The Wright Stuff | Part 4, The X-Planes Go To Washington

They were all pretty great, but for me, the first (Early Flight through WWII) and fourth hangars at the National Museum of the USAF were my favorites. The final hangar includes space travel exhibits, experimental prototype aircraft (the so-called “X-planes”), and presidential transports. There were some cool treasures to be found in the fourth hangar.

Wagnerian

(Da-Dah-Da-Da-Da-Dah, Da-Da-Da-Da-Dah, Da-Da-Da-Dah-Da, Da-Da-Da-Dah!)

The North American XB-70A Valkyrie not only dominates the space but is considered by many to be the crown jewel of the R&D collection. Intended as a high altitude, Mach 3 nuclear bomber, the Valkyrie program was largely abandoned in 1961 with the introduction of surface to air missiles that eliminated its tactical advantage. Nonetheless, the USAF had two built as supersonic test beds. The displayed aircraft made its inaugural flight in September 1964 and achieved Mach 3 in October 1965. The other Valkyrie was destroyed in a mid-air collision with an F-104 in 1966. 

Powered by six General Electric YJ93 jet engines providing 30,000 pounds of thrust each, the aircraft reached 2,056 mph (Mach 3.1) at 73,000' and had a service ceiling just above 77,000'. 

Appropriately near the Valkyrie is the world's only surviving Lockheed YF-12A. It was designed as a high altitude Mach 3 interceptor to defend against supersonic bombers. Thus, while no production Blackbird variants carried weaponry (only cameras), the YF-12 was designed to deploy air-to-air missiles. Despite successful flight testing, budget challenges halted the F-12 from going into production.

Space Shuttle Forerunners

The Martin X-24A was used by the USAF and NASA to evaluate the aerodynamics of lifting bodies. Dropped by a modified NASA B-52, the X-24A conducted high altitude glides to a landing generating data that ultimately supported the Space Shuttle program.

The Martin X-24B was a modified X-24A with improved range and maneuverability in a glide. It was able to demonstrate the ability to glide from high altitudes to a precise landing on a runway. This was a key enabler of the Space Shuttle program.

The Bell X-1B was used to study the effects of heating on supersonic aircraft. I wondered if there were hot mitts in the glove box.

Hypersonic

The North American X-15A-2 was a hypersonic (5x speed of sound) rocket-powered aircraft flown to the edges of space. This example was the second of three X-15s built and possessed modifications that enabled it to reach Mach 6.7 in 1967.

Despite its advanced capabilities, the X-15 possessed a standard analog panel.

Those who flew the X-15 above 50 miles (264,000') in altitude qualified for astronaut wings. Neil Armstrong was an X-15 pilot before he walked on the moon. The aircraft has been at the museum since 1969. 

The Aerodynamic Blade

The Douglas X-3 Stiletto was designed to assess the effects of sustained Mach 2 flight. It was the only aircraft of its kind and first flew in 1952.

Good visibility was not necessarily a key design metric of the Stiletto.

The design of the Stiletto informed the shape of the tiny wings eventually mated to the Lockheed F-104 Starfighter. Also visible here are the six engines of the XB-70 Valkyrie.

Body by Fisher

General Motors' Fisher Body division responded to an early World War II call for a high speed interceptor by developing the P-75A Eagle. While GM subsidiaries produced aircraft under license (the FM-2 Wildcat under license from Grumman, for example), Fisher Body seems like an odd organization to engage in aircraft design. But the Eagle was a sleek, elegant looking fighter with the unusual design characteristic of six propeller blades mounted on two separate hubs. Sadly, only six production P-75As were built and large quantities were never ordered because aircraft like the P-51 Mustang were able to capably fill the need. 

Thrust was provided by the most powerful inline engine existing at the time, the Allison V-3420 (2885 HP). It was essentially two Allison 1710 V-12 engines cobbled together that gave the Eagle a top speed of 430 mph.

I saw this engine on a visit to the Glenn Curtiss Museum in 2016 and had wondered about the sort of aircraft that might make use of it. I will wonder no longer.

The Not-So-Green Goblin

McDonnell’s XF-85 Goblin was meant to ride within long range B-36 bombers and leap into action if the bomber was intercepted after the conventional fighter escort had to turn back home. These “parasitic” fighters would swing out of a bomb bay on a trapeze, engage the enemy, then hook back onto the trapeze for retraction into the bomb bay. At last, that was how it was intended to work in principle.

It was an intriguing idea and early flight tests with a modified B-29 showed that launches from the mother ship could be managed successfully, but that recovery was fraught. Eventually, the Goblin program ended when the USAF realized that aerial refueling of conventional fighters was a better solution to the problem. Still, points for creativity and the Goblin itself is just so damn adorable.

Convair’s sole XF-92A was the first aircraft to fly with a delta wing. Learnings from this aircraft went on to inform other Cold War classics like the F-102 Delta Dagger and B-58 Hustler.

Bell’s ungainly P-59B Airacomet was America’s first operational jet fighter. It wasn’t awesome, but it was first.

The striking composite Grumman X-29A was the first aircraft to fly with a forward swept wing. The model on display is the first of two aircraft built and flown during the 1980s.

"The Mighty Air Banger"

Propeller and jet driven aircraft each have distinct strengths and weaknesses. In an effort to meld the speed of turbine aircraft with the fuel efficiency of a propeller-driven aircraft, Republic gussied up two former F-84F Thunderstreak fighter jets into turboprops.

While it is generally held that the XF-84H was the fastest propeller aircraft ever built, it is also recognized as the noisiest.

Even at idle, prop tip rotational velocity exceeded the speed of sound, creating a continuous sonic boom shock wave that could be heard from miles away and notoriously induced nausea and headaches in ground crews. This earned the two prototypes the unfortunate nickname “Thunderscreech”. After eleven of the twelve test flights of these aircraft ended in emergency landings, the Thunderscreech became another vestigial limb on the aeronautical tree of life.

Out of the Box Miscellany

This “flying saucer” was created by Avro Canada and designated the VZ-9AV Avrocar. The Army and USAF were in search of a unicorn, a vertical take-off aircraft that could achieve supersonic speeds. In reality, the aircraft became unstable just three feet above the ground — exhibiting erratic pitch and roll excursions dubbed “hubcapping” by the engineers — and it only managed to eke out 35 mph of forward speed. Interestingly, wind tunnel testing of smaller models identified this problem in advance, but two full size prototypes were constructed anyway.

Although the strange looking Bell XV-3 never went into production, it performed the world’s first successful Vertical Short Take Off and Landing (VSTOL) with a tilt rotor arrangement. Ultimately, the learnings from this aircraft were funneled into development of the V-22 Osprey. Of the two XV-3s constructed, this is the only survivor.

Photo by Dan.

On April 11 1957, this Ryan X-13 Vertijet demonstrated proof of concept for a vehicle that could launch vertically, transition to horizontal flight, then land vertically on its tail. It was a neat trick, but the USAF lacked enough interest to fund the program further.

The Northrup-McDonnell Douglas YF-23A Black Widow II was in competition for the Advanced Tactical Fighter program that started in the late 1980s. Weight savings were achieved by forgoing vectored thrust capability, but this was obviously an attribute desired by the USAF because the contract went to the prototype F-22 Raptor from Lockheed.

"Spaaaaaaaaaaaaaace...I'm in Space."

Examples of Mercury, Gemini, and Apollo capsules are on display in the space gallery. This is really where my interest in aviation began, as a kid in the 1970s fascinated by the recent history of manned spaceflight. The Mercury and Gemini capsules on display, both built by McDonnell, brought home how small these vehicles really were. The Mercury capsule on display was a production model that never flew. The Gemini capsule was a B model modified for the Manned Orbital Laboratory program that was cancelled before it got off the ground. Both the Mercury and Gemini capsules were encased in Plexiglas such that it was difficult to get good photos of them.

Also on display is the North American Rockwell Apollo 15 command module, Endeavor. Unlike the other capsules, this heat-ravaged artifact is a genuine space traveler and carried Col. David R. Scott, Lt. Col. James B. Irwin, and Maj. Alfred M. Worden to the moon in July of 1971. They were the only all-USAF crew to go to the moon.

Hail To the Chief!

We ended our tour in the Presidential Gallery that displays past transports for the Commander in Chief. All presidential transports allowed walk-through tours.

Douglas constructed the first purpose-built presidential transport. The one of a kind VC-54 was officially dubbed The Flying White House but later came to be known as the Sacred Cow. Built for President Franklin D. Roosevelt, it was equipped with an elevator to lift the president and his wheelchair into the aircraft. 

Roosevelt's successor, Harry S. Truman, signed the National Security Act of 1947 on board Sacred Cow that created the USAF as a separate military branch from the Army. 

Cockpit of the Sacred Cow.

The next purpose-built presidential transport was the Douglas VC-118, The Independence. It served during Harry S. Truman's presidency and was named after Truman's Missouri hometown.

The Independence served as a White House transport for six years and retired from service in 1953.

Cockpit of The Independence.

The Lockheed VC-121E Columbine III was Dwight D. Eisenhower's personal transport while he was president. It was a modified Super Constellation that boasted 18 feet more fuselage, more powerful engines, and greater fuel capacity than standard Connies.

Cockpit of the Columbine III.

A highly modified Boeing 707, the Boeing VC-137C (also known as SAM26000) was the first jet powered purpose-built presidential transport. The famous paint scheme was developed by First Lady Jaqueline Kennedy and designer Raymond Loewy.

This historic aircraft served as Air Force One to Kennedy, Johnson, Nixon, Ford, Carter, Reagan, George H.W. Bush and Clinton. It was the airplane that bore Kennedy home from Dallas following his assassination and was where Johnson was sworn into office in his stead. SAM26000 famously flew Nixon to China in 1972 and Queen Elizabeth II was a passenger in 1983. 

After 36 years and 13,000+ flight hours, SAM26000 was retired from service in 1998.

Cockpit of SAM26000.

Check out the high-tech control center on board SAM26000. Where's the HAL9000?

In a massive space filled with one of a kind and historically impactful aircraft, the final hangar at the National Museum of the USAF is truly amazing. I could have spent all day in any one of the four hangars and still had a meaningful museum experience. To stroll through the entire place in a single day is borderline overwhelming and most certainly awe-inspiring.