B-35 and B-49 Northrop's Flying Wings

[Patron Zero]

Awesome model of the cockpit, frankly I'm surprised there was not an Interociter available to the flight engineer !

http://www.unit16.net/tie2pics/tie205.jpg

[frank2056]

Awesome model of the cockpit, frankly I'm surprised there was not an Interociter available to the flight engineer !

I love that movie! the "Mute Aunt" was scary, too.

[KJ_Lesnick]

Over the years I've read all sorts of stuff regarding the political and technical issues as to why the YB-35 was cancelled in favor of the B-36.  Recently I came across some rather interesting information regarding the YB-35 which seem to illustrate even more of the story than we were previously told.  I'd like to know which of these are true and which are not.


Technical & Performance Issues

• The airplane was said to be unstable and had dangerous spin and stall characteristics (so bad that the USAAF/USAF had allegedly contemplated barring pilots from purposefully putting the plane into a stall or a spin, even for training purposes).  Interestingly pilot who worked for Northrop and flew the B-35 said that the aircraft was not unstable and he had successfully put the airplane into a stall and even a spin and recovered.  Allegedly there was photographic evidence to support it.  He called the claims of the USAF to be basically BS.
  
• The aircraft's drivetrain, which included contra-rotating propellers was known to have serious problems and the equipment which the government furnished limited it's performance.  Presumably this was fixable.
  
• The aircraft had a tendency to "hunt" in yaw (does that mean a tendency to slide and wallow all over the place -- as that was a known trait of the plane), however that was said to be fixable with a type of autopilot.
  
• It has been said that the aircraft was slower at top-speed compared to the B-36, though others have said it was 50 mph faster.
  
• It has been said the aircraft's cruise speed was extremely slow (around 185 mph).
  

,,,

Political Issues

• Louis Johnson who, at the time was the Secretary of Defense, previously sat on Convair's board of Directors raising serious issues as to a conflict of interest
  
• Floyd Odlum, who was a wealthy businessman and had a major stake in Convair, used his connections to manipulate/corrupt the Secretary of the Air Force in order to save his B-36.
  
• The Air Force wanted the YB-35 and B-36 to be able to carry nuclear weapons, yet prohibited Northrop from redesigning it's bomb-bays to be able to actually carry them.
  
• General Henry H. "Hap" Arnold was stated to have preferred the B-35 over the B-36
  
• In an recorded interview, Jack Northrop was told that the YB-35 could be built, but it would be built at Convair.  Northrop thought this was profoundly unfair and refused.
  
• Northrop was really only interested in developing new ideas.  The underwriters of the companies that carried his name realized this and wrote into his contract that he didn't get to make business decisions.
  

[RussC]

There is a lot to this story, and some of it is at the industrial-managerial end, some at the political-pentagon end and then of course the test pilots such as Harry Crosby, Cardenas, Edwards and others. Here are a few more bits-
 
  The AF secretary was a big player in this, and his name was Stuart Symington, and a native Texan in the area of Dallas where Convair was located. His family was and some relations still are active in the State's politics.
 
  The original site chosen for B-35 manufacture was a B-29 assembly plant owned by Martin in Omaha, Nebraska.
 
  The opinions of the test pilots all varied, about the stability and the climb rate and there was a large discrepancy in the power to weight tables. There were many questions about the economy of the machine in terms of fuel loads.
 
  One reason given about the B-35 not being picked was the small bomb bays not being able to take the very large "fat man" type atomic bombs of the era internally. Actually, smaller bombs were in production when the contracts were cancelled.
   
  There is a school of thought in pilot's handling of an aircraft that a good design should be able to be trimmed to fly with minimal input from the pilot, in other words, set the rim tabs to a given zero climb rate and the plane should stay there, even with wind changes, or small shifts in CG or changes in throttle. The B-35 needed vigilance and attention and correction. A lot of pilots disapproved of this and used a trick of putting up more throttle but trimming the nose high and a steeper angle of attack. This effectively plows the airfoil into the air rather than cutting it. The turbulence over the top of the wing, a rolling vortex actually acted as a damper of side to side movements as well as any slight pitching- effectively stabilizing it to the level of flying a DC3 or DC-4 of the era- HOWEVER...doing this also increased the drag to the point that the top speed was less and the great efficiency of the flying wing aerodynamically was lost or nulled to that of a typical B-29 or B-24. It is unclear if the data in the performance tables of the B-35 was made flying in the "cheater" manner or with full control, in fact, since these tables are made over a series of many flights, many pilots, it could be a variety of flight "styles".
   The yaw and pitch problems were supposedly all eliminated in the YRB-49A jet version using automatic hydraulic dampers developed by the Otis corporation. If you take a ride in an elevator and the car comes to a nice smooth stop at your floor without you having to step down or up an inch or two, and it hits this mark without backtracking or sudden jerks to get there - you are benefitting from offshoots of flying wing technology.
 
  There was the issue of the inflight fire in a YB-49 on a coast to coast run supposedly caused by the engines not being serviced with enough oil, but was blamed on the J-47 installation in a wing made for props.
 
  The issue that the plane used a 1934 airfoil cross section that could never operate in the trans-sonic or supersonic, no matter how many engines you put on the machine.
 
  Too much technology at one leap? Political football? Sabotage? just plain incompetance in enough places? Managerial FUBAR? .....Hard to say.
 
  While YRB-49's from EDW were flying tests over the SF bay area and other air bases, the controllers often told the pilots of the flying wing to operate at odd altitudes like 5000, 7000, 13,000 21,000 etc while the other traffic was conducted at even heights. This was because the wing was often invisible to radar at times and was also not easily found in binoculars visually or even in some more powerful telescopes.

[Jschmus]

Can't this be merged with the existing Northrop Flying Wings thread?

http://www.whatifmodelers.com/index.php/topic,19253.0.html

[tahsin]

Whatever the reasons were , they were all sort of corrected when the B-2 model was first shown to an ailing Jack Northrop , same wingspan , same leading edge angle and a few kind words along the way . That's probably all I can say on the subject .

[RussC]

Whatever the reasons were , they were all sort of corrected when the B-2 model was first shown to an ailing Jack Northrop , same wingspan , same leading edge angle and a few kind words along the way . That's probably all I can say on the subject .

  Has been said that he uttered "Now I know why God has kept me alive all of these years" when he viewed the replica and the model is interred with him. It certainly sounds appropo' !

[NARSES2]

I've merged these 2 topics as suggested by Jschmus as they are basically about the same subject

Chris

[KJ_Lesnick]

RussC

The AF secretary was a big player in this, and his name was Stuart Symington, and a native Texan in the area of Dallas where Convair was located.

So, there was a connection between Odlum and Symington?
 

The original site chosen for B-35 manufacture was a B-29 assembly plant owned by Martin in Omaha, Nebraska.

Even though Northrop was going to build it?
 

there was a large discrepancy in the power to weight tables.

I don't understand how that would happen.  Can you explain?

There were many questions about the economy of the machine in terms of fuel loads.

I don't understand -- this was a military bomber, not a commercial airliner unless it couldn't meet range.
 

One reason given about the B-35 not being picked was the small bomb bays not being able to take the very large "fat man" type atomic bombs of the era internally.

According to a page on Wikipedia, they said Northrop was told by the USAAF (which would imply a time period from 1945 to 1947) wasn't allowed to redesign its bomb-bays to accommodate the nuclear bombs.

Actually, smaller bombs were in production when the contracts were cancelled.

At what point did nuclear bombs start to shrink in size?
   

There is a school of thought in pilot's handling of an aircraft that a good design should be able to be trimmed to fly with minimal input from the pilot, in other words, set the rim tabs to a given zero climb rate and the plane should stay there, even with wind changes, or small shifts in CG or changes in throttle.

If it's dynamically stable that's what should happen...

The B-35 needed vigilance and attention and correction. A lot of pilots disapproved of this and used a trick of putting up more throttle but trimming the nose high and a steeper angle of attack. This effectively plows the airfoil into the air rather than cutting it. The turbulence over the top of the wing, a rolling vortex actually acted as a damper of side to side movements as well as any slight pitching- effectively stabilizing it to the level of flying a DC3 or DC-4 of the era- HOWEVER...doing this also increased the drag to the point that the top speed was less and the great efficiency of the flying wing aerodynamically was lost or nulled to that of a typical B-29 or B-24. It is unclear if the data in the performance tables of the B-35 was made flying in the "cheater" manner or with full control, in fact, since these tables are made over a series of many flights, many pilots, it could be a variety of flight "styles".

How do you trim it for a nose-high condition?  As I understand it trimming was determined by airspeed, mach-number, and CG position.  The only way I could think of to jack up the alpha would be to climb the plane higher...

The yaw and pitch problems were supposedly all eliminated in the YRB-49A jet version using automatic hydraulic dampers developed by the Otis corporation.

I know the YB-49 flew in '47, I assume the YRB-49 flew a year or so later?

The issue that the plane used a 1934 airfoil cross section that could never operate in the trans-sonic or supersonic, no matter how many engines you put on the machine.

I didn't know that, but the aircraft wasn't supersonic had the YB-35 won the competition, would they really need to refit it with jets?  I figure you'd just build a new design.
 

While YRB-49's from EDW were flying tests over the SF bay area and other air bases, the controllers often told the pilots of the flying wing to operate at odd altitudes like 5000, 7000, 13,000 21,000 etc while the other traffic was conducted at even heights. This was because the wing was often invisible to radar at times and was also not easily found in binoculars visually or even in some more powerful telescopes.

This is when our knowledge of stealth seemed to begin.  Ironically, it seemed that until the SM-62 that it wasn't realized to it's potential.

[Stargazer]

The original site chosen for B-35 manufacture was a B-29 assembly plant owned by Martin in Omaha, Nebraska.

Even though Northrop was going to build it?

No. The production batch of 200 aircraft was ordered from Martin as their Model 205, and were to be designated plain B-35.

The yaw and pitch problems were supposedly all eliminated in the YRB-49A jet version using automatic hydraulic dampers developed by the Otis corporation.

I know the YB-49 flew in '47, I assume the YRB-49 flew a year or so later

There were actually two different aircraft designated YRB-49As by the Air Force. The first was c/n 1489 (USAAF 42-102369) the Model N-41 which started off as a YB-35, was apparently designated ERB-35 at some point, was planned for flight tests as a YRB-49A but was eventually not flown. The second and only flying prototype was the Model N-52, c/n 1496 (USAAF 42-102376), which started off as a YB-35, became a YB-35A, then an RB-35B and finally an YRB-49A. It apparently flew in 1950.

[RussC]

RussC

The AF secretary was a big player in this, and his name was Stuart Symington, and a native Texan in the area of Dallas where Convair was located.

So, there was a connection between Odlum and Symington?
 
I had always heard the name Symington above all others. I wonder too if that time period had other things involved like the change from a USAAF to an independant USAF right at that same time era.
 

The original site chosen for B-35 manufacture was a B-29 assembly plant owned by Martin in Omaha, Nebraska.

Even though Northrop was going to build it?
 
Yes, but this was not new as the B-29 was built by a variety of companies- Boeing, Bell, Martin (Omaha) and Douglas (I think the Douglas were made in Georgia at Marietta). The flying fortress was made in others factories. The Grummans were also made by General Motors. B-24s were made by Consolidated and by Ford Motor Co.
 

there was a large discrepancy in the power to weight tables.

I don't understand how that would happen.  Can you explain?

According to one article and I think it was the one that accompanies the NASM web site, the published tables were found to be overly optimistic, but there were disagreements. Since the planes are gone, its going to be "person A said this and person B said that" to settle on anything though.

There were many questions about the economy of the machine in terms of fuel loads.

I don't understand -- this was a military bomber, not a commercial airliner unless it couldn't meet range.

It was about the range. You probably have seen that Northrop was considering a jet airliner version, even produced a film showing one.
 

One reason given about the B-35 not being picked was the small bomb bays not being able to take the very large "fat man" type atomic bombs of the era internally.

According to a page on Wikipedia, they said Northrop was told by the USAAF (which would imply a time period from 1945 to 1947) wasn't allowed to redesign its bomb-bays to accommodate the nuclear bombs.

Didn't know that! That smacks a bit of rigging the deck in some ways, yes?. That would just leave the YRB-49 recon ship as a viable machine.

Actually, smaller bombs were in production when the contracts were cancelled.

At what point did nuclear bombs start to shrink in size?

Atomic started decreasing by the start of the 50's ( Mark 5, 6 and especially the Mark 7) but the early thermonuclear jumped back up again in size , especially the Mark 17 which was a lot like the Grand Slam of Barnes Wallis' design. Actually too long to fit in some aircraft. A big table of all this at:
http://en.wikipedia.org/wiki/Category:Cold_War_nuclear_bombs_of_the_United_States
 

There is a school of thought in pilot's handling of an aircraft that a good design should be able to be trimmed to fly with minimal input from the pilot, in other words, set the rim tabs to a given zero climb rate and the plane should stay there, even with wind changes, or small shifts in CG or changes in throttle.

If it's dynamically stable that's what should happen...

Yes

The B-35 needed vigilance and attention and correction. A lot of pilots disapproved of this and used a trick of putting up more throttle but trimming the nose high and a steeper angle of attack. This effectively plows the airfoil into the air rather than cutting it. The turbulence over the top of the wing, a rolling vortex actually acted as a damper of side to side movements as well as any slight pitching- effectively stabilizing it to the level of flying a DC3 or DC-4 of the era- HOWEVER...doing this also increased the drag to the point that the top speed was less and the great efficiency of the flying wing aerodynamically was lost or nulled to that of a typical B-29 or B-24. It is unclear if the data in the performance tables of the B-35 was made flying in the "cheater" manner or with full control, in fact, since these tables are made over a series of many flights, many pilots, it could be a variety of flight "styles".

How do you trim it for a nose-high condition?  As I understand it trimming was determined by airspeed, mach-number, and CG position.  The only way I could think of to jack up the alpha would be to climb the plane higher...
 
The angle of attack would be increased but not enough power to climb. This actually does sound like a balancing act in itself, but maybe the test fliers discovered this "quiet zone" just by trying things until something was found. A gradual climb can be trimmed in too, when I was taking lessons personally years ago, I was dubbed a "leadfoot" to the point of watching the altimeter as much as the horizon until getting a better feel for it all.

The yaw and pitch problems were supposedly all eliminated in the YRB-49A jet version using automatic hydraulic dampers developed by the Otis corporation.

I know the YB-49 flew in '47, I assume the YRB-49 flew a year or so later?
 
1950, according to the labels on some photos.- Looks like Stargazer found the same timeframe while I was typing this also. I'm sill trying to find out how long the YRB was flown for, I see some pictures and some reading that state 1953 or even 54 and 55 but can't pin that down at all.

The issue that the plane used a 1934 airfoil cross section that could never operate in the trans-sonic or supersonic, no matter how many engines you put on the machine.

I didn't know that, but the aircraft wasn't supersonic had the YB-35 won the competition, would they really need to refit it with jets?  I figure you'd just build a new design.
 
   Agreed. But from my reads, the era was moving at a fast pace, everything was about jet power then. It would have delayed things to rebuild from the ground up using laminar flow wings or even thinner cross sections. Also, Northrop was a advocate of keeping a straight airfoil and putting everything inside without breaking that single surface, unlike what was done in other designs like the Hortens or Armstrong Whitworth's. So using a thin wing and a bulged center or a pod was probably off the design table for the company, but later, with J. Northrop retired the B-2 could proceed with a bulged cross section for the engines and crew. The YRB-49 Had both internal and podded jets, and some illustrations show the B-35 with jet pods similar to the fit given the B-36
 

While YRB-49's from EDW were flying tests over the SF bay area and other air bases, the controllers often told the pilots of the flying wing to operate at odd altitudes like 5000, 7000, 13,000 21,000 etc while the other traffic was conducted at even heights. This was because the wing was often invisible to radar at times and was also not easily found in binoculars visually or even in some more powerful telescopes.

This is when our knowledge of stealth seemed to begin.  Ironically, it seemed that until the SM-62 that it wasn't realized to it's potential.

SM-62, the Snark missile?

[ajmadison]

Looks more like a Submarine control room with a periscope in the middle!

The first thing that crossed my mind was 'Starship Enterprise'! 

But very handy for anyone building one, and I think I've got one in The Loft. Not seen it for ages though.

I look at that, and wonder how that can be the cockpit to an airplane (though I've seen reference B&W's so I know its right). Still, looks more like a set from an Irwin Allen production. At least Irwin would have all of those gauges at the engineer's station would be synchronized flashing lights.

[Daryl J.]

I'd love to extend the wing tips into an ogival point much like Hawker did the the tail of the Hunter and Harrier.
Then add a small diameter fuselage extending mostly aft with a very swept ogival butterfly tail.     
Kit:  the new 1/200 one from Cyber Hobby scale-o-rama'ed into 1/72 and twin engines.   

(Folgers with plastic powdered cream, I'm at work)
Daryl J.

[RussC]

I'd love to extend the wing tips into an ogival point much like Hawker did the the tail of the Hunter and Harrier.
Then add a small diameter fuselage extending mostly aft with a very swept ogival butterfly tail.     
Kit:  the new 1/200 one from Cyber Hobby scale-o-rama'ed into 1/72 and twin engines.   

(Folgers with plastic powdered cream, I'm at work)
Daryl J.

  It sounds like you could just as easily take a 72nd scale Revell Go 229 and add the fuselage and sub-tail to that if not minding a really deep wing fillet.
 
 

[KJ_Lesnick]

Stargazer2006

There were actually two different aircraft designated YRB-49As by the Air Force. The first was c/n 1489 (USAAF 42-102369) the Model N-41 which started off as a YB-35, was apparently designated ERB-35 at some point, was planned for flight tests as a YRB-49A but was eventually not flown. The second and only flying prototype was the Model N-52, c/n 1496 (USAAF 42-102376), which started off as a YB-35, became a YB-35A, then an RB-35B and finally an YRB-49A. It apparently flew in 1950.

Understood


Russ C

Yes, but this was not new as the B-29 was built by a variety of companies- Boeing, Bell, Martin (Omaha) and Douglas (I think the Douglas were made in Georgia at Marietta). The flying fortress was made in others factories. The Grummans were also made by General Motors. B-24s were made by Consolidated and by Ford Motor Co.

Understood
 

According to one article and I think it was the one that accompanies the NASM web site, the published tables were found to be overly optimistic, but there were disagreements. Since the planes are gone, its going to be "person A said this and person B said that" to settle on anything though.

So the issue was how much thrust the props produced relative to the specified horsepower and the exact weight?

It was about the range. You probably have seen that Northrop was considering a jet airliner version, even produced a film showing one.

Yeah, but it wouldn't have been feasible.  The pressure-hull requirement would either ended up suffering metal fatigue and going the way of the DH Comet, required a lot of strengthening to avoid metal fatigue negating the benefits of a flying wing, or would have simply not worked.
 

Didn't know that! That smacks a bit of rigging the deck in some ways, yes?

Yup

Atomic started decreasing by the start of the 50's ( Mark 5, 6 and especially the Mark 7) but the early thermonuclear jumped back up again in size , especially the Mark 17 which was a lot like the Grand Slam of Barnes Wallis' design. Actually too long to fit in some aircraft. A big table of all this at:
http://en.wikipedia.org/wiki/Category:Cold_War_nuclear_bombs_of_the_United_States

So Mk.7, Mk.8, and so forth?
 

The angle of attack would be increased but not enough power to climb. This actually does sound like a balancing act in itself, but maybe the test fliers discovered this "quiet zone" just by trying things until something was found. A gradual climb can be trimmed in too, when I was taking lessons personally years ago, I was dubbed a "leadfoot" to the point of watching the altimeter as much as the horizon until getting a better feel for it all.

So they'd pull the stick back and chop the power, then raise the power as necessary to hold the desired speed?

Agreed. But from my reads, the era was moving at a fast pace, everything was about jet power then. It would have delayed things to rebuild from the ground up using laminar flow wings or even thinner cross sections. Also, Northrop was a advocate of keeping a straight airfoil and putting everything inside without breaking that single surface, unlike what was done in other designs like the Hortens or Armstrong Whitworth's. So using a thin wing and a bulged center or a pod was probably off the design table for the company, but later, with J. Northrop retired the B-2 could proceed with a bulged cross section for the engines and crew.

Well depending on equipment it would be inevitable.  I don't know what his views were about applying this to fighters, but if you put a radar in a plane you'd have to have a bulged nose to fit it at the time.

SM-62, the Snark missile?

The Snark