Republic XF-103 Interceptor

Skyraider3D said:

Real shame I was too cheap on that F-84-with-persicope footage. I won't get a second chance for such a reel I don't think and it would have matched the XF-103 footage nicely! :-\

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Orionblamblam said:

And then feel free to post what you'd charge for copies of the DVDs.

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reelarchives said:

I could ship these overseas; however I would prefer to put these all on film cores so the shipment won't be so heavy. The metal cans and reels add about 50% of the weight if not more.

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overscan said:

As international shipping isn't available, we would need a US buyer.


We could think about a combined bid, where instead of donating to support the forum this year, users donate to a common fund to secure these interesting tapes.

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rchurch said:

I'd contribute a fraction as well if it meant getting a digital copy at some point-

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The Artist said:

Have you checked to see if they will scan corporate films like this/these?

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Orionblamblam said:

The Artist said:

Have you checked to see if they will scan corporate films like this/these?

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Nope. Ran the numbers, and kinda had a heart attack.

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I was too low down in the food chain to have a lot juicy information -- just the stuff that circulated at mach 4+ around the engineering department. Enough for a story (see below) but too thin for a book. Also, I've never been quite sure about when the secrecy was lifted -- if ever. Embarrassing stuff like that is often kept secret until all participants are long dead -- maybe my next correspondance will be from Levenworth.


Okay -- here's the entire story of the ill-fated mother-f. From what I see of the pics of the model (thanks guys for the URL -- have to make that my next project). it is pretty accurate.

Republic Aviation was my first job after graduating (1956) with a degree in Physics from CCNY. I had a wife and newborn child to support and the $2800 a year I earned as an electronics tech at Columbia Presbyterian Medical Center wasn't going to hack it. Aircraft had been my passion from an early age (avid model builder). I had learned a lot of aerodynamics on my own and thermodynamics had been my best physics subject. So it was not surprizing that I was offered a job at Republic in the thermodynamics department. The thermo department in the aircraft business is to inlets and engines what the aero department is to the airframe. For supersonic aircraft, the inlet becomes as important as the engine and together they are as important as the airframe. There was (is) a lot of high-falutin aero-thermodynamics involved in design of inlets. In a supersonic aircraft most of the air compression comes from the inlet, not the compressor stages -- so much so, that you would dearly love to get rid of the compressor and run the engine as a ramjet. In theory, it is far more efficient. However, there are some "small" problems. The first of which is that it is really difficult to keep a match burning in a supersonic airstream. You have to get the internal air flow down to subsonic speeds. This can be done by using a convergingerging inlet.

Contrary to behavior at subsonic speeds, supersonic air passing through a converging nozzle slows down (subsonic air speeds up as you all know) and as it slows, the pressure is increased. The ideal, perfect, inlet would slow the air down to mach 1 at the narrowest point, from which it would go to a diverging nozzle to slow down even more -- and raise the pressure even higher -- so that by the time you got to the flame holders, you had really slow air at high pressure. That's the ideal, but nasty things like external and internal turbulence, maneuver-induced instabilities, and a lot of other stuff means that you can't have that ideal mach 1 transition. So you have a transition, via a shock wave, at a slightly higher speed -- say mach 1.4 or so. The shock wave itself acts as compressor -- the air flow is supersonic on one side and subsonic on the other.

Unfortunately, this configuration has a nasty tendency to instability. The shock wave can bounce back and forth -- oscillate -- in the inlet at frequencies ranging from about 2 hz to 20 hz -- in so doing, it can move back and forth inches -- and even feet. Now think of what happens when you have a barrier (the shock wave) with 2psi pressure on one side, and 40 or 50 psi on the other side ( a fraction of an inch away) and that barrier is oscillating at 10 hertz though a foot or more? The inlet, and the aircraft, is destroyed in seconds. Not nice. This is avoided and controlled by having variable geometry inlets. Because the geometry must change for every speed and altitude. The inlet isn't just a pipe -- it is a dynamic thing that changes its shape all the time.

What I described above is called an "internal shock" or "fully started" inlet. They are the most efficient, most difficult to design, and most prone to inlet buzz. Note that the typical plug configuration of early Soviet supersonic aircraft inlet strongly suggests that they opted for the much simpler, external-shock or partially started inlets. By contrast, most American aircraft use a fully-started, internal shock inlet.

The above long lesson on internal aero-thermodynamics is probably more than most of you guys wanted to know. But it is important to understand it in order to understand the issues that led to the XF103 and its timely demise. If you go to the web page (www.collectaire.com/modelpages/xf103/xf103.html) you can see what is an obviously internal shock inlet. What is not visible in the picture (and very unlikely to be correct in the model) is the rather complicated arrangments of plugs, doors, throats, and stuff that makes the inlet work.

Republic liked to build big aircraft. From the P35, to the P47, to F105 (the F84 wasn't all that huge) RAC thunderships were big -- they carried a big ordance load. Always hated by the airforce brass and loved by the pilots who usually came home in them. The "Thud" (F105 Thunderchief) was probably the best of the lot -- and the culmination of Republic's fighter-bomber evolution. As an interesting side note, Alexandr Kartvelli's aircraft looked like the man. He wasn't that tall, but he was kind of squat and burly looking. Had a voice to match. They say that people's pets tend to look like their owners -- well, I think aircraft tend to look a lot like their designers. Sikorski was thin and elegant like his aircraft. Hughes had a refined elegance (Spruce-Goose aside) that mirrored his best racers...and the Wright brothers -- reedy thin and supple. By the way, you should note that many American aviation pioneers have Russian names --
Severski, Piaseki, Sikorski, Kartvelli -- a few others that I can't remember. All of them classmates from the 1912 (?) graduating class of the St. Petersburg School of Aeronautics. Left Russia for better opportunities in the West after the revolution.

Back to Thunder-Blunder. As I said in the earlier post, it was conceived at a time when the most viable nuclear threat was subsonic, high-altitude, intercontinental, manned bombers. Our entry into that arena was the B-36. To counter the massive (non-existant) Soviet bomber threat, we needed a high-altitude interceptor. Didn't have to fight defensive aircraft because no fighters could fly so far (mid-air refueling was still being perfected) -- so no air superiority issues. Big ugly bomber is bound to be bristling with nasty machine guns and cannons -- so don't get in so close -- stand off and lob a missile at them. Ground based missiles didn't have either the range or accuracy -- needed a missile carrier to get them up there. No defensive armament needed on the missile carrier if it is so fast that it can outrun bullets. The idea, now that I think of it, must have been inspired by the ME-263 rocket interceptor -- but writ large -- very large.

I said Mach 3+ because the target speed was classified and probably still is. However, this was before area ruling was discovered and the only way to achieve even modest supersonic speeds was through brute force -- lots and lots of thrust. I don't remember the exact dimensions, but what emerged was about 65-70 feet long (excluding the nose pitot tube) with about
a 40 or 45 foot wingspan. Little, thin, triangular wings -- practically flat plates with barely enough room inside to put the aeleron and flap actuators. All to be fabricated out of that wonder metal -- titanium. It was light, it was strong, it didn't weaken (much) under extreme temperatures -- and it was expensive to buy, and very difficult and expensive to fabricate. I saved a hunk of that titanium. It is a small square about 4" on a side. I've used it for almost 45 years to dress my grindstone wheels -- barely a sign of wear. Machining had to be done in an inert atmosphere, welding was an adventure, as was heat-treating and almost every other aspect of fabrication. These fabrication problems alone would have warranted calling the whole thing a research project -- but here's what else they were trying to achieve:

1. The interceptor missile that was to be used wasn't perfected yet.
2. No one had ever built an operational (as contrasted to a research prototype) ramjet.
3. Inlet aero-thermodynamics entailed a lot of witchcraft and guesswork.
4. We didn't really undersand inlet buzz and prevention/correction methods were brute-force at best.
5. Operational supersonic aircraft flight had just begun -- still a lot of R&D involved.
6. Turbojet engines were puny by comparison to today's.
7. Transistors were still experimental -- aircraft avionics relied on vaccuum tubes and electrical relays. Controls were based on analog, not digital computers. And this was going to require some really fancy control systems to safely manage the transition.

But these problems were minor compared to the engine problem and the weight problem. First the weight problem. You may not think or know this, but weight is really important in a military aircraft. You have an aircraft whose dry weight is say, 50,000 pounds, and you knock of five or six pounds, you'll get a nice bonus for that accomplishment. I remember one day at Republic that one of the engineers had figured out a way to knock off about 100 pounds from the F105 (55,000 pound aircraft) by redesign of the bomb release/ejection mechanism: They carried him on their shoulders around the entire engineering floor while we all cheered (this was before Republic had won the flyoff against the North American F107). Well, cramming in all the required electronic wizardry, the controls, and fabrication difficulties meant that the XF-103 continued to gain weight, week-by-week, pound-by-pound. That weight gain meant additional fuel and more weight. It might have been partially compensated for by an increase in thrust -- but that was where the real trouble was.

At the time, there were only a few jet engine manufacturers in the West: G.E. was probably number one, Rolls-Royce, Westinghouse, SNECMA (French), Fairchild, Pratt& Whitney, and last and least, Wright-Aeronautical. They were late getting into the jet engine business -- after all, when you have only to slug it out with Pratt & Whitney for the reciprocating engine market and you are number 2 in that business, you don't have time to fool around with those new-fangled thingies. They had made a few operational engines but they sure weren't the leaders like G.E. So when DoD came up with the revolutionary idea of turbo/ram engine, Wright jumped in, a.s first, and said they could and would do it. I don't remember the exact engine name -- I think it was called TJ-67-W-9/XRJ57-W-3 or something like that. Note that Republic cannot be given all the blame. In military aircraft design, DoD usually specifies the engine and tells the
airframe manufacturer to build an aircraft around it. In any event, the engine development and aircraft development are usually separate and the aircraft manufacturer can be on wrong end of the stick with the engine manufacturer. The best example of this is the Mustang-- it was a dog as long as it doomed to piddling around with the puny designated Allison(?) engine-- it became a world-beater only after it was retrofitted with the Rolls-Royce Merlin. That was a success story -- the XF103 was the opposite side of that engine/aircraft coin.

Week-by-week, the weight grew and week-by-week, the predicted thrust declined. 50 pounds lost turbo thrust this week, 30 pounds lost ramjet thrust next week, 3% fuel consumption increase the following week, etc. etc. Sometime in 1957, I think it was, the project was renamed from F-103 to XF-103 -- as if to tag it into the X series aircraft made it acceptable. Security went up. Despite the fact that three-views had appeared in Aviation week, despite the fact that the full-sized mockup had been in open view in an unsecured hangar for months. I got caught in that security clamp down-- a sort of Laurel and Hardy comedy act. I was showing a new employee, who knew his math and physics, but squat about aircraft, I was showing him around the cockpit of the mockup. Now this cockpit was up three flights of stairs, some 30 feet off the ground -- and almost half of that distance was taken up that by gaping maw of a barn-door sized inlet.

Anyhow, I'm sitting in the mockup's cockpit and explaining the throttle, the afterburner detent, the transition controls, joy stick, rudder pedals, turn-and-bank, other instrumentation, etc. We had been there about two hours -- when all of a sudden, from below, came the fog-horn bullroarer sound of the company security chief. "What the ---- are you doing up there? Don't you know it is classified SECRET? you'll spend a time in jail I can tell you!" -- and other dire threats. While we had been up there, the elves had come and surrounded the entire mockup with curtains and signs that said "OFF LIMITS"-- No one had bothered to look up to see that we were there -- and had been there before the curtains had come down and off limit signs put up. As it turned out, my blessed boss saved the day. He pointed out that the curtains had not been there before and that the entire mockup had been in plain view for months -- including to the guy who sold greasy sandwiches from a stand next to the left wheel -- and that both of us had the proper clearances (they had come through the day before) and authorization to be there. He sort of apologized and let us off with a stiff warning to be careful in the future -- these were the days of the McCarthy insanity and if there were Soviet agents in every government department, it figured that there had be some in a company run by a Russian (Kartvelli) and that a junior engineer named "Boris" was sure to be suspicious. Actually, my title was "senior engineer", but they were free with titles at Republic and gave them out in lieu of raises -as far as the food chain went, I was still a pretty junior engineer.

By then, the project was no longer an attempt to build a supersonic interceptor -- because the ICMB threat was looming on the horizon and the entire bomber-interceptor thing began to look sillier and sillier. It had graduated to a "titanium fabrication research project." There was some buzz around of renaming it the "X103" as contrasted to "XF-103." The former being an NASA (then NACA) experimental aircraft designation, whilst the "F" made it clear that this was an AF boondoggle -- but NACA would have none of it -- they had their own supersonic embarrassments to get over.

The thrust kept going down, the weight kept creeping up, as did the take off run, the landing run, and the number of jato rockets that would be needed for lift off. And with each passing week, those of us on the 103 project kept sharpening our resumes, looking for ins to the F105 project (still shaky, but a lot healthier) and opening channels to our colleagues down the road at Grumman for possible jobs. Meanwhile, the classified cartoons of the XF103 kept coming out and getting nastier and nastier. Our laison with the engine manufacturer became ever more formal, more difficult, more frustrating, and less informative, despite the fact that very close cooperation for such an aircraft was more important than for any previously conceived aircraft. The culmination came in the following conversation -- I wasn't there (much too low on the totem pole for that) but it was widely reported, orally, by people who had witnessed it.

Lead engineer: "We've got another 75 pound drop in take-off thrust. But I think Wright's shading the truth. It will probably be worse than that."
Weights and Balance engineer:" Not to mention another 53 pounds take-off weight increase this week."
Kartvelli:"What does that do to our take-off run?"
Lead Engineer: "We can manage that with more Jatos -- now that we're going to jettison the package and stuff after use."
Weights & Balance:" We've just got to lose 300 pounds. It has to be done!"
Structures Engineer:" Can't be done. There isn't 300 pounds to lose in the entire 60,000 pound aircraft."
Kartvelli: "What's the projected landing run?"
Aero: "10,500 feet -- but we've got four miles of paved runway at Edwards."
Kartvelli: "What's the landing run without the drag chute?"
Aero: "Ten miles --maybe twenty if you want to use the tires and brakes again."
Kartvelli: "What does the drag chute weigh?"
Structures:"312 pounds."
Kartvelli: "How miles of salt flats beyond the runway."
Flight Test:" Almost 40 miles."
Kartvelli: "Take out the drag chute!"

The following week I was slated to make a high-level presentation, first to our upper management, then to a joint Wright-Republic meeting, and then to the Air Force. The subject was to explain the "logic" of the transition, the discovered points of contradiction that had to be resolved, and the kind of control system that would be needed to make it work -- if it was at all possible from a controls point of view (never mind from the point of view of aerodynamics, thermodynamics, or sanity). I had been preparing this presentation for several weeks --It was Friday when my
boss told me that I would not have to come in for the dry-run that Saturday - that told me the whole story. That was the bad news. The good news was that I had earned a berth on the F105 project.

I have never seen a project terminated so quickly. That monday, the pink slips went out. It took only one week to get the project wrapped up. Photography teams came in to every department. They went through your desk and files and pulled out every sheet of paper having to do with the 103 -- including your laundry ticket and the grocery shopping list if it
happened to be on your desk. Every sheet numbered, stamped, photographed for micro-filming, and then shredded and burned. By the end of the week not a scrap of evidence remained. The mockup was gone. The files were gone. The drawings were gone. The fabrication jigs were gone, as were some 8,000 of our fellow engineers and craftsmen -- all of whom had spent the
entire week assisting in the closing down. Republic collected many millions -- or was it hundreds of millions? Billions? of dollars in cancellation fees. The only truly legitimate part of that was the two weeks severance pay that the engineers got and the one week that the workers got.

So what happened to the XF103? You remember the final scene in "Raiders of the Lost Arc?" The scene were the crated arc is deposited in some huge government warehouse among millions of similar, myserious, indistinguishable crates. I just know that someplace, beneath some mountain or in an abandoned salt mine -- there are thousands of file cabinets filled
with decaying micro-film, tons of oddly shaped pieces of titanium -- and in a huge crate, or more likely, surrounded by dark blue velvet curtains bearing the legend "RESTRICTED AREA -- SECRET- NO UNAUTHORIZED ACCESS"--
behind the velvet curtains is the XF103 mockup.


Boris Beizer

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Mark Nankivil said:

Greetings All -

Thanks to Gerald Balzer, some additional artwork.

Enjoy the Day! Mark

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pathology_doc said:

I think this indicates a weakness of the weapon system concept - it's all very well to say "let's integrate everything from day one", but it can lead to all sorts of problems when some of the systems you're integrating are themselves immature or incomplete. This is the road to unacceptable growth in weight and complexity, not to mention performance letdowns when/if the customer gets their hands on the product and starts putting it through the wringer. I think it really only works when you can take proven, reliable stuff off the shelf - or stuff whose development is clearly trending in terms of reductions in size and weight.

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taildragger said:

Just a quibble, but I think your criticism is of concurrent development, not the weapons system concept - which simply (simple to describe anyway) means to develop an entire integrated system from the start. The elements of the system can be mature components or cutting-edge concepts, depending on the project's risk tolerance, and aren't limited to hardware. The alternative is to design an airplane and then start looking around for suitable systems (radar, guns, support equipment, training programs, etc.) that will fit or otherwise work. That was feasible, but maybe not optimal, 60 years ago - with the complexity and development timelines of today's aircraft it wouldn't work at all.

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Stargazer2006 said:

Given the incredible condition of the model, the subject matter and the rarity of it, I predict the price of this one will reach unprecedented heights!

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Orionblamblam said:

Stargazer2006 said:

Given the incredible condition of the model, the subject matter and the rarity of it, I predict the price of this one will reach unprecedented heights!

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Hmmm. Nothing much about it really screams "vintage." A lot about it screams "built a month ago by Asian slave laborers out of genuine Philifauxno mahagony resin."

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