Specs for North American Extruded Aluminum

[rtwpsom2]

Does anyone know where I can find specifications for extruded aluminum that North american used in house? The first number I came across that I need is C478A-56. It is a piece of extruded angle about 7/8" x 7/8" x 1/8". I do not have access to any original parts, but I do have the big planset available online. The specs are not in there. Is there a source for this kind of thing?

[rtwpsom2]

Found it, it has been renamed IE49 with the A meaning soft material and the -56 meaning a length of 56 inches is needed. So new part would be IE49A-56.

[Cvairwerks]

That's probably a NAA specific extrusion profile callout. You need to get a copy of the SRM for whatever you are looking at. Within the SRM, usually, there are some listings and drawings of the various profiles used on that aircraft so it can have major repairs done in the field. Without a drawing or an orignal piece of it, you can only guess at the info, and the chances that you will be right are pretty slim. As an example, I have some listings in the books on a project that appear to be standard sized bulbed angle. When you look at the actual spec, it's not. Not only is the angle not 90 degrees, but one leg also has a radius to it, so it's not a flat leg.

It's kinda like mechanical archaeology sometimes...lots of digging and research and sometimes some educated guessing.

[rtwpsom2]

Thanks for the help CV, this is a new account so my responses are not posted until a mod can check them, hence my first reply appearing above yours. I guess it's all just a mater of digging deep enough and long enough into the resources I have at hand.

[Cvairwerks]

As my Italian buddies used to say..... Is not to worry.

Giving a material length in an extrusion number is pretty weird. I've never run across that before. Normal drawings would simply call out the extrusion number in a "Male from" statement or on the B.O.M. without a specified length. I suppose that the dash number could have been a standard cut length, but if this is from a wartime production, that would have been incredibly wasteful of raw stock

I'd check a few random other parts to verify that the dash is a length callout before going too far if you are replicating parts.

Have fun.

[51fixer]

Found it, it has been renamed IE49 with the A meaning soft material and the -56 meaning a length of 56 inches is needed. So new part would be IE49A-56.

I'll assume you don't have NAA Blue Prints?
The Extrusion is produced in O condition, it has no heat treatment. If the use doesn't require heat treatment, i.e. non-structural use, than the final part call out will use the A. If it is used in structure it will require heat treatment and the part call out will be changed to a T. Often there is some shaping of the extrusion so it may be bent when soft and then heat treatment will be performed.
The 1E49 off the print is a L shape with equal legs of 1" length, not 7/8" as you stated. Each leg is 1/8" thick, the radius on the inside of the base is 3/32" as is the radius of inside edge of each leg. The included angle is 84 degrees or at the 1" leg edge it is elevated .104 from where it would be if it was a 90 degree L shape.
As you note A is used if it is in as produced temper.
If heat treat is used it is coded with a T.
Length is listed in inches and 16ths.
Example given is 1E49T-10-8 is Heat treated and 10 1/2" long.
Die is listed as L-29033. Years ago some shapes were still avail using the die number. This particular Extrusion isn't listed in the P-51 Structural Repair Manual as it starts with 1E52T. Sometimes the SRM allows substitution of bent pieces of .125 in lieu of the actual extrusion. For some other L shapes of .125 leg thickness the call out is to use O condition, or soft 2024, and use a 3/16ths radius to bend to the angle called out. The legs are called out as 1/16" longer, 3/4" on the extrusion is 13/16" on the substituted bent replacement.
The T-6 SRM has similar substitution examples but extends the legs by 1/32".
Heat treatment would then be required after shaping, if needed, if it is used in a structure.
Since this number isn't called out in either the P-51D or T-6 SRM may I ask what NAA A/C is this used in and where? I'll guess B-25.

[rtwpsom2]

Giving a material length in an extrusion number is pretty weird. I've never run across that before. Normal drawings would simply call out the extrusion number in a "Male from" statement or on the B.O.M. without a specified length. I suppose that the dash number could have been a standard cut length, but if this is from a wartime production, that would have been incredibly wasteful of raw stock. I'd check a few random other parts to verify that the dash is a length callout before going too far if you are replicating parts.

I am not sure if it's the cut length or not, it's for the Sta 248 rear frame assembly on the P-51. It's a pretty long piece but I haven't measured the arc length of it.

I'll assume you don't have NAA Blue Prints?
The 1E49 off the print is a L shape with equal legs of 1" length, not 7/8" as you stated. Each leg is 1/8" thick, the radius on the inside of the base is 3/32" as is the radius of inside edge of each leg. The included angle is 84 degrees or at the 1" leg edge it is elevated .104 from where it would be if it was a 90 degree L shape.

Fixer, your numbers match up with the drawing I have. It would be considered a structural member that would need heat treatment after forming if it was for a real part, however my only interest is in a virtual one. I am doing a CAD model of a P-51B.



It is the one that goes around the edge. There are two halves to it, almost mirror images of each other.

I have the 16,000 drawing set from ebay, not the Flugwerks one. Familiarizing myself with it takes a good chunk of my time while working on this project, so I apologize if I am not up to speed like the more experienced enthusiasts.

If anyone is interested I am doing a blog on it at http://rtwpsom2.blogspot.com. I am always looking for constructive criticism. I am not an airplane guy, per se. I am a CAD guy who likes to do stuff. I want to do the model as true to form as possible, so any real world criticism you want to provide would always be appreciated.

[bdk]

The angle of the raw extrusion may be 84 degrees, but I'll bet that that the angle continually varies around the part- it isn't 84 degrees all the way around. Only a perfect cone would have a continuous angle. The lofted shape will actually determine the angle at any given point.

[rtwpsom2]

And that's what I did here, I created the loft and made a skin out of it, then extruded a piece to that skin. I just needed to know how long the legs were and how thick it was.

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Bottom section:

[51fixer]

My drawing set is like yours that came on a CD.
I also already had a set of microfilm from NASM so I had a printed guide to the set.
The printed guide should be included in your set being the 1st part of the 1st Vol on the A roll. It gives a P/N, Revision, Models of the P-51 it was used on and the Reel Number of the Microfilm where it was located.
The NAA Standard Parts, such as the 1E49 extrusion, are also listed on the guide and have a frame on the Microfilm. Thats what I used to look up the extrusion info. You probably have it as well in your set.
Try printing the index guide pages and put in a binder. It helps to track where things are.
Your work looks very cool. Great job.
When they made the halves for the mounting flange you are addressing they probably had a mold they used. Possibly the material ends were grabbed and the stretched the angle around the mold with a lot of pressure. This would give the shape and also change the angle of the L as required.
I think Eric Trueblood at AirCorps Aviation has produced an enhanced set of the P-51 drawings sold on a hard drive for $2500.

[rtwpsom2]

I have been able to use that a couple times now, though my main source for cross referencing into the rolls is the excel tables from SIG. I combined them all into one multi-tab table where I also keep track of things like this extrusion equates to that drawing and the changes I made to the loft ordinates in order to fix problems with them. The only problem that arrises is that the part and assembly drawings don't always use the codes in those standards. They use other codes like C487, C283, and P787 that aren't listed in there. I have to go through one at a time and look at each one and down in the lower right corner of the drawing there will be a note that says "4E9 WAS C283."

Here is my next question, if you will indulge me a little. Again, not a plane builder in real life so there are things I don't know about standards. I just did the top stringers in the tail fuselage assembly and they used the previously mentioned Tee shaped extrusion with the tear drop shape on the bottom of the Tee. H404 if you want to look yourself. Should this go up or down? I assumed down because it would be a gutter otherwise and I didn't think that was good, but what do I know.