The F-1 engines from the first stage of a Saturn V rocket were used throughout the Apollo program, which launched men to the Moon.
Below is a close-up view of the F-1 engine for the Saturn V S-IC first stage that describes the complexity of the engine. Liquid oxygen and kerosene were used as fuel and initially rated at 1,, pounds of thrust. And it was the launch of Apollo 8, the first human-crewed Saturn 5 mission, in The five F-1 engines burned over 15 tons of fuel per second during its two minutes and thirty seconds of operation to take the vehicle to a height of about 36 miles and a maximum speed of about 6, miles per hour.
The answer is million horsepower. So, at liftoff, the Saturn V took off with 3. As of , the Saturn V remains the tallest, heaviest, and most powerful highest total impulse rocket ever brought to operational status and holds records for the heaviest payload launched and largest payload capacity to low Earth orbit LEO of , kg.
As we advance our technology ever forward, you think that remaking a year old design should be easy, but things are not quite as simple as they first seem.
When the Space Launch System or the SLS was in development, NASA ran the advanced booster competition to find a new booster system, and two of the three entries used liquid fuel engines. Liquid fuel boosters would be safer and could be shut down in the event of a problem, unlike the solid rocket boosters, which cant.
However, unlike the space shuttle, the new boosters would be single-use only and would burn up when they fell back to earth. But which liquid fuel engines would be powerful enough? The boosters could use four same modified RSD engines. But that will be very wasteful of a complex, expensive, and yet highly efficient engine. Now, there is a common myth that says NASA lost or threw away the blueprints, and which, of course, is complete rubbish.
Every design document ever created for the Apollo program is still available. But if it were just a case of wheeling out old designs, they would have done that years ago. The structured light software can use the unique layout of dots to stitch together all pictures of the object being scanned, without requiring the camera to be mounted in a motion controlled rig. After the point map was assembled, Black performed a detailed structured light scan of the entire outside surface of the engine.
Taking the F-1 apart to get at its insides was always part of the plan, but as the team proceeded, it became obvious that actually cracking the thing open without breaking it was going to require specialised tooling - tooling that might have existed 40 years ago but which has long since been destroyed or lost. The exterior scan was therefore used to develop the specialised tooling needed to fit the F-1's nuts, bolts, and fasteners.
Some of the bolts were annoyingly unique - Betts noted that at least one high-torque bolt in the turbopump assembly required its own special torque adapter to remove. The team was able to use the structured light scan of that particular bolt and, in less than half a day, to fabricate a tool using an additive manufacturing method called electron beam melting to quickly "print" 3D projects out of metal powder.
Armed with this and other custom tools, Case, Betts, and Coates took the engine apart, down to its tiniest components. He pulled up a PowerPoint presentation on his laptop and pointed at one particular slide. You'll notice the grey is the scanned data, like we got on the screen here, but it also maps to points. Well, those points are the same points that were mapped in the assembly [the initial scan].
There's only one way that part will fit into that constellation of points, and that's what you see on the lower right. And we did this for all the parts that you see on the shelves here," Black added. The result was a complete and highly accurate CAD model of the entire F-1 rocket engine, down to its tiniest bolt. The fidelity was so good that the scanner even picked up tiny accumulations of soot left on the turbine blades from the engine's previous test firing back in the s.
The engineers removed the soot and re-scanned, but even this seemingly trivial accumulation yielded valuable data - sooting is a problem with kerosene-powered engines, so understanding how it builds up inside the engine could reduce its occurrence. The welds - " "Oh, the welds! And these guys were pumping engines out every two months. It's amazing what they could do back then and all the touch labour it took.
That's one thing we were trying to get knowledge on: what imperfections were OK to live with versus what imperfections are going to give us problems? And one of the holes you can actually see where the drill bit came down at the wrong spot, and the guy just stopped - you can see where he moved over to where the hole was supposed to be and finished drilling the hole.
They kept that and would have flown with that engine. Those kinds of things were pretty neat. You didn't have the kind of advanced manufacturing we had today, so quite honestly, these were hand-made machines.
They were sewn together with arc welders, and it's pretty amazing to see how smooth and elegant it came out. Today, you'd look at doing precision casting, not these thousands of welds. The engine disassembled by Betts, Case, and Coates was number F, assembled in December just as Apollo 8 was carrying three astronauts further away from Earth than any human being had ever before travelled.
F had been test-fired for seconds and then mounted on the S-IC stage of the Saturn V that would have flown as Apollo 19, but the engine was eventually pulled and placed into storage at MSFC.
As the team methodically stripped engine F down, it became obvious that a test-fire of some of the engine's components was within the realm of probability. With F being torn apart to learn from, the team turned to engine F , which had served for years as a display engine at the Udvar-Hazy Centre at the Smithsonian National Air and Space Museum.
F was in even better condition than F, but simply firing the entire F-1 engine straight away wasn't practical.
For one thing, though the F-1s were originally tested at MSFC in the s, that test infrastructure has since been repurposed. In addition, the city of Huntsville has grown up considerably since the Apollo era; lighting off an engine the size of an F-1 at Marshall today would likely blow out every window in the entire city. Instead, the team decided to start with a series of firings on F's gas generator.
An engine like the F-1 is sort of like two separate rocket engines: one small, one large. The smaller one consumes the same fuel as the larger, but its rocket exhaust is not used to lift the vehicle; instead, it drives the enormous turbopump that draws fuel and oxidiser from the tanks and forces them through the injector plate into the main thrust chamber to be burned.
As with everything else about the F-1, even the gas generator boasts impressive specs. It churns out about kilonewtons of thrust, more than an F fighter's engine running at full afterburner, and it was used to drive a turbine that produced 55, shaft horsepower. That's 55, horsepower just to run the F-1's fuel and oxidiser pumps - the F-1 itself produced the equivalent of something like 32 million horsepower, though accurately measuring a rocket's thrust at that scale is complicated. Betts, Case, and Coates pulled the gas generator, the gas generator injector, and the gas generator combustion chamber from F, along with one of the ball valves for the propellant.
Every "soft good" in the gas generator - every seal and gasket - had to be recreated from scratch, since all had hardened or rotted. In the process, the team had to spend quite a bit of time ensuring that they were creating functional seals and gaskets, since plastics technology had changed considerably since the s. Just creating the soft goods required a lot of chemistry work. As the preparation for the gas generator tests continued, though, something happened that caused the exercise to shed its academic roots and turn very, very practical.
Nasa's SLS will most likely be a multi-stage vehicle, with boosters attached to its first "core" stage, but Nasa is holding a competition to determine whether those boosters will be fuelled by solid or liquid propellant. The Advanced Booster competition has finally brought liquid-fuelled contenders into a space dominated for decades with solid fuel boosters built by a company called ATK.
One of the companies selected to compete for the Advanced Booster contract is Dynetics , a 1,employee company headquartered in Huntsville, near MSFC.
Dynetics has primarily done work for the Department of Defence, but within the past five years it has expanded into aerospace. The F-1 gas generator tests that Betts, Case, and Coates were preparing for were set to happen at an extremely opportune time: their exploratory work on the F-1 started near the end of , right around the time Dynetics was selected as a competitor for the Advanced Booster contract. Dynetics had an absolutely golden opportunity; right down the street, Nasa was about to start test-firing an F-1 gas generator, something that hadn't been done in decades.
Through a complex set of letters of agreement, MSFC allowed Dynetics and PWR engineers to use the resurrected gas generator and engine test facilities.
The engineering effort even included cooperation with heritage Rocketdyne engineers in California and Huntsville -- folks who were involved in the original design and testing of the F-1 and who had engineering expertise and advice to contribute to the effort. MSFC conducted 11 hot-fire tests of the gas generator, ranging from 5 to 30 seconds each, with Dynetics and PWR representatives present and assisting.
This necessitated a second series of gas generator test firings in the latter half of February, so Ars headed out to Huntsville to watch. On the morning of 20 February I found myself perched on a set of metal bleachers under an iron-grey Huntsville sky, with the thermometer reading zero degrees celsius - quite a bit cooler than this Texas boy is used to enduring, especially since the wind wouldn't stop gusting.
The payoff was that the observation area sat only a short distance from the gas generator test stand. Through a clearing in a row of evergreens and scrub, separated from us by a dirt path, I saw the test stand itself: a jungle-gym pile of metal and pipes, with personnel scurrying around to make last-minute adjustments.
Because Inconel X was a high-nickel alloy, it possessed a low ductility. This material, coupled with the tubes' large diameter, thin walls, high internal operating pressure, and rounded tube crowns made tapering much more difficult, necessitating the bifurcated design. This arrangement also proved to be lighter than using a single tube to the expansion ratio plane.
Rectangular splice joints had been used for engines with secondary tube widths of 0. For the F-1, with its larger tubes, relatively thin walls, high internal operating pressure, and rounded tube crowns, the "D" splice was developed: The ends of the primary tube and the two secondary tubes were shaped as shown, the ends of the secondary tubes were fusion welded together, and the primary and secondary tubes were induction brazed together.
Adapted from page 57 p. Extraction and adaptation by heroicrelics. This subassembly one primary tube brazed to two secondary tubes was then used in thrust chamber fabrication. Assembling the tube subassemblies into the jacket and end rings was referred to as the "stacking operation" and was done in a "stacking fixture" which kept alignment between the tube bundle, jacket, and end rings prior to brazing the entire entire bundle into a thrust chamber brazing is a process in which joining is accomplished by melting a filler metal into closely fitted joints between a number of metal parts.
An early design for the F-1 thrust chamber had a completely regeneratively-cooled nozzle, all the way to the expansion plane, which incorporated two bifurcation joints.
This concept, however, was altered early on to use the uncooled nozzle extension from the to the expansion plane. Even with "only" primary and secondary tubes, the F-1 had over 3, feet of joints between the tubes to be brazed together.
Here are two photos of the bifurcation joint. The first is of the exterior of the thrust chamber and the second is from the interior:.
Click image for more information about this picture; opens in a new window. Photo by heroicrelics. The brazed joints between the tubes served primarily as a seal to contain the combustion gasses within the chamber. Although the brazed joints provided some resistance to the separating forces generated by the internal gas pressure, the primary load was borne by the jacket and bands surrounding the tube bundle. With the greatly increased power and high thrust-to-weight ratio imposed by the design requirements on the F-1 and the Inconel X tubing, a more sophisticated brazing process than that used with earlier engines had to be developed.
Here are two photos showing F-1 engines early in the fabrication process, with little more than the tubes, bands, and jacket:. De Carlo. Louis Salmon Library, University of Alabama in Huntsville, which also makes this document available as a 4. Turning our attention now away from the minutia of metallurgy and manufacturing and back to the features of the F-1 thrust chamber, the No.
These tubes were similarly marked on the thrust chamber's exterior on the reinforcing bands and straps below the engine's throat. See my F-1 engine tube markings page for additional information. The 70 percent of the fuel used for regenerative cooling flowed through the fuel-down tubes to the fuel return manifold at the end of the thrust chamber. From the fuel return manifold, the fuel was directed up the adjacent fuel return tubes to the fuel injector manifold.
The return manifold was welded to the bottom of the thrust chamber secondary tubes and incorporated four drain ports, located 90 degrees apart, to drain residual fluids. Forty lugs were welded to the inside wall of the return manifold for attaching the turbine exhaust leak-test fixture. Adapted from page 64 p. Extraction, cleanup, and adaptation by heroicrelics.
The fuel return manifold was welded to the thrust chamber after its brazing operation. Here are two photos of the thrust chamber prior to mating with the fuel return manifold.
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