Germany has worked to prevent engines being transferred to Iran for use in drones that are used by Houthi rebels in Yemen against Saudi Arabia.
This complicated trafficking in materials for armed drones is part of the larger Iranian nexus of procurement for its military program. Iran hopes that the end of an arms embargo against it will make it easier to import and export weapons.
According to an article at The National, in the United Arab Emirates, German officials "imposed a ban on the same of model aircraft engines to Iran after a shipment ended up on drones used by Houthis in Yemen." Iran then moved to acquire similar parts from China.
"It emerged that a small maker of engines for miniature versions of well-known aircraft was approached by Germany's domestic intelligence service, which had been monitoring sales of units later found on the battlefield." The report claims the parts were moved from Xiaman to Mombasa.
At the heart of the German portion of this story are 42 twin-cylinder propeller motors that were sent to Athens in 2015. The motors were then moved to Iran.
This kind of dual-use technology, engines that could be used for civilian needs, shipped through a third country, easily hides the end user.
Conflict Armament Research has produced several reports on Iranian technology transfers to Yemen. A report in March 2017 traced the components of a Qasef-1 drone that had been recovered near Aden in 2016.
It includes an DLE-111 two-cylinder engine that was "manufactured by the Chinese company Mile Haoxiang Technology," the article claimed. It was identical to other engines found in attacks near Marib.
The Qasef-1 is a kamikaze drone, which is similar to an Iranian Ababil. The Ababil has its origins in Iranian manufacturing dating back to the 1980s when Iran took over a former Textron factory that made Bell helicopters. The Ababil-style drone has also been exported to Hezbollah.
The decision to highlight the Iranian links to the Houthi drones was made by the US, Saudi Arabia and the UAE as evidence increased of Iranian involvement in Yemen. In 2015, Saudi Arabia led an intervention to support the embattled Yemen government against the Houthis who were threatening Aden.
The Houthis attacked Saudi Arabia with drones and then ballistic missiles. Parts of these weapons were brought to Washington's Joint Base Anacostia-Bolling as part of an Iranian materials display to show Iran's role in Yemen. In 2017, and 2018 the role of Iran was exposed. In addition to the Qasef drone, pieces of a Shahed-123 Iranian drone were also displayed in 2018.
Gyroscopes linked Iran to the drones as well. CAR told the Associated Press in February 2020 that gyroscopes recovered from drones suggested the material was supplied from Iran.
These included similar V9 and V10 vertical gyroscopes found on a Shahed 123 that crashed in Afghanistan, drones used in a September 2019 attack on Saudi Arabia, and an Iranian Ababil-3 drone used in Iraq.
A UN report said the manufacturer of the gyroscope is "unknown." Nevertheless more gyroscopes turned up after the US navy stopped ships transporting materials from Iran to Yemen in 2019 and 2020.
A CAR report in February 2020 on the evolution of UAVs used by Houthis in Yemen documented the engines that originated in Germany. One shipment of 21 engines was sent to Athens in June 2015 and ended up in Iran
"The most significant features of the Sammad-pattern UAV are its shape and its engine. It uses a 3W-110i B2 engine manufactured by 3W Moddellmoroten Weinhold GmbH in Hanau, Germany, CAR noted.
According to the report, the Government of Germany helped support the CAR report. This shows that Germany took seriously the export concerns of these engines. The company was quoted in The National as saying there was "no indication that the engines would be delivered to Iran."
Another report at Tagesshau in German also looks at the export of the motors. It notes that this 3W-110i B2 two-cylinder engine can be used in model airplanes that weigh around 20 kilos.
Later, the engines would find their way onto drones in Yemen that can carry surveillance equipment or munitions. The German report notes that the "Federal Republic of Germany imposes special precautionary measures on goods that can be for both civilian and military uses."
Tracing the drone components is only part of the story. Forty-two engines is not a large number and can't change the course of a conflict. The Houthis have used hundreds of drones of different varieties in recent years. Some of these are long-range kamikaze drones that function more like a cruise missile.
Others conduct reconnaissance. Iran has in the past reverse engineered various components of missiles and drones and it is unclear why Iran needs to import the components.
There are also questions of financing of the Houthis that have been raised. On September 5, The National alleged that Qatar "paid for Houthi drones used in attacks on Saudi Arabia."
Yemen officials have increasingly claimed that Qatar has funded the Houthis, according to reports at Al-Arabiya in Saudi Arabia.
"A dossier circulating in Europe, compiled by an undercover agent, suggests Houthi-Iran drone production is financed by Qatar," The National noted on September 24.
The issue of financing is important because the US has put increasingly tough sanctions on Iran as part of Washington's maximum pressure campaign.
This has made it more difficult for Iran to fund groups such as Hezbollah. On February 9, the USS Normandy intercepted a ship bringing weapons to the Houthis from Iran.
Other shipments were found in December 2019 and April 2016.
The UN has an arms embargo on Yemen due to the conflict there. It is believed that Iranian experts have traveled to Yemen to assist the Houthis in creating an indigenous arms industry, similar to the one Iran pioneered despite sanctions.
That means the Houthis are likely manufacturing many aspects of their own drones now. The US has documented and targeted Iranian Islamic Revolutionary Guard Corps members in Yemen, according to reports in January.
However, the need for engines remains a problem for the Houthis. A report at The Washington Institute for Near East Studies in February points out that the Houthi drones are limited in their range.
The report claims that one of the delta-wing designs the Houthis used is a copy of a Chinese ASN-301 which "itself is based on the Israeli Harpy." It also claims that Iran reverse engineered a British AR-731 Wankel engine for UAVs and also copied a TJ-100 turbojet engine from a Czech company.
The report doesn't provide clear answers on who funds the Houthi program or whether the Houthis build some of the components locally, as they claim to.
Seth Frantzman is a Ginsburg-Milstein Writing Fellow at the Middle East Forum and senior Middle East correspondent at The Jerusalem Post.