Warbird Information Exchange

I am starting to tool up for some rebuilds and have run into an issue when getting some parts converted for the CNC.

for example on the airacobra fin ribs there is no diameter of the lightening holes, they just say 50H1-12 and 50H1-15, 50H1-17 etc are these some standard die? is there any conversion charts out there?

i have an old book from the 40's the "aircraft data book" but it has no ref either.

help

They might be manufacturer's specs. On Boeing designed planes they have BAC numbers for holes that give the dimensions not shown on the drawing for the part.

i thought they might, ive emailed bell but doubt they will help, does anyone have any old bell tech books?

The blueprints are usually drawn accurately. Just use copier to blow up drawing to full scale and measure hole dia.

Randy Tait

i can do that and do have patterns but id rather know

They may have changed the diameter from that pictured by changing the number without redrawing the picture. Also, is that a 45 degree flange or a return lip? Only that spec will tell you for sure.

You might look for a Bell retiree group. Maybe they saved some of those old manuals. In fact, that specification may still be in use. Maybe you can look at some helicopter drawings?

not many people know much about cobra stuff, ill just use the original tails as patterns i guess. i did email bell both in the usa and aus, ive searched everywhere, its supposed to be in the repair manuals but i cant find it and i have them all.

cheers

HI,
I am not 100% on this but I seem to re call seeing a separate drawing for the holes in the Republic drawings for the P47.
I think that maybe why the drawing for the holes on the Cobra has different numbers against them .
100 % No idea how Bell worked though !

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495th F.T.G your not forgotten

interesting... i'll have a look, cheers