Greg Stathatos poses in the cockpit of B-17G Preston’s Pride (44-85738) in Tulare, California. Preston’s Pride – a veteran of the Bikini Nuclear Weapons Tests – may be the only surviving B-17 whose interior fabric remains untouched.
When we began rebuilding Lucky Thirteen we did so knowing that at some point we would have to deal with the bomber’s internal fabric and insulation. Few surviving aircraft of the Second World War still have their internal fabric and even fewer are airworthy. Still, up until late in the F-series, the Boeing B-17 had three insulated, fabric-covered crew compartments: the nose, the cockpit, and the radio room. Having the same needs, Hangar Thirteen teamed up with the National Museum of the US Air Force to find sources capable of replicating this fabric for their restorations of Memphis Belle and Swoose.
This has not been an easy task.
Wartime aircraft insulation will not be easy to replicate. The B-17 used an even three-part combination of cotton, kapok, and animal hair for its insulation, spraying and soaking it in flame-retardant before gluing it directly to the skin between the ribs. For much of the airplane, a pattern called Tempak was used, tube-stitching the insulation between thin sheets of cheesecloth, while a diamond-stitched pattern called Kwilko was used in the nose.
Insulation samples compared with photos taken from B-17Fs Winning Run (42-29944, 303BG) and Memphis Belle (41-24485, 91BG).
On top of this insulation was placed "blankets" of cotton fabric, attaching to the ribs with button snaps. The fabric was roughly color-matched to Boeing's Bronze Green (as discussed here) and had a thin layer of Tempak underneath, giving the finished walls a clean, uniform appearance.
The available references we have on the Boeing B-17's interior fabric and insulation are listed below.
Click here to see an Excel sheet of the materials called for in the blueprints below.
Soundproofing Fabric and Insulation
D-2887: Soundproofing Distribution Specifications
INCLUDES PHOTOGRAPHIC REFERENCES
The interior of Bock’s Car at the NMUSAF. Note the discoloration of the fabric, revealing the tube-stitching of the insulation underneath.