As readers of this website know, there are currently three B-17s located at the Erickson Aircraft Collection located at Madras in central Oregon: B-17G 44-8543 (N3701G), B-17G 44-85829 (N3193G), and B-17G 44-85718 (N900RW). We’ll update the status of all three in this post, though two of those updates will be really short. The main one looked at here is that of the last one listed…44-85718, which is the airplane that was once known as Thunderbird with the Lone Star Flight Museum.

Wing Spars and more Wing Spars

For those closely following the B-17 world, it is widely known that there is pioneering wing spar work underway at Madras on 44-85718. As a quick recap, the spar tubes on the inner wing sections of most flying B-17s have become a weak spot in their continuing airworthiness. There are two FAA Airworthiness Directives (ADs) on the spars after corrosion and cracking has been detected after detailed inspections. Most current (and future) operators are complying with the ADs with inspections and spar tube repairs, where allowed by Boeing technical manuals and the FAA.

In late 2020, Scott Glover and his Mid America Flight Museum of Mt. Pleasant, Texas, purchased 44-85718 and sent it to the Erickson facility at Madras for an FAA AD compliance check. After a detailed inspection, it morphed into a complete IRAN (Inspect and Repair as Necessary) check. With the result of the spar inspection, it was decided that, rather than attempt to repair the rear spar tubes on both inner wing panels, they would be replaced with complete brand new components. This type of work has never been attempted with B-17 inner wing panels primarily because of the unusual aluminum extrusions required of the new parts. The ability and technology to recreate the ninety-year old spar tube design is not readily available. This, along with the complexity of actually removing and replacing the old spar tubes makes it a daunting project. The crew at Erickson was tasked with taking on the job.

First, the aircraft was disassembled, with the fuselage, empennage, and outer wing panels placed in custom-built carriers. Large vertical inner panel wing jigs, based on the original production line jigs and precisely aligned, were built and both inner wing panels were mounted.

As this work was in progress, the search began to locate a source for the unusual aluminum extrusions needed. Each of the four spar tubes (two forward, two aft) required for each wing panel are about 26 feet long and, though their exterior dimensions are constant, the width of the aluminum material tapers, as it moves outboard, from about 1/2′ width to 1/8″ width on the sides of the rectangular tubes. The original Boeing design drawings are very specific about how that taper occurs through the length of each tube: the inner sections are thicker to support the engines and fuel weight. Then the extrusions get thinner further outboard allowing the needed wing flex as established by the Boeing engineers in 1935 when the design was first put to paper.

The B-17 inner wing spars themselves are beefy trusses built up using the upper and lower spar tubes riveted together with supporting structure. Flat spar caps are then riveted to the upper and lower facing sides to provide a riveting surface for the corrugated underskin layer used in the unusual wing design.

So, the search was on for a vendor to produce those extrusions. After making several inquires of different vendors, a complete set of new spar tubes were sourced in the United Kingdom by a manufacturer that makes extrusions for a major European aircraft builder. I’ve seen that paperwork for the UK vendor for what it is worth. The entire process took more than two years to develop the tooling, do test extrusions and, through that trial and error process, produce eight acceptable spar tubes. This was obviously an expensive process with a steep learning curve required but the end result were eight beautiful spar tubes showing up at Madras late last year.

The specialized tooling needed for the extrusions has a limited future, though, due to company demands on the required equipment. There is now a short window for producing additional B-17 spar tubes so there is an effort underway in the B-17 community to have an adequate supply produced to satisfy future needs. It is an expensive proposition and it is no doubt a difficult decision for current operators and restorers to make about investing in parts that might be demanded in the future to keep their B-17 airworthy.

Once the spar tubes were on hand at Erickson, the rear spars were carefully removed from the inner wings sections and placed in custom fixtures to set up for the tube removal and replacement. That work is currently underway. A major challenge in reassembling the wing spars is figuring out how to rivet to the spar tubes. How can a bucking surface for the tail end of each rivet be provided along the interior of a 26-foot long tube? The Erickson crew came up with some unique tooling of their own to satisfy the several technical challenges of allowing the hundreds of rivets used in the spar tubes to be set. They are also using the original type rivets in the rebuilding effort, something else that adds to the complexity.

So, as it stands, the rear spars of each wing’s inner section are in the jigs being worked on. Upon completion, they will be reassembled into each of those wing sections. There are extremely tight tolerances for ensuring everything lines up properly. The four spar tubes of each wing have wing attach fitting bolted into the tubes, and those fittings must perfectly align with the attach fittings on the fuselage center section where close-tolerance bolts are used to tie the parts together. There is no room for error, thus the precise jigs and checks through the process to make sure everything is lining up properly. In the course of the work, each wing panel is being inspected and minor areas of corrosion or damage are being repaired also.

Fuselage Work on 44-85718

As the wing spar tube work is being completed, another Erickson team is working on the fuselage. All the old Thunderbird paint scheme has been stripped off. Work has proceeded from the tail forward replacing corroded frames, longerons, and aluminum skin. Corrosion largely found in the aft fuselage belly has been repaired and a good amount of the aft fuselage skin has been replaced. Work is now underway in the ball turret area. Soon, attention will turn to the nose section and will proceed aft to end up with final work on the bomb-bay section between Stations 4 and 5 where the wing attach fittings and complex carry-through structure is located.

While this plane flew with the Lone Star Flight Museum, questions were often raised about why the lower non-standard nose windows and its non-standard plexiglass nose, remnants from its days as a photo survey aircraft for the French Institut Geogephique National (IGN), were never been replaced. As a recap on this aircraft’s history, it was purchased as a new surplus airplane out of an WAA disposal yard at Altus, Oklahoma, in 1947. It was in the batch of the first four of an eventual 13 IGN B-17s operated for the aerial survey missions for four decades. 44-85718 flew for the IGN as F-BEEC. It was withdrawn from IGN service in 1984 and, after its initial UK-based civil owner, was sold to the Lone Star Flight Museum in 1987, where it remained until 2020. (The complete history of this airplane is told, along with those of the other 45 surviving B-17s, in text and photos in Final Cut: The Post-War B-17 Flying Fortress and Survivors.)

So as this fuselage nose work is beginning, the question is asked again if those small windows are going to be removed and whether a standard plexiglass nose will replace the IGN nose piece. That decision has not been finalized yet, but there is strong consideration being given to leave both in place as reminders of the aircraft’s long heritage as a survey aircraft. It may look a little funny to B-17 Guys and Gals, but it would recognize the primary use of this aircraft though the years and why it survives today. An interesting side note of all of this are the remnants of the IGN markings that can be seen on each side of the nose on the paint-stripped skin.

It is possible that this airplane will be ready for reassembly within two years. All engines and propellers with be overhauled prior to reassembly. All the aircraft systems will receive the IRAN treatment, the intent being a structurally sound, operationally reliable B-17 that will be airworthy and join the already-impressive Mid America collection in Texas.

It is expected that this B-17 will be polished out in its natural metal finish. Presumably, standard AAF markings will be carried. The Mid America Flight Museum has announced it will fly with the name We The People. Bomb group, nose art, and any other markings (if any) have yet to be announced by the museum.

The Ex-Yankee Lady: 44-85829

Yes, the fuselage, outer wing panels, and empennage of they ex-Yankee Lady, 44-85829 (N39193G) are still sitting shrink-wrapped and ready for overseas shipping to the Avspecs Ltd. facility near Auckland, New Zealand for rebuild and restoration. The museum has no update on when that shipping might occur.

As for its two inner wing panels, they are set aside in storage on the Erickson hangar floor awaiting the inner panels of 44-85718 to be removed from the massive wing jigs. At that time, they will both go into the jigs for a complete inspection and a detailed examination of the wing spars. Depending up the results of that inspection, they may eventually received some substantial spar work also.

The rebuilding and restoration of 44-85829 on behalf of the the Charles Somers aircraft collection, located at McClellan Field in Sacramento, is obviously a multi-year project but should result in another rebuilt airworthy B-17 at a future, hopefully not too-distant date.

B-17G 44-8543 (N3701G) Ye Olde Pub

Meanwhile, Erickson’s own B-17G, 44-8543, flying as B-17F Ye Olde Pub, remains parked outside on the ramp ready to fly for the summer airshow season. Recurrent flight crew training was recently completed, so now crew and plane are ready to go. There are several appearance dates scheduled in the northwest this summer.

If anyone is wondering, detailed wing spar and attach fitting inspections on this airplane were completed a few years ago when the wings were off the airplane it remains in full compliance with both FAA ADs.

Oh, and a special bonus for the day I was there…May 28, 2025. B-25D 43-3318 (N88972), which has been in the Erickson hangar for almost two years, was pulled out for its first engine runs after much restorative and mechanical work was done on the aircraft. As part of that work, almost all of the fuselage skin was replaced, as was any corrosion or damage found anywhere on the aircraft. A cursory look at the bomb bay and fuselage interior reveals accurate, exacting work by Erickson. This airplane is technically owned by an obscure U.S. corporation but is going to Switzerland eventually for its owner.

(Thanks to Erickson Aircraft Collection and Jim Martinelli for their time and information in preparing this update.)

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