Defiant's T55 and Valor's T64 have about the same power output. Hence it's quite interesting to ready that Valor cannot hold a hover with one engine out, while Defiant can still hover reliably and fly at up to 150 knots.
“If we lose one engine or the [pusher prop], we are still able to complete the mission, Rotte says."
Remember these are also BD guys so watch the words careful. Also the engines are rated for the demo aircraft. I think Bell is looking for a different engine for the FLRAA. There are of course +/- with both aircraft.
Well when either vendor demonstrates anything close to those numbers, I will believe them. PowerPoint rarely translates to real. Simulation is just that. C-17 was to be able to routinely land on unprepared surfaces, RAH-66 was to do a lot of things, F-35 is suppose to do a lot of things.
Probably both. The Army has done a surprisingly good job of keeping them on their diet. I am impressed and glad at the reported percentages of private money funding this little adventure.
On the otherhand, asking contractors to make large investments of time and capital on yet another acquisition project that falls apart, would be damaging to industry, and is going to directly impact the service's next follow-on program.
I think it's just the industry making noise saying, "this had all better go somewhere and lead to orders this time or everyone is in a tough spot -- including you." The Army's history/reputation is in it's own way. Hopefully this is some emerging self-awareness.
Defiant's T55 and Valor's T64 have about the same power output. Hence it's quite interesting to ready that Valor cannot hold a hover with one engine out, while Defiant can still hover reliably and fly at up to 150 knots.
“If we lose one engine or the [pusher prop], we are still able to complete the mission, Rotte says."
Wouldn't the prop configuration have more to do with hover capability on a single engine? A tilt rotor would seem to be screwed in a hover with one engine anyway.
I hadn’t thought of that. Though with the obvious power loss it would just be to get the bird back on the ground rather than mission completion. Still better than auto rotation. In the event of an engine failure, I imagine they would try to get back to an airfield with the props rotated forward so the wing was doing most of the heavy lifting but what about the landing? Would they do a 45° prop angle to avoid a rotor strike on the ground and try to land conventionally? Or do a full 90° prop angle and do a half power vertical landing?
A lot will depend on where/when you lose power. How high, how heavy, what's under you, etc.
It's "easy" to trade altitude for airspeed/lift if you're under-powered. I imagine that's the preferred solution if safely available to you.
I'm not sure how often that comes to play if you lose power in a hover. Circumstances might be the running landing is the only option available if you do not have power to sustain a hover.
I don't have any tilt-rotor experience, but that would be my guess.
I hadn’t thought of that. Though with the obvious power loss it would just be to get the bird back on the ground rather than mission completion. Still better than auto rotation. In the event of an engine failure, I imagine they would try to get back to an airfield with the props rotated forward so the wing was doing most of the heavy lifting but what about the landing? Would they do a 45° prop angle to avoid a rotor strike on the ground and try to land conventionally? Or do a full 90° prop angle and do a half power vertical landing?
I think it a fair assumption that the V-280 rotor system will have very similar characteristics as the V-22. By this I mean that the rotors are turning "away" from the fuselage and are made to disintegrate in a way as to minimize the possibility of large segments at all. Many modern rotorcraft use this technique with their rotor blades. If the tiltrotor aircraft can be put into a flyable condition with the rotors angled so as not to hit the ground on landing, of course that would be the first course of action.
Del is spot on about "it depends" part. A fully loaded aircraft (max combat load) on the final part of its landing is usually in what is known as "the dead mans curve". It is that part of the flight envelope where the lose of sufficient power means you are not going to sustain flight. This is the reason for dual engines on people carrying rotorcraft, some power is better than none. Most rotorcraft that might find themselves in this situation usually have enough power to make a controlled landing. They may put considerable stress on the remaining engine, but the engines are designed for that. Once on the ground with the cargo out of the aircraft and with somewhere around half of a fuel load, it is feasible the aircraft can get back into the air. This of course would depend on the circumstances the aircraft is in and the crews decision.
To some extent this is a mote argument. Lose of an engine is usually a mission abort criterion so "continuing mission" would be continuing home. So only lose of engine on short final approach into a landing zone seems to be the point. Most landing zones are large enough to accept a short roll on landing, so the only case where this might be worthy of consideration is in urban operations. If you accept that there will be more operations conducted in urban areas, then the situation might be of more concern.
For 20 years, Northrop Grumman has been delivering mission computers to the U.S. Marine Corps for the AH-1Z and UH-1Y helicopters. More recently, the company has been upgrading the cockpits of UH-60L Black Hawk helicopters to a digital standard known as UH-60V. Though first applied to the UH-60V, this Army-owned architecture is a clean sheet, model-based systems engineering operating environment designed to support the most advanced platforms and their missions.
“Our architecture is a flying prototype of what FVL can be,” said Conroy. “These are the capabilities that will enable FVL and the enduring fleet to become the connected and interoperable fleet the Army envisions.”
These mission computers exemplify Northrop Grumman’s approach to software-defined, hardware-enabled digital systems. Using a modular, open systems architecture, the computers provide secure interfaces that allow for the integration of a wide range of systems and sensors. This architecture gives customers the freedom to choose the hardware and software that best meets their needs, regardless of manufacturer. It also provides a lasting path to relevance, adding years of service to proven airframes.
“Our proven mission computers deliver improved capability, commonality, reliability and maintainability to the warfighter, and they provide the foundation for any integrated avionics capability,” said Ricardo Sotura, technical fellow, Northrop Grumman.
What is Future Vertical Lift? Whether performing transport, logistics, strike or reconnaissance duties, helicopters and tilt-rotor aircraft greatly multiply th
As two industry teams develop prototypes that will go head-to-head in a competition for the Army’s Future Attack Reconnaissance Aircraft, both teams wil...
As two industry teams develop prototypes that will go head-to-head in a competition for the Army’s Future Attack Reconnaissance Aircraft, both teams wil...
Some of both, presumably. Remember that 20mm was specified for Commanche long after 30mm was established for Apache. That probably had something to do with the air-to-air mission; 20mm is flat-shooting and fast-firing compared to the rainbow that is 30mm LW. Possibly that's also a consideration for FARA. Is A2A CUAS in the mission set?
AH-1S that's when. Tribes are alive in every flying force (especially in the largest "air force" on the planet). Attack is 30mm, scouts were 7.62/.50cal, and lift didn't get a vote. TomS makes a great point about sound reasoning for going with 20mm, but that may be giving the Army too much credit.
AH-1S that's when. Tribes are alive in every flying force (especially in the largest "air force" on the planet). Attack is 30mm, scouts were 7.62/.50cal, and lift didn't get a vote. TomS makes a great point about sound reasoning for going with 20mm, but that may be giving the Army too much credit.
Magazine size might also play a role in that choice. With less volume dedicated to ammo casings (drum), that's some extra free space for a larger wb stuffed with effectors or systems.
I do not recall the weight difference by round, but one does not have to be a rocket scientist to understand that 30mm is more volume and weight. So I agree with @TomcatViP and @Del that magazine size was likely a decision factor as well.
Remember these are also BD guys so watch the words careful. Also the engines are rated for the demo aircraft. I think Bell is looking for a different engine for the FLRAA. There are of course +/- with both aircraft.
Gov't told competitors for FLRAA to expect their production aircraft to have the Future Affordable Turbine Engine (FATE) available. There is concern though over whether, given how slow gov't is moving on that program, the engine will be leviable when FLRAA needs it so no doubt Bell and Sikorsky are developing fallback plans.
I hadn’t thought of that. Though with the obvious power loss it would just be to get the bird back on the ground rather than mission completion. Still better than auto rotation. In the event of an engine failure, I imagine they would try to get back to an airfield with the props rotated forward so the wing was doing most of the heavy lifting but what about the landing? Would they do a 45° prop angle to avoid a rotor strike on the ground and try to land conventionally? Or do a full 90° prop angle and do a half power vertical landing?
I think it a fair assumption that the V-280 rotor system will have very similar characteristics as the V-22. By this I mean that the rotors are turning "away" from the fuselage and are made to disintegrate in a way as to minimize the possibility of large segments at all. Many modern rotorcraft use this technique with their rotor blades. If the tiltrotor aircraft can be put into a flyable condition with the rotors angled so as not to hit the ground on landing, of course that would be the first course of action.
Del is spot on about "it depends" part. A fully loaded aircraft (max combat load) on the final part of its landing is usually in what is known as "the dead mans curve". It is that part of the flight envelope where the lose of sufficient power means you are not going to sustain flight. This is the reason for dual engines on people carrying rotorcraft, some power is better than none. Most rotorcraft that might find themselves in this situation usually have enough power to make a controlled landing. They may put considerable stress on the remaining engine, but the engines are designed for that. Once on the ground with the cargo out of the aircraft and with somewhere around half of a fuel load, it is feasible the aircraft can get back into the air. This of course would depend on the circumstances the aircraft is in and the crews decision.
To some extent this is a mote argument. Lose of an engine is usually a mission abort criterion so "continuing mission" would be continuing home. So only lose of engine on short final approach into a landing zone seems to be the point. Most landing zones are large enough to accept a short roll on landing, so the only case where this might be worthy of consideration is in urban operations. If you accept that there will be more operations conducted in urban areas, then the situation might be of more concern.
The V-280 rotor system should be more efficient than that of the V-22 both because of later technology, but also because the rotor diameter is not constrained as it is on the Osprey because the specified clearance between rotor tips and the island isn't a factor in the smaller V-280.
Regarding the engine out situation I imagine the cross-shaft is just like it is on all other Tilt-Rotors, normally unloaded unless one engine fails. If the cross-shaft is damaged, it doesn't seriously affect the flight (unlike the shaft in the H-47) unless additionally an engine fails in powered lift mode.
When Popular Mechanics states that Bell says the aircraft can not hold a hover with one engine out, it's not clear whether they're referring to the production aircraft using the promised FATE engine or an older engine as does the demonstrator. FATE will change the whole calculus. In any case, I'd wager inability to sustain a hover should not preclude a nonemergency landing. The Valor would fly most of the way in wingborne mode simply because it's more efficient. Unlike a pure rotorcraft it doesn't have to provide sufficient power to the rotors to keep the thing in the air for the entire flight. For landing there are three options
Transition to full rotorborne mode. Even if it can't sustain hover (at what weight altitude?) it should still be able to maintain level flight and then make a somewhat rough landing like some other engine out twins do, with a limited roll.
Put the proprotors in an intermediate position keeps them clear of the ground, with somewhat more landing rollout. Full control and capability all the way to the ground.
If for some reason the proprotors can't be rotated away from fully forward, then just like Yasotay stated, the proprotor design is such that they'll throw the blades clear of the aircraft upon impact. You land like a fixed wing, albeit with more noise and "excitement".
Well when either vendor demonstrates anything close to those numbers, I will believe them. PowerPoint rarely translates to real. Simulation is just that. C-17 was to be able to routinely land on unprepared surfaces, RAH-66 was to do a lot of things, F-35 is suppose to do a lot of things.
Valid point. From the way the article states it, Sikorsky is saying their simulation predicts they should be able to do that kind of rapid deceleration (they've got to get to 200 knots first), while Bell has actually done it.
[Jay] Macklin, [Future Vertical Lift Business Development Director, Sikorsky Lockheed Martin]: Survivability is so important to every single mission we fly. It makes no sense to send an aircraft, crew and passengers into harm’s way unless we know that we have given them the ability to achieve the objective and get home safely. Survivability is a complex chain with many links. Many of these link to the onboard mission system and the connectivity to offboard sources. X2 Technology plays a role in several of the links. X2 helps us avoid detection by flying faster and lower than other aircraft configurations. The maneuverability of the aircraft with X2 is so much better than single main rotor helicopters as X2 handles very responsively, much like a sports car hugging corners on a racetrack, X2 and our flight control system hugs terrain at speeds previously unimagined. X2 has the ability to operate at a reduced acoustic signature to avoid detection from human threats with shoulder launched rockets or delaying detection so long that automated systems cannot be brought online fast enough to achieve a lock on our aircraft. X2 coupled with onboard flight controls provide an opportunity to break lock with a targeting system through intelligent signature management and rapid maneuverability. X2 can perform a brake turn away from a threat in a fraction of the distance that a single main rotor (SMR) helicopter can, drastically reducing our exposure time and escape the threat faster. These are critical elements of survivability that a SMR simply cannot accomplish. Avoiding detection from radar, avoiding human detection and being able to break target locks when necessary are all assisted by X2 and our comprehensive survivability software and hardware suite all working together. That is one of the many values that Lockheed Martin provides to the Army, we provide this level of integration on a number of DoD platforms across all services and bring the experience of a world leader in advanced military technology in MDO environments.
Sikorsky, a Lockheed Martin Company, has offered its Raider X for the Army’s Future Reconnaissance Aircraft (FARA) Breaking Defense: Let’s move on to sustainment as it relates to Sikorsky’s FARA and FLRAA helicopters. What do they offer the Army in terms of maintainability and sustainment?
Macklin: FARA and FLRAA gave us the ability to build a new helicopter that from the outset is focused on reduced maintenance burdens. This has been exciting! We’ve challenged the team to ask the question “What would it take to make our new helicopters be more like our cars and in many cases even better, where the reliability is increased, maintenance is much easier, and the vehicle is much smarter… actually telling the crew and maintainers well in advance when it sees that something is degrading and pro-actively addressing concerns before they become issues. Switching away from time phased maintenance and into predictive and condition-based maintenance is a game changer. Our aircraft leverage sensor technology that is embedded all over the aircraft and systems to self-monitor and predict future maintenance requirements. The aircraft layout allows ready access to maintenance areas when the needs to arise.
We are fully leveraging the digital transformation and model-based design and maintenance which allows us to Maintain before we Build… using virtual reality to influence our design early in the design process, improving the product for the warfighters. These design enhancements will contribute to the reduction in O&S costs resulting in total cost of ownership savings. We know that we will have to operate in austere environments, with limited crews and limited sustainment for extended periods of time, and our engineering team has risen to this challenge and implemented these next generation technologies to reduce our operating and maintenance costs by over half.
Well when either vendor demonstrates anything close to those numbers, I will believe them. PowerPoint rarely translates to real. Simulation is just that. C-17 was to be able to routinely land on unprepared surfaces, RAH-66 was to do a lot of things, F-35 is suppose to do a lot of things.
Valid point. From the way the article states it, Sikorsky is saying their simulation predicts they should be able to do that kind of rapid deceleration (they've got to get to 200 knots first), while Bell has actually done it.
I will defer to the more aerodynamically knowledgeable here, but will say that I suspect putting a propeller into reverse (beta) will indeed slow the aircraft down quickly, especially when the prop in question is the size of a C-130 prop on a platform 1/5(?) the size and weight. I do wonder at what engineering magic Sikorsky has come up with within the dynamic systems for the torsion going through the power shafts when one does that.
Not to be snarky -but- concerning ourselves with shooting out things, what happens if you shoot the shaft between the top and bottom rotor?
Remember these are also BD guys so watch the words careful. Also the engines are rated for the demo aircraft. I think Bell is looking for a different engine for the FLRAA. There are of course +/- with both aircraft.
Gov't told competitors for FLRAA to expect their production aircraft to have the Future Affordable Turbine Engine (FATE) available. There is concern though over whether, given how slow gov't is moving on that program, the engine will be leviable when FLRAA needs it so no doubt Bell and Sikorsky are developing fallback plans.
Remember these are also BD guys so watch the words careful. Also the engines are rated for the demo aircraft. I think Bell is looking for a different engine for the FLRAA. There are of course +/- with both aircraft.
Gov't told competitors for FLRAA to expect their production aircraft to have the Future Affordable Turbine Engine (FATE) available. There is concern though over whether, given how slow gov't is moving on that program, the engine will be leviable when FLRAA needs it so no doubt Bell and Sikorsky are developing fallback plans.
Sounds like a tracit admission that Army might not have FATE ready in time. This illustrates the concern regarding the extremely slow pace the Army is developing FATE.
Despite COVID-19, the SB>1 Defiant team is testing furiously to catch up with archrival Bell’s V-280 tiltrotor, which has almost 10 times as many flight hours.
U.S. Army To Buy 16 FLRAA Units For Development, Early Production
June 25, 2020
A sources-sought notice released by the U.S. Army June 23 keeps the Future Long Range Assault Aircraft competition on track for the release of the request for proposals next year and lays out new details of aircraft deliveries needed during the development phase and the first lot of low-rate initial production.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
www.forbes.com
www.aerotechnews.com
www.army.mil
www.defensenews.com
