Hot new helicopter/rotorcraft news

[phrogdriver]

So is there an active requirement for Navy Strike FVL variant?

Yes. But it's not necessarily linked with FVL as the Army and Marine Corps see it.

 

[phrogdriver]

It's not that I don't think tiltrotors aren't cool or anything, but I just have concerns on whether they're as survivable in a shooting war as people seem to think they are.
I'm not a 22 guy so maybe i'm way off base here so please correct me if I'm wrong.

The Valor, for the size of aircraft that it is, is a pretty big target from the front. In a service where space is a premium, I think the ideal is to have something that folds up nice that doesn't need a whole evolution to rotate the wings and extend the blades. At least the E2/C2 can start up without unfolding its wings. The V-22 needs to be carted out all folded up.

Sure the 22 can KIND of autorotate, but not very well. In the case of a single engine failure, one nacelle can power both rotors/props through drive shafts that travel through the wings from one side to the other, but how confident are we that they'll perform with battle damage?

I just think it's not very smart to double down and put all of our eggs in the tiltrotor basket.

Sikorsky X2 tech via the Defiant/Raider definitely deserve a second look.

The Fairey Rotodyne was really ahead of its time and I think the technology could use a second look.

Kinda out there, but this is also a really neat concept. Imagine a main rotor that doesn't need the extra weight of a transmission. Bleed air from the turboprop engines is pushed through the rotor blades to tiny tip jets on the end and ignited to spin the blades. Once you transition to forward flight, the tip jets turn off and the main rotor spins entirely decoupled, essentially in autorotation the entire flight. If you lose both engines, you can auto to the deck. You can also land conventionally. #1 and #2 engines along with the wing provide enough forward thrust and lift to keep the main rotor spinning fast enough to provide lift. You don't need a tail rotor. It could carry 19,000lbs and travel 190mph.

This is the kind of BS 80YO sim instructors peddle. I don't work for Bell anymore, so this is mostly unbiased.

"Shooting war?" What in the everloving fuck are you talking about? The V-22 was continuously in Iraq and/or Afghanistan from 2007 until our withdrawal two years ago. It's been shot at a LOT in Africa and Syria as well.

X2 tech is straight garbage. It's heavier and more complex than tiltrotor for far worse results. The SB-1 is an enormous aircraft with abysmal performance. It flies maybe 30% faster than a helo, with worse maneuverability, speed, and fuel burn than a tiltrotor.

What makes you think it can auto? The Ka-52 has ejection seats expressly because coax helos are EXTREMELY difficult to auto--the yaw control is extremely deficient--the pedals reverse on final...but you don't know when. And yes, that's true of the X2 tech as well.

Tiltrotors can auto and glide, depending on the mode of flight. If "battle damage" claims the ICDS, the aircraft is so full of holes no one inside is alive anyway. Will a 60 auto if the entire fuselage is punched full of 12.7mm holes? This is absolutely fucktarded.

Besides, how many successful autos were executed in military rotorcraft in operational use in the last decade? 1? 2? Try the cost benefit analysis on that. TLDR, WTF cares if it autos? There are a a dozen layers in the survivability onion where a tiltrotor is better than a conventional helo or a compound coax...but the auto is supposed to make the difference?

 

[DanMa1156]

 

[IKE]

This is the kind of BS 80YO sim instructors peddle. I don't work for Bell anymore, so this is mostly unbiased.

"Shooting war?" What in the everloving fuck are you talking about? The V-22 was continuously in Iraq and/or Afghanistan from 2007 until our withdrawal two years ago. It's been shot at a LOT in Africa and Syria as well.

X2 tech is straight garbage. It's heavier and more complex than tiltrotor for far worse results. The SB-1 is an enormous aircraft with abysmal performance. It flies maybe 30% faster than a helo, with worse maneuverability, speed, and fuel burn than a tiltrotor.

What makes you think it can auto? The Ka-52 has ejection seats expressly because coax helos are EXTREMELY difficult to auto--the yaw control is extremely deficient--the pedals reverse on final...but you don't know when. And yes, that's true of the X2 tech as well.

Tiltrotors can auto and glide, depending on the mode of flight. If "battle damage" claims the ICDS, the aircraft is so full of holes no one inside is alive anyway. Will a 60 auto if the entire fuselage is punched full of 12.7mm holes? This is absolutely fucktarded.

Besides, how many successful autos were executed in military rotorcraft in operational use in the last decade? 1? 2? Try the cost benefit analysis on that. TLDR, WTF cares if it autos? There are a a dozen layers in the survivability onion where a tiltrotor is better than a conventional helo or a compound coax...but the auto is supposed to make the difference?

Overall, totally agree. Two minor gripes:

• Pedal reversal can be addressed via flight control laws (assuming FBW). I've flown the S-97 Raider sim but was too excited by hovering 20° nose up to think about trying an auto.
• Seahawks alone have had 3-4 autos in the last decade I think... although the ones I know about have been because we lost TR drive, which doesn't come into play for tilt rotors.

 

[phrogdriver]

Overall, totally agree. Two minor gripes:

• Pedal reversal can be addressed via flight control laws (assuming FBW). I've flown the S-97 Raider sim but was too excited by hovering 20° nose up to think about trying an auto.
• Seahawks alone have had 3-4 autos in the last decade I think... although the ones I know about have been because we lost TR drive, which doesn't come into play for tilt rotors.

Fair points, though the rumor mill says that Sikorsky was not confident in the Defiant’s auto capability. They let helo guys assume it could do that, but you’d think if it were a strength of the design relative to tiltrotors they’d be shouting it from the rooftops.

That the actual autos were from a failure mode solely inherent to helicopters is not an endorsement of helicopters, and I think you are saying that too. The idea that simultaneous dual engine failures are happening regularly has a lot of currency in conversation, but not in real risk analysis.

 

[ChuckMK23]

I would be interested in hearing OEI anecdotes of the V-22 - if anyone has any to share.

The South Sudan operation in 2013 where 3 CV-22's were shot to hell (by no-kidding AAA and crew served weapons) is an example and apparently the after action case study was the V-22 performed remarkably despite multiple system losses, with wounded aircrew. The aircraft reportedly fared far better than anyone expected.

 

[phrogdriver]

I would be interested in hearing OEI anecdotes of the V-22 - if anyone has any to share.

The South Sudan operation in 2013 where 3 CV-22's were shot to hell (by no-kidding AAA and crew served weapons) is an example and apparently the after action case study was the V-22 performed remarkably despite multiple system losses, with wounded aircrew. The aircraft reportedly fared far better than anyone expected.

I’ve never had an engine failure, per se. One of my squadronmates had one after a mech left a rag in a fuel cell. In airplane mode, you’ll be fine at most weights. You’re unlikely to hover OEI unless practically empty, so you’re going to want to either burn or dump fuel, then roll on to a runway if available or no-hover to the back of the ship with good winds if not.

 

[number9]

What makes you think it can auto? The Ka-52 has ejection seats expressly because coax helos are EXTREMELY difficult to auto--the yaw control is extremely deficient--the pedals reverse on final...but you don't know when.

Can you please eli5 to me why this is true?

 

[Griz882]

Can you please eli5 to me why this is true?

I’m no expert on the KA-52 but, a conventional helicopter like the Griz-O-Copter has a main rotor which produces a torque. The tail rotor thrust, applied at the end of the tail boom, provides a counter-acting "anti-torque" to keep the helicopter pointing where I want it. As the pilot, when I change the collective pitch of the main rotor, to go into a climb or a descent, the torque required to drive the main rotor goes up or down, and the pilot counters it by using the tail rotor pedals. If I want to yaw the nose to the left or right, I can use the pedals to raise or lower the tail rotor thrust in order to temporarily upset the balance between the main and tail rotor torques and steer the aircraft.

Now, consider how yaw control works for a coaxial helicopter. The torque of the upper rotor is now counter-balanced by the torque of the lower rotor. To yaw the helicopter, the pedal inputs are set up to upset the balance of torques by raising the torque on one rotor (by increasing the collective) and lowering it on the other (decreasing collective), while maintaining the same thrust.

On a conventional helicopter, in an autorotation, the engines are no longer providing torque to drive the main rotor--the rotor is being driven by the relative wind while the tail rotor is still being driven by torque transmitted from the main rotor through the drive shafts, thus I can still use the pedals to change the tail rotor thrust and control my yaw. However, in a coaxial helicopter, when the torque on the rotors is low, differential collective does not have very much control authority: depending on the collective setting, pedal inputs can have a weak effect, no effect, or most surprisingly, a negative effect! To counter-act this, most coaxial helicopters have very large vertical fins to provide good low-speed directional stability and some, like the KA-52, actually have rudders to augment control. But…the KA-52 is an attack helicopter so typically flies low and fast. If there is a catastrophic failure that rudder probably isn’t big enough to keep the ship straight enough for a typical autorotation landing. I have seen some images out of the Ukraine where shot-down KA’s have landed with their crews in the cockpit but I assume these are running landings.

 

[number9]

I’m no expert on the KA-52 but, a conventional helicopter like the Griz-O-Copter has a main rotor which produces a torque. The tail rotor thrust, applied at the end of the tail boom, provides a counter-acting "anti-torque" to keep the helicopter pointing where I want it. As the pilot, when I change the collective pitch of the main rotor, to go into a climb or a descent, the torque required to drive the main rotor goes up or down, and the pilot counters it by using the tail rotor pedals. If I want to yaw the nose to the left or right, I can use the pedals to raise or lower the tail rotor thrust in order to temporarily upset the balance between the main and tail rotor torques and steer the aircraft.

Now, consider how yaw control works for a coaxial helicopter. The torque of the upper rotor is now counter-balanced by the torque of the lower rotor. To yaw the helicopter, the pedal inputs are set up to upset the balance of torques by raising the torque on one rotor (by increasing the collective) and lowering it on the other (decreasing collective), while maintaining the same thrust.

On a conventional helicopter, in an autorotation, the engines are no longer providing torque to drive the main rotor--the rotor is being driven by the relative wind while the tail rotor is still being driven by torque transmitted from the main rotor through the drive shafts, thus I can still use the pedals to change the tail rotor thrust and control my yaw. However, in a coaxial helicopter, when the torque on the rotors is low, differential collective does not have very much control authority: depending on the collective setting, pedal inputs can have a weak effect, no effect, or most surprisingly, a negative effect! To counter-act this, most coaxial helicopters have very large vertical fins to provide good low-speed directional stability and some, like the KA-52, actually have rudders to augment control. But…the KA-52 is an attack helicopter so typically flies low and fast. If there is a catastrophic failure that rudder probably isn’t big enough to keep the ship straight enough for a typical autorotation landing. I have seen some images out of the Ukraine where shot-down KA’s have landed with their crews in the cockpit but I assume these are running landings.

That was really interesting, thank you for posting it!

 

[GroundPounder]

I’m no expert on the KA-52 but, a conventional helicopter like the Griz-O-Copter has a main rotor which produces a torque. The tail rotor thrust, applied at the end of the tail boom, provides a counter-acting "anti-torque" to keep the helicopter pointing where I want it. As the pilot, when I change the collective pitch of the main rotor, to go into a climb or a descent, the torque required to drive the main rotor goes up or down, and the pilot counters it by using the tail rotor pedals. If I want to yaw the nose to the left or right, I can use the pedals to raise or lower the tail rotor thrust in order to temporarily upset the balance between the main and tail rotor torques and steer the aircraft.

Now, consider how yaw control works for a coaxial helicopter. The torque of the upper rotor is now counter-balanced by the torque of the lower rotor. To yaw the helicopter, the pedal inputs are set up to upset the balance of torques by raising the torque on one rotor (by increasing the collective) and lowering it on the other (decreasing collective), while maintaining the same thrust.

On a conventional helicopter, in an autorotation, the engines are no longer providing torque to drive the main rotor--the rotor is being driven by the relative wind while the tail rotor is still being driven by torque transmitted from the main rotor through the drive shafts, thus I can still use the pedals to change the tail rotor thrust and control my yaw. However, in a coaxial helicopter, when the torque on the rotors is low, differential collective does not have very much control authority: depending on the collective setting, pedal inputs can have a weak effect, no effect, or most surprisingly, a negative effect! To counter-act this, most coaxial helicopters have very large vertical fins to provide good low-speed directional stability and some, like the KA-52, actually have rudders to augment control. But…the KA-52 is an attack helicopter so typically flies low and fast. If there is a catastrophic failure that rudder probably isn’t big enough to keep the ship straight enough for a typical autorotation landing. I have seen some images out of the Ukraine where shot-down KA’s have landed with their crews in the cockpit but I assume these are running landings.

And interesting at the same time. Never knew that about co-axial helicopters.

 

[ChuckMK23]

A potential new engine for Griz-o-copter?

Continental Unveils CD-170R Rotorcraft-Specific Heavy Fuel Engine

Continental unveiled its CD-170R jet-A piston-engine variant for rotorcraft at the AERO 2024 GA trade show in Friedrichshafen, Germany, on Thursday.

www.flyingmag.com

 

[phrogdriver]

A potential new engine for Griz-o-copter?

Continental Unveils CD-170R Rotorcraft-Specific Heavy Fuel Engine

Continental unveiled its CD-170R jet-A piston-engine variant for rotorcraft at the AERO 2024 GA trade show in Friedrichshafen, Germany, on Thursday.

www.flyingmag.com

Definitely a European-market-specific innovation. They don't like AvGas, and have a much weaker general aviation market, so Jet A and the like are much easier to find.

 

[Griz882]

Nice engine, but I’d lose a chunk of horse power at close to the same weight. I do seriously love the idea of a FADEC as I am sick of the 1920’s technology tractor magneto that I have now (made worse in that it is a dual magneto). Even an engine governor would be nice (the Enstrom uses a collective correlator) to save some gas.

The real problem on the US is that once something works…like a 1950’s engine…why bother ever changing it? It is very expensive for companies to meet FAA requirements and most owners don’t care as long as the spinning thingy on the front (or top) keeps spinning. But…100LL is on the way out no matter how much pilots kick and scream. Several states are working on bills that will limit the number of take offs and landings per day at GA airports that utilize 100LL and others are looking at outright bans. In most cases the fox isn’t too hard, but getting past the “but it works” types isn’t easy.

 

[Griz882]

And interesting at the same time. Never knew that about co-axial helicopters.

Yes…and all of it learned during a factory visit to the Kaman shop in CT where they were super nice, let my try their K-Max simulator and did a great job presenting the idiots guide to the differences between conventional, tandem, coax, and intermeshing rotor helicopters!