MXB 7740/120 Fiberglass

[Jetman021]

Looking for a substitute to replace MXB 7740/120 fiberglass that is used to fabricate the blocker door facesheet to a CF6-80C2 reverser. I can find the facesheets on the market already made as P/N 1291M24P03. We are seeking to build our own but the MXB 7740/120 has a long lead time and a min of 300 yards when we are only needing about 60 yards.

Best regards,

 

[Compositepro]

Are you not required to use qualified materials? The aircraft manufacturer will have a qualified products list, QPL. If there is an alternative material supplier qualified, you will probably run into the same problem with them. Welcome to the aerospace industry.

 

[Jetman021]

Yes , required to conform with the manufactures specification unless we can find a substitute that a DER with approve.

 

[Sparweb]

A few thoughts about how a DER would approve it.
This Cytec prepreg was tested for the AGATE/NCAMP database:

https://www.niar.wichita.edu/agate/Documents/Materials/WP3.3-033051-100.pdf

The test data is about 20 years old so it was probably used for certification of the part. Now you know the target (part of it).
To come up with your own design, you'd have to substantiate both the material selection and your fabrication process to show the resulting part is equivalent.
But it may come down to a structural test, too.
If you want to thoroughly investigate the process, look at this: FAA AC20-107B

http://www.sparweb.ca