This needs more upvotes. Commercial aircraft must maneuver in existing, busy airports. As aircraft got bigger, wings got longer. At the same time, fuel (read $) efficiency for commercial aircraft is a top priority. The B52 has the luxury of living at an air base. Giant wings are no problem.
Yup, that’s why the 777x can fold the raked wingtips.
Also note the raked wingtips...which Boeing finds to be the best solution to the wingtip design for airplanes that fly long distance like 787, 777 and 767-400.
There are advantages of winglets like 737 for shorter flight missions.
Why do many gliders have winglets then? Hangar space?
Gliders have winglets because they spend a lot time flying at high CL which is where winglets really shine. Gliders are also span limited due to class requirements (13.5, 15 and 18 meter) however modern open class gliders (no wingspan restrictions) have winglets...I think that's because adding span does have limitations and eventually adding spans starts to increase the structural weight and control surface sizes that outweigh the drag reduction of the increase span.
Winglets reduce structural moment: a smaller winglet increases the effective wingspan with relation to induced drag, while not adding in the additional structure far out.
Are there advantages to having bigger wings over smaller wings with winglets?
If you are really interested I recommend:
DOI:10.1007/s11012-020-01230-1
NASA Report: NASA-TN-D-8260
And maybe a bit more easier to read: Wingtip Devices : What They Do and How They Do - McLean
Buckle in, u/twizzjewink
Also, the B-52 was designed in the time period where commercial aviation wasn’t really using winglets, the idea hadn’t been put onto aircraft yet.
It's almost certainly been considered and rejected after a lot of thought.
Yes, winglets (or sharklets) might reduce fuel burn, but they come at a cost. They add weight where you really don't want it, and they exert a force on the wing. Those wings are pushing 70 years old.
It's likely they looked at it, did the math, and decided against.
Serious question, how much of those wings are 70 years old? Or are they like grandpa's old axe that has had 5 new blades and 3 new handles?
The Axe of Grampeus
Was definitely going to Ship of Thesius here. Those things may have a couple OG parts but not many.
Not sure about the BUFFs, but on the -135s I worked overhaul on, we were changing upper spars, wing skins, and stringers. Ribs would usually not get changed. A lot of the metal was original. Worked 62 and 64 model -135s
Guessing this was on the KC's or did you do other variants too?
RCs, TCs, and WCs
Those are some rare birds thank you for keepin em in the air
Thank you but I've moved on since then but it was a very rewarding job
Working down in Greenville were you?
I might have spent some years there lol
I'm assuming many variants as he would have written "kc" in his comment.
Thanks for that
They say our cells regenerate every 7 years. Does that mean we are all the Ship of Theseus?
While wielding: +3 grump, +2 grampa strength, deals +1d6 to items/creatures made of wood.
All the oldest models were chopped in half with a giant guillotine as part of one of the Arms Reduction treaties in the 80s. But even the new ones are 50 years old.
As to which planes have specific parts that are original, probably the frame itself.
The last B-52H left the factory in 1962. Meaning the newest aircraft is 62 years old.
But 1962 was only... oh my god.
Uh ya, Dr Strangelove, Slim Pickens…old.
Are you ok? Do you need some ibuprofen? 🥺👉🏼👈🏼
A couple more years until the oldest flying B-52 has been flying for literally half of all powered flight
Yup we’re old
I'm not that old, just always think the current year is 2000.
Well, OK, I guess the plane and myself are old.
All the oldest models were chopped in half with a giant guillotine
I am pretty sure you are joking, but in the minimal off chance that you’re not, is that real?
awww those babies
Yep. Chopped in half with the pieces placed next to each other at Davis-Monthan AFB so Soviet/Russian satellites can verify our compliance with arms treaties.
I'd love to see a video of that haha
Hoo-lee shit! That's fucking amazing. Thanks!
They’re like grandpa’s old axe AKA Theseus’s ship at this point. The superstructure (and skin) is by and large the same, but most other components have been replaced. They’re currently undergoing a re-engine Source: I currently work with prior BUFF mechanics
Would they undergo x-ray checks or anything to detect metal fatigue or cracks in the superstructure? Seems, to me, unsafe to fly a 50yo plane.
The process tire describing is called “NDI,” or non destructive inspection. TMK it usually happens during periodic “phase” inspections. —- FWIW, the KC-135 has been flying since the 60s
Trigger’s broom
Much better description of the situation
Dave?
It’s just about all original equipment.
Flaps, spoilers, etc may get changed out but the wing skins and spars are all original. The upper wing skin is made up of 5 panels running from the fuselage to about 10 (?) feet from the tip. The stiffeners on the internal side are integral. That is to say, the whole panel was milled from a single piece of metal. The lower wing skin is similar. The last 10 feet or so of the wing is bolted on to the inboard part. I believe this is because at the time they didn’t have a machine big enough to mill the entire panel from root to tip in a single piece.
The spars are maybe not 70 years old, but they are very old- the tooling doesn’t exist anymore and has not for some time.
So if you need a replacement spar, you need to cannibalize a boneyard plane.
A bunch of the B-52s in the boneyard were broken up in such a way that major parts (like the spars) could not be salvaged. I don’t remember which treaty this was part of off the top of my head, but it was an arms reduction agreement.
The Bomber of Thesius?
The newest B52 in the fleet was made in 1962.
Probably nothing about them is 70 years old other than the design.
You'd be surprised. Most of it is original.
There are proposals to extend the B-52 life by replacing the skin on high-fatigue areas.
Yep, the really important structural bits are usually original. Easy to tell by all the sister plates riveted to help with metal fatigue.
Probably the entire skin of the fuselage forward of the wing spire. Every time you see those buffs on the ground the whole front is sagging creating wrinkles in the skin is crazy.
How many times can you replace the skin before your rivets are 5/16" oversize to a Y. Gotta have some pretty good sheet metal guys.
You also have to understand that retrofitting winglets is a non-trivial deal. It involves peeling back (and maybe replacing) the skin on both surfaces of the wing for several feet and tying the winglet into the spar so that the load can be transferred properly. Not cheap.
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you are confising spending money vs wasting money. the millitary LOVES the latter and hates the former.
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If they’re going to update things they should probably start with the engines
My grandpa literally was on the engineering design team for the engines. That the BUFF is still in the air is wild. At this rate the B-52 will be our first military airframe on Mars.
The standard joke is that when the last B-52 is retired in 2243, the crew will be flown out in a C-47.
I would have bet on a C-130.
You'd probably be right but they'd still be in production then since L/M continues to upgrade them and they keep selling.
Already on it.
They already are.
https://theaviationist.com/2023/09/08/testing-of-f130-progresses/
They are doing a re-engine if you aren't joking....
to my knowledge most of those wings are no where near that age (many have been re-winged) BUT your other points still totally stand.
To add to this, have you ever seen the wing flex on a B-52? Or looks like it’s flapping its wings to take off.
Not to mention all the flight testing to characterize and approve the new aerodynamics. That’s a big expense for an airplane that’s already at 2.5x it’s original design life.
Add in the ticking time bomb of 7178 alloy and you’d probably never see a return in your investment.
Kind of an aside from your mentioning of the age of the wings, I heard from an ex RAF guy today that when B-52s retire they will have parts in them that are over 100 years old. I think that is just mental.
They add weight where you really don't want it
Yes and no? It's a complex topic, especially for landing with payloads or turbulences and the dynamic loads it's very bad. But the lift obviously pulls the entire wing up so the weights that bring the wing down such as the engine narcelles and even winglets actually lower the static load during the flight.
You seem really confident that someone's looking at everything.
Winglets weren't a thing back in the day.
Winglets were what they called the ladies of the barracks
Fuel savings from wingtip devices only add up over thousands of flight hours. A military aircraft might log 500 flight hours a year, while commercial airliners can do that in six weeks.
This might be one of the most under looked aspects. I depot B-52s and most that I see have around 20,000 hours on them. That’s less than 350 hours per year.
It does help that the H models spent so many years just sitting alert
B-52H: 👀😳🙄☕️‼️
They didn't "just" sit alert. Yes, they were the primary alert birds after the late '80s, but all BUFF variants sat alert.
Thank you for your BUFF service.
This is the main reason. Airliners are all about squeezing maximum profits from the smallest fuel burn over thousands of hours. A 1% efficiency gain might add up to millions of dollars over 20 years for an airline.
Also, B52's are also able to carry external stores. The relatively small efficiency gain from a winglet will be lost when carrying a dozen cruise missiles externally.
Nothing is "easily modified" on a 60 year old airframe my dude.
The wing flex is already so much on this aircraft that it needs extra wheels at the tip of the wing to stop it hitting the ground. And you think you can just easily add a winglet to that equation?
Good point, that’s why B52s don’t have ailerons, just spoilers
It’s a 70 year old plane, I don’t think you need to add a spoiler warning
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G and H models have no ailerons.
Corrected already
Wait, what?
Yeah no I believed an old rumor, the G and H models have none entirely. Maybe the older models had them bolted down, because they did come with ailerons but I couldn't tell you.
TIL
Older models had a small set that mainly drove the control feel on the yoke from what I’ve heard.
Weren’t the ailerons disabled (bolted in place) to reduce loads on the wings? Something about the spoilers being more than effective enough for roll control, and ailerons merely added unnecessary stress.
The fundamental design is why it still uses 8 shitty inefficient engines vs the powerful new turbofans. The moveable rudder on the b52 is TINY, which means it can only counter the adverse yaw of a little engine going out.
If it’s anything like the E-2, everything was hand drawn and would cost a lot of money to redesign in contemporary CAD programs. But it is the AF so they may have sprung for that.
Weird related anecdote: when NASA first tested winglets they did it in partnership with DARPA and used USAF C-135 airframes to do it.
They quickly realized the fuel savings were significant.
Then the USAF balked at the price and instead spent all the money on cockpit software that would save gas by automating flight profiles for higher efficiency.
The software cost a fortune, and it didn’t/doesn’t work at all.
Had they pulled the trigger on winglets for the 707 fleet, the DoD would have saved billions on fuel by now, but they didn’t want to spend the money up front.
Source on all of this? Especially the part about the “cockpit software” not working at all. Pretty sure whatever software is in these planes is pretty highly classified. But what we do know is that almost all commercial jetliners have used this exact type of software for decades and is extremely effective. I know you’re talking about the 707 fleet specifically and I couldn’t find anything on that. I did find a study on the kc-10, which would cost 1.9 million to install winglets per plane, which would drastically reduce the savings of $221 million over 8 years (source)
Co2 emissions and fuel savings are leat of your worry when your machine is designed to drop Nucs.
Fuel savings are definitely a factor even for bombers. Lower fuel burn = higher range/payload capacity
Not when you can simply refuel whilst in the air.
Aerial refueling isn't that simple from a logistics perspective. They wouldn't do it if it wasn't necessary.
The reason why it’s necessary, is not a lack of winglets.
Obviously, but my comment was meant as a more general statement.
no no no youre supposed to get into an agrument!
Nothing is simple about running B-52's. Sticking a tanker in the air and then filling up from it though is absolutely routine.
The logistics of fuel consumption (and maintenance) is driving the AF to finally re-engine the B-52, fuel burn whether you have a tanker or not is a critical factor on mission planning for any aircraft.
It isn’t the fuel consumption that’s driving the re-engine, though that’s a major benefit. Maintainability and parts availability of the current 60 year old engines are why it’s finally being re-engined.
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The B52H variant is the only one still operational, those have TF33 turbofans (older variants have the smoky J-57 turboJET). Soon, the H models will be reengined with Rolls-Royce F130 turbofans, which is a very slightly modified version of the RR BR725 turbofan that currently powers the Gulfstream G650 business jet. The reasons cited by the Air Force are: 1. GHG emissions (not sure if I believe lol) 2. Fuel consumption / range / operating cost 3. Reliability and availability of parts 4. The IDGs (drive generators) on the F130 are larger, making more electrical power available for aircraft systems which lets them modernize and digitize some of the flight controls / onboard systems.
Dropping Intel Nucs
They have sunk a bunch of money into the new engine program which will give bigger results, I suppose
It will save money over the long term, there’s only likes 70ish airframes but they gonna keep flying till the 2030s
Because it was designed only 2 months after the Wright Brothers first flew
I think they started the design in 1901. They could’ve had it flying sooner, but had to wait for Orville and Wilbur to invent the wing.
B-52 wingtips are fiberglass and hold antennas, so you'd have to move those, AND you'd have to change the wing structure.
Source: Me, former B-52 Electronic Warfare Officer and aerospace engineer.
Likely not worth the engineering/testing vs. the number of hours flown per year.
looks like there is lots of discussions on forums and other websites if you google your title
Too old. Wasn’t a thing back then really.
It's still amazing these are still flying and still will be in the coming decades.
I mean it’s kinda hard to really improve on what it does. It cruises long distances and drops bombs/shoots missiles. The current issues it does have are already in the process of being resolved in the next 5-7 years.
One point i didn’t see mention yet is the added stress on the spar. Adding winglets reduces tip vortices and allows more of the wing surface to produce lift. This added lift near the tip increases bending action on the spar and may be too much for the spar to handle. This is why the 737-400 can not have winglets added, the wing spar cannot take the stress, and it it is way to expensive to redesign the wing. I suspect it is the same on the -52 as a full wing redesign is out of the question. There are so many “draggy” bits on a -52 that winglets are the least of their worries. It would add to cool factor tho!!!
Have you seen how far the wings on a B-52 flex? It is the reason there are wheels on the outboard wing. In flight, the tips are higher than the fuselage. There is quite a range of flexibility to the BUFF wings.
Yes exactly, the fact the wings are so bendy shows the structural is already at it's most efficient state..the engineers allow the wing to flex because the materials it's made of can withstand the flex and not break, but just barley. If it were stiffer aka stronger, it would be heavier. By adding load and weight to the tips changes those loads the structure was designed for it and it might not be strong enough.
All big airplanes of significant wing spans have very large wing bending....see the 787.
Winglets are only used when you have a span constraint. A wingtip extension is always aerodynamically better. The B-52 doesn’t have a span constraint.
Holy shit I recognize exactly where this was taken! This was taken right over Crane County, Texas some number of miles west of the Targa Sandhills Gas Plant (directly South of Monahans, Texas)! The layout of those oil pads immediately struck me as I used to service many of the oil wells & pipelines in this region.
That’s pretty cool that you recognized the pattern!
The BUFF doesn't slip gracefully though the sky like a sharklette.
It grudge fucks the air and makes it submit.
I like the way u think sir.
Aerospace engineer here. Winglets are used for reducing the losses from vortices at wingtips. In a nutshell, the effect of these vortices increase at high angle of attack conditions such as takeoff and landing. Their effect is smaller at cruise condition and usually the efficiency gained in high speed cruise flight is not worth the extra drag they cause.
That is why short range airliners such as 737 or a320(that spend a large portion of time in take off and landing phases) have winglets and long range airliners such as 777 or a350 don't.
As a side note, the affects of winglets were well studied only after late 70s by NASA which was much after the B52 was designed. They could still be retrofitted of course, if they were to be found beneficial for B52s.
Because the plane is like, a hundred years old. They didn’t even think about winglets. In addition, the government cares not about fuel efficiency, it’d cost more to install the winglets anyways.
Bomber, born 1924. Think snoopy and the red baron. Lol
Because they’re from the past, designed and built like 30-50 years before they were a thing.
First jet I can remember with winglets was 747-400
Same reason you don't see winglets on many gliders or things like the TTWD wing design. These wings have a very high aspect ratio. The main benefit of winglets is on shorter, lower aspect ratio wings, where more of the high pressure air under the wing is moving laterally to the tip and "spilling" into the wingtip vortex. On a high aspect ratio wing the length of the wing and it's short chord mean there is less spillage and not much benefit to adding wing end devices. In some cases the added drag of the winglet on a high aspect ratio wing would actually make the aircraft less efficient.
Winglets didn’t exist when the aircraft was designed.
Because the air force says, winglets are for sissies.
The Wing per se, very Wide and with thin pirofile, Is already designed for very long range
Because they are ancient
Because when these were designed in 1845, winglets weren't a thing yet.
I have zero doubt someone has considered adding them over the years.
Something something love shack baby
Glitter on the highway
Can we all just stop and recognize that the B52 is a bad mutha...
Look bro, as a self identified B-52, I’ve traveled the globe since 1955. I’ve bombed more places than you’ll ever visit, and my fuel efficiency means nothing to me or Uncle Sam. I’m an old greasy, slender flying machine that don’t need no change.
This bomber speaks true
Because granpa buff don't need no cosmetic accessories
Bombers can in flight refuel and they can also carry an absolutely massive amount of fuel.
Military jets are not fuel efficient by any modern standard. Adding winglets to make them a little more fuel efficient is not on anyone’s radar. It doesn’t really move the needle in making them more combat effective or more cost effective so they don’t do it.
Also, the military does a ton of research and simulation on aerodynamics and such for various scenarios so for example, if you lose part of a wing, they’ll have an idea whether you should ditch the plane or try to bring it home. That work was done on the B-52 decades ago. Doing it again for a new winglet would be very expensive. They’re doing it for the new engine program and guess what, it’s extremely expensive and time consuming.
The buff is just fine the way it is....
It's almost a 70 year old design. Winglets weren't in the twinkling of an aerospace engineer's eyes back in the day.
Because when a B-52 is doing a bombing run, lowered fuel consumption from winglets isn’t a concern. At all. Add to that the age of the aircraft, which makes altering it difficult.
lower fuel consumption directly translates into longer range and loitering time, so this factor definitely matters. Enhanced endurance and range is part of the reason the plane is being re-engined.
Adding 500miles of range doesn't mean very much when the bomber already has an 8800 mile combat range. The benefits of new engines were obviously deemed a better investment than the task of adding winglets to increase efficiency by 5%.
You're being downvoted but you're exactly right.
old
They would do it if it was really important. It seems like it isn't, so they will just re-engine until they have a better competition elsewhere. Then, they'll make a new bomber
Because you don’t modify what’s already perfect
The buff already has outrigger wheels to mitigate the wing sag issues. Adding even more weight to the ends of the wings would not be a great idea. And with 8 turning and burning, fuel efficiency is not a primary concern....
They were meant to drop nukes and get shot down. Why waste the money. Fuel efficiency? Haha all that fuel is gonna be burning in the air when an s300 blasts off its wing anyways. I know because I'm not an engineer nor a military professional in any way. This is a trash post please don't jump all over it I'm only kidding. 😁
That aircraft was developed before many of her pilot’s grandparents were born. wingtip devices for reducing drag only became a topic of research in the 1970s. The first large aircraft to incorporate the technology was the Boeing 747–400.
To retrofit the aircraft with winglets, it would require a fair amount of engineering. Wingtip devices move the center of lift outboard, and that increases the bending moment on the wing root. So in order to install wingtip devices, they would need to install some doublers on the wing spars. Given the age of of the design, that might actually involve adding more weight than the wingtip devices would save.
Because the wings were not designed for this. The redesigned wings would cost more then the fuel saving
I believe winglets would reduce max allowable crosswind for takeoff and landing. And when u have a bomber sitting a nuclear alert, u don’t want crosswinds to keep them grounded
Fuel efficiency is not high on the Air Force’s priority list when you have 8 engines and mid-air refueling.
Wow I never realized there were redundant engines at each node
Simply put, the B-52 doesn’t need them. Huge wing span and eight engines is plenty to maintain lift and stability. There would be very little to gain, if any. And it would just add unnecessary weight at the tips.
This isn’t a eco-jet making budget travel affordable . It’s purpose is to fly a big bomb onto a target - environment and budget is far far far from the equation !
🫣oooh my god…. No comment, just no comment!
My dad was a b-52 pilot until he moved to F-15’s in the early 2000’s. It always blew my mind that those things were so old.
They don't really need to space to sell ads/PR livery..
Because that's not how Boomer boomers roll.
Why are the engines mounted so far ahead of the wings?
The b-52's ailerons had to be bolted down because they produced so much strain on the wings due to the immense lift of the plane. Just keep that in mind when discussing aerodynamic changes.
You don’t need better fuel efficiency when you can refuel midair
Nothing has made me want to quit Reddit more than this single thread. It’s a singularity of people talking out of their @$$es; a black hole of time suck which is pulling IQ points out of my brain with each passing second.
because the Air force never short of gas
This sub is a lot of what seems like unnecessary questions by kids that think they have an engineering solution lately.
The B52 is by now THUROUGHLY tested airframe that is able to fill the role it is meant to. Why mess with something like that and have new issues pop up for it when you can be absolutely sure it'll get the job done already?
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Even the military cares about consumption. Maybe less for planes, but still. Surely not to save money, but to increase the range and, probably more important, to reduce the complexity of supply chains. They definitely don't care about exhaust fumes treatment.
Also to save money. Despite a large defense budget, fuel still cost $. The more you can save the more you can train, buy equipment, fly etc. Trust me the military cares about fuel savings just as much as an airline.
Logistics wins wars. The less fuel, amo and supplies you need to move to the battlefield the better. A gallon of gas on the front is worth about 3x a that of a gallon as gas at home...why because of logistics. Fighting a peer adversary will definitely be targeting logistics, and saving fuel burned is better than delivering extra gas to battle.
They looked at 707 variants getting winglets 40 years ago AND it was too expensive 😆. 8%, Nope, not worth it. They bullet hole in the foot must really hurt.
Winglets cause the weight to be spread out closer to the ends of the wings, and so the wing structure needs to be able to accomodate. And with how much B-52 wings flex, they probably couldn't do that.
Besides, winglets are just there to improve efficiency by reducing drag, and if they really cared about fuel efficiency they would have reduced the number of engines decades ago. That would be far more effective than the few percent difference winglets make.
This is the single plane that will not die in America. By design.
However the requirements to change a platform like this one would outweigh the cost of a tanker of fuel for the next 50 years. So unless they come out with a new platform upgrades like this will not happen ever.
Side question, but what are the third things from center towards the end of the wings? What function do they serve? Can’t see an inlet as if it was an engine but I feel that wouldn’t make sense anyways.
Fuel tanks
Same reason they didn't go past a render when they were talking about them on c5s. Benefits didn't even come close to the cost and time
If you were designing a practical conventional bomber (non stealth) to replace the B52, what would it look like? Size, supersonic, subsonic, converted commercial aircraft, crew size?
I'll give you a hint...
The wings are so long that I wonder if they would help, like how the 777x doesn't have them
It has 8 engines, and they cost money that could be spent on bombs.
Cause old
i asked my friend who is a military pilot. It's mostly due to the retrofitting costs. These old planes are just old. Some of them my grandfather flew.
winglets essentially add span - wing length, the B-52 already has a LOT of span. No real need. Diminishing returns and all that. Winglets add span but also add weight, drag, and complexity.
Plus, just how sexy do you want your bomber to look? The Buff is already at the limit man.
The length of a winglet will always give less aerodynamic benefit than simply adding the length to the wing.
Adding winglet instead of just lengthen the wing makes sense, from a aerodynamic perspective, when the wingspan is a limitation.
This limitation may come from airport/apron/hangar restrictions.
Because its not worth the savings when the turbines are very inefficient. Hence the project to upgrade all B-52 turbines with newly designed models... they may add winglets next? Who knows.
The best winglet is a bigger wingspan. Military aircraft are not that bounded by the aircraft classes for airports. That is why they are not so dependent on the winglets. Winglets are the best option if you want to increase the performance without increasing the wingspan.