The 6,000 Horsepower Plane that Nearly Killed Howard Hughes - The XF-11

my personal favorite world war ii aircraft will always be the p-38 lighting yes in the late war it may have been outclassed and a little too large to really mix it up with a spitfire or bf-109 but there's just something about a good twin boom design that i seem to like that's why when i discovered that howard hughes had tried to build a high-speed overpowered photo reconnaissance plane that could fly faster than a p-51 but still looked a lot like a p-38 i knew it was time for a new video as most of you know just about anyone in the airplane manufacturing business and some that should have probably stayed out was trying to get a piece of that sweet sweet uncle sam money and get orders from either the navy or the air corps throughout world war ii and unsurprisingly the story of the xf-11 starts with howard hughes trying to get a piece of that pie originally hughes high-speed aircraft was intended to fulfill a variety of roles but because it was to be constructed from wood the army air force neglected to show any interest to try to save the project hughes proposed that the aircraft be redesigned from what was then called the d2 to the d5 which would eventually be made mostly of metal to satisfy the air core now considering what we know about the speed of the mosquito i'm also left wondering just how fast the d5 could have gone if more wood construction was kept in the design but that's a rabbit hole we don't have time for today in any case trying to find a good niche in which he could sell the aircraft to the government it was eventually decided that due to the potentially high top speed of the d5 and its large size it would be ideal for a photo reconnaissance role the initial d5 design was essentially an enlarged version of the d2 and its fuselage used a duramold constructed using resin impregnated layers of wood that were then molded to shape under pressure and heat also when i say that the d5 was enlarged that might be a bit of an understatement for an aircraft that bridged the gap between a potentially heavy fighter and an attack aircraft for its day the d5 was massive with a wingspan of 92 feet and a length of 58 feet it was only a few feet shy of the size of a full b-17 bomber albeit much lighter while the earlier d2 had intended to use the pratt winnie r 2800 engine its larger sibling the xf-11 would feature two massive r48360 cylinder radial engines each generating around 3 000 horsepower which would propel the aircraft to a staggering 450 to 488 miles an hour additionally the aircraft was capable of carrying a 4 000 pound bomb load if needed in an internal bay however just when things were looking ugly for the xf-11 project along came colonel elliott roosevelt son of none other than president roosevelt himself having traveled to los angeles to meet with various aircraft manufacturers specifically about photo reconnaissance aircraft hughes soon got word and invited colonel roosevelt to his facility now i couldn't find any specific details about their meeting however we do know that despite that he was only shown the currently built d2 model rather than the d5 as the d5 was not yet complete roosevelt left hughes's facility impressed afterwards surprise surprise general have arnold began feeling pressure from the white house to order the hughes d5 however the army air force still had big reservations about the dura mold construction and the use of wood in general because at the time the d5 was still intended to be made entirely from durham mold to finally remedy this issue once and for all hughes agreed to redesign the wings and tail booms as all metal construction while the fuselage would remain dura mold after hughes's capitulation general arnold proceeded to order d5s however it should be stated that we have a record that his staff was very much against his decision so with all the proper people on his side howard hughes received an order for 100 examples of his d5 reconnaissance aircraft on october 6 1943 the official contract renamed the d5 to the f11 and plans were for two aircraft to serve as prototypes while the remaining 98 would be production versions in terms of the aircraft's layout it was very similar to the p-38 as we've said however instead of the nose cone of the aircraft containing weapons the front of the xf-11 contained photographic equipment additionally the xf-11's cockpit was pressurized for the pilot's comfort and would maintain an altitude of 10 500 feet cabin altitude all the way up to 33 500 feet because of how tall and large the aircraft was instead of climbing on the wing as you might in a p-38 access to the cockpit was instead through an extendable ladder just behind the nose landing gear interestingly the pilot seat was intentionally offset to the left so a second crew member sitting slightly behind and to the right of the pilot could fulfill his role of navigator photographer to access the photo equipment in the nose the navigator would crawl past the pilot and into the cramped nose cone one of the other interesting features of the xf-11 was its nearly full span wing flaps rather than typical flaps the xf-11s flaps cover the distance between the booms and then beyond the engine the cells out nearly to the wingtip in terms of role the xf-11 was also peculiar relying on a set of spoilers as its primary roll control and featuring relatively small 5 foot ailerons in terms of range the xf-11 was anything but lacking each wing incorporated a hardpoint outside of the tail boom for a 700 gallon drop tank and in addition a 600 gallon jettisonable type tip tank was also proposed however i can't imagine why they were proposing the addition of so much fuel capacity as even with only the aircraft's internal fuel load the xf11 had a 5 000 mile range okay so let's talk about these engines i'll probably do a future video focusing solely on them because they definitely deserve it but the xf-11 was powered by the monstrous r4360 a 28 cylinder behemoth of a piston arrow engine they cranked out 3 000 horsepower each and were housed on the xf11 within a streamlined cowling in typical fashion cow flaps for engine cooling encircled the sides and top of the cowling and under each nacelle was a scoop that housed the oil cooler and provided air to the intercooler and two general electric bh1 turbochargers yes yes i said it they were going to twin turbo those are 4360s eat it lockheed hughes was just ripping off the p-38 but he was also pumping it full of american pratt whitney steroids the turbos were on the inner side of each tail boom and one could be shut down during cruise flight to take full advantage of the remaining turbo operating at its maximum performance rating with all the ducting of the two turbos the space in the boom was tight however the main landing gear still retracted to the rear and into the tail boom attached to the end of each boom was a large 11 foot 8 inch tall vertical stabilizer banding between those stabilizers was the 25 foot eight inch horizontal stabilizer and elevator also interestingly the left tail boom housed additional camera equipment behind the main landing gear overall for reference the xf-11 was lighter than a b-17 but only just weighing in at fifty eight thousand three hundred and fifteen pounds at max weight compared to the b-17's maximum of sixty five thousand five hundred delivery of the first xf-11 was originally scheduled for november 1944 and at a peak production the hughes company intended to deliver 10 aircraft per month by march 1945. however just like every aircraft manufacturer eventually discovers delays were encountered almost immediately by the middle of 1945 the xf-11 had still not flown and the war was coming to an end as the army air force no longer expected a need for such an aircraft it canceled its order on the 26th of may 1945 but hughes was determined to finish the design and the construction of two prototypes proceeded the first xf-11 prototype was fitted with these awesome hamilton standard super hydramatic contra rotating propellers and began its first taxi test in april of 1946 however problems were encountered and after several redesigns the aircraft once again began operational testing in early july still working with the army air force hoping they might change their mind and find a reason to once again order the aircraft hughes opted to make the next test flight a full flight while the army air force had stipulated that the first test should be no more than 45 minutes the landing gear should remain down and locked and communication should be established with their chase plane hughes instead elected to fill the xf-11 with 1200 gallons of fuel which was twice as much as he needed furthermore he also neglected to get a full briefing from his engineers who would have likely reminded him about the propeller seal leak that would quickly become life-threatening in the event that he flew for longer than 45 minutes to further complete our swiss cheese model of mishaps once hues took to the sky radio failures prevented hughes from establishing contact with the 820 chase plane the army air force had fielded just for this test so with a leaking propeller hub and essentially no regard for any safety precautions hughes departed culver city in the first prototype of the xf-11 at 5 20 pm and immediately retracted his landing gear unsurprisingly as it wasn't intended to be retracted something went wrong and the landing gear position indicator failed to show a successful retraction of the right main gear to troubleshoot hughes flew over the pacific before turning back toward land while cycling his gear several times in an attempt to achieve a successful retraction after an hour and 15 minutes of total flight time the prop seal leak on the right rear prop had exhausted its supply of oil and the blades moved to a flat configuration creating a huge massive amount of drag again had hughes simply stuck to the original flight plan he wouldn't have been troubleshooting his gear nor would he have depleted the oil from the propellers reservoir as such and again because they had no communications with hughes upon seeing the aircraft turned back toward land the a-20 figured hughes was maneuvering to return to culver city and broke formation returning to their own airfield likely because hughes had been troubleshooting his gear he believed the drag he felt was the result of his right gear deploying and remaining locked down in addition because the aircraft used spoilers for roll control rather than ailerons as hughes attempted to hold the aircraft level the spoiler further slowed the aircraft closer to its minimum controllable airspeed barely able to control the aircraft and rapidly losing altitude due to him exchanging it to maintain a controllable air speed hughes made a forced landing while trying to stretch his glide to the los angeles county club's golf course however because of the drag of the propeller he would land short and crash into four houses as the aircraft broke apart catching fire in the end amazingly hughes would pull himself from the wreckage before being received by neighborhood residents and paramedics after the accident hughes would suffer major injuries including severe burns 11 broken ribs a punctured lung and a displaced heart remarkably he made a full recovery but he would soon suffer from a codeine addiction for the rest of his life in response to this instance the propellers on the next prototype were swapped for a single set of four bladed propellers made by curtis electric and despite his injuries hughes remained adamant that he also pilot the second prototype in fact he was so insistent he made the second flight that after the army air force initially refused hughes offered a 5 million bond payable to the army air force if he crashed the aircraft despite initially being leery of allowing it money talks and the army air force eventually agreed to let hughes fly on april 4 1947 hughes flew the second xf-11 prototype on its first flight departing now from hughes airport as one can imagine the flight was a big personal victory for hughes after a successful first flight the second xf-11 was delivered to right field in november of 1947 and after further test flights the aircraft was then sent to eaglin air force base in florida where it was noted for having excellent flying characteristics but poor reliability additionally it was disliked by navigators because in-flight access to the cameras was quite difficult despite these complaints though further testing of the xf-11 was conducted from december 1947 through july of 1949. so what happened well tragically the xf-11 in the end became a victim of budget constraints because many b-29s and b-50s had already been converted to reconnaissance platforms and were much less expensive to operate they made the xf-11 irrelevant while the added speed and performance of the aircraft would have no doubt aided to its ability to outperform its competition at the time the air force decided it had much more promising projects to fund as such the x-11 was transferred to shepherd air force base in wichita falls in july of 1949 where it would remain unflown until finally scrapped in november as always guys thank you so much for tuning in to flight dojo up next on the channel we're excited to cover the daimler bins set of double motors and again if you're interested in seeing future content don't forget to subscribe and turn on the notifications button so you don't miss any of our videos

Channel: Flight Dojo

Views: 2,178,125

Keywords: wwii, howard hughes, aviation, weird wings, XF-11, wwii aviation, history, technical history, engineering history, aviation history

Id: W9NapQQnmwY

Length: 12min 44sec (764 seconds)

Published: Wed Jul 20 2022