At first glance, you might think the Henschel Hs 129 was the perfect ground-attack airplane.
Twin engines. A heavily-armored cockpit that protected the pilot from small-arms fire. The aircraft even eventually had the heaviest and most powerful forward-firing cannon ever fitted to a production military aircraft during World War II.
There was just one problem: By all accounts, the Hs 129 was a questionable performer. In fact, the original Hs 129 A-1 series was so badthat the Luftwaffe refused to accept any of the A-1s for service.
The Hs 129 wasn’t a Warthog. It was a turkey.
Still, the aircraft occupies an interesting niche in aviation history. It’s an aeronautical also-ran that reminds us that despite their reputation for Teutonic technical superiority that included producing jet fighters and ballistic missiles, the Nazis could screw up, too.
“The Hs 129 was intended to be the A-10 Warthog of its time, but never came close to achieving that exalted status,” John Little, assistant curator and research team leader at The Museum of Flight, Seattle , told War Is Boring. “Though slow, the A-10 is extremely maneuverable, pleasant to fly and does everything extremely well from plinking tanks to bringing its pilots home alive.”
“The Hs 129 was a dog of an airplane that should have been completely redesigned to incorporate more powerful engines, more reliable engines, lower stick forces, better maneuverability and better visibility,” Little continued. “Unfortunately for the Luftwaffe, the need for the Hs 129 was so great that it had to enter service even though it was far from combat-ready. With that said, the Hs 129 was rugged and popular with its pilots — that’s about all that it has in common with the A-10.”
By the late 1930s, German military planners decided the Luftwaffe needed a dedicated ground-attack aircraft. German pilots who flew ground-attack missions as members of the Kondor Legion during the Spanish Civil War learned that low-level attacks could demoralize the Republicans with strafing runs, destroy installations with more accurate bombing, disrupt communications and pinpoint enemy artillery.
There was nothing revolutionary about the idea of a dedicated attack aircraft — the first planes for that purpose were developed during World War I.
But Hitler didn’t want to fight a war like World War I. He wanted rapid movement that swept away Germany’s adversaries. That strategy called for special aircraft that could support German ground forces.
But design difficulties, intelligence failures and poor decision-making in the Luftwaffe high command plagued the manufacture and deployment of the Hs 129, Little said.
The high command “underestimated the need for a dedicated ground-attack aircraft — and particularly a dedicated tank-killer — until it was far too late,” he said. “For example, prior to Operation Barbarossa , the German Abwehr  had estimated that the Soviets had only about 10,000 main battle tanks. The actual number was about 24,000. By the time the Germans realized that they needed a dedicated tank-busting aircraft such as the Hs 129, the die had already been cast.”
What’s more, the German government treated Henschel as an all-purpose manufacturer and often directed it to build aircraft for other firms.
“Henschel spent much of the war ‘tooling up’ to produce other companies’ aircraft, only to be ordered to switch to another aircraft before having actually produced any airplanes,” Little said.
The result was that Henschel made relatively few aircraft. Counting the three Hs 129 design prototypes and the eight Hs 129 production prototypes, only 870 Hs 129s appear to have been built, compared to more than 33,000 Messerschmitt Bf 109s and 20,000 Focke-Wulf Fw 190s, the Luftwaffe’s main fighter aircraft.
By the time that the Hs 129 entered service in quantity, the German army was on the defensive and the most urgent mission was destroying Soviet armor. When available in sufficient quantity and equipped with adequate armament, the Hs 129 proved to be fairly effective against Soviet tanks.
Unfortunately for the Germans, there were never more than five squadrons of Hs 129s, and they often carried inadequate weapons.
Then there were the design problems. The Hs 129 was slow, with a top speed of less than 200 miles per hour when fully loaded. The plane’s three-inch-thick canopy glass impeded the pilot’s view.
What’s more, the Hs 129’s French Gnôme-Rhône 14M engines were hypersensitive to dust and sand. The engines would frequently seize during flight with no advance warning.
Perhaps embracing the idea that flying a plane that doesn’t kill them might make them stronger, most pilots of Hs 129 actually liked the aircraft for one significant reason — it was damn near indestructible. It could also haul could carry some very heavy Rüstsätze — armament packages — for destroying armored vehicles.
In fact, Rudolf-Heinz Ruffer, Luftwaffe ground-attack ace and recipient of the Knight’s Cross of the Iron Cross, achieved most of his 80 tank kills while piloting an Hs 129. His record made Ruffer was one of history’s most successful tank-killing pilots.
But his love affair with the Hs 129 did not end well. In 1944, Soviet flak hit Ruffer’s aircraft while he was flying a mission over Poland.
He was killed instantly when his Hs 129 exploded.