P-51B CAD Question Thread

[rtwpsom2]

I am doing a CAD model of the P-51B and had some questions I was hoping you guys could help me with. I just joined and so I thought I would start a thread to keep all the questions in one place so as not to clutter up the forum with my begging you guys to look at this or check out that. My first question is in regards to the drawings I have. I bought the ebay set of drawings, not the Flugwerks ones, and am looking at 73-31172, roll E324. Here is my title block.



The notes to the left and the parts list are almost completely illegible. Can anyone take a look at their copies and see if their's are any more legible?

[bdk]

I think that is just a list of changes or updates that were made to the drawing after it was originally released. There may have been errors in the initial release or assembly line improvements were made. In other words, just record keeping.

I'm also curious what your objective is in modeling these aircraft. Do you plan to market the 3D data when your project has been completed, do you want to make phantom illustrations, or what?

[rtwpsom2]

The revision block you mention is in the upper right hand corner of the drawing and isn't shown in here. On this drawing the list above and to the left of the title block is the parts list because this is an assembly drawing. Where it says -2, -3, and -4 means part number 37-31172-2, 37-31172-3, etc. Those parts have their material and material sizes called out because they don't have individual drawings for each of those parts. To read it properly, look at the third block from the top. It's for the -9 part. The next field is quantity, in this case one. Next is material; aluminum sheet conforming to Alcoa standard 24ST. Next is the rough size, .064(?) thick sheet 3.5 inches long by 12.5 inches. Next is the sector of the drawing the part is in, 2. And last is the alloy spec, 22-A-342(?). I can't read the specs on parts -2, -3, and -4.

To the far left is a bunch of general drawing notes. These typically call out standard bend radii and fillet dims, but there are also notes about stuff specific to one plane model or another. It will say "For P-51B do not include hole X in Y sector" and such. The only one of these notes I can make out is the top one concerning which loft drawing to use to get the outer lines of the part.

I have no objective, I just like modeling stuff and I wanted to do a plane.

[bdk]

You are right, it is the notes list. It even says "note" at the bottom. You might find a similar drawing and see if the notes appear to be the same. You might be able to match them up.

How are you determining the loft? Are you scaling from the original loft drawing? Scanning and rasterizing?

[rtwpsom2]

The loft drawing includes ordinates, so I am using those then comparing the resulting splines to the lofts drawings and making minor corrections where needed.

[Ew51]

Hi Rob, here is what mine reads. Hope that helps.

6. Added Master Lines Layout No. 73-31-57
5. 1S74LT (?-???) May be Sub'T. For K734HH
4. For Contours See Fus. Ordinate
DWG 73-00005
3. All Rivet Heads on Rear Face
Of Frame Flush Except -7
2. Outside Corners 1/4 R or Square
1. Inside Corners 5/32 R

Eric.

[rtwpsom2]

Thanks Eric! Can you make out any of the parts list materials column? Mainly I need the size and thickness of the materials and any die number if there is one. I think this is all sheet stuff though. I appreciate the notes a lot in either case. Thanks again.

[Ew51]

Your welcome Rob. I checked out you blog page, excellent work. What program do you use to make those drawings? The following is what I can make out.

-9 24ST ALC SHT .064 x 1 1/2 x 12 1/2
-8 24ST ALC SHT .081 x 1 3/16 x 2 3/4
-7 24SO ALC SHT .064 x 1 1/8 x 7 3/4
-6 24ST ALC SHT .064 x 1 1/2 x 12 1/2
-4 AL Alloy 24ST Alcoa Die 734HH
-3 AL Alloy 24SO Alcoa Die 734HH
-2 24SO ALC SHT .051 x 10 1/2 x 20

Eric

[rtwpsom2]

Eric, I think your my new best P-51 friend. Thank you so much. I hope I can ask again in the future, I have a lot of drawings and you know how much the quality can vary.

I am using SolidWorks, it is a parametric CAD program which means the parts are exactly the dimension I read off the drawing. Which is why it is so important I get the right material dimensions. You have no idea how hard it is when I don't know the right sheet metal thickness.

[Ew51]

Hey Rob glad I could help. If you need anymore more help just let me know and I will see if I can help. Keep up the great work.

Eric.

[rtwpsom2]

Okay, so some interesting news. Erik Hokuf over at Aircorps Aviation has offered me some work doing largely what I have already been doing on the 'Stang. Jim MacDonald, my benevolent benefactor on the F6F and FM-2 projects, has given his blessing to switch gears so I will be switching back the P-51 post haste, and it appears this will now be a P-51C thread instead of the California model.

[AHancock51]

Okay, so some interesting news. Erik Hokuf over at Aircorps Aviation has offered me some work doing largely what I have already been doing on the 'Stang. Jim MacDonald, my benevolent benefactor on the F6F and FM-2 projects, has given his blessing to switch gears so I will be switching back the P-51 post haste, and it appears this will now be a P-51C thread instead of the California model.

I'd be interested in reading your updates and sharing info with you, as I am building a full-scale P-51B to airworthy as well.

[rtwpsom2]

Just keep an eye out for this thread, whenever I have a question I will post it in here. It's nice to see the D model isn't everyone's favorite.

[AHancock51]

Just keep an eye out for this thread, whenever I have a question I will post it in here. It's nice to see the D model isn't everyone's favorite.

Roger that! I'm running the "Lucy Gal" project for the National Warplane Museum. We're doing the Mustang to honor MIA Tuskegee Airman Leland Pennington. He's a local hero...

[rtwpsom2]

If anyone knows what this piece is and can get a couple photos of one I would appreciate it. It seems to be the housing for a spring loaded catch for the instrument hood, but I couldn't say exactly where that would be. I assume on the top of the instrument panel, or maybe under it?

55-73011; Housing, Instrument Flying Hood Release Latch