Tandem Wing Aircraft Were Almost A Thing In WWII | Miles M.35/39 Libellula [Aircraft Overview #83]

foreign we're taking a look at a pair of very unusual and interesting prototypes hailing from the United Kingdom of a tandem Wing configuration they were certainly some of the more unique looking aircraft of the 1940s though many still do not know about these strange designs to this day we are of course talking about the miles M35 and m39b Lee balula libalula referring to a genus of dragonfly known for having two sets of similar span Wings was a designation given to a series of Miles aircraft that experimented with the same concept from the get-go this tandem Wing layout was predicted to have a fair amount of benefits over the conventional Wing configurations including a greater center of gravity range between the two main planes which could help to reduce the required fuselage length and wingspan of an aircraft these characteristics if properly implemented would be hugely beneficial for carrier-based aircraft where every reduced meter of required Hangar space is considered very valuable it could also negate the necessity of a folding Wing mechanism which introduces more points of failure and weight but is usually necessary for most conventional carrier-based aircraft the libalula concept therefore seemed to be a perfect candidate for carrier-borne applications indeed it was the problems being experienced by the Royal Navy in 1941 with their improvised seafire and sea hurricane that inspired miles towards this line of thinking miles aircraft limited an aircraft company originally founded in 1928 under the name Phillips and Powers aircraft would become one of the larger proponents of the tandem Wing layout this was despite their background in more conventional civil aviation where they had produced aircraft such as the miles Hawk major and the found token under lead designer Frederick George miles development would begin on their first military tandem Wing design in early 1942. in November 1941 George miles had been inspired by the site of a heavily modified Westland Lysander he along with several other designers had been looking for a solution to the Navy's carrier fighter problem the attrition rate from Landing accidents was now becoming appalling and he quickly realized that the tandem Wing design could be the answer in his mind a design rapidly formed the pilot could be located in the nose which would provide perfect visibility for takeoff and Landing aboard a carrier with vertical control surfaces on the rear Wings the weight and drag of a tail plane could be removed to allow for the installation of a rear mounted engine this not only further improved Pilot's visibility but also comfort as the noise and vibration of the engine and propeller would be as far away from the pilots as physically possible the whole Arrangement could be incredibly compact in terms of span and the whole airframe would be easy to transport by land and at C it would fit on the elevator of an illustrious class carrier without the need for folding Wings to avoid the bureaucratic complications that came with submitting an unorthodox design for official consideration and because they weren't technically allowed to do anything without the air Ministry say so anyway the development of this new aircraft was done in total secrecy miles opted to First build a small flying wooden mock-up this aircraft designated the M35 featured two high-mounted front Wings directly after the cockpit and two larger swept back wings at the rear to which the twin Rudders were mounted the elevator would be in the front wings and the ailerons in the rear wings and a singled Haviland Gypsy major producing just 130 horsepower would drive the M35 in a a pushing configuration owing to the secret nature of the project miles couldn't exactly roll his new design into a wind tunnel to assess its stability because of this it was decided to build a scale mock-up of the scale mock-up built to one quarter scale and tatoata Loft for an experimental flight did not provide much in the way of encouragement the model initially climbed exceedingly well so well in fact that it threatened to overtake the towing aircraft the Prototype miles m28 but then when the tow line was released the model immediately stalled and plummeted vertically into the ground 150 feet below with zero signs of it trying to recover despite this preference for litho braking rather than gliding miles was confident that the M35 would behave better under its own power and so work continued on the 1st of May 1942 the M35 would conduct its Maiden flight early in the morning it was towed through the streets of reading towards the nearby Airfield its short 20-foot wingspan allowing it to be transported fully assembled but upon its arrival miles's Chief test pilot took one look at the Prototype and said surely you don't expect me to fly that not to be displayed made George miles himself would take over and conduct the first flight trials it was found that the aircraft was initially reluctant to take off and to get it to leave the ground the throttle must be sharply closed while at high speed upon which the aircraft would leap sharply into the air after overcoming this quirky behavior and successfully taking off it was found that the aircraft was essentially uncontrollable though George miles was fortunately and very skillfully able to bring it in for a safe landing without incidents according to Miles the aircraft was in his words catastrophically unstable and the brief flight had been a ceaseless battle to prevent violent pitch oscillations bizarrely one official report states that the aircraft flew successfully the first time it took off climbed to about 200 feet circled the aerodrome and landed it's then reached the somewhat contradictory conclusion that the aircraft behaved quite well with the exception that it was completely longitudinally unstable under all conditions of flight now it's most likely that this was a second-hand report and one which was not written by a witness to the flight and the author of said report instead based their conclusions on nonchalant and slightly biased comments made by the aircraft's designer in a later meeting with air Ministry officials a post-flight investigation found that the control issues had been a result of a misaligned center of gravity which was promptly remedied with ballast for further flight testing additionally miles reported that there had been issues with the engine overheating and to correct this an airscape was added to the rear of the starboard fuselage in the following weeks the M35 logged a number of additional flights which were considerably more successful and the aircraft had demonstrated promising performance and handling buoyed by this miles then submitted a proposal for a naval fighter based on the M35 to the admiralty and the ministry of aircraft production in April who promptly chastised him for producing an unauthorized mock-up of the aircraft and outright rejected the proposal despite this setback George was not to be discouraged as he considered the results of the M35 to be extremely promising he immediately began work on an enlarged bomber design of the same principle to meet a Ministry specification b11-41 which outlined a medium altitude high-speed bomber aircraft that could carry at least 2 000 pounds of bombs this would eventually result in the m39b which would also be built in a small scale for initial flight tests and featured a different though just as unusual design as the M35 the single engine in the rear fuselage would be replaced by twin de Havilland Gypsy engines in the rear wing whilst a tall ventral vertical stabilizer would be added to improve lateral stability the general layout of the front Wings cockpit swept back rear wings and twin outboard vertical stabilizers would more or less remain the same albeit enlarged from the M35 however in order to prevent down wash and improve ground clearance for the propellers the previous mostly High mounted forward Wings would be moved further down and inversely the previously low mounted rear Wings would now be mounted High the m39b was completed in mid-1943 and immediately handed over to the Royal aircraft establishment for formal flight testing whereupon flight trials would begin on the 22nd of July these trials would predominantly be undertaken by George miles and flight lieutenants HV Kennedy and despite some setbacks involving the landing gear collapsing overall handling characteristics were deemed to be fairly good some small alterations were needed to improve stability during takeoff and Landing mainly Shifting the center of gravity a little and some minor trim adjustments but on the whole these changes were not major as a small scale mock-up with placeholder engines the aircraft was of course significantly slower than its intended full-scale production version reaching a maximum speed feet of just 164 miles an hour its smaller size also brought with it another unexpected problem it was reported that due to the lightweight construction of the fuselage the cockpit would experience alarming lateral oscillations and the entire front of the fuselage would warp and Bend from side to side which made for some hair-raising moments in its earlier flights but this was soon fixed by the addition of heavier gauge ply skin the m39b received plenty of Praise with test pilot Don Brown reporting that the aircraft showed no sign of longitudinal instability or other undesirable characteristics on the contrary it handled perfectly normally like any other twin of its power and with the additional advantage of no swing on takeoff and no Wing drop at the stall though not officially tested with it the aircraft was planned to have a fairly impressive Armament capable of holding up to six thousand pounds of ordinance in its Bombay along with mounting twin 20 millimeter cannons in the cannons carrying such a load was not to be a problem even during takeoff from a smaller Airfield a typically ingenious mechanism had been devised by Miles allowing the elevator to be operated normally over their full range on the rear wing but when the flap was deflected the elevator mechanism was also activated allowing the flap and elevators to work in unison this also had the benefit of greatly reducing the stall speed of the aircraft during takeoff which was often the most dangerous time for a Bomber Crew other than encounters with the enemy of course development of the M39 would remain a private Venture until September of 1943 several months after its completion when it peaked the interest of the British Air Ministry who offered a formal development contract perhaps optimistically attempts were also made to Garner interest from the US Army Air Force after it came to miles's attention that they were working on the xp-55 which shared some design features with the M39 and this would ultimately fall through though as the xp55's flight testing had left right field of the opinion that the design was not worth further development despite the official backing from the air Ministry only a single prototype of the m39b would be produced the specification to which it had been built was actually canceled before the aircraft was even complete but instead of ordering it scrapped the m39b was taken from miles and put through an accelerated test program at re farnborough this was done to explore the feasibility of the tandem Wing design in an envisioned high-speed jet bomber instead to which miles may have still received a production contract but at the conclusion offset trials the benefits of Tandem Wing aircraft were now being nullified by those of rear-facing jet engines which allowed the same visibility and advantages that the liba Lula designs had boasted and after a period of further testing back at Miles the M39 was eventually scrapped in such a climate of Rapid development the m39b stood no real chance against its emerging jet-powered competitors the earlier M35 might have had more luck had the air Ministry shown some initiative but it's impossible to say how successful it would have really been as such they remain an unusual and fairly unknown aircraft despite their striking Aesthetics a good concept that was simply overshadowed by an emerging technology now if you want to find out more about these fascinating designs fear not for I am working on one of my longer Deep dive videos where I will cover the entire series of experimental miles aircraft in detail for there were quite a few but that is a topic for another day as always thank you all so much for watching and a big thank you of course to the patrons whose names you will see here with Christmas just around the corner I'll be taking some time to myself but there should probably be at least one more video for December after this so keep an eye out for that and hopefully I'll have some channel news in the not too distant future a big thank you as well to our wing Commander tier patrons our top tier members uh once again patreon is being a bit slow with updating my list so if I have missed anyone I apologize in advance and I'm probably going to put up some polls this week or next week for some video ideas for next year so please stand by for further details but as always thank you all so much for your continued support and I'll catch you all next time goodbye

Channel: Rex's Hangar

Views: 147,120

Keywords: Miles aircraft, Miles Libellula, Miles M.35 Libellula, Miles M.39B Libellula, Libellula, tandem-wing, tandem-wing aircraft, four wing aircraft, aviaiton, history, plane video, rexs hangar, rex's hangar, Miles M.35 & M.39 Libellula

Id: vmQJd_yaJkI

Length: 14min 42sec (882 seconds)

Published: Sat Dec 24 2022