Hot answers tagged

35

That photograph distorts the perspective. Just Google for "helicopter air-to-air refueling" and look at the image results. Many show other perspectives from which you can see that it is not possible for the blades to contact the hose or basket - the probe is longer than those on a fixed-wing craft for exactly that reason. This video shows a CH-53E Super ...


21

It is possible to drive the two rotors of the V-22 Osprey from a single engine using a segmented driveshaft connecting both engine shafts via gearboxes: The drive shaft is depicted in blue in the left wing. Source Each engine drives its own rotor and the connecting shaft. If one fails the same rotation speed is maintained, but each rotor receives now half ...


18

Can it be? Sure. Let's take a look at what it would be replacing. The A-10 was designed from the ground up to be a platform for moving the GAU-8 into range of the target. It has good low speed flight characteristics. The engines are mounted high and to the rear to protect them from FOD (both debris kicked up by the GAU-8 and hostile weapons fire). The ...


17

The V22 Osprey yaws by tilting one rotor backwards from the vertical and one forward by moving the swashplate up on one side and down on the other causing a cyclic change to the rotor blade angles of attack. This is accomplished using the pedals in just the same way as a helicopter. Since the rotors are tilted from the vertical, this introduces a ...


15

Tilt rotors and virtually every other VTOL aircraft with more than one lift rotor (Chinook, K-Max) or proprotor (AW609) must employ a shaft between these lift units, so when one engine is out the other keep the units turning will half power (which doesn't mean half rotations per minute, but half maximum torque). That's why available power reserve on the ...


11

They are classified as Tiltrotors, which is its own category for all the obvious reasons. If the President were flying in a Marine Osprey, the callsign would be Marine One. If he were in an Air Force Osprey, it'd be Air Force One.


11

Under the FAA, a CV/MV-22 Osprey is considered to be a powered lift aircraft. Under 14 CFR §1.1: Powered-lift means a heavier-than-air aircraft capable of vertical takeoff, vertical landing, and low speed flight that depends principally on engine-driven lift devices or engine thrust for lift during these flight regimes and on nonrotating airfoil(s) for lift ...


10

The V-22 is not without its strong points as a support aircraft. However, CAS is a specialized role for which it will never truly be ideal. That's not to say it wouldn't be feasible to deliver weapons with one, once modified appropriately. The good news is that you could likely bring it up to roughly attack-helicopter levels of armament. I estimate you'd ...


10

This seems to be a hot topic - in principle, the V-22 should be able to fly and land in autorotation, but tests so far did not demonstrate this. The manufacturer's position is that autorotation was never part of the specification. What it comes down to is the inertia of the rotating parts relative to the aircraft's mass. The requirement to fold the rotors ...


9

When fully extended the probe does extend past the rotor of the HH-60G; however, there is a potential for the probe not to extend. And in that case, the probe is well inside the rotor disc. Still, refueling can still be accomplished. Just like single-engine refueling, it takes more care but when you need fuel you do what you must. And in my 20 years flying ...


9

A fixed nacelle landing is an emergency procedure practised routinely in a flight simulator, however actually getting this condition is very rare to date. In short, we reduce gross weight if able, calculate a touchdown speed, fly a shallow approach, and shut down engines after touchdown on rollout. As for "hanging on the proprotors" in airplane mode, ...


9

The protrusions you're asking about are vortex generators. As to how they work, there is a separate Stack Exchange article on that: How do vortex generators work? (Please note, the linked question/answer does not even MENTION the CV-22, and is thus not a duplicate question to this one.)


6

The Osprey's engines drive the rotors at 412 RPM in heli mode or 333 RPM in forward-flight mode, according to this article. With a rotor radius of 5.8m, that puts the tip velocity at 250m/s, or about 75% the speed of sound, at the higher RPM. So they aren't near supersonic yet because the blades are short enough. But there is a possibility of reducing blade ...


6

There are no 'private' Ospreys thus far (all are operated by USAF, USMC and JSDF)- the Bell Boeing MV-22 Osprey used by the US Marine Corps's HMX-1 presidential helicopter squadron: ... will conduct presidential support missions, which means these aircraft will carry presidential support staff and news media representatives travelling with the president," ...


6

There is nothing that prevents tilt rotors from performing an autorotational landing, in theory. AugustaWestland AW 609 has already demonstrated this. The Bell XV-3 also did this. However, V22 has not demonstrated autorotation in any practical sense. The descent rate is too high for safe landing. The failure of V 22 to autorotate is due to the high wing ...


5

The rotor size helicopter (or a tiltrotor, in this case) is determined by its aerodynamic requirements, most importantly, its hover characteristics. The main constraint is the weight that has to be lifted by the helicopter at a give a altitude. In this context, it can be seen that the blades of V-22 are actually smaller. For example, V22 has a Max. TOW(Take-...


5

The probe is the furthest point forward on the Pave hawk helicopter. It also has an IR sensor to properly line up the boom(the female end). Obviously the procedure for approach is to come from behind to avoid such things from hitting the rotor blades.


5

Instead of having a set of contra-rotating proprotors on each side, if you're after decreasing the disk loading, a span increase would also do the trick, allowing wider proprotors. However the Wikipedia paragraph starts by saying: Due to the requirement for folding rotors... The main contributor to its less-than-ideal size is the folding requirement to ...


5

" However, two Osprey 38-foot rotors weigh 4,654 lbs (JANE's, 1998-9, p. 557.)" this quote is from http://www.freepatentsonline.com/8382030.html That would put the mass of a single V22 rotor at 1050 kg. The quoted source dates from 1998, so some improvements may have been made, but it is unclear to which parts of the rotor this refers, so it's only a ...


4

Welcome to AviationStackExchange and to provide a short answer to your question, yes there are autorotation measures that are similar to those featured on helicopters. The basis for most of my answers pertain the unique drive shaft system, which allows for redundancy between proprotors, something other twin-engine fixed wing aircraft usually lack, so here's ...


3

The cross shaft of the V-22 is normally unloaded. It only takes up the load if an engine fails, at which point everything continues as normal albeit with reduced power. Alternatively, if the shaft is damaged, but you've still got two good engines, the aircraft flies as normal because the shaft isn't being used anyway. On the CH-47, though, the shaft is ...


3

The difference is because when the cargo is inside the aircraft the weight is spread across the cargo compartment floor, whereas when it is carried externally, the weight is concentrated entirely on one or both cargo hooks. The cargo hook attachment points are reinforced, but they still have a weight limit. When the cargo is inside the aircraft the weight ...


2

The Osprey is closer to a helicopter and if I was going to chose from a fixed wing pilot or rotary pilot to train on it I'd choose the rotary pilot. The rotary wing physical skill set is so much more demanding than the fixed wing one. A helicopter pilot could master fixed wing cruising flight in the Osprey far easier than a fixed wing pilot could master ...


1

The lift is provided by the rotors only. The rotors are powered by Rolls-Royce T406 engines, which are turboshafts: all useful generated turbine power is converted into shaft power for the rotors. Note that turboprops do convert some of the exhaust energy directly into propulsion thrust, turboshafts do not. All helicopters can provide enough rotor thrust to ...


1

There is one disadvantage: it makes control dependent on engines running. This disadvantage effectively precludes using it on any aircraft carrying people. Usual requirement for a critical system, which controls are, is that the probability of fatal failure must be estimated to be less than $10^{-9}$ per hour of operation. There are simply no propulsion ...


1

It is my belief is it would allow the use of highly complex airfoil geometries that would increase the efficiency of the aircraft. The best airfoil is one that adaptively changes shape to meet current requirements (read: flaps or flaperons that run the entire length of the wing). What would be the advantages of using thrust vectoring only for control of ...


1

The V22 will be contributing as a CAS platform for the USMC along with KC130s until the service finds a suitable platform to replace the A10. Marines are actually running out of fighter jets. At this point, only about 87 of its 276 F18's are serviceable at any time. For any flying arm, roughly 30% availability is really bad! And the A10 cost \$20,000/hr ...


1

CAS, no. Mini-gunship, firing standoff weapons in coordination with marines on the ground, quite likely will happen. The V22 should be able to substitute, albeit with less effectiveness, any role the C130 performs for the marines(cargo, tanker, gunship, ISR). There will be scenarios where C130s can't get to the airspace but V22s are embedded with the MAGTF ...


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