Tag Archives: engine

J-2X Progress: Turbomachinery: One More Pic

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The previous article for this blog, the one down below regarding progress with the J-2X turbomachinery, was written about 2 weeks ago.  There is an inherent lag in the process for big articles. That’s just the way things are. So, that being said, I am tossing a supplemental entry on here to provide an update: The turbopumps for Engine 10001 are assembled!

Below is a picture of the Pratt & Whitney Rocketdyne team responsible for assembling the Fuel Turbopump standing around the completed unit. Way to go guys!


J-2X Extras: Rebuilding the Past

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Several years ago, I was determined and ready to buy a new vehicle.  I happened to be at my grandparents place at the time in upstate New York and my grandfather saw me perusing the local paper for dealerships making good deals.  I told him that I was interested in getting a new pickup truck, something that I could use to go back and forth to grad school and carry all my stuff.

 

“Well, I’ll tell you what,” he said, “the best darn vehicle I ever had was a 1937 Ford Pickup.  That thing just ran forever, it seems to me.”  Then he winked, smiled, and added, “And, even better, I met your grandmother while I was driving that thing.”

 

So I went on down to the local Ford dealership and announced to the salesman wearing a plaid jacket and striped tie that I wanted to buy a pickup truck.  My new best friend smiled a huge smile, shook my hand, and led me over to the part of the showroom dedicated to their latest line of beautiful F-150s.

 

“No, no,” I said, “I want to buy a 1937 pickup.”

 

“But we don’t sell used cars here, son, and certainly not classics like that.”

 

“I don’t want a used 1937 pickup,” I replied.  “I want a new 1937 pickup.”

 

“There is no such thing,” he said, in an obvious state of confusion or maybe annoyance.

 

I scratched my head.  “I don’t understand.  I mean, you guys still have the drawings and such, right?  And if you can build these big, shiny new things, then you can certainly go back and build something more simple, right?  My granddad told me not to get suckered in.  He said that I don’t need all these new-fangled bells and whistles.”

 

For the next hour, the salesman, named Pete by way (Pistol Pete, he chuckled to himself), tried to talk me into buying one of the current year models.  He showed me everything, explaining with fast-talking expertise the dramatic advantages that his trucks had over the competition and even, he tossed in for me, far older models.  But I was not totally convinced.  Pistol Pete just shrugged and gave me his business card with a scribbled phone number for someone at their corporate headquarters who might be better able to help me.  I left thinking that might have just lost the best friend I’d had for the last ninety minutes.

 

The next day, I called the corporate headquarters and tried to make clear what I wanted.  I got bumped from department to department several times until I finally got someone named George seemingly willing to indulge me. 

 

I told George what I wanted, but I also told him that I was impressed with what Pistol Pete the salesman had shown me.  I said, “I’d really like to get that 1937 pickup with an automatic transmission, with overdrive, and cruise control.  I would really like more speed and better handling.  Better gas mileage too.  Also, I’m thinking that I need more safety stuff, so I’d like that pickup to have air bags, modern crushable bumpers, and the latest auto glass.  Plus, I’d like a bit more life and reliability, so building in that self-diagnostic system and computer would be good.  And I read that some new body materials are less prone to corrosion, so build it out of new stuff.”

 

“So,” said George, who sounded perpetually half asleep when he spoke, “you want a 1937 pickup truck, with all modern features, built to all modern standards, with more performance, with better reliability, and with greater safety.  Do I have that right?”

 

“Finally,” I said, “someone who understands!  You’ve got it!  That’s exactly what I want!”

 

“Right, then we will have to design you a new vehicle from scratch.  That will take about two years of design effort, building a few prototypes, and then another couple of years of road testing and then certification from the federal highway authorities — which, by the way, will result in a bunch more changes unless you only want to drive it on Sundays and holidays like an antique car.  Overall then I’m projecting that we’re talking, maybe, forty or fifty millions dollars as a starting point.”

 

“Huh?  What are you talking about?  That’s outrageous,” I yelled into the phone in dismay.  “You built this thing 50 years ago, didn’t you?  It didn’t cost that much then for goodness sake, even with inflation.  Surely you’ve got the drawings just lying around somewhere, right?”

 

“No, actually we don’t,” said George in his tired monotone.  “And even if we did and we had to build exactly a 1937 pickup, as it was built back then, it would be a project.  To start, we would have to rebuild all of the tooling, recreate the materials we used back then, and reconstitute suppliers who have long since gone out of business.  Add to that all of your new requirements and, well, you’ve got a whole new vehicle, right?  So, basically, we’ll just have to start from scratch.”

 

I hung up the phone in an utter daze.  Several weeks later, I bought a little Toyota pickup.  I drove it for lots of years.  I plan to someday tell my grandson that it was the greatest thing ever on four wheels and see where that leads…

 

One of the first questions that I got when I started this blog was why we didn’t just dust off the drawings of the old J-2 used for the Apollo Program and use that rather that launching into the J-2X development effort.  Hopefully this little story provides a bit of insight by way of analogy.  As we go along, I will tell you about the actual changes between the Apollo-era J-2 and the J-2X of today.

J-2X Progress: Delivery of the Development Program HEXs!

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Cain Tubular Products of St. Charles, Illinois has completed fabrication of the full set of heat exchanger (HEX) coils for the J-2X development engines.  These coils have been delivered to Pratt & Whitney Rocketdyne for the next step in the fabrication process that involves integration into the hot gas ducts being assembled by Arrowhead Products in Los Alamitos, California.  The very first three units are already there and in work.

Below is a photo of the Cain brothers at their facility with their handiwork on display.

The HEX is a component of the engine that contributes only indirectly to engine operation.  Specifically, it is used by the rocket stage to develop pressurant gases for the liquid oxygen tank. 

During flight, as the engine pulls liquid oxygen from its storage tank on the stage, and as the tank drains, you need something stuffed back into the tank to replace the liquid or it will potentially collapse.  Also, due to the physics of cryogenic liquids, the pumps on the engine require a certain amount of pressure at the engine inlet in order to function effectively.  From the perspective of getting payload to orbit, the most efficient stuff to put into the tank to fill the volume vacated by the liquid is warm gas.  But where are you going to get warm gas while the vehicle is hurtling through space?  Trying to carry it in high-pressure tanks might work, but such tanks get very heavy very fast as the vehicle design gets larger.  So, the better answer is this: You make warm gas while you’re flying.

Within the engine, the HEX is placed in the discharge of the engine turbines where very hot gas is allowed to flow around the coils during operation.  Dense cryogenic helium is fed into the HEX inlet, it flows within the coil tubing, that tubing is surrounded on the outside by the hot gases which makes the tubing very wary, and then, at the HEX outlet, we get very warm, much-less-dense helium.  That warm helium is then fed back to the stage to pressurize the liquid oxygen tank.

While there is certainly nothing patently new or exciting about heat exchangers in general — the radiator on your automobile, for example, is a heat exchanger serving a different purpose — it should be noted that due to the extreme conditions experienced within a rocket engine, and the stringent requirements placed on this particular piece of hardware, fabrication of the J-2X engine HEXs constituted its own small development effort.  Cain Tubular Products did an exemplary job in deriving a unique fabrication process for this critical part and in delivering these parts in time to support the development test program.