well as fire a type of homebrew guided missile called the Sadid.

Up until this point, much of Iran’s drone strike capability comes from engineers packing the vehicles with explosives that detonate once the robot crashes into a target. When Israel shot down one of Hezbollah’s Ababil drones during the 2006 Israel-Lebanon war, investigators found 30 kilos of explosives in the wreckage.

But at the Shahed’s media debut, IRGC officials made sure to tell reporters the plane could carry eight Sadid missiles. Footage aired on Iranian television at the time showed a Shahed in flight firing a projectile. The camera quickly cut to a new scene of a missile slamming into a target.

Away from the cameras, though, Iran may be having trouble delivering on its drone missile hype. “Shahid-129 was supposed to get armaments in form of Sadid air-to-ground missiles, but research and development of these cannot be completed,” says Tom Cooper. “It’s because of items Iran can’t obtain due to U.S. sanctions.”

Imagery from the conflicts in Syria and Iraq tends to support the idea that all might not be well with Saidid production. Despite the heavy involvement of Iranian drones in the Syrian conflict, observers have yet to capture an image of one bearing missiles … or receive credible reports of a direct strike by an Iranian UAV.

Sightings of Shahed-like aircraft are rare over Syria compared to other UAV types, but no one has yet spotted a missile-bearing Shahed-129 in the conflict. That same goes for Iraq, where Iranian drones are reportedly surveilling Islamic State terrorists on behalf of the Iraqi government.

Iran and its proxies, however, would very much like the world to believe its drones are killer drones, like America’s Predators and Reapers.

In early 2014, Iraq’s Asa’ib Ahl Al Haq armed group released a video purporting to show militia members directing a Shahed-129 missile strike against Islamic State targets in Iraq.

“Asa’ib Ahl Al Haq is a directly controlled proxy of Iran and was developed during the Iraq War from splinters originally associated with Muqtada Al Sadr’s Jaysh Al Mahdi,” explains Phillip Smyth, a researcher at the University of Maryland who tracks Islamist militant groups.

Closer analysis, however, reveals the heavily edited and stylized video to be a forgery. The footage of missile strikes is actually from videos released by the Iraqi Ministry of Defense showing its manned aircraft striking Islamic State with American-provided Hellfire missiles.