Take a Boeing B-17G Flying Fortress. Remove the nose. Bolt a jet engine where the bombardier used to sit. Now fly it. That is not a thought experiment. From 1947 to 1966, the Curtiss-Wright Corporation did exactly that — operating a modified B-17G as an airborne engine test bed from Caldwell Wright Airport in Caldwell, New Jersey. The aircraft tested jet engines, turboprops, and advanced piston engines, all mounted in a specially designed nacelle where the glass nose had once given bombardiers their view of targets over occupied Europe.

Why a Bomber Became a Test Bench

In the late 1940s, jet engine technology was advancing faster than aircraft designers could build new airframes to test them. Engine manufacturers needed a stable, well-understood platform that could carry heavy test equipment, fly at a range of speeds and altitudes, and be modified without enormous expense. The B-17 was perfect. Thousands of B-17s were available as war surplus. The aircraft was thoroughly understood — its handling characteristics, structural limits, and performance envelope were known down to the last rivet. And the nose section could be removed and replaced with a custom engine nacelle without affecting the aircraft’s four main engines, which continued to provide the primary thrust and flight control. The result was one of the strangest-looking aircraft ever to fly: a World War II heavy bomber with a jet engine protruding from its nose, surrounded by instrumentation and exhaust plumbing, while four Wright R-1820 radial engines droned away on the wings behind it.

Testing the Engines of Tomorrow

The Curtiss-Wright test B-17 evaluated an enormous range of powerplants over its nearly two decades of service. Early tests focused on the company’s own jet engine designs, including variants that would power the next generation of military and commercial aircraft. Later, turboprop engines were mounted in the nose — strange hybrids that combined jet turbine technology with traditional propellers. The nose-mounted position was ideal for testing. The engine under evaluation received clean, undisturbed airflow — no interference from other engines or airframe structures. Instrumentation cables ran from the test engine back through the fuselage to recording equipment operated by flight engineers. Every parameter — temperature, pressure, thrust, vibration, fuel flow — was measured and logged on each flight.

Not the Only One

Curtiss-Wright’s B-17 was not unique. Several other B-17s and B-29 Superfortresses served as engine test beds during the postwar period. General Electric, Pratt & Whitney, and other manufacturers all used modified bombers to flight-test their engines. The Boeing B-29 was particularly popular for larger engines, as its airframe could handle the weight and thrust of more powerful designs. But the Curtiss-Wright B-17 holds a special place in aviation history because of its longevity. Operating from 1947 until 1966, it spanned the entire golden age of jet engine development — from the earliest turbojets to the high-bypass turbofans that would power the Boeing 747.

Sources: World War Aviation (Instagram), Curtiss-Wright Corporation, Smithsonian National Air and Space Museum