S97 Raider

[heli1]

Originally Posted by 212man

Otherwise known as 'taking off and landing'!

Also known as ground resonance?

[The Sultan]

Heli1

No. Sounds more like what caused the prototype F-22 crashed.

Fighter prototype crash not caused by aircaft flaw - UPI Archives

[IFMU]

Vertical released this:
https://www.verticalmag.com/news/sik...initial-report

Ground resonance is not a factor for rigid rotors. Article says it was a flight controls software issue. I have no idea what they did on Raider. I know for a fact that they did not use the X2 flight controls and software guys on Raider.

[Jack Carson]

Landing Gear Strut input to Flight Controls

Does the Raider use full or limited motion flight controls? The S-76 SHADOW aircraft was used as part of the early development of the Comanche flight control system. The SHADOW utilized a limited motion force control for the cyclic system and a full motion collective. During flight test we did experienced multiple spurious down collective inputs in a hover. All were recovered by the safety pilot in the rear cockpit. The SHADOW flight control system also received inputs from the landing gear struts during takeoff and landing.

[IFMU]

I think all the Sikorsky FBW uses a normal collective and a unique trim sidearm controller. The RAH66 didn't have pedals but everything else has.

I'd flown in the back of the Shadow a few times as a young engineer, including once when my old man was up front for a demo. It was a good aircraft but the technology definitely moved ahead since those days.

At Schweizer we also built a Shadow style FBW 333. We didn't get to do a lot with it but it was a fun project.

[SansAnhedral]

Lockheed Martin Reaffirms Support For Sikorsky?s Raider | Defense content from Aviation Week

The fly-by-wire (FBW) Raider was taxiing to its takeoff position when the mishap occurred. The digital flight control system unexpectedly transitioned from simple ground mode to augmented flight mode before the aircraft became airborne. The crew lifted into a hover but, unable to stabilize the helicopter, quickly put it back on the ground, the Raider coming down heavily, upright and level on the runway. The two company test pilots powered down the engine and shut off the electrics before egressing. The Raider suffered substantial damage, but they escaped with minor injuries— the impact-absorbing landing gear, composite airframe and crew seats working as designed.

[SplineDrive]

Incorrect Flight State

Originally Posted by SansAnhedral

Lockheed Martin Reaffirms Support For Sikorsky?s Raider | Defense content from Aviation Week

... if the FCC was not in the correct flight mode, I suspect there was a substantial amount of excitement packed into the phrase "unable to stabilize the helicopter". Glad the rest of the systems worked as intended and the pilots walked away. Makes it a good landing.

[CTR]

Priorities and Engineering Bandwidth

While l wish the Raider team success in achieving their goals, I don't see Lockheed's priority stacking placing them anywhere near the top.

Whenever an accident like this occurs it raises the question "What else have we missed?"
This introspection leads to a deep dive into system design and integration lab regression tests.

If the Raider was Sikorsky's only development program, it would be all hands on deck to get ship two back into flight test. But with getting the CH-53K production ready, the Defiant back on schedule for achieving first flight, and bill paying production programs like the Presidential Helicopter and Blackhawk, where is the Raider program going to find the resources it needs?

[SplineDrive]

Originally Posted by CTR

If the Raider was Sikorsky's only development program, it would be all hands on deck to get ship two back into flight test. But with getting the CH-53K production ready, the Defiant back on schedule for achieving first flight, and bill paying production programs like the Presidential Helicopter and Blackhawk, where is the Raider program going to find the resources it needs?

Sikorsky appears to be hiring in CT, TX, and WPB, so perhaps they're willing to do all of the above. At this point, what's required to regression check and complete the second Raider aircraft is fairly small potatoes, assuming all the big ticket items were already manufactured and paid for before assembly was halted.

Guess we'll see.

[CTR]

Originally Posted by SplineDrive

Sikorsky appears to be hiring in CT, TX, and WPB, so perhaps they're willing to do all of the above. At this point, what's required to regression check and complete the second Raider aircraft is fairly small .

Unless Sikorsky can steal experienced Flight Control System specialists from other aerospace companies, they will be hard pressed to man up the teams required to support all their FBW programs.

[IFMU]

Unless Sikorsky can steal experienced Flight Control System specialists from other aerospace companies, they will be hard pressed to man up the teams required to support all their FBW programs.

They have a lot of flight controls talent, and one would have to assume there is some commonality between the systems. They had enough talent they didn't need to keep the X2 guys when they closed Elmira!

[The Sultan]

From FI:

The company has no plans to build a replacement for the first prototype, but that could remain as an option, he says.

97 Ship 1 appears to be a complete write off.

[Lonewolf_50]

Sultan: Might they not repair it, rather than replace it?

[The Sultan]

Lone,

As the gist of the article was that they are concentrating on #2 and #1 was lessons learned the impression was #1 is done. I guess they could move the data plate to a new fuselage (if they had one) and call it 1, but that is cheating.

[SplineDrive]

Originally Posted by The Sultan

Lone,

As the gist of the article was that they are concentrating on #2 and #1 was lessons learned the impression was #1 is done. I guess they could move the data plate to a new fuselage (if they had one) and call it 1, but that is cheating.

Right... I haven’t seen anything that indicates AC1 will fly again.

Since it seems clear that development has been slower than ideal, hopefully they can roll the changes made to AC1, over the last couple of years, more cleanly into AC2. Its build was apparently stopped well before completion (for example, just now assembling the transmission) which should be helpful if there was some hardware evolution along the way.

Bet Raider AC2 flies before SB>1 does :-)

[The Sultan]

Spline

A better bet would be will they fly in 2018 or 19? Hover only does not count. They have to go beyond the airport perimeter and do a full circuit.

[CTR]

Originally Posted by SplineDrive

Bet Raider AC2 flies before SB>1 does :-)

I am predicting Defiant flying first, but only for a limited hover envelope before being pushed back in the hangar to be finished being built and software completed.

Raider Ship 2 will then fly to
expand the flight envelope before risking it on the defiant.

[SplineDrive]

Originally Posted by The Sultan

Spline

A better bet would be will they fly in 2018 or 19? Hover only does not count. They have to go beyond the airport perimeter and do a full circuit.

Progress has certainly been slow, but we both know RAIDER has been out of the airport perimeter and done more than hover. As for schedule, we'll see.

[IFMU]

Raider back in flight test:
https://www.verticalmag.com/news/sik...h-s-97-raider/

[SansAnhedral]

Did it actually fly for a full 90 minutes? That's pretty amazing. That would be almost 10% of the entire flight time that ship 1 saw in its over 2 years worth of flight test.