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This is the place where the majority of the warbird (aircraft that have survived military service) discussions will take place. Specialized forums may be added in the new future
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technical people, help me?

Sat Dec 27, 2014 9:04 am

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 :spit

Re: technical people, help me?

Sat Dec 27, 2014 9:07 am

Image

Re: technical people, help me?

Sat Dec 27, 2014 9:24 am

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.

Re: technical people, help me?

Sat Dec 27, 2014 10:01 am

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

Re: technical people, help me?

Sat Dec 27, 2014 11:52 am

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

Randy Tait

Re: technical people, help me?

Sat Dec 27, 2014 10:33 pm

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

Re: technical people, help me?

Sun Dec 28, 2014 9:48 pm

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?

Re: technical people, help me?

Mon Dec 29, 2014 5:14 am

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

Re: technical people, help me?

Mon Dec 29, 2014 4:44 pm

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 !

Re: technical people, help me?

Mon Dec 29, 2014 5:35 pm

station 342 wrote: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 !


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