VIDEO - Bell V-280 Valor Reaches 80 Knots (New tilt-rotar aircraft)

YouTube, Bell Helicopter Corp. channel ^ | Feb 6th, 2018 | Staff

[gaijin]

2-min YouTube video showing V-280 Valor well out of hover.

Nacelles are not yet fully rotated forward, as pictured above, but clip shows project coming along nicely.

Nacelles feature rotational gear overlaid with video MOSAIC, apparently this feature is still technically sensitive;

Osprey nacelles rotate as an integrated unit, Valor nacelles are bisected into fixed and rotational subcomponents.

[Captain Rhino]

Only Recon and SOCOM assigned Marines are parachute qualified, so there is no bailing out for us. Parachute qualification is more common in the Army but that raises the inevitable requirement for parachutes and those are not part of standard crew or passenger on-board equipment in either service.

Actually the MV-22 and, I assume, the VX-280 are pretty crashworthy. Rotor blades have sequenced explosive bolts so they detach outward from the fuselage. The composite fuselage is pretty tough and doesn’t have an engine/transmission/rotor assembly mounted above it any longer to crush the passenger compartment on impact. And the wings are designed to breakaway.

However, the scenario you postulate, shedding a blade into the fuselage is very bad. Impact may or may not sever the fuselage completely. It might sever/damage flight controls or create so much induced vibration that the aircraft is uncontrollable. Shedding the other blades from thee damaged rotor might be a way of eliminating the vibration if you are in horizontal fight but you’ll never be able to hover even if you can stay aloft on one rotor. Eventually, you would have to shed the good rotor’s blades in order to “glide” in (and you are not gliding far on those wings). Either way, you are eventually crashing/landing really hard.

Crashing is never desirable and people still can and will end up dead but, for most scenarios, your chances of surviving a crash in tiltrotors are better than in the helicopters they replaced/are replacing.

[Spktyr]

The V-22 does not have ejectable rotor/prop blades. Instead they are made of carbon fiber and disintegrate to ‘broomstraw’ on impact.

[Spktyr]

Ducted-fan lifters have some really ugly problems. Per the wikipedia article:

Less efficient than a propeller at cruise (at lower thrust level).
Good efficiency requires very small clearances between the blade tips and the duct.
Requires high RPM and minimal vibration.
Complex duct design, and weight increase even if constructed from advanced composites.
At high angle of attack, parts of the duct will stall and produce aerodynamic drag.

The last two are the biggest problems. Weight and the fact that the ducted thruster partially stalls if the airflow over it is at a great enough angle to the intake of the duct. It’s part of why the Moller SkyCar has never progressed past a tethered hover.

[Captain Rhino]

Thanks!

[Spktyr]

Here's a picture of one that crashed off Okinawa - *zero* fatalities, by the way - in 2016. This one went down after a mid air refueling accident where the refueling hose from the air tanker went into the rotor arc on one side and damaged the rotor, something that has taken down conventional Marine helicopters in the past. (For those that don't know, Marine and Navy aircraft generally use probe-and-drogue refueling, where the tanker trails an unguided fuel hose behind it in the sky and the pilot of the aircraft being refueled has to fly his aircraft's extended refueling probe into the socket on the end of the hose. Leaks are common. Having the hose hit the refueling aircraft is also not unheard of. This video shows a not unrelated kind of accident with a CH-53 conventional helicopter. It also had to have an emergency landing and was only slightly less serious.)

Note the "broom straw" or "broom stranding" of the rotors - so they do actually do this in the real world, not just the laboratory - which is always a non-trivial concern when dealing with things that 'should' happen. :P In this case, the pilot managed to limp his crippled Osprey to just off the beach and ditched it in airplane mode. All five crew got off fine, only two suffered injuries.

[ROCKLOBSTER]

Thank you gentlemen, those are excellent pieces of information answering a layman’s question. Here’s another.

Regarding saving lives, and crashworthiness, I’ve often wondered this of conventional helicopters and passenger aircraft of any size for that matter:

If they can drop a tank or large piece of field gear from a cargo plane via a parachute, why can’t they similarly lower a relatively light disabled aircraft, or fuselage, to the ground at 20MPH instead of 200?

The helicopter could have the “explosive bolts” on the rotor hub, and a braking mechanism on the tail rotor, allowing a clean drop of the core of the aircraft.

They’ve had “rocket fired parachutes” on ultralights for quite some time now.

It seems preserving the irreplacable human cargo, and maybe even the plane, would be well worth the weight penalty or additional cost.

[Spktyr]

The heaviest aircraft that’s been successfully parachute-saved is about 6000lbs. The Osprey in this article can weigh up to **60,000lbs.**

When they’re air dropping a 60,000lb static load from an airlifter, the aircraft has to be traveling under 170 knots at most or the parachutes don’t work. The parachutes and reinforced pallet structure needed to support the parachutes can also consist of up to 5Klbs of the weight. A single G-11 parachute weighs 250lbs. On a static 60K lb load being shoved out the back of an airlifter, you need 12 of the things, not an insignificant weight.

https://www.globalsecurity.org/military/systems/aircraft/systems/images/60klvads.jpg

https://www.globalsecurity.org/military/systems/aircraft/systems/60klvads.htm

Parachutes also occupy a lot of space. On the Very Light Jets and general aviation craft like the Cirrus SR-22 equipped with an airframe parachute, the single recovery parachute can take up 1/3 of the usable fuselage space.

Short version - all but the lightest planes and choppers can’t afford to give up the weight and space for parachute systems they are often moving too fast to be able to deploy safely anyway.

This is why ejector seats are common on military airplanes. And the Russians, who are better at choppers than we are, incorporate crew bailout or crew ejection systems in their newer helicopters.

[Spktyr]

Also, modern main battle tanks are not air droppable. In fact, the lack of an air drop capable armored vehicle with the retirement-without-replacement of the not-very-good M551 Sheridan ‘light tank with a big gun’ is currently causing some consternation in the Army and Marines.

The M1A2 SEP v4 ‘Super Abrams’ is already knocking on the door of 73 tons. The soon to be added Israeli Trophy active protection system will add another half a ton to that. That’s 147,000lbs before you fill the fuel tanks, install a basic ammo load on board, etc., etc. 42k lbs is considered the safe upper limit for parachute deployment systems we have with 60K being bleeding edge and sometimes not working.

[ROCKLOBSTER]

Once again, great information.

Thank you.

[AppyPappy]

That’s why you drop APC’s. They can kill tanks with ATGM’s while fighting ground troops and air assets.

[Spktyr]

Modern tank active protection systems make that a lot harder, as recent events in Chechnya and Lebanon have shown, not to mention Syria. Modern APS means you have to saturation attack a tank so protected now. The Chechens reported that it could take 7-10 or more launches with vehicle- or stand-mounted ATGM to take out an Arena-protected Russian tank.

[Spktyr]

Here’s Arena taking out an RPG on a range:
https://www.youtube.com/watch?v=vMY0p_2KrYg

Merkava 4s with the Israeli Trophy APS taking out ATGMs and RPGs in combat.
https://www.youtube.com/watch?v=SQA4ecTD8wk

Given how effective these systems have proven in real world combat and given how effective Russian Kornet missiles are proving this year and even now in raping Turkish Leopard 2s in Syria, there’s no question as to why the US Army finally ordered Trophy for the Abrams this year instead of continuing to wait for the vaporware Raytheon Quick Kill system.