X-Plane losses due to Ulmer leather gaskets

[OM]

...In the Wikipedia article on Jean "Skip" Ziegler, it's mentioned that Skip and observer Frank Wolko were killed during a Bell X-2 captive-carry flight test over Lake Ontario. X-2 number 46-675 suddenly exploded, and the cause of the blast was traced to a rocket engine gasket made of Ulmer leather, which decomposed and became explosively unstable after sustained exposure to liquid oxygen. While it's stated that the cause was not determined until after "several other X-Plane losses", the stub entry fails to not which other X-Planes were lost. Anyone happen to have a list of lost planes that contributed to determining the Ulmer gasket was at fault?

http://en.wikipedia.org/wiki/Jean_%22Skip%22_Ziegler

 

[Andreas Parsch]

Anyone happen to have a list of lost planes that contributed to determining the Ulmer gasket was at fault?

X planes lost to "Ulmer leather":

• X-1D (48-1386), lost on 22 August 1951
• X-1 #3 (46-064), lost on 9 November 1951
• X-1A (48-1384), lost on 8 August 1955

A reasonably detailed account about how the cause for the explosions was eventually tracked to Ulmer leather should be in Jay Miller's "X Planes", which I haven't at hand right now.

 

[Dr Aircraft]

Aircraft X-1A (48-1384) (Photo of private collection)