According to
The Lore of Flight:
John W. R. Taylor, et al. wrote:
As with so many ideas which are now commonplace, the variable pitch propeller was first produced at the Royal Aircraft Factory at Farnborough. In 1916 an R.E.8 took off with a four-blade propeller capable of being set to either a fine pitch or a coarse one according to the command of the pilot. It had wooden blades, held in rotary bearings in a steel hub, and weighed about 50 lb more than the usual all-wood propeller.
Note that this is not the first use of a variable pitch propeller on an aircraft as that milestone belonged to the British Army Dirigible No 1/Nulli Secundus as noted in a
previous post. However, it may be the first
airplane with one - depending on when the Zeppelin-Staaken R.VI flew. The book goes on to state that:
John W. R. Taylor, et al. wrote:
In 1924 the Gloster/Hele-Shaw/Beacham propeller was patented, and this was the first constant-speed design actually to be flight tested, on a Gloster Grebe fighter in 1927.
(Source: John W. R. Taylor, ed.,
The Lore of Flight (New York, New York: Crescent Books, 1978), 234.)
According to the
History of Technology:
Quote:
The first reliable air speed indicator was a U-tube manometer called the velometer, designed and patented by Frank Short at the Royal Aircraft Factory at Farnborough in 1912. Connection to a pitot-static head on a wing strut allowed the measuring element to be well away from the slipstream, while the indicator could be placed in front of the pilot. The velometer was manufactured by Casella and Elliott Brothers and was often supplied to military aircraft on a standard instrument panel.
(Source: Graham Hollister-Short and Frank A. J. L. James, eds.,
History of Technology, vol. 18 (London: Bloomsbury Academic, 1996), 99. via
Stack Exchange)
I had the thought of looking into the first aircraft with an angle of attack (AoA) indicator and in the process I came across an excellent
article that covered the history of AoA measurement. It pointed out leading edge stall tabs and stall warning horns were the first actual AoA indicators - albeit only in one direction. It made me realize that what I am actually after is the first example of what is traditionally thought of as AoA indicator - that is to say a vaned instrument. Luckily, the same article was able to point me in the right direction. In 1962, a company called Monitair filed a
patent application for an "Angle of Attack Measuring Device". Unfortunately, determining the first aircraft to use such a device was beyond a quick Google search.
A radar altimeter, called a "terrain clearance indicator", was first tested in a United Airlines aircraft on 8 and 9 October 1938.
[1][2] Unfortunately, while finding news about the event was easy, determining what the specific aircraft was has proved difficult. (In the process, I found a
story that mentioned an "automatic direction finder" was tested on an American Airlines DC-3 around the same time.) While a picture on
page 5 of the 25 October 1938 of the
Kansas City Times shows the interior of the aircraft, but does not name it, an article on page 4 of the 10 October 1938
Daily News states that: "United Air Lines used its famous "White Tail" Boeing flying laboratory for the test flight." Although the specific model is not stated, based on the aforementioned picture it seems to be a Boeing 247.
EDIT (21-08-02): An
article in the January 1939 issue of
Popular Aviation provides a bit more detail about the invention of both the radar altimeter and the automatic direction finder.