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Archives at The Museum of Flight

Series II. Lear Avia Inc., 1884-1946, 1957, 1975, 1998, undated

Series II: Lear Avia Inc. is the second largest series of the collection. It documents the research, development, and manufacture of Lear Avia’s key World War II-era products, notably clutches, screw jacks, motors, and aircraft navigation and radio equipment and parts. In addition, there is documentation of other products which reflect the company’s post-war considerations for manufacture and production. These are not just limited to the field of aeronautics but include such products as home video cameras, dishwashing machines, dry shavers, and yacht controls. The company also sought to develop a patent program during this time which is well documented here, as evidenced by the large patent subseries, which includes many patent applications. The bulk of the series focuses on the company's activities from late 1939 to late 1944, although dates range from 1884 to 1998. There is overlap in some materials within the series for both the predecessor company, Lear Developments (1931-1939) and the later form of the company, Lear, Inc. (1944-1962), due to company restructures as well as patent and production timelines.

The series is broken down into eight subseries: administrative records, correspondence, financial records, legal records, photographs, publicity materials, research materials, and technical files. Some series are further subdivided for clarity and are detailed below. Materials are generally, but not always, arranged by date, with undated items at the end of each series. When able, circa dates have been provided.

Many folders and documents include original identification numbers, such as "L-D-12" or "P-1100". No legend has been located to fully explain what each of these means, but they have been retained as original context and some are defined within the materials, such as P-# (project number). For others, the Processing Archivist made judgment calls based on context. For example, “L-D” numbers seem to focus on disclosures (notice of invention) or possibly “development,” which fit into the patent series. “L-I” numbers generally coincide with “infringement” or possibly “investigation,” thus were placed in legal cases. “L-P” match with documents that focus on Publicity and were sorted accordingly. In some cases, there are exceptions such as an “L-P” marked clipping that was not Lear-specific and was placed in the Research files instead of Publicity.

The folders marked as “[RM files]” by the Processing Archivist are the former office files of Richard Marsen, patent attorney and engineer for Lear Developments and Lear Avia Inc.

Subseries A: Administrative records holds a small amount of material which includes meeting minutes, correspondence about office logistics, and a 1943 organizational chart. Two spiral-bound notebooks shed light on Richard Marsen’s daily schedule from May 1939 through November 1941. Entries typically include date, time, and very brief notes. For example, “Mon., July 3, ½ day (aft) – Lear re: ADF-6” and “Sat., Sept. 16 AM, Lear, gen, mail, etc.”

Subseries B: Correspondence is primarily general in nature, or covering multiple topics that do not easily fit into one specific subseries. Most of the correspondence in this section is between various Lear Avia offices and personnel around a variety of ongoing projects, patents, employee matters, and day to day business, although a small amount is more personal in nature. There is also a large quantity of Richard Marsen’s outgoing correspondence from 1940-1944, which touches on a wide array of topics, including patents, financial matters, and ongoing Lear Avia projects. Correspondence that relates to a specific theme, such as publicity or a patent, is found within those respective subseries. For example, a letter about an invention’s patentability would be found in the Patent documentation subseries.

Subseries C: Financial records includes invoices, statements, receipts, and correspondence relating to license agreements, contracts, and royalties (primarily with AT&T and RCA), patent filing fees, and office expenses.

Subseries D: Legal records has been further divided into three subseries. The first, Documents of incorporation, includes official copies of name change notices as the company changed from Lear Developments to Lear Avia Inc. in December 1939, and also as it transitioned from Lear Avia Inc. to Lear, Incorporated in October 1944. Related correspondence is also present. The next subseries, Legal cases, includes materials related to infringement and interference lawsuits, including legal briefs, statements and related supporting documentation, such as diagrams, patent copies, and correspondence. The bulk of material in the series relates to the 1941-1945 Joseph Dugan v. Lear Avia suit, which alleged that certain Lear Avia products, namely the Learmatic Navigator, ADF-6, and the dual direction finder, were infringing on Dugan’s patent (no. 1,959,264). The case was dismissed in Lear Avia’s favor.

Lastly, Patent documents, by far the largest subseries, primarily highlights patent applications of WPL and other Lear Avia employees, including but not limited to Henry Bruderlin, T.S. Harris, and John Wehner. Generally, it is easy to note when WPL was directly involved with a design as he often signed sketches with his initials and patent applications included his name when he was sole or co-inventor. However, it is not always obvious if an inventor is a Lear Avia employee or an outside contractor whose design was licensed for manufacture by Lear Avia. The Processing Archivist assumed a direct connection as a Lear Avia employee, unless it was clear the inventor was not related to the company. In those cases, patent applications have been placed in the Research files subseries. Note that a "patent application" may include the following documents: application, drafts, oaths, amendments, appeals, affidavits, diagrams, oversize technical diagrams and blueprints, sketches, correspondence, photographs, copies of related or predecessor patents, notes, research materials, and filing receipts. Not every application includes all of these items. Abbreviations used by Richard Marsen include "Aus" for Australia, "Can" for Canadian, and “Germ" for German.

Patents of note include the application for the LearMatic gyromatic navigator, invented by WPL and one of Lear Avia’s most successful and well-known products. The file includes documents on related parts and/or improvements. Other notable patents relate to the automatic direction finder (ADF), screw jacks, motor construction, and the “Fastop” clutch; all of which were key products and processes of Lear Avia during World War II. Also included are assorted applications around items that Lear Avia considered for post-war production.

The patent documents subseries also includes an undated patent filing chart; notes on progress of patents; patent search requests and related correspondence with fellow patent attorney, R. Clyde Cruitt; trademark documentation; and diagrams and sketches. Many of the sketches and diagrams lack contextual information, such as titles or labels to indicate what the object actually is, artist signatures or other indications of who drew them, or detailed date information.

Subseries E: Photographs contains 85 black-and-white photographic prints, primarily 8x10”. This series is arranged alphabetically by topic, not chronologically. Five photographs depict partial views of aircraft, likely used for testing Lear Avia products, including a Fairchild 24 with the “first swept antenna manual loop.” Additionally, 49 photographs feature Lear Avia employees and workspaces. There are two black-and-white photographs of the first annual Lear Avia, Inc., Grand Rapids Branch employee picnic on August 28, 1943. Identified staff include WPL; Dick Mock; Arlie Ryberg, chief mechanical engineer; and R.L. Drake, also chief mechanical engineer. Locations include various rooms in the Vandalia/Dayton, Ohio facility, such as the stock room, assembly areas, noise room, machine shop, and the blueprint and mimeograph room. Also included are 11 images featuring cockpit instrument panels with Lear Avia products installed. Lastly, 22 prints feature various Lear Avia products, including the AMT-1 transmitter, an automatic direction finder (ADF), a UT-4 transmitter, and a portable 2-band battery operated receiver.

Some images do have identifying information, such as date, location, and names, but most do not. While the bulk of photographs are in this subseries, note that some photographs and negatives are present in other series, usually in context with a press release or product information, and are noted when included in other folders.

Subseries F: Publicity materials includes many company press releases, some with publicity photographs; advertising materials such as product announcements and brochures; logos and decals; and clippings and articles about the company, its products, and employees, including the appointment of Henry S. Roberts as head of Public Relations and Dickey Chapelle, who later gained fame as a war photojournalist, as press liaison.

Subseries G: Research materials has a substantial amount of collected items that were not created by Lear Avia but were likely used by Lear Avia staff to support manufacture and/or design of company products. Due to this, there is some overlap with materials found in the Patent documents and Technical Files subseries. Types of material include correspondence, diagrams, oversize technical drawings, sketches, and brochures from other companies, such as Sperry Gyroscope and Radio Frequency Laboratories. Also included are patent copies ranging from 1884 to 1945 of similar, related, or preceding ideas and products; technical data such as reports and specifications; and instruction manuals.

Following the general research files, there is a subseries for Patent research files. These have been arranged alphabetically by name of part/product. The Lear Avia in-house numbering scheme (i.e. “patent research files L-10”) has been retained in the folder titles.

Finally, Subseries H: Technical files subseries is quite sizeable and relates to products designed and manufactured by Lear Avia. Similar to the Research materials subseries, there is overlap with Patent documents, particularly in the form of patent copies. The Processing Aarchivist placed some folders that included patent copies within Technical Files instead of Patent documents because of contextual clues, including the lack of an “L-D” number (defined as specifically being relevant to a patent application or patented development). Some files maintained in this series relate to products that were still under consideration for production or, on the other hand, were discontinued or rejected for follow-up. These are often noted with an “L-U” or “L-X” identification number.

Also included in the technical files are correspondence, sketches, oversize technical illustrations, diagrams, notes, parts lists, graphs and charts, photographs of parts and products, and instruction manuals. Some materials relate specifically to the Engineering department, such as procedure manuals, organizational charts, log sheets, and project update reports.

The office files of Charles Littell, an engineer for Lear Avia, are a noteworthy subset of materials. Grouped in 11 legal size folders and two oversize folders, Littell’s files include material similar to the rest of the subseries but also include employee documents such as wage memos, company event announcements, newsletter drafts, and union booklets. The subseries also includes technical diagrams produced by Littell. The Littell materials have not been reorganized in any way so as to not break original context, as they did arrive with some original order. One folder consists only of photographic material, although there are a small number of photographs and negatives in several of Littell's folders. Another folder relates to "transmitter test," and the rest are a mix of materials, ranging from 1940-1945, with a small batch of correspondence from 1957.


  • 1884-1946, 1957, 1975, 1998, undated

Language of the Materials

Most materials are in English, but some materials are in other languages, including Bengali, French, German, Italian, Japanese, Romanian, and Spanish. When non-English language materials are present, it is noted on the individual folder.

Conditions Governing Access

A computer hard drive is not accessible, pending digital preservation procedures. The rest of the collection is open for research and is accessible in the Dahlberg Research Center by appointment. For more information contact us.


From the Collection: 285 Cubic Feet (190 legal size full-width document boxes (15 ½” x 10 ¼” x 5”), 2 legal size half-width document boxes (15 ½” x 10 ¼” x 2 ½”), 6 record cartons, 2 card boxes (12” x 4 ½” x 5 ½”), 9 oversize boxes (19” x 4” x 15”), 7 oversize boxes (20 ½” x 3" x 16 ½”), 7 oversize boxes (24 ½”x 3” x 20 ½”), 2 oversize boxes (40” x 2 ½” x 32”), 9 oversize rolled storage boxes (40” x 9” x 9”), 21 oversize folders (30” x 40”), 50 oversize folders (35 ¾” x 47 ¾”), 1 oversize folder (24” x 75”), 38 bagged rolled storage (60” x 5” x 5”), 1 Quadruplex tape (15 ¼” x 15 ½” x 3"))

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