[R-390] The OD discussion (Dead Horse Walking)

[Craig C. Heaton]

Hi Roger,

 

Good to hear you chime in! Been waiting for one of the list experts.

 

So, now I'm really a cornfused West Virginian. Had to go out to the garage
and flip over a bare bones IF module. It has some disc caps in it, think I
recall some disc in the RF section too. Any idea as to what type of disc? 

 

Guess I could dig out my Y2K, scroll down the parts list and google the mil
number if there is one listed. At this point, I'll look and see where the
Collins guru's used the disc, review of section 5 and 7 for homework
tonight.

 

Once again, Roger, thanks for the info.

 

Craig, 

 

__________________________________________________________

 

Craig said, 

> For some reason, the engineers which designed our beloved 
> R-390/A chose not to use ceramic disc caps for bypassing, 
> etc. 

The year had something to do with it. 

Ceramic disc with mil spec ratings were not yet in existence.



I am not sure Ceramic disc caps even existed in 1950. 





During the design process, life is a multi choice test. You may only choose
answers from a select list of available parts. 

Available parts being defined as existing in a mil spec catalogue. 

Collins was waging a paper struggle to get lots of R390 parts in the mil
spec approved list. They just saw no need to fight the process for caps. 

Sheet metal and gears are one thing. sort of give me's. 

The mechanical filters were a bit more effort. 

The caps were just to accept what was listed. 

This was a cost reduction program. 

Roger AI4NI

 

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