121–130 of 209 posts
Reading it made me appreciate (again) the "old" way of knowledge sharing- books and publications. I'm amazed that it's so under-appreciated tool nowadays.
Four years from concept to first flight for the B-52 is impressive. The "over one weekend" claim (which the body of the article refutes) is annoying.
Earlier quoted context omitted.
How long have the B-52 jet engines had monocrystalline fan blades? That must have an enormous impact on efficiency and performance. They became available in the late 60s. https://www.americanscientist.org/article/each-blade-a-singl...
They're still using the original TF33 engine they were delivered with in 1961. Presumably the fan blades have been replaced many times over during maintenance, but I don't know if there's any advantage to switching to better blades if you don't change the operating parameters to take advantage of them. There's a plan to replace all the engines with a modern turbofan (RR F130).
To anyone who's wondering how is such a feat possible: it's covered in the first few chapters of Dan Raymer's Aircraft Design. Reading it made me appreciate (again) the "old" way of knowledge sharing- books and publications. I'm amazed that it's so under-appreciated tool nowadays.
There is an obvious downside to how cheap it is nowadays to "publish" something, whether on social media, in a blog or in something resembling a book, we are now surrounded by low-quality content and it can be hard to tell the good from the bad.
Another benefit of books and magazines is that you have an instant idea of how relevant the information is, "Electronics Weekly 1970", possibly not the latest best advice on using microcontrollers!
Earlier quoted context omitted.
Conceptualized is a perfect word. The claim that it was designed in a weekend is like those “overnight success” stories that ignore the decade of work that someone put in to get to that point.
The current F-22 looks and acts nothing like the YF-22 that won the competition (despite the YF-23 being much better, but that's another story). The fact that the B-52 production was not just similar to the prototype, but similar to a complete mockup is a testament to the accuracy of their initial vision. The fact that the US continues to use that design after so many decades is even more amazing.
The first prototype of the B-52 may have been designed in a weekend. The B-52 of today was iteratively designed over decades and the current H models are entirely different planes than earlier models (although structurally very close to the G model). Another HN commenter mentioned GPS being designed over a holiday. But we spent years and years in the military debugging GPS and making it functional. Claiming that some…
Not even that is true. Here's the timeline from the article.
> In July of 1948, Boeing received a contract from the still-new U.S. Air Force to design and build a new heavy bomber.
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> So when Boeing’s three-man presentation team arrived at Wright Field Air Force Base on October 21, 1948
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> Warden suggested to the Boeing team that they do away with their design and come back to him with a new one that included turbojet engines ... unbeknownst to Warden at the time, Schairer happened to be carrying some work he’d already done on the possibility of a jet-powered bomber in his briefcase, giving him just enough of a foundation to think a redesign might be possible
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>The next morning, which happened to be a Friday, the Boeing team returned with their newly jet-powered B-52 design, only to find that Warden remained unimpressed.
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> The two soon joined Schairer, Wells, Carlsen, and Blumenthal in the increasingly cramped hotel room, pouring over sketches and quickly-scribbled mathematical computations. Computers wouldn’t become a common facet of aviation design for decades to come. It was up to these six men and their witts to design an entirely new bomber… and they had just 48 hours to do it.
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> By Sunday, the team had compiled a full proposal that they turned over to a local stenographer to type up a clean copy. By Monday morning, they arrived back in Warden’s office with not only a fully-realized 33-page B-52 proposal but a silver, hand-crafted, 14-inch model of the bomber itself. Warden immediately took to the weekend design.
So, July -> October 26th (Monday morning)
4 Months isn't bad at all but it's not quite the 4 days suggested in the headline.
As a non airforce/aeroengineer, can someone explain why the smaller dual engine nacelles haven't been replaced with a larger turbofan engine? surely its more efficient and lower maintenance? is it that it would alter the centre of drag/gravity/thrust too much and would require too much engineering?
And if the rudder were made large enough to maintain directional control, the loads in the aft fuselage would be large enough that the aft fuselage would need to be re-designed.
Out of the loop, exactly why does the USAF still fly this? Is it really a better alternative to putting some bomb bay doors on a modern Boeing? Without dismissing the entire field of aircraft design... the mind is definitely attracted to the concept of buzzsawing some doors onto the bottom of civilian airliner.
> Is it really a better alternative to putting some bomb bay doors on a modern Boeing? The B-52 can carry about 70,000 lbs of bombs. You can't just hang that amount of weight from the floor of a 777, you're going to have to redesign the entire aircraft to support the load. The B-52 also has a range that's absolutely insane. With a combat load it can fly 8,800 miles, beating a 777-200LR by a few hundred miles. If it's…
One could put an entire Cheyene Space Mountain complex into one BUFF.
then again, what do I know? Just that their carrying capacity is freaking awesome.
Out of the loop, exactly why does the USAF still fly this? Is it really a better alternative to putting some bomb bay doors on a modern Boeing? Without dismissing the entire field of aircraft design... the mind is definitely attracted to the concept of buzzsawing some doors onto the bottom of civilian airliner.
You say "putting some bomb bay doors on a modern Boeing" as if that is something that you can just do without redesigning the entire aircraft. Some other the changes you would need: - Retraining the entire fleet of pilots for the new aircraft. - Recertifying the entire set of currently available weapons that the B52 can drop. - Integrating modern military radios/crypto/satcoms/datalinks/etc with the civilian Boeing s…
Earlier quoted context omitted.
The current F-22 looks and acts nothing like the YF-22 that won the competition (despite the YF-23 being much better, but that's another story). The fact that the B-52 production was not just similar to the prototype, but similar to a complete mockup is a testament to the accuracy of their initial vision. The fact that the US continues to use that design after so many decades is even more amazing.
Any recommendations for an overview resource that better explains your statements? Both about the YF-23 design being better, and about why the B-52 design is so good.
F-22 won the competition on two and a half points.
First and foremost, the YF-23 was going to be built in 10-11 states while the YF-22 was going to be built in almost 30 states, so something like 40 senators had their state's financial interests at stake with the jobs this would bring in (though nobody involved would ever openly admit this was one of the big reasons). Of course, spreading stuff out increases all kinds of costs and with so many small places, once the main run of planes was done, all these sub-contractors moved on too. As a result, the US can't get all the F-22 parts they need and the F-22 is going to be scrapped way before what would otherwise be necessary.
Second, is that the F-22 had vectored thrusters, so was theoretically more maneuverable. This is somewhat debated because making a YF-23 variant with vectored thrusters was possible and even without it was more than capable of turning a pilot's brains to mush (by far the biggest limiting factor for any manned fighter). Ironically, the big selling point of the F-35 is to be so stealthy that you can kill targets before they can see you due to stealth without the need to dogfight which was the exact YF-23 strategy too (and of course, vectored thrust seems to be a needless and cost-adding addition to the F-22 as the strategy for them is also to engage at ranges where maneuvering isn't a critical task). In every other category of consideration, the YF-23 was far ahead of requirements while the YF-22 was barely satisfactory.
The half point is the stated delivery concerns. The Air Force claimed they were worried that the planes wouldn't be delivered because the B-2 was already behind schedule. As EVERY plane is ALWAYS delivered behind schedule, this is very dumb reasoning. While the YF-23 team had worked for years to make a ready-to-ship plane in the YF-23, the YF-22 was a cobbled-together mess to the point that the entire airframe was redesigned multiple times. As a result of this and that spread-out construction crew, the F-22 was way behind schedule and way overbudget.
Northrop Grumman allegedly asked about using YF-23 designs in a bid for the next-gen Japanese fighter project, so maybe there's hope for it yet (I'd note that the profile of the Russian SU-57 has a strikingly similar look).
EDIT: As to the B-52, the real issue is that making a new plane would give marginal benefits to the airframe while the retraining and costs would be large (not to mention the usual teething problems of a new design). This is similar to how they tried so many times to replace the m4. Better systems exist, but they weren't worth the upgrade (lots of people suspect that their new rifle will be too heavy for most soldiers too).
The most profitable upgrades to the B-52 are the internals and electronics and this has been done several times.
The second best upgrade is more modern and efficient engines, but this has been a very slow to happen. They've announced plans to do this, but I suspect it will be longer than they think. They are claiming reduced maintenance time and a 30% increase in efficiency. Not a bad upgrade, but also not that huge when you consider that's basically 0.5% for each year since it was first designed.