Jack B. Baumann Aircraft Designations


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Okay, I admit to having thoroughly over-researched this! There's a lot of confusion and mistruths out there about Jack Baumann and his aircraft designs. I've done my best to untangle things but there are plenty of gaps in Baumann's career that need to be filled. Hopefully, this will be of interest to some. I have broken it down into section. If you are just here for the (admittedly brief) designation sequences, you may want to skip down ...

Jack B. Baumann Aircraft Designs

Jack Boyer Baumann (1914-1996) was born in Knoxville and went to the University of Tennessee to study engineering. I am sketchy on his earliest designs but I believe that he had a hand in both the Lacy-Baumann glider (NC11539) and the Velie radial-powered Baumann-Minsky B (NC18151) ... since both have connections with Knoxville and the latter was owned by a "J Baumann". (Some details on these designs would be appreciated if any members know more.)

What's in a Name? "... Jack is a notorious domesticity for John!"

Jack Baumann's name causes some confusion. "Jack B. Baumann" is the name which appears on the one aviation patent of his that I've found. Flying Magazine (June 1950, pg. 56) names him as "John B. Baumann" but I've found no evidence to suggest that Jack was a short form for 'John' in Baumann's case.

(Just to cover other possible confusions, the now-defunct Baumann Floats, LLC was founded by Bud Baumann - no relationship to Jack. Likewise, Jack Baumann Field in Rio Vista, CA, has no connection to J.B. Baumann. In 1995, Rio Vista Municipal Airport was named Jack Baumann Field to honour a local businessman and avid pilot, John Henry Baumann. J.H. Baumann had been a USAAF bomber pilot during WW2 and Baumann Road neighbouring the airport was also named after him.)

On Aerofiles, the late, great K.O. Eckland said of the biplane BT-120 Aerobat that Jack Baumann "resurrected the design as the post-war Baumann Brigadier". Not true, of course (just an inevitable artifact of maintaining a huge, complex website). Other confusions surround the fate of the third BT-120 airframe. As some sources claim, the aircraft was eventually assembled by amateurs from stored components found after WW2. Another story claims that the third BT-120 was completed as a wingless 'ice boat'. I favour the postwar construction from parts - parts of the third BT-120 airframe certainly was used for ice boat racing on frozen-over Green Bay ... but not until the Winter of 1995. [1]

There are also a number of widely-spread myths out there about Baumann's connections with the Piper Apache ... which I will address further on.

Baumann Aircraft Designations and Corporate Entities

While working at Taylor-Young Airplane Company ('Taylorcraft' in Alliance, OH) Jack Baumann designed a small cabin biplane for personal use. The B-65 two-seater cabin biplane flew in 1938. That airframe was re-engined as the B-90 before Baumann moved on to an enlarged design. To market his 4-seat B-100 cabin biplane, the Baumann Aircraft Corp. was founded in 1938 with Jack as President. This tiny firm oversaw the higher-powered B-120 cabin biplane and the early stages of its open-cockpit, tandem-seat trainer derivative - the BT-120.

As will already be obvious Jack Baumann's designs were designated "B" followed by the type's total engine horsepower. AFAIK, only nine Baumann 'B' designations were assigned - this includes two re-engined airframes (four if the B-290 and unbuilt B-360 are regarded as re-engined B-250 derivatives). Of course, if forum members are aware of other Baumann designs - 'B' designations or not - I would be thrilled to hear about them.

The sole exception within Jack Baumann's 'B' designation series was the BT-120 Aerobat. This was because the BT-120 had exactly the same horsepower as the preceding B-120 cabin aircraft. To skirt the problem, Baumann simply added 'T' for Trainer to his designation prefix. Construction of the BT-120 trainer began at Knoxville in the summer of 1940 - which would prove to be a busy year for Baumann.

In early 1940, civic officials from Menominee, MI contacted Baumann Aircraft Corp. They were offering incentives to move the firm to a new airport to be constructed in their county (the Menominee County Airport being a national defence project under the Michigan Works Project Administration.) In June 1940, Jack Baumann visited Menominee, accompanied by his young assistant (and first cousin), Billy F. Baumann. The county of Menominee was offering space and even to funding materials needed to begin BT-120 contruction. A deal was struck and Baumann began arrangements to move his operation from Tennessee to Michigan.

The BT-120 Aerobat was aimed at the Civilian Pilot Training Program (CPTP) started in 1938. However, the small size of the Baumann Aircraft Corp. argued against it getting any government contracts. As a result, the firm was reorganized along more professional lines. To increase the chances of a BT-120 sale, the Baumann Aircraft Corp. was superceded by the Mercury Aircraft Corp. [2] The role of President was taken over by businessman F.L. Bette, [3] Jack Baumann became Chief Engineer and shared the Vice presidency of the new company with its General Manager, R.D. 'Dick' Smith.

Jack Baumann and the Mercury Aircraft Corp.

With the new Mercury Aircraft Corp. established at Menominee, MI, the first BT-120 was test flown at Knoxville in late September 1940 ... although it did not receive its Type Certificate from the Civil Aeronautics Administration until August 1941. By then, the aircraft was in Menominee (having arrived in late February 1941 via Escanaba airport, 55 miles to the north). [4] On 11 March 1941, the local newspaper reported that the second BT-120 had been completed. [5] That sounds grander than it was - Mercury was building its airframes on the second floor of the Northern Hardware & Supply Co. building on Menominee's Main Street.

Parts for a third BT-120 airframe were finished in Menominee but these components were not assembled by Mercury Aircraft. [6] Alas, the CPTP was questioning whether is really required aerobatics training aircraft. The market for which the BT-120 had been created was disappearing. One of the three BT-120s was used for a short time to train CPTP pilots but no production order was forthcoming from the government. The writing was on the wall and Jack Baumann handed in his resignation. By late October, Mercury Aircraft had hired a new engineer [5] to replace Baumann but with no orders, funds quickly ran out. By November, Mercury was offering flying lessons to locals with the finished aircraft. It didn't help. By July 1942, Mercury Aircraft Corp. had closed (and the Menominee airport would not even be completed until late 1942 or early 1943).

Choosing Mercury as a company name may not have been very wise. A company with exactly the same name - Mercury Aircraft Corp - had failed in Fairfax, KS, back in 1932. There was still a Mercury Aircraft operating out of Hammondsport, NY. Originally, that name had been a trademark for the Aerial Service Corporation (formed in 1920 by former Curtiss personnel to support war-surplus JN-4 Jennys). [7] That firm's original designs now tend to be called 'Aerial Mercury' types to distinguish them from what came next. In early 1929, the firm rebranded itself as Mercury Aircraft Inc. to market its new Mercury Chic T-2 [8] and Mercury Kitten high-winged monoplanes. By the time Baumann adopted the Mercury name, the Hammondsport namesake was mainly a parts supplier to Curtiss. [9]

Of course, a poor choice of company names would have been a minor factor. Baumann's Mercury Aircraft Corp. represented a personnel expansion and moving operations 800 miles north. Menominee was a faltering lumber town and Mercury had to start night school courses to teach locals welding before they could even begin building BT-120 components. When the CPTP decided to drop its aerobatics trainer requirement, the game was over. Jack Baumann had seen it coming and taken a job with the Frankfort Sailplane Company in Joliet, Illinois under Stanley Corcoran. [10]

"Go West, young man, go West" - Jack B. Baumann in California

Jack Baumann didn't stay long with Frankfort Sailplane. Instead, he accepted a position with the Lockheed Aircraft Corporation - moving to Burbank, CA, in January 1942. At this stage of the war, Lockheed Burbank built P-38 Lightnings at its Plant B-1 and licensed Boeing B-17s at Plant A-1. However, J.B. Baumann then seems to disappear without a trace for the duration of the war. I am at a completeloss as to what Jack did at Lockheed during WW2. There seems to be no mention whatever of Jack until he leaves Lockheed to develop his new aviation concepts. The new company - the Baumann Aircraft Corporation - was formed after the war's end in 1945.

The exact company name is worth noting - Baumann Aircraft Corporation [11] There are plenty of references to a 'Baumann Aircraft Company' - including in reminiscences by Jack's cousin and test pilot, Billy Baumann. However, the B-290 sales brochure clearly lists the firm's name as the Baumann Aircraft Corporation of Pacoima, CA. Locations may have shifted around with Jack - NASM lists Burbank; Flight International says North Hollywood; while Aerofiles has Santa Barbara. By 1950, the location of the Baumann Aircraft Corporation was most definitely Pacoima.

Obviously, working at Lockheed was a revelation for Jack in terms of modern, stressed-skin aircraft construction techniques. Baumann's new design was the B-250 Brigadier light twin. The distinctive feature of the B-250 was its engine installation. Twin Continental C125 HO6 engines were mounted, facing backwards on the wings' leading edge. Extension shafts led to the trailing edge to drive 2-bladed, variable-pitch Sensenich pusher propellers. That drive system would form the basis for all further Baumann Aircraft Corporation designs.

The B-250 Brigadier pusher twin first flew in June 1947. With its shoulder-mounted wings and forward engine cowlings, the view was a bit restricted from the rear seats of this five-seater. However, cabin noise would have been reduced by placing the props well aft of the passenger seats. The prototype was hand-assembled from what sounds like mainly war-surplus materials. The B-250 Brigadier prototype (NX30025) first flew on 28 June 1947. The flight trials were successful but the aircraft was somewhat underpowered. Baumann's attention turned towards a high-powered derivative, the B-290 Brigadier.

The prototype B-250 was then sold to Piper Aircraft to act as a pattern for their planned derivative - the PA-21. That, however, is a story in itself and will be told in a later post. https://www.secretprojects.co.uk/threads/jack-b-baumann-aircraft-designations.32804/#post-372871

Selling the B-250 to Piper provided $25,000 towards building a higher-powered Brigadier. The prototype B-290 Brigadier (N90616) flew on 25 June 1952. The B-290 gained an added 40 hp from its Continental C145s but was otherwise identical to the B-290. This was the aircraft Jack Baumann had hoped for but, still, there was insufficient interest to raise financing for production. Worse, on January 8, 1953, the B-290 crashed while landing at Pacoima, CA. [12] The fuselage was heavily damaged while both pilot Ward C. Vettel and flight engineer Thomas Cox were injured in the crash.

Baumann had plans for two developed variants. The B-360 Deluxe Brigadier was to gain another increase in power - with twin 180 hp engines, as the designation number suggests. The B-480 Super Brigadier was to have more power still. But this was to be no re-engined B-290. The B-480 Super Brigadier was to have all-over larger dimensions. Neither development saw fruition. The badly-damaged B-290 Brigadier prototype was repaired to flightworthiness. And that may be the cause of some confusion ...

Some online sources claim that as many as three B-290 Brigadiers were built. Since none but N90616 (c/n 102) were registered, that seems extremely unlike. It may be that contemporary announcements of the proposed B-360 and B-480 caused readers to assume that prototypes had actually been built. Or perhaps the explanation is more mundane. The prototype B-290 appeared over the years in a number of paint schemes. In most photos, the registration - N90616 - can be clearly read but, perhaps, the differing schemes have mislead people?

It could be argued very loosely that three Brigadier airframes did exist - the B-250 (c/n 1, NX30025/N30025), the B-290 (c/n 102, N90616), and components completed as the Custer CCW-5 'Channel-Wing' prototype. Some sources claim the CCW-5 to have been a converted B-290. Others say that the CCW-5 was built under contract by the Baumann Aircraft Corporation which used components of the unfinished third Brigadier prototype. I guess your conclusion will depend upon how you define 'conversion'. Either way, the CCW-5 used the Brigadier fuselage largely unchanged as was the tail. Its difficult to tell how much (if any) of the Brigadier's wing went into the Custer prototype. [13]

As for Jack Baumann, he returned to Lockheed after shuttering Baumann Aircraft Corporation. He pops back up in 1966 when his name is associated with the development of ultra-quiet, low-speed surveillance aircraft for the US Army - a story I will cover in more detail in a later post. By 1967, Jack was living in Los Alto, CA. In 1969, he was sent to Schweizer Aircraft in NY to help construct the prototype YO-3A recce aircraft. Then Jack returns to corporate obscurity. In 1983, Jack B. Baumann retired from Lockheed. He died at 81 in February 1996.


[1] 'Mercury Number 3 BT-120 Airplane Used As Ice Boat On Bay, Marinette-Menominee Eagle-Herald, 30 December 1995, page A1.

[2] The local newspaper lists the firm's name as Mercury Aircraft Co. Inc. - eg: 'Mercury Aircraft Co. Inc. Will Locate Its Factory In Menominee', Marinette Eagle-Star, 15 June 1940, page 1.

[3] Although generally named as F.L. Bette, the President of Mercury Aircraft is listed as 'F.L. Betts' in the Aircraft Year Book of 1941. I'm unsure which is correct (although Betts is the more common surname).

[4] This suggests that insufficient progress had been made on the Menominee airfield. The BT-120 was routed through Escanaba, the first airfield on Michigan's Upper Peninsula. In 1936, the City of Escanaba began expanded its airport (under the Work Projects Administration program). Perhaps Baumann was regetting his choice of locations?

[5] Marinette Eagle-Star, Mercury Aircraft BT-120 First Plane Made In Menominee, 11 March 1941, page 3.

[6] Marinette Eagle-Star, Menominee Mercury Aircraft Co. Hires New Engineer, 28 October 1941, page 12.

[7] Oddly, the extant Mercury Aircraft Inc. incorrectly lists 1921 as its start date. Adding to the confusion is now-Mercury Corporation's use of the name 'Mercury Aircraft Corporation' - despite not seeming to make any aircraft parts today.

[8] The Mercury Chic T-2 parasol trainer was originally powered by the same 65 hp Velie radial as the Baumann B-65.

[9] There were other aviation suppliers with related names - the Mercury Manufacturing Co. of Chicago, Mercury Chemical Co. of Detroit, etc. So rebranding as Mercury Aircraft hardly set Baumann apart from the pack. I suspect that, with war on the horizon, this hasty rebranding was more about Baumann's (or his partners') concern over having a German-sounding name than a well thought through marketing decision.

[10] This firm had been formed at Frankfort, MI, in 1939 but Stan Corcoran was convinced to move to new facilities at Joliet in 1940 to build TG-1A training gliders for the Air Corps.

[11] When listed correctly, the form always seemed to be 'Baumann Aircraft Corporation'. That may have been an attempt to distinguish the Californian firm from the earlier, Knoxville-based Baumann Aircraft Corp. If so, the attempt failed. Almost invariably, the name was clipped by journalists (and others) to 'Baumann Aircraft Corp.'

[12] Crash photo - University of Southern California Digital Library, Los Angeles Examiner Photographs Collection, 1920-1961, Plane crash (Pacoima), 1953.
-- http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll44/id/72548/show/72544/rec/340

[13] A second, 'production-model' CCW-5 was completed in 1964 - looking much the same but featuring a raised horizontal tail. However, by that date, the Baumann Aircraft Corporation was long gone. The Baumann-built CCW-5 (N6257C) was written off in Sept 1967 at Gander, NL. When Willard Custer cancelled N6257C's FAA registration in Sept 1970, he reporting it as "destroyed".
-- http://www.custerchannelwing.net/images/CCW5_1.jpg


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There are persistant reports out there that Jack Baumann's B-250 Brigadier light twin had a strong, direct influence on the design of the Piper PA-23 Apache. Not really. Let's set the record straight ...

In July 1949, the Piper Aircraft Corporation bought the B-250 Brigadier prototype, drawings, and rights to the design. Piper wanted a merger with Baumann Aircraft Corporation (with combined operations at Piper's facility at Lock Haven, PA). It was planned that the Brigadier would be re-engined as a tractor-engined light twin. This concept received a Piper PA-21 designation on 30 August 1949. (It seems that the PA-21 designation may also have been applied later to the sole B-250 for internal use.)

Jack Baumann was either determined to run his own show or he was just stuck on the pusher configuration. Either way, Baumann rejected the proposed merger. Piper then suggested a compromise. Under this agreement, there would be no corporate merger. Piper would continue work on its tractor PA-21 concept. Baumann would be free to develop his Brigadier series ... so long as they were always pushers (tractor-engined Baumann Brigadiers would be prohibited under this agreement). Jack Baumann agreed to these conditions.

Under the agreement, the Piper Aircraft Corporation paid $25,000 (roughly $270,000 is 2019 US dollars) for the B-250 prototype and rights. According to Aviation Week (28 November 1949), Piper planned "to fly its new tractor version of the Baumann Brigadier in January [1950] at Lock Haven, PA." But Piper was planning more than a "tractor version". The PA-21 was to be powered by two 190 hp Lycoming tractor engines for a cruising speed of 165 mph (versus 149 mph cruise for the B-250). But Piper also announced airframe modifications - including "raising the wing, lengthening the tail, enlarging luggage compartment". Gross weight would be 4,200 lbs (1,900 kg) rather than the 3,500 lbs (1588 kg) for the B-250.

According to that Aviation Week article, the B-250 "was sought after Piper structures engineers decided it well adapted to simple fabrication using flat sheet without much press work and with no compound curves. [...] As a result of this planning Piper has set a maximum price of $20,000 on its new twin-engine plane." That sounded great but, even with tractor engines, the shoulder-winged Brigadier was a fairly complex design. Projected production costs for the PA-21 showed that Piper couldn't match its promises, leading to the cancelling of the PA-21 programn. However, in meantime, the Stinson Division of Convair had been bought by the Piper Aircraft Corporation.

The Stinson buy-out gave Piper access to another light twin design - the Stinson Twin Stinson. Introduced in 1952, the Twin Stinson was a low-winged, twin-tailled 4-seater with a fabric-covered fuselage. It was powered by two 135 hp Lycoming O-290-D-2s ... so had slightly more power than the B-250. [2] It had already occurred to Piper engineers that combining features from the planned PA-21 and the Twin Stinson would give them everything they wanted in a light twin. Accordingly a new semi-monocoque fuselage was designed. This was mated to the Twin Stinson low wing, nacelles, and undercarriage to produce the PA-23 Apache.

The story goes that this new fuselage was based on B-250/PA-21. The problem is that the Baumann fuselage looks nothing like the first PA-23 Apache. Indeed, it just looks like a metal-skinned Twin Stinson. So, most likely, Baumann construction techniques were applied to the PA-23 fuselage but nothing more. Some sources even claim a Baumann influence in the PA-23's single fin and rudder. Actually, the PA-23 tailplane came directly from Piper's unsuccessful single-engined PA-6 of 1944. A more squared-off, Brigidier-ish tail wouldn't appear until the PA-23-250 Aztec of 1959.

So, the Baumann B-250 Brigadier (and what Piper learned with its PA-21) had some influence on the design of the PA-23 Apache. But that influence was modest. Obviously, Piper was quite capable of designing its own airframe. The firm tried to cut a corner in buying the rights to the B-250. Once the marketing department and bean-counters had gone over the numbers, the Brigadier proved to be a false start. The PA-21 programs was dumped for what turned out to be a great little earner. Piper donated the sole Baumann B-250 Brigadier to a local technical school and the PA-21 program was quickly forgotten.


[1] Aviation Week, New Two-engine Lightplane Market Ahead: With models already developed, four firms are readying all-out 1950 sales campaigns, Alexander McSurely, November 28, 1949, pp 12-14 https://archive.org/stream/Aviation_Week_1949-11-28/Aviation_Week_1949-11-28_djvu.txt

[2] When the PA-23 Apache prototype (N23P) appeared in July 1953, power was provided by 150 hp Lycoming 0-320-A HO4s.


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Jack Baumann Back at Lockheed ... On the Quiet

At some point Jack Baumann returned to Lockheed but I don't know when ... or what he was doing there. When Jack finally breaks cover, he was working as a design engineer at the Lockheed Missiles and Space Company division at Sunnyvale, CA. By the mid-'60s, Jack was in an LMSC group under Andrew D. Galbraith (later joined by Dr. Sherman M. Seltzer). [1] Jack emerged out from corporate obscurity when he, together with 'Don' Galbraith, conceived of an ultra-quiet surveillance aircraft for potential use by US forces in SE Asia.

By 1965, the US Army had a requirement - issued through the Defense Advanced Research Projects Agency (DARPA) - for a nocturnal reconnaissance platform which would be acoustically undetectable by people on the ground when the aircraft was flying at 1,200 feet above ground level. [2] The design challenge was to minimize typical noise generated by an airplane's propulsion system and airflow over general airframe excrescences. The LMSC design team which included Jack Baumann chose to base their 'Quiet Thruster' (QT-1) surveillance aircraft upon a fabric-covered sailplane - the proven, single-seat Schweizer SGS 1-26A kit glider. [3]

'Cuty' - Jack Baumann and the Lockheed QT-1 'Quiet Thruster'

The goal of the 1966 QT-1 design was to turn Schweizer's medium-performance sailplane into a powered aircraft capable of performing low-speed, low-altitude, surveillance missions without being detected from the ground. To that end, the LMSC team would mount a converted Volkswagen air-cooled HO4 car engine on the Schweizer glider. To lower noise, a reduction system would be used for a slow-turning propeller. The exact layout arrangement was revealed in a patent application - US Patent Des. 212,719.

The patent for a High aspect ratio aircraft was filed on 09 Oct 1967 by Galbraith and Baumann (as assignors to Lockheed Aircraft) with the patent was assigned on 12 Nov 1968. As indicated, this was purely a design patent. [4] However, the drawings give a good sense of the planned layout for the QT-1 (see images attached). The 55 hp VW engine was mounted to the top of the welded steel-tube fuselage frame aft of the wing. Directly above the wing was a rubber belt reduction system driving a long shaft. That slow-turning extension shaft passed over the cockpit canopy to a vertical brace in the extreme nose. Directly forward of that shaft brace was the raised, 4-bladed propeller.

By the time the patent had been filed, DARPA had already rejected the specifics of the QT-1 design. DARPA had begun to increase the number of sensors required for the new quiet surveillance platform. Worse, a second crewman was stipulated to aim these sensors. With size and weight growing, a more powerful engine would be required. That was something of a moot point. In place of the VW automotive conversion, DARPA was stipulating a powerplant which met Federal Aviation Regulations type certification requirements for aircraft engines. That would lead to the QT-2 developed under Stanley A. Hall. [5] Although the QT-2 followed the exact layout of the unbuilt QT-1, AFAIK, Baumann was not directly involved.

'Yo-Yos' - Jack Baumann and the Lockheed YO-3A 'Quiet Star'

As a follow-on to the QT-2 program, Jack Baumann joined Ernie Schweizer at Elmira, NY (home of the Schweizer Aircraft Company) to reconfigure a Schweizer SGS 2-32 sailplane as a recce platform. [6] Whereas the QT-2 was a 'least-mod' SGS 2-32 adapted for quiet powered flight, the new aircraft would be quite different. The SGS 2-32 wings were given thicker skins and some portions were sealed to hold fuel. The wings were also reinforced to accept inward-retracting main undercarriage legs devised using Cessna 182 components (the sailplane's monowheel having been dropped in favour of a tail-dragger landing gear arrangement). Most notably, the wing would now be low-set on a nearly unrecognizable semi-monocoque aluminum fuselage.

The biggest change was in abandoning Baumann's original, QT-1 type powerplant arrangement in favour of a more conventional nose-mounted engine position. The belt propeller speed reduction system was retained but now set directly between a 210 hp Continental IO-360D HO6 engine and its propeller. Acting as a reduction gear, those enclosed V-belts still raised the propeller thrust line (just not as high as on the QT-2). [7] Initially, the propeller was a fixed-pitch (ground-adjustable) six-bladed unit as one the QT-2. That would later be switched to a three-blader made by Ole Fahlin - constant-speed, variable pitch with very broad blades (found to be just as quiet at low rpm but providing better top speed performance).

Besides slow-turning propellers, the aircraft would feature more extensive muffling. The cowling itself was sound-insulated. Crossover pipes fed all exhaust gases to starboard and out to an acoustical fairing. From the rear of the cockpit to the tailplane, gases passed through a long, dissipating and resonating muffler. Another change was the cockpit covering. With no overhead extension shaft, the canopy could be much enlarged. This oversized, one-piece canopy was hinged at the rear in an attempt to address QT-2 crews' concerns about bailing out. The pilot sat in the rear seat with a dedicated 'technical observer' up front to operate the sensors.

The new prototype, known as 'Quiet Star', became a company test bed but 10 aircraft were delivered to the US Army as YO-3As. Nine of these YO-3As would see service in Vietnam. In-theatre, the aircraft were found to be underpowered but with an impressive sensor. The YO-3As operated in hunter-killer teams using 'starlight' night vision to 'light up' targets in the dark for armed aircraft. The main sensor was a Xerox Night Vision Aerial Periscope (NVAP). The bulk of this NVAP was in the forward cockpit with only its scanner head protruding from the YO-3A's belly. Looking through the NVAP viewer, the 'TO' could rotate its scanner head 360°. An associated Infrared Illuminator (IRI), mounted under the rear fuselage) would then provide covert target acquisition for NV goggle-equipped 'killers'.

After the 'Cuty'/'Yo-Yo' saga, Jack Baumann drops back into corporate obscurity. I have no idea what he was doing between 1969 and 1983 when Jack retired from Lockheed.

[1] In one anonymous recounting, experienced engineer Don Galbraith is described as coming down from "sales and marketing" while Jack Baumann was said to be in the drawing office. Not so, but there is an interesting bit: "After reviewing what had gone before in the way of lowering noise in piston-engined aircraft, Jack found that N.A.C.A. [...] had done some work on this concept."

Some online sources equate the QT-1 with the X-26B and claiming that prototype construction was begun based in 1966. Obviously, here, the original concept (and its start date) have been conflated with the QT-2 and QT-2PC/X-26B.

[2] The US Navy was working on a similar concept for a quiet surveillance aircraft, the X-26. This would eventually be satisfied by the USN version of the QT-2 - the X-26B - based on the two-seat Schweizer SGS 2-32 sailplane.
-- https://www.globalsecurity.org/military/systems/aircraft/images/x-26b-pic2.jpg

[3] The Schweizer SGS 1-26A featured a welded steel-tube fuselage and tail structures mated to aluminum-framed wings. The entired structure was then covered in doped aircraft fabric to create a very smooth exterior. From a development point of view, the SGS 1-26A had the advantage of being a certified aircraft (whereas the 1-26 had been for amateur builds).
-- http://www.126association.org/RestorationImages/026/New Fuselage Paint.jpg
-- http://www.126association.org/RestorationImages/026/WingsOn 02.jpg

[4] From the terse patent: "The characteristic features of our design as disclosed reside in the parts shown by means of full lines in the drawings: We claim: The ornamental design for a high aspect ratio aircraft, as shown and described." (According to the patent application, Jack Baumann then resided in Los Alto, CA.)
-- Patent Des. 212,719: https://patents.google.com/patent/USD212719S/en

[5] Hall managed the QT-2 program (code-named 'White World') from a Lockheed Aircraft Service hanger at the then-San Jose Municipal Airport (SJC). The small QT-2 series would be powered by a range of aero-engines - from the 100 hp Continental O-200A to a 165 hp Wright Aeronautical RC2-60 Wankel-type rotary (derated from 200 hp with a rubber belt reduction system of 4:34-1 at 5,500 rpm; some sources say derated to 185 hp). Ironically, those Wright rotary powerplants were adapted car engines.
-- O-200A: https://live.staticflickr.com/4835/44130297710_9d46db158b_b.jpg
-- RC2-60: https://1000aircraftphotos.com/Contributions/Visschedijk/6898L.jpg

[6] Here, I've chosen to paraphrase rather than quote. The Quiet Aircraft Association (QAA) website reproduces pages from an anonymous manuscript on the Lockheed QT series. I'm not sure if this was an oral transcript but it consists mainly of run-on sentences with bizarre punctuation.

[7] On the YO-3A, the reduction ratio was 3.33:1 (versus 4:34-1 for the QT-2). The engine/enclosed V-belt arrangement is visible in this photo of NASA's YO-3A, N818NA:
-- https://www.itstactical.com/wp-content/uploads/2014/08/nasa-yo-3a-mp-2.jpg


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Aircraft Designation for Designs by Jack B. Baumann

Jack B. Baumann - Early Undesignated Aircraft

Lacy-Baumann glider - (??) no details
-- Listed as reg. NC11539, based at Knoxville, TN
-- http://www.aerofiles.com/regs-11.html
-- http://www.airhistory.org.uk/gy/reg_N41.html

Baumann-Minsky B (Velie) - (??) no details
-- Listed as reg. NC11539, based at Knoxville, TN
-- Registered to "J Baumann/Knoxville"
-- "(Velie)" presum. means a Velie M-5 engine?
-- http://www.aerofiles.com/regs-18.html
-- http://www.airhistory.org.uk/gy/reg_N54.html

Jack B. Baumann 'B' Series Aircraft Designations

Baumann B-65 - 1938 single-engined cabin biplane, x 1 (NX18151)
- B-65: 2-seat cabin biplane (for Jack Baumann's personal use)
- B-65: 1 x 65 hp Velie M-5 5-cyl. radial engine,* span (??) m
-- * An improved Detroit Aircraft Engine Corporation Aircat

Baumann B-90 - 193? Re-engining of Baumann B-65 prototype, x 1
- B-90: Improved 1938 B-65 (for Jack Baumann's personal use)
- B-90: 1 x 90 hp Lambert R-266 5-cyl radial,* span (??) m
-- * Lambert Engine and Machine Co took over Velie engines

Baumann B-100 - 1940 single-engined, 4-seat cabin biplane, x 1*
- B-100: Negative-stagger biplane with retrac. main undercarriage
-- * Reg. NC18160, aka 'B-100 Mercury', aka 'Mercury B-100'
- B-100: Full-span ailerons (lower wing), full-span flaps (upper)
- B-100: 4-seat cabin a/c with vague similarity to Beechcraft 17
- B-100: 1 x 100 hp Allied Monsoon 4-cyl.,** span (??) m
-- ** US-built version of Régnier 4EO (usually listed as 90 cv)
-- B-100 flew 03 Jan 1940, mixed constr., re-engined as B-120
-- http://www.aerofiles.com/mercury.html

Mercury B-120 - 1940 single-engined cabin biplane
- B-120: Re-engined B-100 prototype (found to be underpowered)
- B-120: 1 x 120 hp Ken-Royce 120-G 7-cyl radial,* span (??) m
-- * LeBlond 120-7 made by Rearwin's Ken-Royce Engines division
- B-120: (II) Re-eng. B-100 prototype (found to be underpowered)
-- aka B-100 Mercury, aka Baumann B-120
-- http://www.aerofiles.com/mercury.html

Mercury BT-120 Aerobat - Tandem 2-seat trainer for CPTP
- BT-120: Military trainer derivative of B-120 cabin biplane
- BT-120: 1 x 120 hp Ken-Royce 120-G 7-cyl radial, span (??) [1]
-- Narrowed B-120, upper wing flaps deleted, spatted main u/c
- BT-120 s/n 1: NX/NC20471, compl. Sept. 1940, B-100's wings/tail
-- BT-120 s/n 1 airframe cut up for Mercury employee training
- BT-120 s/n 2: Completed Oct. 1940, built from tooling & jigs
-- BT-120 s/n 2 (reg. NC33900) employed teaching CPTP students
- BT-120 s/n 3: Not completed during WW2, stories conflict*
-- * One version: completed as wingless aerosan iceboat
-- * 2nd version: completed after war from left over components
-- aka BT-120 Mercury, aka B-120 Mercury Aerobat
-- http://www.aerofiles.com/merc-bt120.jpg
-- http://www.antiqueairfield.com/images/mercury_bt120/mercury_bt120_frame_rrq.jpg
-- http://www.antiqueairfield.com/articles/show/90-gene-horsman-s-mercury-bt-120-restoration

Baumann B-250 Brigadier - 1947 5-seat light twin, x 1*
- B-250: Shoulder-wing monoplane, pusher props, trike u/c
- B-250: 2 x 125 hp Continental C125 HO6s,** span 12.50 m
-- Cabin a/c w/ fwd pairs of seats + rear row of 3 seats
-- * Prototype (c/n 1) NX30025, first flew 28 June 1947
-- ** Mounted on leading edge, ext. shafts drove pusher props
-- Hand-built B-250 prototype sold to Piper to act as PA-21
- Piper PA-21: Planned tractor-engined B-250 development
- PA-21: 2 x 190 hp Lycoming engines, raised wing, etc.
-- PA-21 desig. sometimes applied to Piper-owned B-250
-- http://www.airwar.ru/image/idop/aliner/brigadier/brigadier-5.jpg

Baumann B-290 Brigadier - 1952 5-seat light twin, x 1*
- B-290: Higher-powered development of B-250 Brigadier
- B-290: 2 x 145 hp Continental C145 HO6s, span 12.50 m
-- Prototype B-290 (N90616) first flew on 25 June 1952**
-- * There are doubtful claims of up to 3 x B-290 built
-- ** N90616 donated EAA Aviation Museum, poss. scrapped
-- B-290 options: Pax, utility, ambulance, "plush" exec.
-- Baumann describe utility B-290 as a "station wagon"
-- https://www.airhistory.net/photos/0127907.jpg
-- https://1000aircraftphotos.com/Contributions/WestinLarry/12741.htm

Baumann B-360 Deluxe Brigadier - (Project) 1952
- B-360: Higher-powered development of B-290 Brigadier
- B-360: 2 x 180 hp Lycoming (anticipating O-360?), span 12.50 m
-- B-360 Deluxe Brigadier not proceded with
-- Deluxe Brigadier name from Aero Supplies catalogue

Baumann B-480 Super Brigadier - (Project) 1952
- B-480: Enlarged, higher-powered B-290 development
- B-480: 2 x 240 hp Continental O-470 HO6s, span (??) m
-- B-480 Super Brigadier not proceded with
-- Super Brigadier name from Aero Supplies catalogue



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Michigan Aircraft Manufacturers
, Robert F. Pauley, Arcadia Publishing, Mount Pleasant, SC, 2009, pp 104-05 (with consistent misspelling as 'Bauman').

The Aircraft Year Book For 1941, Howard Mingos (Ed.), Aeronautical Chamber of Commerce of America, Inc., New York, 1941

Aviation Week, New Two-engine Lightplane Market Ahead: With models already developed, four firms are readying all-out 1950 sales campaigns, Alexander McSurely, November 28, 1949, pp 12-14
-- https://archive.org/stream/Aviation_Week_1949-11-28/Aviation_Week_1949-11-28_djvu.txt

Flying with the Schweizers: The Story of Schweizer Aircraft, William and Paul H. Schweizer, iUniverse, Bloomington, IN, 2019 (unpaginated)

Flying Magazine, Notes on Civil Flying, Jan 1950, page 6

Popular Science, Oct 2004, The Quiet Demise of the Cuties and the Yo-Yos, Stephan Wilkinson, pp 30-35

Army Aviation Magazine, Feb 2020, YO-3A: Historical Perspective, Mark Albertson.
-- http://armyaviationmagazine.com/index.php/history/not-so-current-2/1016-yo-3a

Marinette Eagle-Star newspaper - various editions (1940-194)

Marinette Eagle-Star/Herald-Leader newspaper - various editions (1995)

US Patent 212,719 (USD212719S)
-- https://patents.google.com/patent/USD212719S/en

Aerofiles - American airplanes: Ba - Bl
-- http://www.aerofiles.com/_ba.html

Aerofiles - American airplanes: Ma - Me
-- http://www.aerofiles.com/_ma.html

Aerofiles - The Mercury Story by Eugene Horsman, 1/6/02
-- http://www.aerofiles.com/mercury.html

Antique Airfield: Website of the Antique Airplane Association and the Airpower Museum
Gene Horsman's Mercury BT-120 Restoration, by member Gene Horsman, July 02, 2008
-- http://www.antiqueairfield.com/articles/show/90-gene-horsman-s-mercury-bt-120-restoration

AirHistory.net - The Aviation History Image Archive
-- https://www.airhistory.net/photo/14540/NX30025

Airport Data - Aircraft N33900 Data, 1940 Mercury BT-120 C/N 2
-- http://www.airport-data.com/aircraft/N33900.html

Airport Data - Aircraft N90616 Data (re: Billy F. Baumann on B-290)
-- http://www.airport-data.com/aircraft/N90616.html

Aviastar - Baumann Brigadier 250 - 1947
-- http://www.aviastar.org/air/usa/baumann_brigadier-250.php

NASA Cultural Resources (CRGIS): Fred Weick Archives Collection
Aeronautical Reminiscences of Fred E. Weick
, Rough draft transcripts from tapes, 1985 (but based upon recordings made beginning 20 Feb 1976).
-- https://crgis.ndc.nasa.gov/historic/Fred_Weick_Archives_Collection#Transcripts_from_.22Aeronautical_Reminiscences.22 - Tapes 14, 15, and 16

Plane & Pilot: Baumann "Brigadier" - 1947
-- https://www.planeandpilotmag.com/article/baumann-brigadier/#.XfbXiRt7m00

QAA - Development of the Quiet Aircraft - Schweizer (2-32) aka USN X-26/A - QT-2, QT-PC (Prize Crew,) QT-2PCII, USN X-26/B, Q-STAR - YO-3A
-- http://www.quietaircraft.com/history.html

QAA - Army-Lockheed YO-3A "Quiet Star": Great Stories
-- http://www.quietaircraft.com/greatstories.html

SuperCub.Org - What's a PA-21? (Archive)
-- https://www.supercub.org/forum/archive/index.php/t-34331.html

1000 Aircraft Photos - Dan Shumaker Collection No. 3394. Piper PA-23 (N1953A c/n 23-1)
-- https://1000aircraftphotos.com/Contributions/Shumaker/3394.htm

1000 Aircraft Photos - Larry Westin Collection No. 12741. Baumann B-290 Brigadier (N90616)
-- https://1000aircraftphotos.com/Contributions/WestinLarry/12741.htm

custerchannelwing.net - The Custer Channel Wing Aircraft - The Aircraft
-- http://www.custerchannelwing.net/TheAircraft_bs.html

Air & Space Magazine - Lunch With Willard: How a meeting 50 years ago solved a photographic mystery
-- https://www.airspacemag.com/history-of-flight/lunch-with-willard-16535800/

Sources of Interest (but not found)

Baumann, Jack: The Utilization of Light Aircraft in Medical Practice, October 24-28, 1958. Listed in Ross A. McFarland Collection in Aerospace Medicine and Human Factors Engineering - 2: Inventory of the Manuscripts compiled by Mary Ann Hoffman and Roberta A. Ritchie, Fordham Health Sciences Library, Wright State University School of Medicine, Dayton, OH, 1987. Although listed as a manuscript, the 4-days dating suggest this may have been the transcript of a conference presentation rather than a print publication.

The Story Of The Mercury BT-120 (no details) mentioned by Jack's assistant and first cousin, Billy F. Baumann while reminiscing on the Airport Data website. Note: Airport Data's Mercury Production List (http://www.airport-data.com/manuf/Mercury.html) conflates Jack's BT-120 with Hammondsport-based Mercury Aircraft.
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