Blown/bubble canopies

[Milosh]

I was wondering what the rejection rate was due to the difficulty in forming.

 

[fliger747]

At least several: Many years ago the Washington TV new person Leslie Stahl was interviewing Senator Strom Thurmand, who it was obvious that she heartily detested. She was trying to nail him down on some subject and he replied "several". Undeterred she with great snark says "Define several Senator". His reply" "Two or more"...

I know it wasn't an exact science and there was controversy between blown and molded. Blown being optically better?

 

[FLYBOYJ]

I was wondering what the rejection rate was due to the difficulty in forming.

One of my last assignments at Lockheed was inspecting the first canopies to be used on the F-22.
The sub contractor I was at (Sierracin) was making canopies for the F-16. IIRC the rejection rate was about 20%. Rejected canopies were sold to boat racers who used them on their rigs.

 

[herman1rg]

Interesting thought, I have no idea whether they are blown or moulded.

 

[Milosh]

So that is where they came from. Thanks

 

[FLYBOYJ]

TRANSPARENCY PRODUCTS BY PPG FOR THE AEROSPACE INDUSTRY - PPG Industries - Aerospace

 

[ThomasP]

Hey FLYBOYJ,

At what stage(s) in the process were you inspecting the canopies? (i.e. blowing/molding stage, laminating stage, coating stage, final, etc) Also, the manufacturing engineer in me is curious about the steps it is necessary to go through for such a canopy.

 

[FLYBOYJ]

Hey FLYBOYJ,

At what stage(s) in the process were you inspecting the canopies? (i.e. blowing/molding stage, laminating stage, coating stage, final, etc) Also, the manufacturing engineer in me is curious about the steps it is necessary to go through for such a canopy.

For the most part, upon completion. A Lockheed manufacturing engineer would first go in and observe/ bless their processes. Along the way I would go in and look at material certs and their sub-contractors, observe their control of materials and ensure their manufacturing paperwork was completely filled out. In the end a canopy was placed in a large room painted black with white yarn strung in boxes on the walls and on the ceiling making about 1" squares. Under a black light the inspector was given this square tool measuring about 1" x 1" welded on a stick. From inside the canopy you would sit there and hold the tool up (under black lighting) and see how much distortion was within the canopy comparing the squares within the room to the square tool. I can't remember the inspect and reject criteria but IIRC it was pretty tight.

This was in 1988/89, I'm sure there's more accurate ways to do this today.

 

[ThomasP]

Hey FLYBOYJ,

Neat stuff, I am having fun visualizing what you describe. Thanks for the info.