Liberty V-12 Aircraft Engine Drawings and related correspondence [Photographs of Liberty V-12 engineering drawings from the National Archives], bulk: 1917-08-24 - 1926-01-05, 2008-04-16

Document Type: Technical Data (Drawing).

Purpose: Authoritative reference.

Source: Government Military.

Scope: Folder includes 1300+ digital images of drawings, and parts of drawings, related to the V-12 Liberty aircraft engine. The drawings originated from the U.S. Army Signal Corps, Aircraft Section (2018) and Navy Department: Bureau of Construction and Repair (1917), and later, Bureau of Aeronautics (1922).

Contents (from the ReadMe text file): The DVD-ROM disc contains: "a photographic survey of the Liberty V12 related engineering drawings housed at the National Archives II, 8601 Adelphi Road, College Park, MD 20740-6001.

The photos were taken over April 16-17, 2008 using a hand-held Sony F717 digital camera. Edge distortion (barrel shaped effect) from short focal length of lens (equivalent 28mm) will be very apparent. Since pictures were taken hand-held without the benefit of image stabilization, and no flash was permitted, it was felt for maximum clarity to stay as close to the document as possible at the expense of distortion. It will be noted that the background color changes from time to time. This is due to the automatic color balance of the camera inexplicably changing based on subtle variations. In hindsight it should have been on a manual setting for photography under florescent lighting.

The cartography reading rooms where the engineering drawings are produced for viewing does have a small room with a camera stand. Were pictures desired that would allow quality printed reproductions, then the use of this would be recommended to permit the use of a longer focal distance, which would reduce the amount of lens distortion. It would entail a considerable commitment of time, as there is insufficient space in the room to spread out the documents. Quite a bit of carrying material to and fro would be required. Digital scans would obviously be the ideal form of reproduction, and accurately capture a scale image.

The wood apparent at the edge of most views is there to (not always successfully) hold the document flat. Many of the standard Liberty drawing were stored tightly rolled. And those that were flat were once stored rolled, and even after all these years flat storage wanted to revert to being rolled-up upon release!

The photos are organized as they are stored and retrieved (pull request) at the archives. Individual file names are the original drawing number with modifications as noted further below.

Bureau of Aeronautics (Record Group 72) Record Identification: BuAer #37 BuAer #929-A BuAer #929-B BuAer #1792 BuAer #2878, Box 1 BuAer #2878, Box 2 Engine Volumes 37 Engine Volumes 45

Brief comments on the drawings-

BuAer #37. Single ink tracing, dated August 24th, 1917. From U.S. Navy Department, Bureau of Construction and Repair. Four view general layout of an (early) preliminary 330hp engine (3" to one foot scale). The drawing was too long to get a useful overall photograph, so there are eight pictures suffix a through h, creating a mosaic.

BuAer #929-A. Single rolled drawing blue-line copy 1/4 scale of side elevation (traced January 18, 1918). From the Aviation Section, U.S. Army Signal Corps. Also shows a partial plan view of the front mounting points of the crankcase. Overall view and three mosaic pictures suffix a through e.

BuAer #929-B. Single rolled drawing blue-line copy (1/4 scale) Single overall view of rear elevation. Traced January 5, 1918. From the Aviation Section, U.S. Army Signal Corps.

BuAer #1792. Single rolled drawing, full size ink tracing of carburetor (fuel) strainer, assembly and details. Overall view and seventeen mosaic pictures suffix a through r. Dated June 13, 1922. From the U.S. Navy Department, Bureau of Aeronautics.

BuAer #2878, Box 1. Box of eighty-eight larger component and assembly drawings in rolled storage (327 images). Original dates from January 21, 1918, with revision dated July 12, 1921, Linen backed paper copies, believed to be Van Dyke process (white lines on brow background.) Overall view followed by detail views where appropriate with alpha suffix. Part numbering matches that given in the Signal Corps maintenance, service, and overhaul manual. In as much as the parts which existed at the time of publication. Drawings for the gun-interrupted drives and gasoline pump are also present, but do not appear until a later edition of the service manual. Going by drawing dates they must have only just missed inclusion in the first edition of the Corps manual. Conspicuous by their absence were the drawings for the upper and lower crankcase halves. Pity, as these would have been the largest and most complex of the drawings. Probably they were spirited away decades ago as a trophy.

BuAer #2878, Box 2. Box of five hundred twenty-eight smaller component and assembly drawings in flat storage (738 images). Continuation of above. Drawing sizes are 30x20", 20x15" and 15x10".

Engine Volumes 37 (38 images). A large format book by the "War Department, Airplane Engineering Department, Signal Corps, U.S. Army [which existed from May to August 1918]. Book is labeled "Confidential". Gives 1/4 scale elevation and section views of a pre-production engine (shows early scupper oiling system.) Six pages with tracing paper overlays inked in red showing oil distribution. Unfortunately the book is severely crumpled at the binding, preventing the pages from lying flat and distortion free. Overall views of pages with and without overlay, and various detail views.

Engine Volumes 45, Inverted Liberty V12, Naval Aircraft Factory, Philadelphia Naval Yard, circa 1926. 130 blue print drawings and 75 pages of parts lists (assemblies, components, alpha and numerical order detailing new, modified, and standard components and assemblies to convert a standard Liberty to inverted. Larger drawings folded up into a bound large format book and the paper is in a brittle state preventing good flat copies from being obtained. Also the blue prints are not of as high a contrast as the other drawings above. The larger drawings were too large to get an overview (one drawing was eight feet long!) so mosaics were taken. There are one series of general half-scale elevations and sections in four sheets, and these are numbered 63692-1, 63692-2, 63692-3, and 63692-4 with alpha suffix detail mosaics. These are not all inclusive mosaics, as the inverted Liberty was slightly outside my interests. At a minimum one image of the title block was taken to document what existed. This, or the overall view (if feasible), is given the primary drawing number with detail mosaics following. Detail views were based on views which I thought might assist in reverse engineering the standard upright Liberty V12, or were details that just caught my fancy. Some overall pictures of the bound book are also included.

Also enquired after, were any engineering drawings for the four, six, and eight cylinder variants of the Liberty. For example an eight cylinder crank case drawing would shed light on the details of the missing V12 upper and lower crankcase drawings, and one would just need to extrapolate a few extra cylinders. However that above was the extent of the drawings they had. Not searched at this time were the still and motion image departments, or the text base repositories of the National Archives.

Enjoy!

Douglas Kephart Glen Mills, PA 19342-1206 USA

05 May 2008"