Aircraft Design Firsts

[Noha307]

You have first fighter for inflight refueling, you missed the first plane that does the refueling.

This is a tricky one. The first mid-air refueling was done between two DH-4s, but it is a stretch to call them tankers since I doubt the equipment was actually built into the aircraft in any way.

I would suggest the first airplane to be designed as a tanker. (It is interesting to note that I don't believe there has ever been an aircraft that was designed from the start to be a pure tanker. I'm pretty sure that every aerial refueling airplane built has either been a development/modification of an earlier design or has also included a non-liquid cargo carrying capability.) The best bet for that may be the KC-97.[1]

The first use of the probe-and-drogue system was a Lancaster that was used to refuel a modified Gloster Meteor F.3, EE397, on 7 August 1949.[2]

The first aircraft to employ a flying boom seems to be the KB-29P:

(Source: Wikimedia Commons)

There is no first aircraft with a two bank radial engine. Because there is no such engine. There are 2 row radial engines.

Good clarification. Thank you!

Another first, what propeller aircraft broke the sound barrier? Was breaking the sound barrier mentioned?

That's a good question that I don't have the answer to. I always hear it mentioned that the T-6's tips do that, but this is by no means to suggest that it was the first to do so.

Two other firsts that I recently came across are:

• The He 111 (!) was the first airplane to carry an air launched cruise missile, the V1.[3]
• The first airplane with a synchronization gear was apparently Fokker A.III serial number A.16/15.[4] It is worth noting that, similar to the jet engine, there is a robust debate over who was first to come up with the technology and who copied who.

EDIT (23-03-19): While it doesn't mention if it was the first, T6 Harvard Aviation has a frequently asked questions page that explains why the propeller tips go supersonic.

EDIT (24-05-06): In regards to what airplane was being refueled by KB-29s like the one above, it was apparently an F-86:

(Source: Wikimedia Commons)

Interestingly, pictures of this sequence were used in the 1953 film The Magnetic Monster. An eBay listing with another angle used as a press photo reveals that this particular flight likely took place on 2 August 1951 and the F-86 was an "A" variant, serial number 49-1172. (For pictures of KB-29s refueling other aircraft, see the KB-29 tag on the Air Refueling Archive blog. Notable is a picture of early Pilot Director Lights or Pilot Director Indicators.) Meanwhile, the book Seventy-Five Years of Inflight Refueling states on page 27 that "Boeing tested its new boom in the autumn of 1948" - although it is unclear if this was simply solo flight testing or an actual hookup.

EDIT (25-01-16): Although using a hose-and-reel system, a recent thread included an interesting report about testing with a B-17E, 41-2539, and B-24D, 40-2352, in 1942-1944.

Last edited by Noha307 on Thu Jan 16, 2025 6:09 pm, edited 4 times in total.

[Noha307]

The winner for the first jet aircraft with thrust vectoring is likely the Bell X-14. While the company had an earlier aircraft that could be considered to have thrust vectoring, the Model 65, both entire engines on it rotated, making it more of a tiltjet. The X-14, instead, fits the more common conception of thrust vectoring where the engine stays in place and the nozzle rotates.

[Noha307]

I've already touched on air brakes, but one feature I don't believe I've mentioned yet is dive brakes. While I don't have enough information for a definitive answer, as both first flew around the same time, there are two possibilities for first aircraft with them. One is expected, the Ju 87. However, the other is much more obscure: the Northrop BT, predecessor to the SBD. The BT likely does hold the distinction of first airplane with Swiss cheese-style dive brakes:

(Source: Wikimedia Commons)

(Source: Wikimedia Commons)

[bdk]

I always hear it mentioned that the T-6's tips do that, but this is by no means to suggest that it was the first to do so.

2250.00 Takeoff RPM (600 HP)
37.50 Revolutions Per Second
9.08 Prop diameter in feet, maximum 9'1" from Type Certificate Data Sheet
28.54 Circumference in feet= Pi X Diameter
1070.10 Feet/Second= Revolutions X Circumference
1100.00 Feet/Second= Speed of Sound on a Standard Day

Below 45F, the prop tip will exceed the speed of sound with a full length T-6 prop (-12)
Below -4F, the prop tip will exceed the speed of sound with a minimum length T-6 prop (-14)

Of course the airflow over the blade goes faster than that, so it probably isn't the prop tips you are hearing.

[Noha307]

Of course the airflow over the blade goes faster than that, so it probably isn't the prop tips you are hearing.

Good explanation, thanks for the math.

NOTAR technology, defined as "use of directed air to provide anti-torque control" (to quote Wikipedia), doesn't seem like it belongs on a warbird website, but I was surprised to learn it actually dates back to World War II. The first helicopter to use the technology is the Cierva W.9, which first flew in 1945:

(Source: Flickr)

While we're on the subject of helicopters, the first one to use a "fenestron", or ducted tail rotor, is the second prototype Aérospatiale SA 340 Gazelle. (The helicopter, F-ZWRA, is now on display at Aeroscopia.) However, in an interesting connection to the entry above, the first patent for a "fantail", to use the non-trademarked term, was by the same company that developed the W.9.[1]

(Source: helis.com)

[dhfan]

I think your mention of an air brake on Mosquito W4052 could be a case of right company, wrong aeroplane by some years.

When the DH.80 Puss Moth was first built in 1929, it was 7mph faster than expected. They put it down to clean entry and what we would now call streamlining.
As a result of this the glide angle was too good making it difficult to land. The solution was to modify the shock absorber fairings so they could be turned through 90° which reduced the glide ratio from 1 in 10.5 to 1 in 8. I'm sure those figures will mean more to a pilot than it does to me - I can only sort of understand it.
Source "DH A History of de Havilland" by C. Martin Sharp

[DH82EH]

A steeper glide angle, for a given airspeed, means that distance covered after passing over an obstacle will be less.
Therefore one can touch down sooner on the strip and have more runway in front of you for the roll out.
Hope that helps dhfan.

Andy

[dhfan]

That makes sense.
Paraphrasing a bit, because I'm too idle to go and take the book off a shelf, the modification was initially because Geoffrey de Havilland found it difficult to land at Crux Easton, a place he knew perfectly well and had landed at many times before as his father was the vicar there.

Did any Puss Moths find their way across the pond?

[DH82EH]

Yes!
At least one under its' own power! Jim Mollison.
They were also subsequently licence built at Downsview Ontario ( I've landed my Tiger there
A friend of mine owns the only airworthy one in North America. It is one of the last Downsview built ones.
It was built as CF-AVA and is currently U.S. registered.

Andy

[Noha307]

I think your mention of an air brake on Mosquito W4052 could be a case of right company, wrong aeroplane by some years.

When the DH.80 Puss Moth was first built in 1929, it was 7mph faster than expected. They put it down to clean entry and what we would now call streamlining.
As a result of this the glide angle was too good making it difficult to land. The solution was to modify the shock absorber fairings so they could be turned through 90° which reduced the glide ratio from 1 in 10.5 to 1 in 8. I'm sure those figures will mean more to a pilot than it does to me - I can only sort of understand it.
Source "DH A History of de Havilland" by C. Martin Sharp

Interesting, thanks! I really appreciate the source as well!

Another difficult first to pin down is the first airplane with a telescopic gunsight. As noted in a previous post, reflector sights sights go back to the First World War. Tube type collimator sights also existed at the time, with examples such as the Aldis sight. However, it is important to note that the Aldis sight is not technically a telescopic gunsight - it does not provide any magnification.[1] The problem is obviously then determining which - of the various airplanes having tube gunsights - actually had magnification. The A5M, BF2C, D.XXI, F3F, I-15, Ki-27, Ki-43, P-6, P-26, SBD, TBD all had tube type gunsights at one time or another, but it is not clear which, if any of them, are actually telescopic. (For reference, the TBD used a Mark III, Mod 2.[2]; the F3F a Mark III, Mod 4.[3]; the SBD a Mark V.[4]; and the I-15 an OP-1[5])

The U.S. Signal Corps had a "Unit Sight, Type A-1 (Telescopic)" as early as 1925.[6] This is likely the same as a 1918 sight made by Eastman Kodiak.[7] This was mounted in a USD-9A biplane.[8] Again, however, it is not apparent if it actually provides magnification.

As an aside, I have wondered for a while what these true telescopic sights were supposed to be used for. The original reflex sights would have been a benefit since they remove most of the parallax and make it so the user does not have to have their eye directly behind the sight. However, the actual telescopic sights seem like they would be very difficult to use in combat since any movement of the airplane would be greatly exaggerated due to the magnification.[9] I did see one suggestion that they may have been used for identification of targets, which would seem to make sense.

On the subject of gunsights, the website Aircraft Gunsights has a number of examples.

[Noha307]

Compared with the other firsts so far, finding a complete answer to the question "what was the first aircraft to have a dive bomber crutch/swing arm" was surprisingly easy:

The bomb-crutch was tried at the Martin test plant in static tests and then flight-proven at the Proving Grounds on January 7–8, 1931 by Lieutenant Commander Ostrander in the XT[5]M-1. [Ed: In the original passage, XT5M was incorrectly rendered as XTSM.] There were no snags and this vital piece of equipment became standard fitting to all "heavy" dive bombers.

Peter C. Smith, Dive Bomber!: Aircraft, Technology, and Tactics in World War II (Mechanicsburg, Pennsylvania: Stackpole Books, 2008), 43.

Incidentally, the XT5M is described separately as the first dive bomber designed to carry a 1,000 lb pound.[2]

The first operational aircraft to use the crutch is likely a development of the XT5M, the Martin BM.

[Noha307]

Some of the earliest use of aerial radio direction finding appears to be a system called "Telefunken Kompass Sender" that was employed with Zeppelins in World War I. However, this is apparently a one way system, with the ground stations relaying positions to the dirigibles, but no specialized equipment in the airships.[1] Popular science also produced an article in April 1918 about "How the Zeppelin Raiders Are Guided by Radio Signals".

The U.S. Navy was also involved in a series of early experiments with the technology. Some of the first airplanes equipped with radio direction finding might be the NC boats used in the first aerial transatlantic crossing in 1919.[2][3] A year later, on 6 July 1920, a U.S. Navy F5L was able to use only radio signals to fly 94 miles to the battleship USS Ohio without knowing its location and then return.[4] The equipment used is pictured below:

(Source: Google Books)

EDIT (21-11-03): For more information, the website Hellschreiber has a very detailed page about the history of radio air navigation through World War II.

Last edited by Noha307 on Wed Nov 03, 2021 10:55 pm, edited 1 time in total.

[Noha307]

Hydro-methanol/water/anti-detonation injection/war emergency power/boost was apparently invented by a Brit named Harry R. Ricardo.[1] (For those interested, the book mentioned in this reference is available on Hathi Trust.) However, while Ricardo worked on aircraft engines, much of his research was also related to land-based engines and this may be where he first implemented ADI. There were apparently also experiments in the 1930s by J. F. Campbell and F. Prescott at Wright Field into alcohol and water injection respectively. However, there is no indication that any engines were actually flown on aircraft. More testing was also carried out by Bristol (on an Armstrong Siddeley Jaguar) and Pratt & Whitney.[2]

Determining the first airplane to use ADI is more difficult. Apparently Spitfire I's had some form of boost, which was used as early as June 1940.[3] However, this apparently took the form of increased supercharger pressure and did not use any sort of water injection. The BMW-801 D-2 engine Fw 190 A-4 could accept MW 50 injection in late 1942, although it seems the system was never actually fitted.[4] However, this does suggest that the system may have at least been tested on an airplane by this point. In any event, operational use of MW 50 on either the Bf 109 and Fw 190 apparently did not occur until 1944.[5]

EDIT (22-06-19): According to a table on page 372 of the book Vees for Victory! by Daniel D. Whitney, starting on 1 August 1943 the P-47 was to be the first Army Air Force fighter to have water injection equipment installed on production aircraft.

Last edited by Noha307 on Sun Jun 19, 2022 9:05 pm, edited 1 time in total.

[Noha307]

On the subject of the first gun turrets, the Aircrewman's Gunnery Manual states:

• No one knows exactly who should get credit for inventing the modern turret. The first crude models came out in the 1920's. One was a circular mount, illustrated on this page, which the United States developed to put a little flexibility into bomber guns. The Russians tried a movable platform, cranked by hand, in which the gunner sat right out in the open, fighting the slipstream as well as the enemy.
• The modern power turret—driven by electricity and mounted inside the bomber—was developed after many experiments in the 1930's and proved its worth in action in the second year of World War II. Its effect on air strategy was spectacular. At last the bomber—heavier and slower than the fighter plane-could really fight back.

(Source: Ibiblio)

While too long to reproduce here, part one of the book Aircraft Fire Control by the Sperry Gyroscope Company also includes a brief history of gun turret development in the United States.

However, in the vein of the previously mentioned papers on helmet mounted sights and radar warning receivers, the one of the best treatments of the subject is Air Force Historical Study No. 54, the Development of Aircraft Gun Turrets in the AAF 1917-1944 by Irving B. Holley, Jr. A cursory reading seems to support the notion that the Boulton Paul Overstrand was the first aircraft with a powered gun turret. In reference to remote control gun turrets, it notes that one was at least proposed for the tail position on a B-18. Finally, the A-20 depicted after page 136 (168) is the XA-20F, 39-725:

(Source: Flickr)

EDIT (21-12-27): The subject of remote control gun turrets was mentioned in a previous post, but thanks to a recent purchase of Lockheed's Aircraft Design Sketch Book, I came across some concepts for early Blackburn remote controlled turrets. Luckily, someone named Robert Hurst has already covered the topic in significant detail - with the drawings from the aforementioned booklet - in an Axis History Forum thread, so instead of rehashing the subject here, I will just suggest that anyone interested check it out. He has a series of similarly well-researched and illustrated threads (1, 2, 3, 4) that I suspect may be based on Emmanuel Gustin's books.

Last edited by Noha307 on Mon Dec 27, 2021 8:04 pm, edited 1 time in total.

[Noha307]

While drop tanks were covered in a previous post, conformal fuel tanks have not. The Germans appear to have been first with the technology. In or before Spring 1940, the Luftwaffe developed the preproduction Bf 110 D-0, which had a 1,050 liter Dackelbauch, or "dachshund belly", fuel tank.[1] The operational version allowed Bf 110s in Norway to escort bombers all the way to Norway.[2]

(Source: Wikimedia Commons)

Another early example of CFTs was the "slipper tank" used by Spitfires. They were apparently first fitted to Mark VBs in September 1942.[3][4] According to an American patent for the design, a British patent was filed in August 1942.

(Source: Armoured Aircraft Carriers in World War II)

More pictures can be found in SAS 1946 and Key.Aero threads. Also, a Royal Aeronautical Society article on the possibility of an escort Spitfire includes more information on the subject.

On a different subject, the first flight of a composite or parasite aircraft combination took place on 17 May 1916, when a Felixstowe Porte Baby carried a Bristol Scout.[5]

(Source: Wikimedia Commons)