Italy’s Bizarre Flying Barrel | The Stipa Caproni [Aircraft Overview #55]

on october the 7th 1932 a highly experimental aircraft prepared for its first flight this was the steeper caproni or the caproni steeper depending on who you talked to it was designed by luigi steeper and built by giovanni caproni's aircraft company though it may have looked like this strange love child of a gb racer and a dustbin it was in fact an innovative design that despite appearances was completely flyable and represented an early example of ducted fan technology now while the steeper caproni may have been an odd blustery and somewhat terrifying machine the sponsor of today's video endel is a far more relaxing affair do you have a hard time focusing on your daily tasks do you find your productivity suffering due to stress or anxiety or do you find that the sweet embrace of sleep never quite arrives and you spend six hours staring at your ceiling in a muted rage endor could very well be the solution for you endl is an environment-based non-profit app that takes everything we know 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he returned to his education and spent the post-war years earning academic degrees in aeronautical hydraulic and civil engineering he then found himself a job with the italian air ministry where he worked his way up to the position of general inspector of the engineering division during the mid to late 1920s he began to work on several theories for making aircraft more efficient as a hydraulic engineer he knew that the velocity of a fluid increased as the diameter of the tube through which it passed narrowed called bernoulli's principle the relationship between the velocity and the pipe diameter was a well understood axiom of fluid dynamics by the 1920s applying bernoulli's principle to airflow steeper believed he could increase the efficiency of an aircraft's engine by directing the prop watch through a venturi tube steeper called his concept an intubed propeller he designed built and tested several aircraft models that featured this new concept and after multiple iterations had gone through rigorous wind tunnel experiments steeper believed he had worked out the optimum shapes which the propeller and tube would be designed to as it turned out the optimal shape for the tube's inner surface turned out to be almost exactly identical to that of an aerofoil and so in many ways the tubular fuselage of his design essentially resembled that of a wing that had been rolled up into a tubular shape steeper published his findings in the bravista aeronautica along with design drawings for a single engine test aircraft he then approached his superiors at the air ministry about the possibility of building his plane and the minister for aeronautics keen to showcase new innovations almost immediately agreed the decision was made to build a small aircraft that was to be powered by a 120 horsepower engine this was not the ideal outcome for the realization of the design but rather it represented a compromise firstly building a smaller aircraft would of course save money and if the endeavour turned out to be a failure then the loss would be reduced and secondly there had been no major wind tunnel tests done on larger complete models and so there was no data available to determine the maneuverability aerodynamics and the general behavior of a larger design however on the flip side it was acknowledged that steeper's design was written out with larger aircraft in mind and indeed it was considered poorly suited for smaller ones but with the ministry reluctant to finance a larger project for the reasons mentioned just before luigi stipa had to make do with what he had eventually he came to an agreement with the air ministry and they contracted the caproni aviation company to construct the experimental prototype as regular viewers of this channel already know count gianni caproni was no stranger to experimental designs you only have to look at the ca 16 over plano or the ca 90 to get clear evidence of that and as a result of these adventurous designs his company was probably the most qualified in italy to take on the challenge of realizing steeper's theory in terms of its construction the aircraft in general was rather simple but it featured some notable changes from the wind tunnel models that i will cover shortly as mentioned earlier the tubular fuselage resembled a wing that had been rolled up and as such its construction closely resembled that of normal wings as well it had two strong main rings which could be considered large circular spas on these spas were mounted longitudinal ribs which were similar in design to wing ribs and these were braced by a series of smaller spars which were again circular like the main ones the elliptical wings looked almost comically flimsy but that was only a visual effect courtesy of the fuselage's size these wings were built in the traditional manner being made of wood with a fabric covering and to improve strength the wing spars ran along almost the entire span passing through both the tubular fuselage and the engine nacelle itself at the rear the rudder and horizontal stabilizers were mounted onto the trailing edge of the fuselage it was hoped that by placing the rudder and elevator in the path of the air pushed back by the propeller they would allow a superior level of control and so in turn the size of the control surfaces could be reduced in the end this reduction would never take place and in fact it would be later suggested that their size be increased rather than decreased the 120 horsepower engine took the form of the four-cylinder de havilland gypsy iii this drove the so-called intude propeller which was a two blade fixed pitch wooden unit that fit snugly within the dimensions of the fuselage this engine was supported by a frame that was connected along with the wing spars to the main circular spas of the fuselage when first completed the engine was housed in a small nacelle however there is evidence that this was removed on multiple occasions though it is unclear if this was to test the effects of the aircraft's handling or if this was due to some sort of heating or cooling issue now i mentioned earlier that the prototype featured several differences compared to the original wind tunnel models some of these differences are worth noting as they directly impacted the performance of the aircraft firstly to simplify the construction the tubular fuselage was redesigned to be symmetrical in steeper's original design the fuselage was dissymmetrical so that it could generate a certain amount of lift even at zero angle of attack but with the new changes this lift was reduced while at the same time overall drag increased secondly the wings were braced by four steel wires whereas on the original wind tunnel model this was not the case it's unclear whether this was an oversight by a luigi steeper or whether it was the result of further investigations that deemed it necessary to reinforce the wings in this way regardless of the decision this and the changes to the fuselage affected the overall drag which meant that the estimated top speed climb rate and general handling characteristics of the aircraft would not match the predictions of the earlier wind tunnel tests but even with the negative effects of these modifications the plane was expected to be perfectly airworthy and so construction continued as planned for those who first gazed upon it it must have been a rather strange sight and while caproni was silently adding another sticker to his weird aircraft design bingo card the tubular plane was made ready for its first test flights the date of the first flight was october the 7th 1932 and despite some suspicious glances from onlookers the pilot already had some praise for it before it even left the ground since the propeller diameter was the same as that of the fuselage the steeper caproni sat very low to the ground and thanks to a fairly wide undercarriage this meant that it had excellent ground handling characteristics that being said it did look rather comical when it was being taxied around the airfield before taking off flying the aircraft was caproni test pilot domenico antonini a veteran test pilot who had flown many of caproni's more bizarre designs such as the huge ca-90 biplane for example after pottering around the airfield to get a feel for the engine and the throttle antanini powered up and the barrel-like plane took off for the first time overall the aircraft behaved well in the air and antonini found it easy to handle following the first successful flight a series of test flights were conducted to gather data and evaluate the soundness of luigi's steepest theory these first tests did indeed confirm that the design seemed to make more efficient use of the engine compared to a more conventional design though the redesign of the fuselage had reduced the additional lift it provided it still created enough that it had a superior climb rate over a conventional aircraft with the same engine and it also had a very low takeoff and landing speed of just 68 kilometers an hour it was also incredibly stable in fact it was sometimes too stable with subsequent test pilots complaining that it was difficult to pull the aircraft into banked turns what was unknown to both steeper and caproni at the time but was later revealed by further testing was that the tubular fuselage generated far more lift than expected as such the required wing area for stable flight was less than what was designed and had further models being built the overall wing size could have been much smaller although the design increased the efficiency of the aircraft in terms of engine power required for lift the design also created so much drag that it essentially canceled out any of its benefits as a result of this the aircraft was slower than expected reaching a top speed of just 131 kilometers an hour with the engine threatening disintegration if it was pushed any further some of this aerodynamic drag was created by the modifications made during construction but some of it was created by the intubed propeller design in general ultimately the low-powered engine and bulky propeller were not enough to take advantage of bernoulli's principle and generate superior thrust and so when the aircraft was handed over to the regia aeronautica for testing it failed to outperform conventional designs though it was reviewed favorably by air force test pilots the decision was made to cancel further development and no additional prototypes were built this was a huge disappointment to steeper and caproni as well who had come to appreciate the potential of the design steeper had designed and built several models for larger aircraft specifically flying wings equipped with two or four issued propellers and they tried to secure funding for a new project however these attempts ultimately failed had a larger prototype been built it could well have been very easy to fly if the steeper caproni was anything to go by but this flight of fancy would never come to pass though the air ministry didn't embrace steeper's design it didn't stop them and the italian government from using it as a propaganda tool steeper patented his intuit propeller design in germany and in the united states and his work was published in multiple countries in fact a large amount of my source material comes from a naked technical memorandum that was written up in 1934 unfortunately this remarkable aircraft was eventually scrapped but a three to five scale replica was built in australia in the 1990s it was built by lynette zakuli and aerotech queensland and it made at least two flights in 2001 it's unclear if the replica was ever flown again after this but it can be found on display at the toowoomba airfield which is not too far away from where i live so maybe i'll do a follow-up video where i go and pay to visit although italy made no further efforts to develop steeper's design a more advanced derivative would be realized in 1940 though the caproni campini n1 was nowhere near efficient enough to be practical it did make use of a ducted fan compressor buried in the fuselage and by adding additional fuel to a combustion chamber in the tail it gave italy the laudable claim of producing the world's first afterburning aircraft but that's a story for another day as always thank you all so much for watching and i also apologize if my voice sounds a bit off with this one and for the next few videos right before i went away on my holiday i started coming down with a cold which obviously makes my voice sound a bit more rubbish than usual so apologies for that and of course thank you all to the patrons including the wing command to tie patrons i shall be updating the list as soon as i get back home but as always thank you all so much for watching and i'll catch you all next time goodbye

Channel: Rex's Hangar

Views: 147,540

Keywords: aviation history, airplane documentary, stipa, caproni, stipa caproni plane, caproni stipa, giovanni caproni, luigi stipa, rex's hangar, weird plane, plane video, aeroplane video, aviation, history, aircraft, interwar period, ducted fan, strange plane, bizzare planes, Italy’s Bizarre Flying Barrel

Id: X3K0QPfmznY

Length: 16min 0sec (960 seconds)

Published: Thu May 19 2022