69

It is a sensing wheel that is part of the antiskid braking system. It contains an electronic sensor to measure the true groundspeed of the airplane. See NASA Technical Note D-4836, Landing Loads and Accelerations of the XB-70-1 Airplane (1968), bottom of page 3 of the document (page 5 on the PDF):


42

The canister contains a small parachute and either a spring or an explosive charge to kick the chute out when it is needed. It is a precaution for spin flight tests, that's why it is called a spin chute. See here for a video of the spin chute of the F-35. I guess now I should explain how a spin chute works. When an aircraft spins, it will rotate around a ...


38

Short answer: This design will probably work, but it will not be very efficient. It can be tweaked into flying, but when you start tweaking, you would continue such that the outcome would look differently. Now let's look at your questions one by one: How feasible is it to use a propellor larger than the wingspan? Is there any law of physics that ...


30

It appears to be a Celera 500L, owned by Otto Aviation Group. This article has more information: "Unmasking The Bullet-Shaped Mystery Aircraft After It Reemerges At Victorville" The registration also provides us with a designation for this mystery plane—the Celera 500L. It is the only aircraft registered by the company with the FAA. The War Zone ...


27

It is a spin recovery/stabilization chute, installed during testing for high AoA test flights. The following image shows it being deployed on the ground. Image from fas.org


26

The 'Y' in YF stands for prototype according to the Tri-Service aircraft designation system. The 'F' stands for fighter, so YF stands for prototype-Fighter. These aircraft are operated by the US Department of Defense (USAF or USN). For example, YF-22 is the prototype (technology demonstrator) version of the F-22 Raptor. The 'X' series is the name given for ...


26

From what can be gleaned from the Net, it was instability. The Avrocar had plenty of power but was unstable. The resulting behavior made it uncontrollable when leaving ground effect. In this publication I found an illustration which tries to explain what went on: Any asymmetry in flow would shift the center of pressure, resulting in a wobbling motion called ...


25

Two X-29's were built, and the only difference between the two is that #2 has an externally mounted spin recovery chute attached to the tail. That is what you are seeing in this picture. The chute is packed in the tube structure and the "arms" are structural to distribute load. Source The only significant difference between the two aircraft was an ...


18

Perlan II will climb to extreme altitudes on wave lift, not thermal lift. Wave lift is created when strong winds blow approximately perpendicular to a mountain range, and the wind speed increases steadily with altitude. This creates a standing wave in the atmosphere, kind of like the ripple behind a rock in a fast moving stream of water. On the leading edge ...


18

$\sf \color {SteelBlue} {\text {Known facts}}$ Seen at Southern California Logistics Airport (Victoville, KVCV) Parked at transient parking On April 12th, 2017 $\sf \color {SteelBlue} {\text {Aircraft apparent characteristics}}$ Pusher Propeller behind tail, not ducted High aspect ratio un-swept wings Light wheels/gears Low ground clearance Maybe 2m ...


18

Great find, a vehicle with so many new design features in a time before Computed Fluid Dynamics, and hard to test in a wind tunnel where the device could only be mounted in a fixed position. From this source: Takeoff, hover, and landing were controlled by deflecting vanes in the engine exhaust: in horizontal flight by four fins mounted just above the ...


15

I actually have a lot of experience in the shipboard systems that you are talking about. First, the gyro's do not keep the boat upright, they counter the rolling effect of waves but they cannot completely remove them. Gyro's of all designs work on the principle of conservation of angular momentum. That means that a spinning object will tend to impart a ...


15

It‘s a BV-347 technology demonstrator: In 1969, the Army and then-Boeing Vertol entered into a partnership to improve upon their cargo helicopter fleet, and thus the BV-347 was borne from a CH-47A Chinook that was provided by the Army as a technology demonstrator, according to retired CW5 Jim Kale, who now serves as a tour guide for the U.S. Army Aviation ...


13

Tip jet rotors are still being developed, none of them are ramjet powered as far as I know. The Dragonfly DF1 is tip rocket powered, while the Pegasus uses air jets powered by a conventional engine. Ramjet technology has not improved, so the cases for using them on rotor tips has not changed. They are still too heavy, thirsty and noisy.


13

Lockheed Martin Sabre Warrior UCAV (concept): Source Source From Defence Forum India: The Sabre Warrior drone is 46 feet long, with a 36-foot wingspan, capable of taking off with 30,000 pounds of load using a 22,000-pound trust afterburning turbofan engine. It has two modular payload sections, which can be changed by soldiers in the field. Each ...


12

The aerodynamic forces resulting from surface deflections are orders of magnitude larger and faster (in their rate of change) than the gravitational forces obtainable by shifting the centre of mass. Additionally, as OP seems to realize, yaw control would not be feasible with this method. So overall it would not be impossible, but it has no clear ...


11

These are just two canards with forward-swept wings. There is no general rule that the wing has to be in the back once it is swept forward. In both particular cases the configuration was selected to achieve the highest degree of agility possible. If you command a pitch-up in a conventional configuration, you first need to decrease lift in order to achieve ...


10

Because the YF-23 lost the Advanced Tactical Fighter program to YF-22, from which F-22 was developed. Actually, the YF-22 had thrust vectoring and was the more agile of the two.


10

It reduces moments in the wing spar. Major points of axial drag in this design are the wings and the fuselage. You'll see that two engines are close to the fuselage, and the other two are midway along the wing. By placing two engines further out, they are also located where the lift is generated, reducing the necessary strength of the wing spar. Both of ...


10

Yes, you can, you don't need anything other than the words EXPERIMENTAL to be visible by the passenger. Your PPL is fine for flying experimentals, although like any other aircraft change, I would get instruction from an experienced instructor in that type/model before going solo. Experimental aircraft can have some pretty different handling characteristics. ...


9

The YF-23 lost the Advanced Tactical Fighter program to the YF-22, however it has not been made public why. The ATF evaluation is still classified and details about the YF-23's performance are not easy to come by. They are both excellent aircraft, performed similarly, and there is much speculation why the YF-22 won. Global Security states that... ...


9

Short answer: No. Or at least, nothing that's been demonstrated that I'm aware of. Whether there have been experimental R&D aircraft or developments, I'm not sure - but I can't find any. The simplest reason is just because there's no need for them - they offer no real advantages over a conventional internal combustion or jet engine, so as with so much ...


9

I once led a group of Antonov engineers through the aircraft exhibition of the Deutsches Museum in Unterschleissheim near Munich. There are two halls connected by a walkway, and from that walkway you can see the restoration workshop which is located between those halls. When the group had long left the walkway, one engineer still stood in the middle of it ...


8

For aircraft, none. Hybrid drive trains are used because: They offer, rather limited, efficiency improvement by being able to operate the engine closer to its optimal conditions. Because spark-ignition engines are more efficient at higher power settings, the hybrid can get advantage by having smaller engine, running it at (relatively) high power or not at ...


8

The two inner engines are in the expected position. Keeping the engines as close to the fuselage as possible has two main benefits: Less adverse yaw in the case of an engine failure Less stress on the wing on the ground and during landing from the engine weight The outboard engines are certainly unconventional. Most aircraft with four engines, expecially ...


8

This is the heat distribution during reentry for the Orion capsule: So the leading edge is hotter than the trailing edge, even for very large angles of attack (almost perpendicular). I assume a disk would have a similar heating profile. So spinning the disk would move the edge of the disk from a high-heating area to a less hot area. This suggests ...


8

Sailing vessels work by exploiting the motion difference between the air and the water. The sail holds the air and the keel holds the water. Unless you have some severe wind shear (which comes with its own problems), or you have truly massive sails, there's no gradient for you to exploit because it's all air.


8

Yes, there are. Everything is regulated in Germany. Your regular experimental aircraft would have to follow JAR 23 and the LBA has transferred the supervision and certification of experimental aircraft to the Oskar Ursinus Vereinigung (OUV). Before you begin work on your experimental, be sure to contact them and talk to an OUV assessor. This assessor will ...


7

Well, the URL should give it away already ... The AC-130 is a turboprop aircraft with relatively low wing loading. It can be operated from (almost) unprepared airstrips. Now compare it to the 747-400: Higher minimum speed means more distance to the taget, higher tire pressure means operation from established airbases with a long runway. Just look at the T-...


7

The Advanced Tactical Fighter (ATF) competition was different than some of the other fighter competitions. The planes never squared off in any kind of mock combat. The pilots who flew the YF-22 never flew the YF-23 so there was no way to directly compare the 2 in that way. The competition focused on whether or not the planes met the requirements. Both ...


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