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S97 Raider

Old 6th Jul 2022, 05:01
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Originally Posted by The Sultan View Post
Lone wrote:
On the pushing down this is hard successfully for an aircraft that lives nap of earth.
If you were a pilot you'd understand how odd that statement looks.
It only takes a few feet of down and then "away from the aircraft" for that exhaust to be below the tail. But if the rocket ignites while still in the rack? Yeah, a problem.
And no, NoE isn't 5 feet off the ground...but as you've never flown it how would you know?

As to the missiles in the cabin: certainly an opportunity for an own goal.
If one does not learn how to use the arm/disarm toggle switch that's been on aircraft since before I got my wings over 40 years ago, yeah, you could shoot yourself
While that's a minor concern it does need to be addressed. Something like an overcenter lock for the door that opens a circuit when doors are closed, but the circuit closes when the doors open/deploy. Many other ways to peel that onion as well, but the concern you raise needs to be addressed in the human factors engineering phase.
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Old 6th Jul 2022, 07:58
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Originally Posted by Lonewolf_50 View Post
If you were a pilot you'd understand how odd that statement looks.
It only takes a few feet of down and then "away from the aircraft" for that exhaust to be below the tail. But if the rocket ignites while still in the rack? Yeah, a problem.
And no, NoE isn't 5 feet off the ground...but as you've never flown it how would you know?.
Lone,

While not a pilot (something about having too high of an IQ) I have thousands of hours in the front or left seat of military helicopters so I am very familiar with NOE day and night operations. Drop before ignition is a bad idea and would result in more than a few own goals.
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Old 6th Jul 2022, 14:01
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Originally Posted by The Sultan View Post
Lone,

While not a pilot (something about having too high of an IQ) I have thousands of hours in the front or left seat of military helicopters so I am very familiar with NOE day and night operations. Drop before ignition is a bad idea and would result in more than a few own goals.
It is certainly fraught with technical chances for malfunction, yes.

There is ordnance that is released in an unarmed state in a variety of military aircraft. (Arming delays come in a variety of forms, our torps had the low tech solution of a lanyard...). Since most munitions would be guided, the 'drop and ignite' poses little obstacle to the munition getting to its target, but, all of that violated the KISS principle and requires a substantial change in arming and ignition logic . That would make the munitions for the Raider bespoke / non standard with the other users of that munition. That's a bit of a red flag for most people in the acquisition field.

Your point on "there's a better way to carry/deploy those weapons" has merit.

I had envisioned, when I saw the original Raider design, that an internally carried weapons module would be deck / floor mounted and "roll" or "pivot" about 210 - 240 degrees on fore and aft arms. The mount would (in my mind's eye) be a circular or hexagonal rack that could revolve like the cylinder in a revolver-style pistol.
After deployment, it would hang adjacent to and below the edge of the door.
The bottom of the cylinder, or the bottom two positions on the cylinder, would be the only ones that could fire. (that should keep the rocket exhaust below the horizontal stab and pusher prop, but it would take some better modeling and dynamic testing to confirm that).
Yeah, that's a rube goldberg device for sure, but then so is every helicopter out there.
That kind of approach would require more moving parts in terms of the door hinge (or a sliding door rather than a hinged door), and of course that leads to more things that could malfunction.
I'd sketch it for you on the back of a napkin if were were in a bar, but this format doesn't lend itself to that kind of illustration.
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Old 7th Jul 2022, 18:49
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A couple of other details that have not been discussed in this thread re:RaiderX gull wing door weapons deployment:

1. The entire rack with stores is hanging from the single-cantilever door, which looks to be operated with short-coupled linear actuators pushing on lugs. This seems like it would be extremely structurally difficult to create a sufficiently stiff deployed-door state - particularly with the major historical vibration problems on every X2 platform ever built.

2. Rotation of the stores rack into the deployed position (~ 90 degrees or so) would also apply torque and spin the seeker heads on guided munitions like AGM-114.
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Old 7th Jul 2022, 19:27
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Originally Posted by SansAnhedral View Post
particularly with the major historical vibration problems on every X2 platform ever built.
The X2 TD was better at 250kts than a UH60 in cruise. I can't comment on its progeny.
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Old 7th Jul 2022, 19:36
  #466 (permalink)  
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Weapons Bay Actuation

SansAnhedral,

Perhaps a weapons bay actuation configuration similar as shown in the attached US Patent is more realistic.

https://pdfpiw.uspto.gov/.piw?PageNu...11%2C370%2C544

Maybe Bell will be willing to license the design rights to Sikorsky;-)


Last edited by CTR; 7th Jul 2022 at 19:41. Reason: Error
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Old 7th Jul 2022, 21:13
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Originally Posted by IFMU View Post
The X2 TD was better at 250kts than a UH60 in cruise. I can't comment on its progeny.
True, at 6000 pounds the X2 AVC did not saturate and maintained right around 0.5 IPS in all directions.

Its unfortunate that a practical/useful platform using X2 technology requires about minimum double that gross weight, which has proved to be a bridge too far for both AVC system designs Sikorsky has built since.

Just like CTR suggested above, perhaps Raider-X will license another recent Bell patent in their search for a solution!
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Old 7th Jul 2022, 21:20
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Originally Posted by IFMU View Post
The X2 TD was better at 250kts than a UH60 in cruise. I can't comment on its progeny.
The vibration in the X2 was brutal. That's why they had active vibration suppression for a single seater where the only goal is to not kill the pilot (all surviving test pilots will say it was great and ready for production no matter how bad it is). Relative to the UH-60, not a good example. It carries vibration suppression devices to make 130+ knots. On the S-97 you could tell from crew comments they were reluctant to go above 190 knots due to vibration as engineers worked to get it tolerable enough so they good dash to their max speed of 230 knots.
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Old 8th Jul 2022, 02:14
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Originally Posted by IFMU View Post
The X2 TD was better at 250kts than a UH60 in cruise. I can't comment on its progeny.
I don't have the exact numbers immediately to hand but IIRC, in the entire X2 TD program the total time at 250 knots was only a few minutes. It is interesting the FAI offered Sikorsky the opportunity to take the world helicopter speed record (wingless compounds are classed as helicopters) which involves flying along over a measured course, doing a 180 and then flying the same course in the opposite direction (to account for the effect of wind) and taking the average of the two runs. This would be quite a feather in X2 technology's cap and would give great bragging rights for the technology. However, Sikorsky turned them down.
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Old 8th Jul 2022, 02:38
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Sultan:

I may be overlooking something, but I can't recall any existing helicopter that has a dedicated weapons bay for missiles. For FARA, neither competitor can get the speed the Army wants without an internal bay (and retractable gear).

In the case of Raider-X they're using the space that could be used for a cabin on a different version of the a/c', a "B" model used as a light transport. In the case of Invictus, they can be slimmer because there is no interest in using that area for anything other than missile carriage.

Lone Wolf:

I for one think your "revolver" idea is really clever, although eight missiles might be a tight fit. The big bugaboo would be weight, since Army has tight limit on acceptable gross weight for FARA.
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Old 8th Jul 2022, 04:16
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Originally Posted by Commando Cody View Post
However, Sikorsky turned them down.
That was all on the VP at the time. He was a former Lockheed guy. He just wanted the program done. Too bad, because besides the FAI record there was still engineering and flight test work to do.
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Old 8th Jul 2022, 15:07
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Sikorsky would have had to fly straight and level and with the aft propulser free wheeling to qualify for the helicopter speed record attempt. Otherwise Bell could have claimed it years ago with their modified UH-1 and its prodded jet engines.
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Old 8th Jul 2022, 15:12
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Maybe Sikorsky is re-using some previously engineered designs?


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Old 8th Jul 2022, 15:35
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Originally Posted by retoocs View Post
Maybe Sikorsky is re-using some previously engineered designs?
Very interesting, thanks for the photo. Looking at the gooseneck hinge on the door, and the ball-lock strut attached to the hinge in the door, it does not look like the weapons are actually attached to the door. There must be a secondary mechanism that is actually supporting the weapons rack.

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Old 8th Jul 2022, 15:38
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Let’s remember the Sikorsky of Lockheed isn’t the Sikorsky of X2 days. The whole concept has lost its way since the triad of Lockheed Boeing and it’s Sikorsky bench warmers have been pushed aside. It started with Raider when the X2 team was pushed aside by its own leadership at the time for the next team to show anyone to include the X2 team it’s easy. So Raider went down the so called experts route chasing Army supposed dreams and requirements instead of letting the original X2 team do the Y next version of the X2.
The X2 was fast, smooth at the time it flew its speed flight. But after that speed flight the X2 team lost control of the X2 destiny to the marketing and program future chasers and the so called next team of Raider.
X2 was to finish its speed test flights and maneuvering flights to close out the modeling of an X2. It went over 250 kts at cruise 71 % power and it had speed and power remaining, vibes were good and the matrix set up for the AVCs was ingenious and set the stage for the Y aircraft. The X2 team had about 9 flights remaining but as mentioned the team was basically shutdown by leadership now chasing their idea of the Raider.

The X2 team wanted to after those 9 close out flights put a new design set of rotor blades on the X2, install a real AFCS system, an active tail and active collective to truely close out the X2 design model. The Y version the X2 team envisioned was a two engine S76 sized aircraft with a gross weight ~ 13 to 14000 lbs. But good things end when good things happen due to so called self proclaimed experts and leaders that have self in mind instead of promoting and supporting the real experts to move forward to get it done and accomplished.

S97 out of the gate was the wrong aircraft, one engine and no power or payload and capability for true over 200 kt speed or margin. Power to weight to drag basic computations didn’t add up and the aircraft structurally was under designed so it couldn’t do the maneuvers planned for such a capable concept. Then SB1 Defiant came along to scale up a design which we all knew wasn’t a viable path for the concept. So in the end what was good and had potential to change the way the helicopter could fly ended back with Raider and with the triad of Lockheed, Boeing and then the Sikorsky tag alongs chasing stupid Army requirements instead of letting the original X2 team follow thru on the concept and a Y platform aircraft so when it was time we could of offered a viable awesome finished product sooner than later.
The goal of the X2 team was accomplish all KPPs with the X platform on the X2 Demonstrator and then move onto the Y version as mentioned. If they were allowed to progress just think in less than 10 years we would be here today with a viable maneuvering and speed demon weapons platform. But here they are still in the big program paper chase with the so many experts of Lockheed and Boeing and Sikorsky now developing a one engine (still waiting the 15 years now ITEP magic engine) Raider X or FARA FLARA or …… and still a true Y Plane of the X2 has never flown to close out and prove the true viable capabilities of the X2 design and platform.

Again the X2 design and the X2 demonstrator met all its KPPs and if the original team was allowed to continue moving forward on its path the full potential as outlined would be a real accomplishment for the industry. As great as the ACH 66 Comanche now the the X2 follows its fate. Shame we don’t let the small selected group do the development for it has proved over and over in history it can be done.

But here you are design by committee, self proclaimed experts, dream requirements half baked and now in competition in a chase. So
good luck with the chase and the big program burdens. Go slow and drag it out and keep changing requirements as the Army leadership changes and the corporate leadership changes. To bad you don’t let the dedicated smart people move forward.

And really sad UTC sold Sikorsky..

Last edited by BLloydK; 8th Jul 2022 at 20:31.
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Old 8th Jul 2022, 19:13
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BLloydK,

Thank you for one of the most interesting and enlightening posts I have read on PPRuNe in a very long time. Looking forward to your future posts.
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Old 8th Jul 2022, 20:37
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Originally Posted by heli1 View Post
Sikorsky would have had to fly straight and level and with the aft propulser free wheeling to qualify for the helicopter speed record attempt. Otherwise Bell could have claimed it years ago with their modified UH-1 and its prodded jet engines.
IIRC, the Bell 533 often flew with a wing, which I believe would disqualify it, the rotor not being the only lift surface. More importantly, the podded jets were not integral to the rotorcraft's lift/propulsion system, which is a requirement, but merely an auxiliary thrust system independent of the helicopter's operation itself. Otherwise you could just hang a big enough jet on anything and just force your way through the air, with no advance in helicopter technology. The X2 TD does not use any auxiliary means of propulsion, the pusher is powered by the vehicle's normal engine/transmission and so would qualify as a helicopter for record purposes.
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Old 8th Jul 2022, 21:23
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Sultan:

"Impact of weapon exhaust on the tail has always been a concern and looked at very closely. Thatís why the weapons are placed on all helicopters I know of where the tail rotor is not directly behind it. On the Raider the pusher is very big and face on to the back blast. If damaged the pusher wouldnít just stop working, but be significantly out of balance. If the unbalance is large enough you loose the whole tail."

I wonder if you've hit on another, unannounced, reason why Bell changed the location/type of tail rotor on Invictus. In the initial configuration, the shrouded tail rotor was directly in line with the fuselage. This was no big deal on previous uses of this technology. However, in the case of the Bell 360, this also puts tha air flowing through it would be in line with the exhaust from missile launch. Their studies might have indicated this turbulence could potentially be a problem. Moving it to a conventional design higher up takes it out of this area. Could that be another reason for the move?



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Old 8th Jul 2022, 21:56
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Originally Posted by BLloydK View Post
Let’s remember the Sikorsky of Lockheed isn’t the Sikorsky of X2 days. The whole concept has lost its way since the triad of Lockheed Boeing and it’s Sikorsky bench warmers have been pushed aside. It started with Raider when the X2 team was pushed aside by its own leadership at the time for the next team to show anyone to include the X2 team it’s easy. So Raider went down the so called experts route chasing Army supposed dreams and requirements instead of letting the original X2 team do the Y next version of the X2.
The X2 was fast, smooth at the time it flew its speed flight. But after that speed flight the X2 team lost control of the X2 destiny to the marketing and program future chasers and the so called next team of Raider.
X2 was to finish its speed test flights and maneuvering flights to close out the modeling of an X2. It went over 250 kts at cruise 71 % power and it had speed and power remaining, vibes were good and the matrix set up for the AVCs was ingenious and set the stage for the Y aircraft. The X2 team had about 9 flights remaining but as mentioned the team was basically shutdown by leadership now chasing their idea of the Raider.

The X2 team wanted to after those 9 close out flights put a new design set of rotor blades on the X2, install a real AFCS system, an active tail and active collective to truely close out the X2 design model. The Y version the X2 team envisioned was a two engine S76 sized aircraft with a gross weight ~ 13 to 14000 lbs. But good things end when good things happen due to so called self proclaimed experts and leaders that have self in mind instead of promoting and supporting the real experts to move forward to get it done and accomplished.

S97 out of the gate was the wrong aircraft, one engine and no power or payload and capability for true over 200 kt speed or margin. Power to weight to drag basic computations didn’t add up and the aircraft structurally was under designed so it couldn’t do the maneuvers planned for such a capable concept. Then SB1 Defiant came along to scale up a design which we all knew wasn’t a viable path for the concept. So in the end what was good and had potential to change the way the helicopter could fly ended back with Raider and with the triad of Lockheed, Boeing and then the Sikorsky tag alongs chasing stupid Army requirements instead of letting the original X2 team follow thru on the concept and a Y platform aircraft so when it was time we could of offered a viable awesome finished product sooner than later.
The goal of the X2 team was accomplish all KPPs with the X platform on the X2 Demonstrator and then move onto the Y version as mentioned. If they were allowed to progress just think in less than 10 years we would be here today with a viable maneuvering and speed demon weapons platform. But here they are still in the big program paper chase with the so many experts of Lockheed and Boeing and Sikorsky now developing a one engine (still waiting the 15 years now ITEP magic engine) Raider X or FARA FLARA or …… and still a true Y Plane of the X2 has never flown to close out and prove the true viable capabilities of the X2 design and platform.

Again the X2 design and the X2 demonstrator met all its KPPs and if the original team was allowed to continue moving forward on its path the full potential as outlined would be a real accomplishment for the industry. As great as the ACH 66 Comanche now the the X2 follows its fate. Shame we don’t let the small selected group do the development for it has proved over and over in history it can be done.

But here you are design by committee, self proclaimed experts, dream requirements half baked and now in competition in a chase. So
good luck with the chase and the big program burdens. Go slow and drag it out and keep changing requirements as the Army leadership changes and the corporate leadership changes. To bad you don’t let the dedicated smart people move forward.

And really sad UTC sold Sikorsky..
A lot to unpack here, least of which is my sneaking suspicion that we were just graced by a post from an esteemed Sikorsky test pilot.

Based upon the commentary above, it would seem that there is some belief that the increased gross weight of the aircraft would not necessarily guarantee an inherent increased vibration problem that we have witnessed on S97 and SB1.

While I understand and agree with the power limitation and drag issues mentioned on committee-designed Raider and Defiant...had the "Y-2" been built as described, what would have prevented the same vibration-based limitations the contemporary ships have experienced when it comes to ABC/LOC flight with essentially the same rigid rotor system (aside from perhaps much improved fuselage stiffness designs)?

Also was the S-76 sized "Y-2" concept at Sikorsky referred to as ACER (or maybe ASIR) at any point?

Last edited by Senior Pilot; 10th Jul 2022 at 03:45. Reason: Remove possible outing
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Old 13th Jul 2022, 08:25
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Bell Makes Progress

Bellís FARA entry looks substantially more complete than Sikorskyís.

https://www.thedrive.com/the-war-zon...-in-new-photos
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