What if the Northrop B-49 entered operational service.

Detecting, tracking, and killing a nuke with a Shackleton...good luck. A long patrol in a Shackleton would be considered cruel and unusual punishment by many - "shaky shack" was an apt nickname. IMHO the name was an insult to that great explorer...

Early Shackletons had mostly black interiors. This was changed to brown and other hues after it was discovered that black wasn't great for crew morale on long maritime patrols.
 
Nice picture of a YRB-49A in the initial posting. Over the USSR in 1950 or so, its light wing loading would have given it altitude cruise capabilities not otherwise available until the U-2 six years later (Yes, I know about the British Canberra, but this altitude was reached with virtually no fuel and could not be maintained over distance) The six J-35 engines in the YRB-49A outperformed the eight earlier J-35s in the original B-49 series. The six later engines developed about 20% more basic thrust and further benefited from improved internal ducting to the four wing engines and no induction losses for the two underwing podded engines. The developed RB-49 series would have toted huge underwing drop tanks which, in the absence of provision for bomb payload, could nearly double range.

The low wing loading and relatively thick airfoil of the Northrop flying wings allowed efficient flight at lower indicated airspeed than conventional configurations then available, pushing the Mach-stall "coffin corner" to a substantially higher altitude. This is probably the only real advantage of a jet powered flying wing. Certainly the pitiful pressure ratio of the J-35 compressors (or most early compressors) had to be overcome with slick aerodynamics to get usable altitude performance.

Dynasoar
 
Not to hijack the thread, but what was expected survivability of the B-36? Seems like it would be easy pickings for Soviet fighters. Especially when they stripped off the defensive guns.

Ric350
The B-36 could cruise at 50,000 feet. Soviet fighters of the day would have had extreme difficulty intercepting them.
 
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IMHO if some of the controllability issues could have been managed (not cured without fly by wire), the RB-49 could have been a much better recon platform that the RB-36, and the bomb bay issues become a non-issue. Higher speed will certainly help to make interception at altitude even more of an issue.
 
In actual operations the ONLY successful intercept of an U-2 was made by a English Electric Lightening in 1984 (long after the U-2 had been withdrawn from front line service due the SAM threat). Mig-25s, F-104s, F-106s, F-4s, F-15s, Mirages, you name it took a shot at the title, mostly for bragging rights, they ALL failed.
Do you have a citation on the MiG-25 failure? Mr. Google seems to think "U-2" stands for "SR-71," which is obviously a rather different kettle of fish, and half the time that "MiG-25" means "MiG-31". Okay, they're related, but...

Incidentally, Wikipedia claims that

In September 1962, Fighter Command organised interception trials on Lockheed U-2As at heights of around 60,000–65,000 ft (18,000–20,000 m), which were temporarily based at RAF Upper Heyford to monitor Soviet nuclear tests.

It cites the British public records office in support, so I have no reason to doubt this. It makes me rather curious as to what the 1984 demonstration actually...well...demonstrated. Perhaps the latter was with a non-compliant U-2?
 

CalBear

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Do you have a citation on the MiG-25 failure? Mr. Google seems to think "U-2" stands for "SR-71," which is obviously a rather different kettle of fish, and half the time that "MiG-25" means "MiG-31". Okay, they're related, but...

Incidentally, Wikipedia claims that



It cites the British public records office in support, so I have no reason to doubt this. It makes me rather curious as to what the 1984 demonstration actually...well...demonstrated. Perhaps the latter was with a non-compliant U-2?

The MiFG-25 incident was in an article I read years ago. I have no idea if there is anything on the 'Net.

The RAF scheduled interception trials. They succeeded in a theoretical sense with the interceptor reaching the proper altitude, but not a usable firing solution, although some debate remains to this day whether this was due to safety concerns or actual operational limitations of the Lightenings. The 1984 effort was a rather incredible achievement, with the intercept happening OVER 66K by an EE Lightening F.3 that actually conducted a diving attack (from over 88K) and achieved a firing solution and lock on. No one really believed that it could be done until it happened. The Lightening as one hell of a special aircraft.
 
IMHO if some of the controllability issues could have been managed (not cured without fly by wire), the RB-49 could have been a much better recon platform that the RB-36, and the bomb bay issues become a non-issue. Higher speed will certainly help to make interception at altitude even more of an issue.

Though not stealthy by today's standards the RB-49 would've had a much smaller radar cross section than the RB-36 (ofcourse what plane wouldn't) and from some directions the RB-49 might have been very hard to maintain radar tracking on due to the weak return.
 
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Not to derail the thread, (well any more than it already has been J ) but one of the main reasons for the ‘featherweight’ program was BECAUSE while no concurrent Air Force and most Navy planes could not ‘intercept’ the B-36 the Banshee in fact could with a good radar intercept crew to back it up. Whether it could actually knock said bomber down or not was questionable but quite a few ‘cocky’ B-36 crews, (who as a general rule would always ‘return’ to CONUS running an ‘attack’ profile to show off to Continental Air Command how ‘invulnerable’ they were) would suddenly find a pair of Banshee’s flying close by especially at night when the crew could not easily spot the oncoming jets.

By luck more than design the Banshee engines and wing surface was sufficient that it actually COULD maneuver at 43,000ft effectively enough to at least have a shot at the B-36 carrying a war-load and the SoD and LeMay were well aware of these incidents. The Admiral in fact had every reason to be confident it could be done. Again the ‘problem’ was if the B-36 had ‘awareness’ of the incoming interceptor(s) (usually at least 4 in two pairs) they could maneuver to very much limit the possible intercept positions and as noted while the Banshee COULD maneuver above 40kft it couldn’t do it as well as the B-36. (Hence the use of a “hammer-and-anvil” intercept pattern)

Then the main question was could the likely single pass by one or two Banshee’s actually take down the bomber? Two ‘shots’ of 8 each 2.75in Folding Fin Aerial Rockets, (https://en.wikipedia.org/wiki/Folding-Fin_Aerial_Rocket) with a ‘range’ of about 3700 yards but high inaccuracy the ‘chances’ without closing to point-blank range were slim. (Oddly enough the ‘consolation contract’ given to Northrup supposedly to take the ‘sting’ out of losing the XB-35/49 contract for the F-89 interceptor was specifically designed as basically an “anti-B-36” weapon with its high altitude, over 45,000ft, and high number, over 104 FFARs, of rockets in a single salvo. Further, (as compared to the Banshee) it had an onboard intercept radar to allow it to better refine its own intercept solution. Unfortunately as noted it didn’t quite live up to expectations in real life and very seldom managed anything but ‘staged’ intercepts, especially once the ‘featherweight’ models came on line

These issues taken in context finally make ‘sense’ of the Genie un-guided nuclear air-intercept-rocket. General consensus has it they were designed to take out ‘formations’ of attacking bombers but even a cursory study of the time shows that wasn’t how US doctrine operated nuclear bombers so it would be obvious that would not be how the USSR would do so either. What DOES make sense, when taking into account the literal issue of an interceptor getting only ‘one-shot’ at an attacking bomber you really need to ensure that ‘one-shot’ does the most damage possible and that’s where the nuke warhead comes in.

The inter-service rivalry shenanigans of the late-40s through 50s was a major factor in the US being behind and caught off-guard by Korea and Soviet advances but frankly it’s tough to see a way they would not have happened given the political climate of the post-war/pre-Korea “normalization” and “draw-down” doctrine. That this lead to continued efforts by politicians to find a way to ‘cheaply’ fight the Cold War till the late 70s meant that the US military was going to be handicapped in any conflict where it could not or would not bring it’s full, (up to and including nuclear and all strategic elements) might to bear on an enemy.

The open ‘preference’ of one service and one specific weapons system to the point where an appointed official is openly discussing a major service as being obsolete and needing to be eliminated while cutting budgetary and support to ALL branches is almost criminal and rightly should have been called into open question far sooner than it was.

Randy
 
S. Marlowski wrote:
Better Question I should say, what if the B-49 just entered service.

IF, (huge if there mind you) the (Army) Air Force, Pratt-&-Whitney and Hamilton Standard had all gotten together initially and tested compatibility and operation of the combined system as they were supposed to have done, (since neither the counter-rotation gear nor the Hamilton props had been all-up tested with a pusher configuration system and multi-prop layout) and the vibration and eventual failure modes been identified and corrected prior to installation as ‘promised’ by the AAF then the initial Y/XB-35 design might have had a better chance to be accepted. That’s a possible point where the B-35 itself might have been in service by 1944, (being built at Convair as Northrup didn’t have the facilities) which if the B-35 is in service then it’s possible there is more incentive to ‘convert’ them to B-49 configurations but you still have the range and payload issues.

One thing Northrup could have done differently was to put a central bomb-bay where the main crew/tail-cone area was and significantly reduce the size of that are. Turning the resulting area into an Atomic Bomb capable bay would have been easier but it would mean ‘compromising’ Northrup’s ‘clean’ design which he was loath to do for any reason. (Early adoption of a multi-wheel main gear would help as well)

Similarly getting a working RB-49 into service would be challenging because it would require, (again) “ruining” the ‘prefect’ flying-wing design because you’d eventually have to move all the engines to the exterior of the aircraft. One wonders if they’d have thought of the expedient of putting the ‘4’ engines on-top in twin pods and leaving the singles external and lower. Control wise the specially designed engine pod pylons DID help with the stability problems far better than the ‘air separators’ every did and the ‘over-and aft’ positioning of jet engines was a consideration in both late war German and post war allied designs.

The ‘stealth’ qualities were noted at the time but were not by themselves enough to save the design. Aft-over external engines would have actually somewhat increased speed and lowered drag and internal fuel would have given the design much of its initial range back. I can’t find my anime reference picture atm but one idea I’m pretty sure was never considered by anyone was mating a ‘Burnelli’ style “lifting fuselage” section to the center of the flying wing which would have allowed a more conventional ‘tail’ section AND a rather huge amount of payload to be carried. (In the case of the afore mentioned anime it was a cargo aircraft carrying a monster tank prototype that was stolen in flight J )

In the end the B-49 wasn’t going to be the ‘bomb-truck’ the Air Force wanted and the B-36 was.

Northrup in fact DID have designs for more 'advanced' versions of the Flying Wing in the 1950s:
http://www.up-ship.com/apr/v0n0.pdf

They weren't enough to sway the Air Force though and still had less performance than the B-36

Randy

Edit added Scott Lowthar's APR site link: http://www.aerospaceprojectsreview.com/
 
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I wonder if something more like the Avro Vulcan's planform would have provided many of the structural and aerodynamic benefits of a flying wing with better inherent flight stability. A Vulcan like design but with a shorter nose section built in the early 1940's using piston engines with rear facing propellers.
 

Errolwi

Monthly Donor
The MiFG-25 incident was in an article I read years ago. I have no idea if there is anything on the 'Net.

The RAF scheduled interception trials. They succeeded in a theoretical sense with the interceptor reaching the proper altitude, but not a usable firing solution, although some debate remains to this day whether this was due to safety concerns or actual operational limitations of the Lightenings. The 1984 effort was a rather incredible achievement, with the intercept happening OVER 66K by an EE Lightening F.3 that actually conducted a diving attack (from over 88K) and achieved a firing solution and lock on. No one really believed that it could be done until it happened. The Lightening as one hell of a special aircraft.
There is a good article on this in The Aviation Historian magazine, available for purchase online.
 
Randy,

Two excellent posts which bring up a number of topics which should be enlarged upon. Not to ignore CalBear's Lightening zoom climb U-2 intercept. Expect to post sporadically over the weekend between trying to get my Grumman Tiger back into the air after a fun filled unsymmetric flap retraction during the Go part of a touch-and-go landing.

Have no direct experience with B-36 "intercepts" by Banshees, but considerably later Vought aircraft claimed that their early F7U-3 Cutlass, powered with Allison J-35s rather than Westinghouse engines (the J-34 "Gutless Cutlass") could statically top the over-target altitude performance of the Featherweight. Though the Vought plant was just down the road from Carswell AFB, no actual demonstration (to my knowledge) took place.

The use of nuclear devices ( sort of like the Genie) to stop intercontinental strategic bombers was initiated by the Russ. A small number of tall towers were noted north and northwest of Moscow in the early '50s. Originally thought to be some kind of far-horizon radars (but why not on the northern coast?) later evaluation was elevated nuclear mines in the anticipated path of our bombers. Later discussion involved their use of manned aircraft to fly and detonate the bombs where needed. SAC's response, before flash curtains, was to issue eye patches (silver on the outside-fuzzy black inside... had one for years) which aircrews would wear on the way in. If flashed but still flying, discard the patch and keep going. Gave the Reds an excuse to call us 'Yankee Air Pirates" which kind of stuck with me.

The suggestion that B-49s be redesigned with pod mounted jet engines on fin-like struts located on the upper trailing edge strikes me as brilliant. Say six engines in individual pods distributed as widely as engine-out controllability permits. Places the engines out of radar view, distributes their weight along the span, but more significantly boosts lift circulation strength in a way not done before. Lift would be increased by the jet efflux and entrained air in a way Kutta and Joukowsky would appreciate. Improved L/D and higher ceiling.

Dynasoar
 
The suggestion that B-49s be redesigned with pod mounted jet engines on fin-like struts located on the upper trailing edge strikes me as brilliant. Say six engines in individual pods distributed as widely as engine-out controllability permits. Places the engines out of radar view, distributes their weight along the span, but more significantly boosts lift circulation strength in a way not done before. Lift would be increased by the jet efflux and entrained air in a way Kutta and Joukowsky would appreciate. Improved L/D and higher ceiling.
Dynasoar

What, if any, would that engine placement do for the B-49's flight stability? Especially pitch stability?
 
Draconis,

I believe that raising the thrust line by a moderate distance above the wing would tend to compensate for the pitch-up inherent in an otherwise untrimmed wing. Thus a reduction in trim drag. The fin-pylon engine supports would increase (if of sufficient lateral area) yaw stability and reduce the need for damping. Recall that the B-35 series propeller thrust line was above the wing.

The 'high engine' variant of the RB-49 should show improved L/D for better range, higher service ceiling, more wing internal volume for fuel and less need for yaw damping.

Wish I had thought of it!

Dynasoar
 
I wonder if something more like the Avro Vulcan's planform would have provided many of the structural and aerodynamic benefits of a flying wing with better inherent flight stability. A Vulcan like design but with a shorter nose section built in the early 1940's using piston engines with rear facing propellers.
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Vulcan’s greatest advantage was its large vertical fin - mounted well aft of the center of gravity - which produced ample doses of yaw stability.
To achieve the same stability, Northrop would have needed to add even larger vertical fins to the wing tips ... or extended central fuselage.

Plenty of flying wings flew stable before the invention of electronic stability augmentation systems: Hortencia, Fauvel, Lippish, Convair, Verhees, Dyke, Marske, etc. but the Horton Brothers were the only ones to achieve yaw stability without vertical fins. Note that most of the Horten designs had greater leading edge sweep than Northrup’s various wings. Leading edge sweep can help improve both yaw and roll stability.
The shallow leading edge sweep on the propeller driven NFW made perfect sense at the 390 mph top speed, but less sense on the 490 mph jet version.
So one of Jack Northrup’s failures was a failure of imagination. If he had thought farther ahead - towards trans-sonic flight - he would have swept his leading edges more, improving stability, etc.
 
——————————————————————————

Vulcan’s greatest advantage was its large vertical fin - mounted well aft of the center of gravity - which produced ample doses of yaw stability.
To achieve the same stability, Northrop would have needed to add even larger vertical fins to the wing tips ... or extended central fuselage.

Plenty of flying wings flew stable before the invention of electronic stability augmentation systems: Hortencia, Fauvel, Lippish, Convair, Verhees, Dyke, Marske, etc. but the Horton Brothers were the only ones to achieve yaw stability without vertical fins. Note that most of the Horten designs had greater leading edge sweep than Northrup’s various wings. Leading edge sweep can help improve both yaw and roll stability.
The shallow leading edge sweep on the propeller driven NFW made perfect sense at the 390 mph top speed, but less sense on the 490 mph jet version.
So one of Jack Northrup’s failures was a failure of imagination. If he had thought farther ahead - towards trans-sonic flight - he would have swept his leading edges more, improving stability, etc.

400px-Avro_Vulcan_B_Mk_2.svg.png


upload_2018-9-1_14-33-7.jpeg



That's what I had in mind. A greater swept leading edge and a nearly straight trailing edge with rear facing propellers. But without or a much reduced extended nose section. And with a single tail fin at the centre rear of the wing. You think there would be a need to extent the tail to improve the effectiveness of that single tail fin and rudder?

Was the knowledge of aircraft design advanced enough by 1940 to build a design like this?
 
Draconis,

I believe that raising the thrust line by a moderate distance above the wing would tend to compensate for the pitch-up inherent in an otherwise untrimmed wing. Thus a reduction in trim drag. The fin-pylon engine supports would increase (if of sufficient lateral area) yaw stability and reduce the need for damping. Recall that the B-35 series propeller thrust line was above the wing.

The 'high engine' variant of the RB-49 should show improved L/D for better range, higher service ceiling, more wing internal volume for fuel and less need for yaw damping.

Wish I had thought of it!

Dynasoar

And if one single tail fin and rudder was installed at the rear centre of this new model B-49 would that provide sufficient yaw stability and control?
 
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