Warbird Information Exchange

The collection of digitized wartime Aero Digest issues that AirCorps Library recently made available revealed a few more claims of aviation firsts. Now, of course, like the Bonanza firsts mentioned in a previous post, these have to be treated carefully as they may involve a bit of marketing bluster. However, if nothing else, they do provide a useful starting point for further research.

First up, is an advertisement by Goodyear titled Trail Blazing in the Skies:

(Source: “Trail Blazing in the Skies,” Aero Digest, September 1943, 18.)

Next is AiResearch, with an advertisement titled AiResearch "Firsts" in Oil Cooling:





(Source: “AiResearch ‘Firsts’ in Oil Cooling,” Aero Digest, October 1943, 132.)

The idea of quieting jet engines goes back years before the first noise requirements for American aircraft (of any type) were laid out Part 36 in 1969. For example, in 1956, United Aircraft Corporation was assigned a patent, 2,845,775, for "noise suppressors for jet engines". The first mentions in newspapers of the phrase "hush kit" seem to appear in 1972 in reference to their development for Rolls-Royce Speys and RB211s for Hawker Siddeley Trident IIIs used by British European Airways.[1] Around the same time, Boeing, Douglas, and Pratt & Whitney were working on noise reduction programs as well.[2][3][4] By the early 1980s, a company called Shannon Engineering, sponsored by Community Transport (aka Comtran), had developed a number of the devices for Boeing 707s.[5][6][7][8]

Another noise reducing technology, the sawtooth chevrons now seen on the trailing edge of aircraft like the Boeing 787, was developed by NASA. The first aircraft to fly with the design was a NASA Learjet 25 at Lorain, Ohio on 15 March 2001. It was followed shortly thereafter by a Honeywell Falcon 20.[9] The registration of the Learjet 25 is not mentioned in the report, but NASA apparently operated two of them: N566NA and N616NA.[10] (The answer may be found in the Special Mission Learjets chapter of a book titled The Learjet History.) The device itself was patented as "Chevron Exhaust Nozzle for a Gas Turbine Engine", 6,360,528 B1.

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The first experiments with zinc chromate were carried out between 1917 and 1924 by Dr. Henry A. Gardner, director of the Institute of Paint and Varnish Research Laboratories.[1][2] However, it took a number of years for the invention to be appreciated. Ford was apparently the first company to use it on production aircraft, with reports mentioning its use on the Ford 5-AT displayed at the 1931 National Aircraft Show.[3] (Advertisements promoting Ford's "progress" appeared a year later.[4]) Nearly simultaneously, the Towle Aircraft Company, founded by a former Stout/Ford employee, was using it on their TA-3 flying boat.[5] Unsurprisingly, the U.S. Navy showed an early interest in the technology due to the corrosive nature of salt water.[6] By 1935 a new formulation, P-27, had been developed in concert with Berry Brothers as part of their Berryloid brand.[7]

The origin of the propeller synchronizer (not the propeller synchrophaser mentioned in a previous post) is still unclear. However, a few more bits of evidence have trickled out. A bibliographic entry mentions an article in the August 1932 issue of Aviation that describes a "new instrument" that is "designed to provide visual means of obtaining propeller synchronization".[8] In addition, by August 1943 Curtiss-Wright had developed the technology to perform the function automatically.[9] Interestingly, somewhat related in concept (and in the realm of "aircraft instruments that didn't catch on" mentioned in another previous post) is the propeller pitch gauge used in the Bf 109. As a constant speed propeller was not introduced until the E-4 variant, the earlier versions had manually adjusted propeller pitch.[10]

Finned propeller spinners, or Rippenhaube, appear to have been first used on the Fw 189.[11] (Both it and the Ar 96 entered service in 1938, but the latter did not employ the Argus As 410 engine that had said finned spinners until later.) However, there are two potential inspirational predecessors that are important to note. One, a modified Fokker C.I that was mentioned in a previous post, used a highly swept "rotary propeller" that more or less is a scaled up version of the finned spinner. The other is was a pneumatic design by Ratier that employed a bladder filled with compressed air. The similarity with the finned spinner is that it also used aerodynamic force to change pitch. However, instead of powering an oil pump, it simply releases the compressed air. It was first tested on a Caudron Phalène and later used on the Caudron C.362.[12]

Finally, as a possible predecessor to the cooling fan on the Fw 190, pictures of the Curtiss XP-3A, 26-300, and Thomas-Morse XP-13A, 29-453, both appear to show that they used the technology.[13][14] Furthermore, an article in the July 1944 issue of Aviation also shows a design from 1936, but it is not clear to what aircraft it belonged.[15]

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In a direct follow-on to the post above, the Verville VCP-1, A.S. 40216, appears to feature a similar cooling fan design:

(Source: Bruce Robertson, ed., United States Army and Air Force Fighters, 1916-1961 (Fallbrook, California: Aero Publishers, 1961), 21.)


(Source: San Diego Air & Space Museum via Flickr)

In a second image from a book - and similar to pictures of another aircraft apparently testing the technology in a previous post - many of the firsts in aircraft radio may have happened in a Fokker Super Universal, NC9779, operated by the Radio Corporation of America, or RCA:

(Source: Cradle of Aviation Museum via New York Heritage Digital Collections)

The caption in the book reads:

(Source: Joshua Stoff, Long Island Aircraft Crashes, 1909-1959, Images of America (Portsmouth, New Hampshire: Arcadia Publishing, 2004), 127.)

Coincidentally, the aircraft depicted above NC9779 on the same page is the Curtiss Tanager, which is relevantly described as "the first plane to effectively incorporate wing flaps and slots". It was the winner of the Guggenheim Safe Aircraft Competition in 1929.[1]

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As mentioned in a previous post, NACA experimented with de-icing boots in the 1930s, but the big effort during the war was apparently related to redirecting hot exhaust gasses from the engines to the leading edges of the wings and tail.[1] This effort would eventually lead to a unique series of designations for one-off variants across many of the major multiengine bombers - XB-24F, XB-25E, and XB-26D. (As an aside, there was a similar XB-25F, but it tested a different technique using electrical coils.) However, the system was previously tested on a PBY and before that a Lockheed Electra Junior, NC17396, operated by the National Advisory Committee for Aeronautics.[2][3]

(Source: Wikimedia Commons)

The 1930s and 40s were also a period of great experimentation with "plastic" in aviation.[4] As noted in a previous post, this is evident from the wide variety of options included in a chart published by Aero Digest in July 1943. However, what was termed "plastic" at the time - for example, Bakelite or Formica - is not something we would recognize as such today. Much of it was thermosetting phenol formaldehyde resin rather than the modern polyethylene formulations.

The origins of impregnated plywood in aviation seem to lie in the Haskelite Manufacturing Corporation and its construction of airplanes using plywood during World War I:

(Source: Wikimedia Commons)

However, true "plastic" airplane production apparently didn't begin until the late 1930s, when the company was approached by Sherman Fairchild and Virginius E. Clark about the possibility of developing a flush-skinned airplane without rivets. The result was the Fairchild F-46, which was the first airplane to be built with the new "Duramold" process.[5][6]

Around the same time, Harry Atwood (not to be confused with Lee Atwood, with who he has apparently no apparent relation, despite working for the predecessor to North American!) had developed the "Airmobile", NX15318, which was built using birch impregnated with cellulose acetate - a material he called "Duply". This process was slightly modified by Eugene Luther Vidal, who patented it as "Weldwood".[7] The Airmobile is reported to have flown in 1935, putting it two years ahead of the F-46's first flight in 1937. So, while the F-46 was the first airplane built using "Duramold", the Airmobile is "perhaps the earliest of experiments with laminated thermoplastics for aircraft components".[8]

Duramold (or Haskelite, which was identical) would later be used in the AT-21, C-76, H-4 and T-50.[9][10][11] In addition, Weldwood was used by Vidal's company Aircraft Research Corporation in their abortive attempt to build the XBT-11. Meanwhile, Timm Aircraft came up with "Aeromold" technology which was used in its N2T trainers. Lastly, there is the XP-77, but I cannot find a reference to support which, if any, of the aforementioned materials it used.

Airframe manufacturers were not alone in making use of these new materials. As early as 1924 NACA was studying the possible construction of propellers from Micarta.[12] Similarly, the Schwarz Company in Germany had invented a process for building propellers out of "Compreg" material. It was as a result of license agreements with the company that Erco was able to obtain the rights to the design around 1937.[13]

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To build off the materials theme of the last post, the Society of Automotive Engineers published a compilation of various papers presented over the years titled History of Aircraft Lubricants in 1997. (See the The History of North American Small Gas Turbine Aircraft Engines for a similar aerospace technical history produced by an industry association.[1])

The discussion of plastics in the last post is also an excellent segue into claims of the first use of flush or recessed rivets in aviation as the goal of both was to make a smoother skin for increased speed. In March 1941, a man working for Douglas Aircraft Company, Vladimir H. Pavlecka, was issued a patent, 2,233,820, for countersunk rivets.[2][3]

Now, for a bit of a foray now into aircraft intakes.

The first aircraft with an inlet cone may have been the prototype of the MiG-21, the Ye-2, which first flew on 14 February 1955.[4] In the West, it was also a prototype: the P.1B. While the original progenitors to the English Electric Lightning, the P.1As, lacked an inlet cone, the these later variants incorporated one. It was on 4 April 1957, that the first of the three P.1Bs, XA847, flew for the first time.[5]

Between these two milestones was the first flight of another aircraft: the F-107. It has already been mentioned in a previous post for potentially being the first modern aircraft with a side-stick. However, this was apparently not the only innovation it introduced. It also may have been the first aircraft with variable intake ramps or, as it was known at the time, variable-area inlet ducts (VAID). While the first F-107 first flew earlier, the third aircraft, 55-5120, was only one to have VAID installed. It had its first flight on 10 December 1956.[6] While I was not able to find a patent showing the F-107, I did come across a later one, 2,876,621, depicting the design of the F-104.

The first aircraft with a splitter plate, per se, may have been the F-4 Phantom II. If so, the first airframe with them would be YF4H-1, 142260.[7] However, it is worth noting that the problem the device solves - turbulent boundary layer air being ingested into an engine - was something that was being addressed as early as the P-51. As can be seen in pictures of its accident, the original NA-73X had its oil cooler intake flush mounted with the bottom of the fuselage. It may even even have been the cause of the accident.[8] Therefore, later Mustangs featured a gap at this location. Furthermore, the difference between a splitter plate - which could be defined as a separate part extending ahead of the intake - and an intake with an integral separation is blurry. Even the pre-prototype for the F-4, the F3H-G, featured this design.[9]

The diverterless supersonic inlet, as seen on the F-35, was first tested on an F-16, 83-1120.[10][11]

Also on the subject of powerplants, in a situation not uncomparable to the Kommandogerat in the BMW 801 (see previous post), the Germans were again first with autothrottles. (At the same time, it is worth keeping in mind the narrative myth of German superiority in technology.) Although I was unable to find specific dates or detailed descriptions, the Me 262 was equipped with them. (While searching for information on the subject, I discovered the Germans also invented a yaw damper for the 262 as well.[12]) However, the modern commercial autothrottle was invented by a man named Leonard Greene and tested on a C-53, 11636, 42-68790, N733A, in 1956.[13][14] (Mr. Green's work on the stick shaker was mentioned in a previous post.) The technology was called "AutoPower" and apparently received patent 2,881,635.

The subject of self-sealing fuel tanks was mentioned in the initial post of the thread, but hasn't been discussed until now. It was invented by George J. Murdock, who would receive patent 1,386,791 for the design. (For a very detailed narrative of advances during World War II, see the "The Story of the Self-Sealing Tank" in the February 1946 issue of United States Naval Institute Proceedings.)

A related technology, the crashworthy fuel system (CWFS), was apparently pioneered by Dr. S. Harry Robertson III in the 1960s.[15] The result was that the first CWFS was installed on a UH-1H in May 1970.[16] (Another article, which may offer additional detail, is unfortunately behind a paywall.)

EDIT (23-01-08): On the subject of splitter plates and boundary layer control, a picture of the F7U at the National Naval Aviation Museum shows an interesting series of baffles between the intake and fuselage.
EDIT (24-06-28): As an addition to the story of the self-sealing fuel tank, there was apparently a lawsuit over credit for its invention filed in 1967. The plaintiff alleges he began experimenting with the technology in the mid-1930s and his patents of late 1941 and early 1942 were infringed upon by Martin-Marietta.[17]

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First off, to follow up on the subject of self-sealing fuel tanks in the last post, the first single point refueling system (also known as pressurized or underwing refueling) may have been on either the de Havilland Comet.[1] Around the same time, Boeing was developing a similar system for the B-50.[2]

A different type of fluid management was first patented in 1975.[3] The first aircraft with toilets were mentioned in a previous post, but the "Recirculating Toilet System", 3,922,730, invented by Monogram Industries, Inc. for the first time allowed aircraft to use differential pressure to move human waste instead of gravity.

The Sikorsky Archives claims that "the S-61 was the world's first certified amphibious helicopter with twin turbine technology and a nautical hull design evolving from the Sikorsky clipper ship era".[4] However, a HUP-2 was modified with outrigger floats in 1958 to enable it to land on water.[5] (The distinction is roughly analogous to the difference between the first flying boat and the first floatplane mentioned in a previous post.) To further complicate things, it was noted in a post in a different thread that R-4s landed on water. However, at least some of these landings were apparently conducted with temporary flotation bags. So it could be argued that the HUP-2 had the first integral system, even if it was only a prototype.

Lastly, although it's not truly a "design" first, in the vein of passenger accommodations it is worth noting that the first aircraft with a safety card may have been the Boeing 377, DC-4 or L-049. Cards for these aircraft were issued by Pan American World Airways in the late 1940s or early 1950s.[6] However, emergency exit diagrams, such as an example for the B-25, have existed in manuals since at least World War II.

EDIT (23-11-04): It appears that the XB-51, and not the Comet, was the first aircraft with a single point refueling system:

(Source: Scott Libis, The Martin XB-51, Air Force Legends 201 (Simi Valley, California: Steve Ginter, 1998), 4-5.)

The Comet first flew three months before the XB-51, but given that the reference that supports the Comet's claim is from 1952, it is possible that the system only appeared on later aircraft and not the prototype.

EDIT (24-06-28): An early perspective-type view evacuation diagram similar to the modern style - along with basic emergency instructors for passengers - can be found on starting on page 2-37 and in a the 1963 Flight Manual for the C-54, T.O. 1-C-54D-1. The text of a passenger briefing starts on page 8-9.

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Push/Pull Circuit Breakers

The standard aircraft push/pull circuit breaker was apparently developed by a company that was originally known as Klixon Precision Products. It is not clear exactly when the company was started, but one website seems to suggest 1956.[1][2] Newspaper articles for a "Klixon" thermostat go back to 1929, when they first appear as an add-on for water heaters. They are described as being both Woodward-Wanger and Westinghouse products.[3][4] It is not clear if this is the same company that made circuit breakers, but the product type is similar enough that it stands to reason it could be related. The first mention of Klixon circuit breakers - in this case of the "automatic reset type" described in a patent filed in 1948.[5] Another patent filed in 1957 helpfully describes the brand as being "manufactured by Metals & Controls Corporation, Attleboro, Massachusetts".[6] By 1959, they had been acquired by Texas Instruments, according to a newspaper article.[7]

The Klixon 7277 seems to be the original - or at least the definitive - model. It is described by one supplier as being "[o]riginally developed as an alternative to slow-blow fuses".[8] The earliest reference to the Klixon 7277 I found was in a 1963 issue of the periodical Iron Age, where it is described as being introduced by the Metal & Controls Division of Texas Instruments.[9] The brand briefly came to public prominence when it was the focus of an National Transportation Safety Board investigation into the crash of Flight 255 in 1987.[10] It is now owned by another company called Sensata Technologies and their full product line of aircraft circuit breakers can be seen in a catalog modern catalog.[11]

The oldest aircraft that I could find they were used in was the Boeing 727.[12] However, it is entirely possible there are earlier aircraft that I missed.

An article on aircraft circuit breakers does exist in the October 1943 issue of the journal Transactions of the American Institute of Electrical Engineers, but unfortunately access is behind a paywall.[13]

Shark Fin Pitot Tube

In another case of not necessarily the first, but first of a certain configuration, the patent for the standard "shark fin" pitot tube seen on so many wartime aircraft was filed by Kollsman on 3 May 1938 as "Trapped Self-Draining Pitot-Static Tube", 2,204,367.

Spring Loaded Kick-In Step

This is a difficult one to answer. However, to set an absolute latest date, the Vought F4U Corsair features such a design.

Note that this first specifically relates to spring loaded kick-in steps that return to flush with the skin of the airplane after use. This distinction is important because open steps without a door had been used on fabric covered airplanes for many years prior.

Nine-Bladed Propeller

Similar to the NACA tests with six and eight bladed propellers mentioned in a previous post, MT-Propeller began testing the world's first nine-bladed propellers on a Piper Cheyenne on 11 March 2019.[14]

Horizontally Opposed Engine

According to an article by the EAA Vintage Aircraft Association, the first horizontally opposed aircraft engine was the Continental A-40. The first aircraft powered by the new engine is not entirely clear, but it may have been none other than the Taylor E-2 Cub, predecessor of the famous J3C. The E-2 first flew with a Brownbach Tiger Kitten - the source of the Cub name - but it was quickly replaced by the A-40. The author, Mark W. Stewart, notes just how revolutionary the A-40 was for aviation. For the first time, aircraft designers had an engine that was significantly cheaper, smaller, and lighter than a radial engine. It was certainly these characteristics that attracted Taylor to the engine. It can be argued that the J3, and ultimately the Piper Aircraft Company, owes its success to the little engine.[15]

First Single Engine Turboprop

The Boulton Paul Balliol.[16]

First Twin Main and Nose Wheel Aircraft

The Boeing B-29 Superfortress is known for many advanced features - pressurization, remote control gun turrets - but a paper from 1986 about the history of landing gear notes one lesser known innovation: it was the first aircraft with both twin main and twin nose wheels.[17]

Hydraulic Fuses

Hydraulic fuses, which compartmentalize hydraulic lines so that the complete contents of the system are not lost in the event of a break, really came to prominence after accidents like Japan Airlines Flight 123. The first aircraft to have them is not clear, but one forum thread claims they were used on L1011s.[18]

Wheeled Floats

The first aircraft with wheeled floats, at least in the modern sense, may have been the C-47C.[19]

Siren

Everyone with the slightest bit of aviation knowledge is familiar with the Stuka dive siren or "Jericho trumpet" and, as covered in a recent post in the cliche origins thread, its infamous overuse in movies. However, I recently learned it actually has a competitor for claim of first airplane siren. The Ju 87 apparently did not have sirens until the B-1 variant, which was first produced in 1937.[20] However, in October 1935, a General Aircraft Monospar, ST10/34, VH-UST, was fitted with one to warn beachgoers when sharks were spotted.[21] (As a historical footnote, the CIA attempted to replicate the technology in the late 1950s.[22])

EDIT (23-07-24): It is worth noting that the patent for the heated pitot tube was mentioned in a previous post.
EDIT (24-01-07): Just for reference, a reddit post shows an example of one of the shark fin pitot tubes immediately after it was taken out of its original new old stock cardboard box.

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"Wheeled Floats

The first aircraft with wheeled floats, at least in the modern sense, may have been the C-47C.!!"

I'm pretty certain the C-47C was not the first aircraft with modern-day amphibious floats.

If nothing else, here is a shot of an L-1 on EDO 49-4000 amphibs. There were 12 O-1 floatplane conversions.
Given the fact the C-47C did not fly until July, 1942, I'd wager the L-1 installation beat it.
The C-47 floats were built by Edo, I'd bet they had built some before, if for nothing else than proof of concept.

In his book "The DC-3: 50 Years of Legendary Flight", Peter M. Bowers writes, "...Edo had built smaller amphibious floats before and during the war, with retractable nosewheels and main wheels behind the step, but the model 28 was by far the biggest...then or since".

But perhaps it took visions of a large government contract for them to do more work on the concept. The Army ordered 150 sets of C-47 floats, I have never learned how many were actually built or installed. Bowers mentions just two ID'd by serials. I'd bet a lot of brand new floats were scrapped.

I'm sure there is a float historian out there that could tell us more.

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Remember the vets, the wonderful planes they flew and their sacrifices for a future many of them did not live to see.
Note political free signature.
I figure if you wanted my opinion on items unrelated to this forum, you'd ask for it.

MIL-F-5508A from 23 March 1950, "Fuses, Aircraft Automatic Quantity- Measuring, Hydraulic" certainly predates the L-1011 by a long time.

The Fairey Flycatcher flew with wheeled floats in the 1920s. Not claiming it as a first but it predates the C-47.

Aeronut, note the OP, it says amphibious floats "...in the modern sense", which The Fairey floats were not.

The Flycatcher floats did not have nosewheels, the main wheels did not retract completely into the float, and we're located just ahead of the step. So very different than modern day amphibs.

There were also earlier floats that had the struts and wheels that could pivot above the water line. So those don't qualify as modern either.

There are several amphibious float equipped aircraft at the local field...a Beaver (which I have flown in), various Super Cubs or clones thereof, a Murphy Moose homebuilt, Kodiaks and the occasional Cessna Caravan and 206. Even a SIAI-Marchetti SM.1019, a turbine powered development of the Cessna L-19/O-1 Bird Dog.
All have nosewheels and fully retractable mains.

_________________
Remember the vets, the wonderful planes they flew and their sacrifices for a future many of them did not live to see.
Note political free signature.
I figure if you wanted my opinion on items unrelated to this forum, you'd ask for it.

Thanks guys! This is why I'm grateful for the responses. I knew there was a good chance my answers weren't right, but I also knew that if they weren't someone with more knowledge would respond with the correct (or a closer) one. I will readily admit to not doing as much in-depth research on those two firsts as some of the other ones.

In regards to JohnB's response: ̶D̶o̶ ̶y̶o̶u̶ ̶(̶o̶r̶ ̶a̶n̶y̶o̶n̶e̶ ̶e̶l̶s̶e̶)̶ ̶k̶n̶o̶w̶ ̶w̶h̶e̶r̶e̶ ̶I̶ ̶c̶o̶u̶l̶d̶ ̶f̶i̶n̶d̶ ̶a̶ ̶c̶o̶m̶p̶l̶e̶t̶e̶ ̶l̶i̶s̶t̶ ̶o̶f̶ ̶E̶d̶o̶ ̶f̶l̶o̶a̶t̶s̶ ̶c̶o̶m̶p̶l̶e̶t̶e̶ ̶w̶i̶t̶h̶ ̶p̶a̶r̶t̶ ̶n̶u̶m̶b̶e̶r̶s̶?̶ ̶I̶ ̶k̶n̶o̶w̶ ̶t̶h̶a̶t̶ ̶E̶d̶o̶ ̶f̶l̶o̶a̶t̶s̶ ̶a̶r̶e̶ ̶v̶e̶r̶y̶ ̶p̶r̶o̶l̶i̶f̶i̶c̶,̶ ̶b̶u̶t̶ ̶d̶e̶t̶a̶i̶l̶s̶ ̶o̶n̶ ̶t̶h̶e̶m̶ ̶-̶ ̶o̶r̶ ̶a̶n̶y̶t̶h̶i̶n̶g̶ ̶a̶b̶o̶u̶t̶ ̶t̶h̶e̶ ̶c̶o̶m̶p̶a̶n̶y̶ ̶-̶ ̶a̶r̶e̶ ̶s̶p̶a̶r̶s̶e̶.̶ ̶U̶n̶f̶o̶r̶t̶u̶n̶a̶t̶e̶l̶y̶,̶ ̶i̶t̶ ̶i̶s̶ ̶m̶y̶ ̶u̶n̶d̶e̶r̶s̶t̶a̶n̶d̶i̶n̶g̶ ̶t̶h̶a̶t̶ ̶E̶d̶o̶'̶s̶ ̶a̶r̶c̶h̶i̶v̶e̶s̶ ̶w̶e̶r̶e̶ ̶d̶e̶s̶t̶r̶o̶y̶e̶d̶.̶ Actually, it looks like Kenmore Air has a relatively comprehensive model list. Apparently, they were the distributor for Edo in the northwest and acquired the rights to the brand in the 1980s.[1]

In regards to bdk's response: Now we just need to figure out if the suggestion in the 1945 paper was ever tested on an aircraft. At least we now have pushed the absolute latest date and aircraft back further: 1950 and Martin 202.



Hmm... that's an interesting one:

(Source: Hush-Kit)

You're right it's not quite the modern style, but it does seem to be a step in that direction. There was a term I came across for the modern style of floats - I think it was some kind of portmanteau/marketing term - but unfortunately, I can't remember what it is. Either way, thanks for sharing. I had not seen that before.

Sliding Canopy
Similar to the discussions of retractable windshields and uses of transparent plastic mentioned in previous posts is that of the first sliding canopy. A comment on reddit suggested that the Royal Aircraft Factory S.E.5, may have been the first aircraft to have a modern style canopy - as seen on A8910:

(Source: Wikimedia Commons)

Prior to that, the S.E. 4 was designed with a completely enclosed canopy, but reportedly never flew with it:

(Source: WW2Aircraft.net)

However, it doesn't appear that either of these slid to open and close. The reddit comment above suggests the He 70, but this is not correct. The honor of first sliding canopy seems to belong to the Curtiss XP-31 Swift, which first flew in either 1931 or 1932:[2][3]

(Source: Wikimedia Commons)

Integrated Catapult Launch/Holdback Gear
For many years, carrier aircraft required a cable called a catapult "bridle" (two attach points) or "pendant" (single attach point) to attach them to the shuttle for launch. (This is where the two prongs sticking off of the bow of postwar carriers came from. They are "bridle catchers" that caught the bridle/pendant after every launch.) Eventually, however, these features were incorporated into the nose landing gear of the aircraft, which attached directly to the shuttle. The first aircraft to be designed in such a way was the Grumman E-2 Hawkeye and the first at-sea launch was accomplished on 19 December 1962 from the USS Enterprise.[4]

Collapsible/Foldable Airstair
The subject of the first airstair was mentioned in a previous post, but when the first foldable or collapsible airstairs appeared is something else. The first aircraft with such a configuration may be the Convair 240. A patent titled "Coacting Door and Movable Stairway Combination", 2,531,263, filed 20 February 1947, clearly depicts a Convairliner. The design - complete with an identically shaped plate in the middle of the airstair - can be seen in a picture (source) of a Convair 580, N345GS, taken in January 2023.

Lastly, while researching this thread - or sometimes just while perusing the internet - I come across various articles or pages that are both technically interesting and incidentally relevant, but I haven't found a way to use. Others are subjects that I would like to write "firsts" for, but haven't gotten around to. They have been building up in one of my browser windows, so I am just going to dump them below in case anyone is interested or a use can be found for them in the future:

• Igor Sikorsky’s 66 Patents Awarded in America
• Particulars of the German VDM
• German Variable‐Pitch Propeller Mechanisms: A Report on the Characteristic Features of the V.D.M., Junkers and Argus Types
• Vintage 1930-40's WWII Breeze Corp Inc. Aircraft Engine Starter Breech Coffman
• Stearman Maintenance
• Why Castor Oil?
• Engine Theory: Basic Layout
• Aircraft Radio Systems
• Aeronautic Radio
• Radars Big Comeback: Display Options are Key
• In the Cause of Flight: Technologists of Aeronautics and Astronautics
• Aircraft
• Adel Clamps
• The AdelWiggins Group
• Early Spies in the Skies

EDIT (25-03-03): According to a Waco company brochure, "winter top" bearing somewhat of a resemblance to the one seen on the XP-31 was offered as an option on the Model A. However, it appears as though it does not slide and instead the left side of the enclosure attaches to the top of the side opening door built into the fuselage.

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Tri-State Warbird Museum Collections Manager & Museum Attendant

Warbird Philosophy Webmaster

Aircraft Communications Addressing and Reporting System (ACARS)
ACARS was first used by Piedmont Airlines in mid-1978.[1] (It is worth noting that, as seen on the first datasheet for the system, ACARS originally stood for "Arinc Communications Addressing and Reporting System".)

Moving Map Display
Somewhat related to the subjects of the first glass cockpit mentioned in a previous post and the first heads up display also mentioned in a previous posts (1, 2) is that of the moving map display. One of the first aircraft to have this technology was the Hawker Siddeley Trident:

(Source: Wikimedia Commons)

Unlike modern satellite navigation systems, the device in the Trident used doppler radar to position a pen nib over a paper map in a concept not dissimilar from the instructor station in Link trainers.[2]

However, prior to the Trident ever entering service, Vickers Viscounts were equipped with a moving map display that was based on the Decca Navigator system:


Datalink
There is a good chance the first aircraft to use a datalink was the Convair F-106 Delta Dart. The Hughes MA-1 Automatic Flight Control System (AFCS) in the aircraft used a Time Division Data Link (TDDL) to connect with the Semi-Automatic Ground Environment (SAGE) for Ground Controlled Intercept (GCI).[3]

Link 4 was one of the first datalink systems, but aside from the fact it was developed in the 1950s, readily available information on the subject is sparse.

Aircraft Eyeball Vent
When the eyeball air vents were first used is not entirely clear (it turns out finding pictures of the underside of overhead consoles on old aircraft is difficult!), but one source notes individual fresh air vents were introduced on the de Havilland Comet at some point between the 2 and 4B/C variants.[4]

Although not the traditional "eyeball" style (as they don't move in multiple axes), Beechcraft 18s had rotating air vents as early as World War II. Officially named "Cap Assem - Cold Air Plastic", 183921, they can be seen in cabin pictures from the period.[5]

Tail Illumination Lights
Reportedly, TWA was the first airline to start using lights to illuminate their logo on the vertical stabilizer on their Boeing 741-100s in the 1970s.[6][7]

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Tri-State Warbird Museum Collections Manager & Museum Attendant

Warbird Philosophy Webmaster

Stepless Cockpit
The subject was approached in previous posts about retractable windscreens and plastic, but a previous thread raised the subject directly. The answer is difficult due to the difficulty of establishing when the concept started (i.e. it really only becomes a definable characteristic when contrasted with non-stepless cockpits), but the Sikorsky Ilya Muromets is one contender.

Upward Hinged Nose
A patent for a "Cargo Landplane", 2,323,279, filed by the Glenn L. Martin Company in August 1942, depicts just such a design. However, the Waco CG-4 had already entered flight testing in May of that year. (The British Horsa flew in 1941, but did not have a hinged nose until later versions.[1])

Although using clamshell doors instead of an upward hinge, the Me 321 first flew on 25 February 1941.

Life Raft
This is an interesting question because it can be divided into two different categories depending on whether or not the life raft is intended to be deployed for others in need of rescue or for the occupant(s) of the aircraft itself. The "Austin Life-Float" was first tested from an airplane in mid-1921.[2][3] By 1932, a raft complete in its own container had been developed by an Army Air Corps pilot named George P. Tourtellot.[4] Life rafts "housed in the fuselage, behind the pilot's headrest" had entered service with the Army Air Corps by 1938.[5] However, the Navy was unsurprisingly ahead of them. Aside from a slightly different vertical stabilizer, the main difference of the F4B-4, first delivered in February 1933, was a larger headrest to accommodate a life raft.[6] Charles Lindbergh had them both beat, though, with one in the Spirit of St. Louis.[7] Yet, it could be argued that this was a one-off, non-production example.

Overwing Escape Slides
The first aircraft with escape slides was mentioned in a previous post, but it was not until later that the overwing version was invented. The first aircraft with one is not entirely clear, but according to a picture on Airliners.net they were in use as early as July 1981 on Boeing 747s. These may have also been the first escape slides that could evacuate more than one person side by side.

Crew Rest Compartment
This is another tricky one, as pointed out by two (1, 2) different Airliners.net threads, the large flying boats of the 1930s had "crew rest areas". However, similar to the case of the stepless cockpit above, the modern conception of the term is something different. Furthermore, although it is the class 1 areas that garner the most attention (as the multiple clickbait style articles and videos about the "hidden areas for the crew" attest), there are class 2 and 3 facilities that, at minimum, are nothing more than seats that can recline. The first modern, class 1 style crew rest areas may belong to the Boeing 747.

"Six Pack" Instrument Arrangement
The answer is unclear, but the Royal Air Force standardized on such an arrangement in 1937, so the answer may be something British. However, standardization had apparently already been proceeding in this direction, as the referenced article notes that the Pioneer Instrument Company previously advertised a "'recognized primary blind-flying instrument group" of three instruments.[8]

Stormscope
The Ryan Stormscope, a device used for detecting lightning strikes, debuted at the 1976 Reading Airshow and was the subject of an article in Flying the following year.[9]

Duraluminum
The Junkers J 1, mentioned in a previous post, has been described as the first all metal aircraft. However, it used electrical steel. It not until the J 3, a development of the J 1, that duraluminum was first used in an aircraft.

However, there is a confounding story: the DeChenne Aeroplane. The airplane, which first flew on 4 July 1911, is claimed to be the first all aluminum airplane, as not only its airframe, but also its engine, were reportedly constructed with aluminum.[10] However, details on the actual construction can be hard to come by and some reports seem to suggest that fabric and other materials may have been used as well.[11]

Multiple Ejector Racks
This is another one that is hard to pin down. However, the results seem to point to the F-4C, F-4D, F-105 and F-111 as being the first to use it operationally.[12]

Lastly, following up on a previous post, it's time for another link dump:

• Blind Flying
• Aviation Fuels Technical Review
• A History of Aviation Gasoline
• The Long, Twisted And Slightly Ridiculous Story Of Avgas (Part 1)
• Types of Aviation Hydraulic Fluids
• What Types of Hydraulic Fluids are Used in Aircraft?
• Aviation Hydraulic Fluid
• Types of Hydraulic Fluid for Aircraft
• Autosyn Application for Remote Indication of Aircraft Instruments
• Soviet / Russian RWR (Sirena, Beryoza, Pastel)
• Computing Gunsight Head Up Displays
• Snap-Shoot Gunsight for Fixed-Gun Fighter Aircraft
• ADI: Attitude Directional Indicator
• Aircraft Propulsion: A Review of the Evolution of Aircraft Piston Engines
• The Jet Engine
• Transportation-Markings Database: Aeronautical Navigation Aids
• Radar Fundamentals (Part II)
• Merlin Ejector Exhausts
• Peripheral Vision Horizon Display (PVHD)

EDIT (25-03-03): In regards to attempts to prescribe a standard grouping of instruments, T.O. 01-1-160 did so for Army Air Force airplanes.

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Tri-State Warbird Museum Collections Manager & Museum Attendant

Warbird Philosophy Webmaster

Eyeball vents came along a lot earlier than the Comet...The Official name is Punkah Louver and was used in MkV Tropical Spitfires and Dehavilland mosquitos.Im thinking 1930,s at least.

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