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This one is "Chuckie" and is wearing "Madras Maiden" now.

Watched it fly and kicked the tires in 2010 at the Military Aviation Museum in Pungo, Va.  Appears to be in Oregon now.

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It's all just different now

https://www.historynet.com/wp-content/uploads/2022/11/Dallas-Air-Crash-scaled-1200x900.jpg

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This one is "Chuckie" and is wearing "Madras Maiden" now.

Watched it fly and kicked the tires in 2010 at the Military Aviation Museum in Pungo, Va.  Appears to be in Oregon now.

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I didn't know Ye Olde Pub was still flying, that's awesome.

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Best that can be done. It's hard showing future generations a pile of wreckage and explaining what it used to be.

https://media.npr.org/assets/img/2022/11/13/ap223167973554341-18cea89b2105a397175bffc19f7e58a7ee0d650b-s1100-c50.jpg

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These aircraft will be fixed, AD's exist on every aircraft that have ever flown or are still flying.  Every aircraft flying right now has cracks in it, just depends on where and how big they are, its the reason why we have NDT inspectors.

The primary structure of the B-17 inner wing panel consists two truss-type wing spars, forward and rear. Each truss-type spar is built up of of two spar chords, upper and lower, that are assembled with tubular members forming “N” type trusses. The upper and lower spars, both front and rear, are themselves attached to the fuselage center section with steel terminal fittings that are bolted into the inner end of the spar chords. The terminal fittings attach to matching fittings on the fuselage center section and are held together with special tapered pins. Thus, there are four main attach points that hold the wings to the fuselage, along with two other specialized secondary attach points located between the upper and lower spars.

The spar chords were originally manufactured as an extrusion and many smart people have since tried to figure out how exactly this was done back in the 1940s. The challenging feature of the spar chords is that they taper down from the wing root to the length of the section. The taper is both outside and inside the hollow square tubular chord.

The process to extrude these parts in the exact dimensions as required to match the Boeing design is apparently no longer available; that machining capability is long gone. This is why the inner wing sections now so rare…original spar chords are needed to build up a wing and there are few undamaged components available. Trying to re-engineer a new wing spar chord using modern components would require a massive effort and re-certification with the FAA that is not practical. It is left to restorers to use the original Boeing specifications for construction and repairs to the wing structure.

The other problem with the B-17 inner wing is the steel terminal fittings where each of the four spar chords connect to the fuselage center section. Each of the four attachment fittings are slid into the respective spar chords and precisely held in position with eight close-tolerance bolts. It was determined back in 2002 that the spar chords and the steel attachment fittings were subject to cracking around the holes drilled to hold the bolts. This generated an Airworthiness Directive issued by the FAA in 2001 that requires close inspection of these components to find and repair any cracking found. The AD offers several methods of compliance for the inspection, but if cracking is found then repairs are obviously required. The procedure used to repair the cracked components has to be coordinated with and approved by the FAA. (The text and comments on the 2001 AD make for interesting reading, at least for some B-17 aficionados.)

This brings us to the work on the right inner wing panel of Champaign Lady. As part of the rebuilding process of the wing, each of the spar chords were closely inspected both inside and out, with the interior inspection a laborious process of moving a camera along the entire length of the chord checking each surface. The inspection determined that there was cracking in the areas of the steel terminal fittings on three of the four attachment points. These were repaired exactly in accordance with FAA input and Boeing instructions as contained in the AAF Technical Order on Structural Repairs for the B-17G. Essentially, the damaged area was removed and replaced with a new extrusion. The new sections were spliced in with a solid inner core extending as specified beyond each end of the gap, with external plates added fore and aft to the spar chord. Holes were carefully drilled and bolts added to hold the entire assembly together.

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So glad I got a ride on Aluminum Overcast when I had the chance.

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Ground 'em and preserve them.  We're not building any more B-17s.

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Ground 'em and preserve them.  We're not building any more B-17s.

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I flew on the Nine-O-Nine with my grandfather who himself had took 24 trips to Germany and France on one previously.

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I'm sure glad we finally got our ride in the Yankee Lady a few years back...

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It's all just different now

https://www.historynet.com/wp-content/uploads/2022/11/Dallas-Air-Crash-scaled-1200x900.jpg

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You do know some of us lost friends on that aircraft

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These aircraft will be fixed, AD's exist on every aircraft that have ever flown or are still flying.  Every aircraft flying right now has cracks in it, just depends on where and how big they are, its the reason why we have NDT inspectors.

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Hopefully the B-24’s and B-29’s aren’t effected also.

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So glad I got a ride on Aluminum Overcast when I had the chance.

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Ground 'em and preserve them.  We're not building any more B-17s.

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Not as far as we know. Although the AD isn't out yet, it only appears to be aimed at B-17 specific issues.

The CAF B-29 is finishing up a heavy maintenance cycle and we expect it to be out on summer tour in late May (beginning in Memphis).

The CAF B-24 is done with its mid-season maintenance cycle and will be heading to the Dyess AFB airshow this weekend, then out on tour with the rest of the airplanes in May.

I'll be on the crew (copilot) flying the Liberator to Dyess this weekend, so any ARFCOM folks who are there please come out and say hello.

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Also are you flying at the WW2 Weekend in Reading this year?

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Thank you for the donation and the rides. It is only with support like yours that they'll keep flying for future generations to experience. I sincerely appreciate it.

I'm not personally scheduled to fly at Reading as of currently, no. If I can work my way on to the schedule, though, I am going to try.

But the Ladies will be there.
https://www.ar15.com/media/mediaFiles/470117/IMG_7828_jpg-2788156.JPG

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These aircraft will be fixed, AD's exist on every aircraft that have ever flown or are still flying.  Every aircraft flying right now has cracks in it, just depends on where and how big they are, its the reason why we have NDT inspectors.

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Not as far as we know. Although the AD isn't out yet, it only appears to be aimed at B-17 specific issues.

The CAF B-29 is finishing up a heavy maintenance cycle and we expect it to be out on summer tour in late May (beginning in Memphis).

The CAF B-24 is done with its mid-season maintenance cycle and will be heading to the Dyess AFB airshow this weekend, then out on tour with the rest of the airplanes in May.

I'll be on the crew (copilot) flying the Liberator to Dyess this weekend, so any ARFCOM folks who are there please come out and say hello.

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Here is some info I ran across. It is from a facebook Vintage Aviation group, so I can't really say how accurate it is.

Vintage Aviation Museum

With B-17 wing spars being a hot topic, here is some information regarding how they are made and why it is challenging to reproduce them.  In the picture the wing spars locations are circled in blue. The spar carry thrus that go thru the bomb bay have been reproduced. The wing attach fittings have been reproduced. The wing spar tubes themselves have not been reproduced yet. Each wing takes 4 tubes, so 8 tubes per plane.

The B-17 has a forward and a rear wing spar, and each spar is a truss, consisting of an upper and lower tube, hereby referred to as the "Spar Tubes".  The Spar Tubes are square tubes with round corners.  The outside dimension of the tube is constant (2.688"  or  2 11/16"), while the wall thickness tapers to the other end.  It actually tapers at a linear rate to a point around the outboard nacelles, and then tapers at a different linear rate to the end, where the outboard wing panel is attached. (1/8"). The Upper tube differs from the Lower tube in both the thickness and the double taper rate, due to the differing tension and compression loads placed upon the upper and lower Spar Tubes.  These tubes were 2024 aluminum alloy,  originally drawn over a mandrel (which is basically a steel form of the inside of the tube) in order to give it the correct dimensions.  Thickness tolerances were +/- 10% per the Boeing drawing.

2024 aluminum is a heat-treatable, aerospace grade aluminum with high tensile and yield strengths, due to Copper being an alloy metal.  This also makes 2024 difficult to weld, due to the weld changing the heat treatment of the material and how the other alloy metals are affected by the heating and cooling process, causing cracks which will propagate under load.

Ideas about casting the tubes or making them out of carbon fiber face an uphill climb, as any changes from the original part or material need an engineering assessment and approval by the FAA - the "Experimental" designation aside.  Remember, the B-17s are part of the warbird experience ride program, and operate on a non-experimental license (I believe it is a Limited license, but don't quote me).  Casting aluminum does not have the same strength characteristics of 2024.  Milling the center out of the tube might work if the spar tube was 6 inches long.  As it is, they are 300 inches long.  Chemical milling?  Looked into that.  Nested tubes riveted together to get the right thicknesses?  *THAT'S* a lot of tubes, work, money, and it would STILL need FAA approval.  Carbon Fiber?  They use that on wings these days, but the wing spars are still aluminum.  The rivets would need to be a different metal, due to the epoxies and other material associated with carbon fiber parts - Remember Boeing and their problems with the 787 fasteners?  Not to mention the HUNDREDS of rivets in each Spar Tube.  That would need to be looked at by engineers.
Probably the easiest way to get any wing spar problem solved is to make the Spar Tubes just like Boeing did.  They have lasted this long, haven't they?

https://www.ar15.com/media/mediaFiles/46582/342890831_760985242222541_38960698147631-2796801.jpg


one of the reply comments states that it is estimated to cost approx $500k to make this retrofit do to a complex square aluminum tubing required that isn't really manufactured anymore, but was very common back then.

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Would making them out of steel be offset by the deleting of armor and other weight-saving measures to make it feasible?

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Remember, the B-17s are part of the warbird experience ride program, and operate on a non-experimental license (I believe it is a Limited license, but don't quote me).

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Here is some info I ran across. It is from a facebook Vintage Aviation group, so I can't really say how accurate it is.

Vintage Aviation Museum

With B-17 wing spars being a hot topic, here is some information regarding how they are made and why it is challenging to reproduce them.  In the picture the wing spars locations are circled in blue. The spar carry thrus that go thru the bomb bay have been reproduced. The wing attach fittings have been reproduced. The wing spar tubes themselves have not been reproduced yet. Each wing takes 4 tubes, so 8 tubes per plane.

The B-17 has a forward and a rear wing spar, and each spar is a truss, consisting of an upper and lower tube, hereby referred to as the "Spar Tubes".  The Spar Tubes are square tubes with round corners.  The outside dimension of the tube is constant (2.688"  or  2 11/16"), while the wall thickness tapers to the other end.  It actually tapers at a linear rate to a point around the outboard nacelles, and then tapers at a different linear rate to the end, where the outboard wing panel is attached. (1/8"). The Upper tube differs from the Lower tube in both the thickness and the double taper rate, due to the differing tension and compression loads placed upon the upper and lower Spar Tubes.  These tubes were 2024 aluminum alloy,  originally drawn over a mandrel (which is basically a steel form of the inside of the tube) in order to give it the correct dimensions.  Thickness tolerances were +/- 10% per the Boeing drawing.

2024 aluminum is a heat-treatable, aerospace grade aluminum with high tensile and yield strengths, due to Copper being an alloy metal.  This also makes 2024 difficult to weld, due to the weld changing the heat treatment of the material and how the other alloy metals are affected by the heating and cooling process, causing cracks which will propagate under load.

Ideas about casting the tubes or making them out of carbon fiber face an uphill climb, as any changes from the original part or material need an engineering assessment and approval by the FAA - the "Experimental" designation aside.  Remember, the B-17s are part of the warbird experience ride program, and operate on a non-experimental license (I believe it is a Limited license, but don't quote me).  Casting aluminum does not have the same strength characteristics of 2024.  Milling the center out of the tube might work if the spar tube was 6 inches long.  As it is, they are 300 inches long.  Chemical milling?  Looked into that.  Nested tubes riveted together to get the right thicknesses?  *THAT'S* a lot of tubes, work, money, and it would STILL need FAA approval.  Carbon Fiber?  They use that on wings these days, but the wing spars are still aluminum.  The rivets would need to be a different metal, due to the epoxies and other material associated with carbon fiber parts - Remember Boeing and their problems with the 787 fasteners?  Not to mention the HUNDREDS of rivets in each Spar Tube.  That would need to be looked at by engineers.
Probably the easiest way to get any wing spar problem solved is to make the Spar Tubes just like Boeing did.  They have lasted this long, haven't they?

https://www.ar15.com/media/mediaFiles/46582/342890831_760985242222541_38960698147631-2796801.jpg


one of the reply comments states that it is estimated to cost approx $500k to make this retrofit do to a complex square aluminum tubing required that isn't really manufactured anymore, but was very common back then.