The Missing Centurions

Without a doubt, the greatest period in Aviation development occurred between Dec 17, 1903 and Nov 11, 1918.  in 15 years,  Aviation went from Hot Air Balloons to Spads, Sopwith Pups and Fokker Dr.I Dreideckers.  From an aircraft that flew for 12 seconds at a dizzying altitude of 20’ for a whopping 120’ to aircraft that were capable of 8g and altitudes of 20,000’ represents a spectacular advance in Aviation Technology especially in light of the design support technology available. .

First Flight

Sopwith Pup

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  Spad
  Source

Fokker DR.I
15 years later
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IMHO, the second greatest period of Aviation development occurred between 1940 and 1955.  While there are exceptions, the average aircraft in 1940 was capable of roughly 200-300 mph, ceilings in the mid 20’s and ranges maxing out in the hundreds of miles.

Brewster Buffalo
Source

 15 years later, propeller driven aircraft were capable of 350-400 mph, ceilings in the 30’s and ranges of thousands of miles.  In the same time frame, a new technology was developed.

That technology was, of course, jet engines.  During the 15 years in question, jets went from dreams in inventor’s minds to Mach 2+ capable aircraft and ranges of hundreds of miles to, quite literally, globe circling distances.  

Initial jets ranged from the ME-262, Germany’s most famous jet, to the P-80, America’s first famous jet, to Britain’ Gloster Meteor.  The ME-262 first flew combat in the last few months of WWII and was generally successful, but gave rise to the Air to Air community’s truism “Quantity has a quality all of its own”. The Allies were able to overwhelm them with numbers and jump them on Takeoff and Landing when their speed and maneuverability was low.

ME-262, P-80, Gloster Meteor T-B

The P-80, while build in 1943, was not ready for service in WWII, but saw extensive action in Korea.  However, it was quickly outdone by the Mig-15 and relegated to an air to ground role.  During and after the war, the P-80 evolved into the classic T-33 and flew essentially forever with the USAF.  Bones flew the T-33 in the mid to late 80’s. 

The Gloster Meteor was in service with the RAF until 1955, but was completely obsolete.

Other jets were built directly after the war, but few received any longevity with the USAF, not because they were not well built and capable of performing the missions they were designed for.  Rather, advances in Aviation Technology rendered them obsolete almost before they came off the drawing board.

This brings us to the point where Sarge asks the question “Juvat, where in the heck are you going with this post?”

Well, those magnificent aircraft were rendered obsolete by the introduction of a series of aircraft collectively known as the “Century Series”.  This name stems, of course, from the fact that the Series started with the F-100 and ended, depending on source, with the F-111 or F-117.  Since all were 100+ and 100 = Century…ergo the Century Series.

From Sarge’s authoritative source:

“The unifying characteristic of the Century Series aircraft was advanced performance and avionics when they were introduced. The F-100 was the first aircraft in the USAF capable of exceeding the speed of sound in level flight. The F-101 was the first aircraft in the USAF capable of exceeding 1,000 mph (1,600 km/h). The F-102 was the first aircraft in the world to utilize area rule in its design. Three of the Century Series aircraft — F-101, F-102, and F-106 — were armed with nuclear air-to-air missiles. These weapons, designed to destroy incoming nuclear-armed Soviet bombers even when not scoring a clear hit (due to the nuclear explosion radius, shock wave and radiation burst), were the only nuclear weapons in USAF arsenal at the time to be under sole control of their pilots (during a mission).” 

So, the Century Series included the F-100 Super Sabre (AKA the Hun), F-101 Voodoo, F-102 Delta Dagger, F-104 Starfighter (AKA Zipper), F-105 Thunderchief (AKA the Thud), F-106 Delta Dart, F-111 (Never officially named, but universally called the Aardvark or just Vark) and/or the F-117 Nighthawk (sometimes referred to as the “Wobblin’ Goblin due to its reported handling characteristics).  The series represented a significant jump in capabilities from the first generation of jet aircraft.

But, Juvat, those aircraft are mostly in sequence, what happened to the missing numbers?

That, my Friends, is the point of this post.  I know, Sarge. Finally!

The first of the missing Centurions was the 103.  Officially, it was known as the XF-103.

Artist Conception Republic XF-103

  The XF-103 was a proposal by Republic Aircraft for a Mach 3 capable interceptor.  Typical of Republic Aircraft, the unofficial name of this aircraft was the Thunderwarrior.

Achieving Mach 3 in the 1950s was a problem as metallurgy was not quite advanced enough to make a conventional turbine engines whose turbine blades could withstand the temperature of the friction heated air at speed.  Republic proposed a hybrid engine system for the 103 which used a conventional J67 turbine engine at lower speed and a ducted RamJet to power the aircraft at higher speed.

Another interesting feature of the 103 was there was no canopy.  There were two oval windows on either side, but forward visibility was provided by a periscope which projected the forward view into a Fresnel lens for the pilot.  Ejection from the aircraft was via a supersonic escape capsule which would eject downward.  Boarding the aircraft was via the escape capsule which was lowered from the aircraft, the pilot would sit down and the capsule would be raised up into the aircraft.

A mockup was built of the aircraft, but metallurgical problems with the engine were such that the J67 never entered production and substitute models did not produce the thrust needed to accelerate the jet to speeds required for the Ram Jet to function.  The program was cancelled. Source

The next of the missing Centurions is the 107.  Murph at Lagniappe’s Lair is fortunate in that he has pictures of one of the two F-107 in existence today. The aircraft, of which 3 were built and flown, was a successor built by North American aviation as a successor to the F-100. 

Looking at the wing sweep, tail and aft fuselage you can see the F-100 lineage.

 

I got a chuckle out of this description of the aircraft.

"The F-107A will be remembered forever, if it is remembered at all, for being configured as no jet had been before or since: the sharp-edged maw of its air intake, feeding a prototype Pratt & Whitney YJ-75 engine, was just above and behind the cockpit, giving the otherwise sleek fighter the look of a fourth grader with an oversize backpack. In an era of dart-like Mirages and Delta Daggers, the F-107A was a single-engine-jet Winnebago." Source

I’ve always thought the aircraft looked like an aviation version of the cartoon spies from Mad Magazine’s series “Spy vs Spy”.  But that’s just me.

The F-107’s unique design with the air intakes above and behind the cockpit was necessitated by the semi conformal belly weapons bay.  The theory was that air flow around conventional intakes would interfere with the release dynamics of the weapons carried in the bay.  The impact of an ejection by the pilot caused by his not being able to see an enemy aircraft behind him don’t seem to have come under much consideration.

In any case, the Air Force decided to have a fly off between the F-107 and the F-105.  We all know which aircraft won that competition, all though officially the results were close.

Three models were built in 1956 and the aircraft successfully achieved Mach 2. The story contained in the Air and Space Magazine article linked above of the # 2 aircraft’s delivery to the Air Force Museum is an interesting insight into the difference in yesterday’s Air Force and today’s.  Suffice it to say were it not for a Zippo lighter, the F-107 would be lost.  F-107 Source

The third in the missing Centurion Series, is the XF-108 Rapier. 

Artist's Concept of XF-108 Rapier
Source: Anynobody-Own Work

 The Rapier was a design proposal from North American Aviation for a long range Mach 3 capable interceptor using many of the design features of the XB-70 Valkyrie. Air Defense Command planned on buying 480 of the aircraft.  Evaluation was made on the aircraft as to it potential as an escort fighter for the XB-70.  As a result of the conversion from manned bombers by the Soviets into using nuclear missiles, the F-108 was cancelled.  However, many features of the aircraft were incorporated into other North American aircraft. The A-5 Vigilante incorporated the fuselage design and the YF-12 used the Hughes ASG-18 fire control system developed for the Rapier.  Only one mockup was built before the program was cancelled.

Finally on our tour de force of missing Centurions is the XF-109.  

There is some confusion on line about exactly which aircraft was the XF-109 was supposed to be.  One suggestion was that it was intended for a variant of the F-106B.  The answer, at least according to Sarge’s Authoritative source is it is the unofficial designation for the Bell D-188A .  The aircraft was proposed as an 8 engine VTOL Mach 2 fighter.  Proposed in 1955, (very early for this technology) it was intended as a multirole aircraft for the USAF and USN.  (F-111/F-35 anyone?) The aircraft had an area ruled fuselage single seat and high mounted wings.  On the end of the wings were pods containing two J-85 engines each.  This is the same engine that powers the T-38.  Two additional engines were mounted, conventionally, at the rear of the fuselage for thrust in horizontal flight, and two were mounted vertically behind the cockpit to assist in vertical flight.  When taking off, the wing pods were rotated vertically then rotated back to horizontal as the aircraft transitioned to horizontal flight.  Think V-22.

One mockup was built and the program was officially cancelled by the Air Force in 1961.  The Navy had wised up and cancelled their participation a year earlier.

So, Juvat, what about the other numbers between 109 and 117.  Well, at this point in the game, the number crunchers (Last Name McNamara) came into power in the Pentagon and a new Tri-Service numbering system   came into use.  The decision was made the USAF could continue to use the old numbering system up through the F-111 and then change over to the new system.  So everything 112 and above were not used, the exception being the F-117 which was designated to enhance its deniability.

This would leave us with only the F-110 unaccounted for.  Here’s the “official” story:

"The USAF received Phantoms as the result of Defense Secretary Robert McNamara's push to create a unified fighter for all branches of the military. After an F-4B won the "Operation Highspeed" fly-off against the Convair F-106 Delta Dart, the USAF borrowed two Naval F-4Bs, temporarily designating them F-110A "Spectre" in January 1962, and developed requirements for their own version. Unlike the navy's focus on interception, the USAF emphasized a fighter-bomber role. With McNamara's unification of designations on 18 September 1962, the Phantom became the F-4 with the naval version designated F-4B and USAF F-4C. The first air force Phantom flew on 27 May 1963, exceeding Mach 2 on its maiden flight" Source

And the rest, as they say, is History.