Update on B-17G Champaign Lady (44-85813) at Urbana, Ohio

[aerovin]

I just posted an update to the restoration of B-17G 44-85813, better known as Champaign Lady, by the Champaign Aviation Museum at Urbana, Ohio. Most of the work is now ongoing with the wing sections.

https://www.aerovintage.com/2022/02/18/b-17g-champaign-lady-update-02-18-2022/

[Pat Carry]

Thanks Scott. Things are looking good there in Ohio!

[tom roberts]

Great article Thanks

[JohnB]

When I saw that during my epic 2011 B-17 viewing trip (5 aircraft in two days) I was amazed by the quality and quantity of work they had done.
A lot of the cockpit items were newly fabricated, the fuselage was very well along in the build process.

I remember thinking then "wait until they get to the wings, their complexity will make the fuselage look simple and quick" .
So here we are, ten years later....

[blue3992]

I just posted an update to the restoration of B-17G 44-85813, better known as Champaign Lady, by the Champaign Aviation Museum at Urbana, Ohio. Most of the work is now ongoing with the wing sections.

https://www.aerovintage.com/2022/02/18/b-17g-champaign-lady-update-02-18-2022/

From that link is the below comment regarding the B-17 spars, and how there is no method to remanufacture them today.

I've seen this issue with the B-17 spar described before, and have always been fascinated. Can anyone point to more details on this issue? I know just enough about metal machining to be dangerous. Is there any more detailed description out there as to what exactly is challenging about making the spars, and why it can't be done with modern machinery?

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.

[Chuck Giese]

I just posted an update to the restoration of B-17G 44-85813, better known as Champaign Lady, by the Champaign Aviation Museum at Urbana, Ohio. Most of the work is now ongoing with the wing sections.

https://www.aerovintage.com/2022/02/18/b-17g-champaign-lady-update-02-18-2022/

From that link is the below comment regarding the B-17 spars, and how there is no method to remanufacture them today.

I've seen this issue with the B-17 spar described before, and have always been fascinated. Can anyone point to more details on this issue? I know just enough about metal machining to be dangerous. Is there any more detailed description out there as to what exactly is challenging about making the spars, and why it can't be done with modern machinery?

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.

These statements are not quite accurate. These tubes are currently being manufactured in Europe. Also, there is no external taper to these tubes. There are two different internal tapers per tube, in addition, the upper and lower tubes have different tapers as well.

[bdk]

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.

One way to do this would be to roll (shrink/squeeze) a square extrusion to the needed internal dimensions and then machine to the needed external dimensions.

[menards]

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.

One way to do this would be to roll (shrink/squeeze) a square extrusion to the needed internal dimensions and then machine to the needed external dimensions.

Its my understanding that the internal dimensions need to be exactly with certian tolerances, other wise the part is not usable. "Close" is not good enough.