1969, a watershed year in aerospace, witnessed two major innovations take flight. Apollo 11 landed humans on the moon for the first time, just months after the first supersonic commercial airliner, Concorde, conducted its maiden test flight.
In the same decade, aircraft manufacturers around the world also pursued new technologies and innovation in aerospace. Companies like Rockwell International, General Dynamics, and North American Aviation pushed the limits in a race for supersonic speed.
The iconic aircraft that emerged during this era provide lessons in design that are still valuable today. For Boom, the research and understanding of historic aircraft was the first step in the design of XB-1, Boom’s supersonic demonstrator.
What aircraft inspired Boom and what can be learned from this momentous era in aviation history?
F-86 Sabre
Manufactured by North American Aviation, the F-86 Sabre was the first swept wing fighter built after World War II. The aircraft was originally intended to feature a straight wing design. However, research by German aerodynamicists at the end of World War II revealed the massive benefits wrought by swept wing. Swept wing enabled a reduction in drag and compressibility problems at supersonic speed.
The F-86 was developed early in the 1940’s. While the design was quickly considered outdated before the 1960’s, the tried and true flight control system has inspired many aircraft today. The Boom XB-1 flight control system is very similar to that of this 1947 jet fighter and was selected for its simplicity and practicality.
F-100 Super Sabre
The F-100 was the first Air Force fighter specifically designed to fly supersonic. Compared to the F-86, the F-100 had slightly more sweep and a thinner wing, allowing it to achieve a maximum speed of 864 miles per hour.
A tailhook was built to slow the aircraft down in case of emergency landings, while a small wing fence intended to reduce the risk of nose pitching. Despite the extra measures, the F-100 was infamously known for the “Sabre Dance,” given the aircraft’s tendency to fall into a severe stall known as pitch-up.
The lessons learned from Super Sabre educated the entire aviation industry in effective tail design and placement. For XB-1, this meant designing a tail to maximize handling qualities at extreme angles of attack.
Convair F-102 Delta Dagger
“Keep it simple and make it fast.”
This philosophy propelled the design and manufacturing of the F-102 Delta Dagger.
The F-102 was the first operational supersonic interceptor and delta-wing fighter of the U.S. Air Force. However, the aircraft battled significantly more transonic drag than previously anticipated, resulting in a redesign and the introduction of its “coke bottle” configuration.
Despite the initial drag concerns, the swept delta wing of the F-102 proved to be a highly efficient wing. As a result, the XB-1 wing is extremely similar for its ability to balance both high and low speed efficiency.
F-104 Starfighter
Manufactured by Lockheed Martin with a Kelly Johnson design (the same team that contributed to the Lockheed Blackbird), the F-104’s key objective was speed. At 14,080 lbs., the aircraft was significantly lighter than comparable fighters of its time.
Unlike the Super Sabre and Delta Dagger, the Starfighter possesses virtually no wing sweep and a very short, thin wing span. Couple this with an extra sharp leading edge, the aircraft reduced drag and achieved speeds of up to 1,404 miles per hour.
The Starfighter’s impressive supersonic performance came at the cost of poor handling qualities at low speed. Given the Starfighter’s unfortunately high crash rate, the aircraft earned the nickname as ‘widowmaker.’
For XB-1, the Starfighter represents a powerful lesson in finding design balance between efficient subsonic and supersonic speed.
F-14 Tomcat
Featuring a variable-sweep wing, twin-engine, and two-seat design, the Tomcat was capable of a maximum speed of 1,544 miles per hour.
The 2D variable engine inlet of the F-14 is very similar to XB-1, given its efficiency. Likewise, this navy fighter was the first to use composite structures, a material benefit that has proven critical for its strength, weight, and stability at high temperatures.
Design experimentation in supersonic aircraft during the 1950’s and 60’s opened new doors for future innovation. The era witnessed both significant success through the discovery of delta wing designs and failures through the learning of the F-104 Starfighter ‘Widowmaker.’
For Boom, this early innovation has resulted in improved design, efficiency, and cost reduction. Applying lessons in aerodynamics, materials, propulsion, stability, and structure, the legacies of yesterday have fueled a supersonic future.
