Tour around the North American XB-70 Valkyrie - the greatest cold war bomber that never was.

hello and behind me is a north american xb70 valkyrie which was a high-speed high-altitude bomber designed to replace the b-52 although by the time it was flying it was essentially superseded by the icbms so it was used to research our high-speed flights and in this video i'm going to take you on a detailed tour of it i make videos about planes and some rockets if you enjoy trip reports on board flights around the world and tours through interesting aircraft in museums then check out my channel i'm also on instagram and facebook now we'll start at the nose first up you'll notice that it's quite a bit higher than the rest of the aircraft and that was intentional so that it wouldn't alter the air flowing under it and hitting the splitter which was important for the whole design and i'll explain that shortly the black ramp just forward of the windscreen was a variable position canopy similar to that on concord it could be raised at higher speed to improve aerodynamics or lowered as you can see here to increase visibility during landing and takeoff further back is the canard which are like smaller wings they allow the crew to trim the aircraft across different ranges of speed they could also be used as flaps to increase lift during low speed stages such as landing and takeoff as the delta wing shape itself did not generate a lot of lift at low speed and by the way below that is a prototype lockheed yf-12 interceptor version of the a12 reconnaissance plane and i will be doing a tour video through both that and the sr-71 on my channel let's walk further back and i'll explain why the aircraft is this shape you've got this small gap here at the top of the splitter and this essentially removes the boundary layer air which is otherwise turbulent and reduces engine efficiency then directly below that you've got the main vertical splitter this creates a shock wave which is an area of high pressure air extending behind it on both sides of the aircraft the wing is perfectly located to capture the shock wave and it generates additional lift in fact north americans engineers expanded on this idea and at this black device here the wing tips could actually pivot downwards 65 degrees at high speed and keep the shock wave underneath the wing and promote further lift here's a photo of this actual aircraft flying and you'll notice that the canopy at the front is streamlined for high speed and the outer aspect of the wings is angled downwards trapping in the shock wave now let's have a look at the forward landing gear and you'll notice that the tyres are silver i'll mention this in more detail later but the entire aircraft would heat up due to a skin friction from the supersonic air rushing past so normal rubber wheels would melt while sitting in the wheel well at cruising altitude so they infuse the rubber with aluminium to help reflect the heat ethylene glycol which is used in car engine coolant is also piped through the wheel wells to remove some of the heat in fact elsewhere the jp-6 fuel was also pumped around the aircraft working as a heatsink before eventually arriving at the engines and rapidly increasing in temperature quite a lot there now here you've got the main air inlet unlike the sr-71 they did not use the ramjet principles so air would have to be slowed down to subsonic speed by creating shock waves inside the inlet so that the air would cross those and therefore slow down these vents here had an important role in removing air to optimize the pressure just before the engine inlet and just behind these and before the main landing gear was the internal bombay where both conventional and nuclear weapons could be stored obviously being a supersonic jet no weapons were stored on external pylons as that would affect the aerodynamics here we are at the main landing gear and you'll notice a smaller sensing wheel which was a very early anti-lock braking system the smaller wheel measures the ground speed without any skidding and compares this to the braked main wheels which could lock up through clever mathematics done over milliseconds this system could calculate the maximum braking safe to apply without locking the wheels and again the tyres were silver to help manage the heat now earlier i mentioned the wingtips folding downwards to trap the shock wave they also had the benefit of adding more vertical surface to the aircraft which maintains directional stability and allowed them to use smaller vertical stabilizers at the back which was a problem in an aircraft this tall remember that the b-52's large single vertical stabilizer could actually be folded over at 90 degrees to help it fit in a hanger as you can see there's no horizontal stabilizer which would usually be responsible for pitch control so instead there are these six per side elevons on the wings trailing edge and these functions both elevators and ailerons and there's also twin vertical stabilizers which has the added effect of redundancy if one is damaged but it also creates a larger amount of vertical surface without having to have a larger single fin which again would require a much larger hanger now let's have a look at these engines and it's pretty amazing seeing these six exhaust nozzles all lined up next to each other i don't know about you but the xb70 really does look like a spaceship they had fully variable convergent divergent exhaust nozzles which meant that the pressure could be optimized by increasing or decreasing the diameter of the nozzle it's a similar principle to increasing water pressure by partially covering a hose with your finger now the general electric yj93 turbo jets did come with an afterburner or reheater as the british call them what's interesting is that they initially plan to use zip fuel boron was added and it could produce 40 or more power than standard fuel but when it was burned it would produce toxic exhaust material that was sticky corrosive and highly abrasive and damage the engines so they came up with the idea of using standard fuel in the engines but then add the zip fuel in the after burner but this ended up being too expensive and complicated and they canned the idea here's an example of the engine that they had sitting below the aircraft now you can't really see them when they're on board which helps reduce aerodynamic drag although obviously accessing them for maintenance becomes more of a chore now the yj93 was designed for both the xb70 and the north american xf-108 rapier interceptor which would have been a long-range mach 3 capable interceptor designed to stop soviet supersonic bombers but when the xf-108 was cancelled because the soviets built icbms instead that put added financial pressure onto the xb70 as it was now the only recipient of this engine now it could produce 28 000 pounds of thrust each with the afterburner powering it to a top speed of mach 3.1 with a service ceiling of 77 000 feet it was powered by jp6 aviation fuel which was specifically designed for the xb70 and was stable enough to withstand the high temperatures from the aerodynamic heating so that it could be pumped around and used as a heat sink but to still reduce the chances of auto ignition nitrogen was injected into it during refuelling and a supply on board was used to replace the space in the fuel tanks as the jp-6 was burned up now to talk about the aerodynamic heating at mac 3.1 the friction created by the air flowing past the skin could create a huge amount of heat on average the skin would reach 450 degrees fahrenheit with the leading edge reaching 630 and up to 1000 degrees fahrenheit in some of the engine components now titanium was used all through the sr-71 and that was preferred although it was expensive and rare the best source of it was also from the soviet union so the sr-71 program required the cia to actually set up shell companies in other countries then buy the titanium from the soviets and then ship it secretly to the usa to avoid having to do all of this on a much larger scale as the xb70 was a much bigger aircraft they had to look at alternatives they used a honeycomb stainless steel for areas that would reach only 450 degrees fahrenheit and only use a titanium for high temperature areas like the nose the leading edge of the canals and the vertical stabilizers as with the sr-71 they also pumped fuel around the aircraft to act as a heat sink before it was sent to the engines initially it had a crew of four the pilot the co-pilot the bombardier and the defensive systems operator although when its role was changed to a research aircraft it was reduced to just the pilot and the co-pilot now the interior was pressurized and comfortable in fact they said that the crew could have worn short sleeve shirts although they would have still worn proper flying suits to enable high speed and altitude ejections they had a clamshell ejection capsule which could protect them from the supersonic winds and had its own oxygen and pressurization system the crew could actually be inside it and ready for ejection and still control the aircraft via a control stick on the one occasion that it was used when the other of the only two xb70s ever built crashed after an in-air collision the pilot's arm was actually crushed by the closing clam shells although he did survive in the end soviet surface-to-air missiles could now reach the xb70's altitude so the alternative was low level infiltration and flying below radar detection but at low altitude it could not fly any faster than a b-52 therefore the xb70 became redundant before production even started they then became high-speed research aircraft for nasa and the one remaining aircraft that you see here today is on public display at the national museum of the usaf in dayton if you enjoyed the video please give it a thumbs up and check out my channel for many more similar videos thanks for watching

Channel: Paul Stewart

Views: 153,803

Keywords: xb-70, xb-70 valkryie, Valkyrie, north american xb-70, xb70, xb70 bomber, nuclear bomber, north american, aviation, airplane, plane, vehicle, avgeek, aviation tour, aircraft tour

Id: O8GvQ_N_lLk

Length: 9min 44sec (584 seconds)

Published: Thu Mar 31 2022