PPRuNe Forums

PPRuNe Forums (https://www.pprune.org/)
-   Rotorheads (https://www.pprune.org/rotorheads-23/)
-   -   Sikorsky SB-1 flies for first time (https://www.pprune.org/rotorheads/619699-sikorsky-sb-1-flies-first-time.html)

SASless 18th Apr 2022 18:29

A Tiltrotor Test Pilot warns against the choice of that style aircraft over the Sikorsky candidate.

https://breakingdefense.com/2021/04/...ot-tells-army/

SansAnhedral 18th Apr 2022 19:17


Originally Posted by casper64 (Post 11217296)
Tilt rotors are plain silly, except for semi-tactical/strategic transport from a ship where higher distances (over a flat sea) can be covered more quickly. I still cannot imagine a tiltrotor doing 100kts NOE…. And with NOE I mean real NOE, so not at a 100ft but 20ft, being agile enough to really follow the terrain like a Huey or Blackhawk could.

Where are you getting this mentality?

See 4:25 specifically, which comes after the footage of the XV-15 dogfighting the A-4 and OV-10


SplineDrive 18th Apr 2022 19:35


Originally Posted by SASless (Post 11217452)
A Tiltrotor Test Pilot warns against the choice of that style aircraft over the Sikorsky candidate.

https://breakingdefense.com/2021/04/...ot-tells-army/

Ah, yes, the oh so objective fluff piece from a Sikorsky Corporate Fellow.

Lonewolf_50 19th Apr 2022 02:03

Spline Drive, I had the same takeaway by the time I was done reading the article. :p

SASless 19th Apr 2022 02:28

I saw the bias being more of a Marine vs Army thing and some interesting issues being used to buttress his arguments.

He compares the V-22 to the UH-60 for lateral separation standards and rotor wash conflict.....but they are two different sized aircraft....and certainly much different downwash patterns.

His views about "rapid buildup of forces" also seems a bit of a Red Herring as there are a lot of far more important factors that would affect that notion.

OGE Hover capability and comparative lifting capacity at altitude or high Density Altitudes is an issue as our experience in Afghanistan taught us with the Chinook being the shining star there.

I wonder what the arguments would be were there a Tandem Rotor design being thrown into the mix.

A bigger question than which style of aircraft is the better choice is are our planners correctly seeing what the real world missions for the new aircraft are going to be.

Is the traditional "Air Mobile" concept outdated where large mass sized units....say Divisions and Brigades are to be lifted or shall the need morph to more of a Marine style expeditionary sized unit structure with a lighter footprint be the new way of war.

One strategic view is the possibility of having to take on Peer Level or Near Peer level adversaries such as Russia and China.

Recent events in Ukraine challenge some traditional thinking once held about the Russians.....and in order to fight China they either have to come to us....or we have to go to them and helicopters would only be one part of the force structure that would require.


Commando Cody 19th Apr 2022 05:41


Originally Posted by SASless (Post 11217357)
Not being a candidate for a Lying Contest....20 feet as a standard minimum height for NOE ffight in a Huey.?

Memory serves it was Three Feet in the Huey long before the Term was NOE and was called "Low Level" or " Contour" flight.

I know for a fact we flew lower than 20 feet above the ground (includes trees, brush, rice paddy dikes and road right-of-ways.....going around or between tall trees sticking up over the rest.

I can benefits to either style aircraft....Sikorsky Comanche or the Bell Tiltrotor but each also have detrimental characteristics to be considered for the Task.

The Tiltrotor puts the important bits higher due to the diameter of the Prop-Rotors in airplane mode....and certainly does in either transition or helicopter mode.

Commanche does not.....as it the Rotor system that is the highest part of the aircraft and it would have the smallest radar cross section compared to the Tilt Rotor.


Those are good polints.

In the original LHX performance specs, there was no requirement for very low RCS and I would argue that there was no need to be. Once the speed, endurance some agility and climb performance as well as max weight and allowable power specifications were lowered, Tilt-Rotor was no longer a viable candidate. Similarly, the FARA specs as solicited preclude a Tilt-Rotor candidate being competitive.

A question out of curiosity: in the extreme NoE operations you mention, do you remember the speeds? Thanks.

Commando Cody 19th Apr 2022 05:58


Originally Posted by casper64 (Post 11217296)
Tilt rotors are plain silly, except for semi-tactical/strategic transport from a ship where higher distances (over a flat sea) can be covered more quickly. I still cannot imagine a tiltrotor doing 100kts NOE. And with NOE I mean real NOE, so not at a 100ft but 20ft, being agile enough to really follow the terrain like a Huey or Blackhawk could.

I note the V-280 has already demonstrated that it at least meets the Army's FLRAA low speed agility requirements, which exceed that of Huey and Black Hawk while as yet Defiant has not.

Commando Cody 19th Apr 2022 06:05

,Lonewolf 50: When A-12 died, DoD directed USN to buy F/A-18E/F as an "interim" aircraft to fill the gap between A-6 retirement and arrival of the much better concept than A-12, A-X (later A/F-X). DoD/Congress direction to develop the "something for everyone" JSF was still a few years in the future.

SASless 19th Apr 2022 06:55

CC....first we have to agree to the definition of "Nap of the Earth (NOE)". My recollection is that was a new concept taught by the Army circa 1974-75 which followed after the earlier "Contour and Low Level" methods.

My recollection of "Contour flying" was just that....picking contour lines on maps....seeking cover from observation using hills and other terrain features with a varying flight path along the ground and "Low Level" was generally straight line but close to the ground.

NOE incorporated both and added a varying airspeed as appropriate from hover to normal cruise speed. The other two methods were done at normal cruise speeds.

During Vietnam War days.....the Army elected to abandon the down in the weeds tactics that had been doctrine and went to an administrative assignment of operating heights due to the amount of helicopter and airplane traffic that was present.

Scouts were in the treetops with their gun cover from 1,000-1500 feet higher....Huey's had from 1500 to 2500....Chinooks and Skycranes had 2500-3000 and fixed wing had from there on up.

Necessity oft times meant we reverted to that which we had been taught prior to arriving in country as it made very good tactical sense when the bad guys were doing their best to bag themselves a Gong for shooting down a Helicopter.

The Sultan 19th Apr 2022 19:22

Relevant V-22 Comparison
 
As discussed above the SB-1 required three refuelings to make the 700 mile journey from West Palm to Nashville. From an article on The Drive discussing real life operations of the V-22:


From Hickam Field in Hawaii, the Ospreys flew 1,998 nautical miles to Wake Island with three refuelings by KC-130Js flown by Marine Aerial Refueler Transport Squadron 152 of 1st Marine Air Wing (1st MAW). Thats almost 2.5 times the MV-22s operational range,
Further proof of the benefits of a tilt rotor.

SASless 19th Apr 2022 19:27

What about CH-53's, CH-47's, UH-60's with AAR capability....they would have been able to make the same flight perhaps with more refuels along the way depending upon whether they had extra tankage installed.

SansAnhedral 19th Apr 2022 19:47

More refuels, and likely at minimum twice the flight duration at much lower altitude. Not to mention the absolute beating any pax would take in those ships flying edgewise rotors for hours on end.

I cant even fathom riding in a paint shaker like SB1 for anything approaching those missions.

Commando Cody 20th Apr 2022 05:29

One other thing about the article about the Tilt-Rotor "test pilot's" recommendation...

He got to actually pilot Tilt-Rotors. What I mean by this is that there have been guest and non-company pilots that have flown and evaluated every Tilt-Rotor design that's ever flown. Whereas with X2 (I'm excluding the XH-59 because Sikorsky has said it was an ABC and not representative of the more advanced X2 technology), no non-company pilot has ever been allowed to pilot (i.e. have full control) any X2. In fact, AFAIK only one non-company person has ever even flown in any X2.

For those who might point out an Army civilian experimental test pilot flew in the S-97 in August of 2020, he was not allowed to use the collective and have full control because as the accompanying Sikorsky test pilot explained (this is a direct quote), “I am not confident sitting in the left seat of that machine and letting somebody take it for a spin around the block",

SplineDrive 20th Apr 2022 12:25


Originally Posted by Commando Cody (Post 11218173)
One other thing about the article about the Tilt-Rotor "test pilot's" recommendation...

He got to actually pilot Tilt-Rotors. What I mean by this is that there have been guest and non-company pilots that have flown and evaluated every Tilt-Rotor design that's ever flown. Whereas with X2 (I'm excluding the XH-59 because Sikorsky has said it was an ABC and not representative of the more advanced X2 technology), no non-company pilot has ever been allowed to pilot (i.e. have full control) any X2. In fact, AFAIK only one non-company person has ever even flown in any X2.

For those who might point out an Army civilian experimental test pilot flew in the S-97 in August of 2020, he was not allowed to use the collective and have full control because as the accompanying Sikorsky test pilot explained (this is a direct quote), I am not confident sitting in the left seat of that machine and letting somebody take it for a spin around the block",

https://www.army.mil/article/252221/...ly_sb1_defiant

Army XPs flew Defiant late last year, or is this the "non-company person" piloting an X2 you're referring to?

SASless 20th Apr 2022 13:17

The Sikorsky view.....which towards the end of the article the question about if there is room for/need for the Tiltrotor and the new Sikorsky designs.....and the Sikorsky VP suggests that is the case....there is he says.

He qualifies his statement by offering a couple of criteria that should be used in making the distinction between the two concepts.

The question then becomes....how does the DOD make those decisions.....what factors should they use to score the Pro's and Con's of the two different aircraft designs?

https://www.thedrive.com/the-war-zon...gram-officials

Lonewolf_50 20th Apr 2022 13:34


Originally Posted by Commando Cody (Post 11217641)
,Lonewolf 50: When A-12 died, DoD directed USN to buy F/A-18E/F as an "interim" aircraft to fill the gap between A-6 retirement and arrival of the much better concept than A-12, A-X (later A/F-X). DoD/Congress direction to develop the "something for everyone" JSF was still a few years in the future.

JSF was very much the child of the Roles and Missions debate that raged in Washington after the Gulf War of 1991, the major reduction in defense budgets, the agreement that 'stealth' had proved itself and had to be part of any next gen tactical aircraft, and the perception among politicians that a one size fits all aircraft was better and cheaper than F or A aircraft development.
By the late 90's (which is about the time frame I was referring to as regards my previous post on how money was in a lot of ways not available for Seahawks (despite the R as a B/F fusion being nearly a decade old) JSF was as I mentioned in the "figuring it out" phase (the choice of Prime had not yet been made) and was attracting serious money.
I later found out that something like 109 congressional districts had a finger in the F-35 production pie, which in retrospect 'cancel proofed' that program rather nicely. Rotary wing aircraft, in my limited experience on the acquisition side, didn't and don't get that kind of deep political support.

Originally Posted by SASless (Post 11217660)
Scouts were in the treetops with their gun cover from 1,000-1500 feet higher....Huey's had from 1500 to 2500....Chinooks and Skycranes had 2500-3000 and fixed wing had from there on up.

You may find it interesting that, in Iraq back in the early to mid 00's, the airspace C2 scheme more or less ceded 3000' and below to rotary wing/Army assets (though sometimes Fixed Wing was able to get down lower for particular purposes), 3000' and above to fixed wing, with a lot of effort taken to fold in the UAV/Drone air space coordination as it was new. That looks a lot like what you were seeing in 'Nam 30 years earlier.

If you look at how Air Defense is doing in Ukraine now, rotary wing like Valor or Defiant is going to need to use (operationally) terrain masking (among other tools) to be able to enter and exit hot zones.

SplineDrive 20th Apr 2022 13:46


Originally Posted by SASless (Post 11218355)
The Sikorsky view.....which towards the end of the article the question about if there is room for/need for the Tiltrotor and the new Sikorsky designs.....and the Sikorsky VP suggests that is the case....there is he says.

He qualifies his statement by offering a couple of criteria that should be used in making the distinction between the two concepts.

The question then becomes....how does the DOD make those decisions.....what factors should they use to score the Pro's and Con's of the two different aircraft designs?

https://www.thedrive.com/the-war-zon...gram-officials

Well, the DoD should have more information at hand than the Sikorsky executive non-speak in that Warzone article.

JohnDixson 20th Apr 2022 17:45

RePost 407:
I note the V-280 has already demonstrated that it at least meets the Army's FLRAA low speed agility requirements, which exceed that of Huey and Black Hawk while as yet Defiant has not.”
Can you be specific and pass along where the 280 is more maneuverable than the UH-60? Weight, speed pitch rate/roll rate/yaw rate etc.
Thanks.

SASless 20th Apr 2022 17:59

Nothing empirical....but I found upon living in the tree branches when possible resulted in not being shot at ever.....but upon leaving them...the incidence of getting potted at increased greatly.....as the Chinook is an attractive target.

.30 Caliber/7.62 was a concern to about 1500 feet...... .50 Cal/.51 Cal was a concern up to about 3000, and when 37MM and bigger showed up there was no way to get out of range by climbing.

Then when the Manpads showed up....back into the treetops we went.

Flying in the desert or mountainous areas and being confronted with modern Manpads and .51 Caliber or 20mm has got to be a worrisome situation to fly in If you wish to become an old Geezer.

SplineDrive 20th Apr 2022 19:25


Originally Posted by JohnDixson (Post 11218458)
RePost 407:
I note the V-280 has already demonstrated that it at least meets the Army's FLRAA low speed agility requirements, which exceed that of Huey and Black Hawk while as yet Defiant has not.
Can you be specific and pass along where the 280 is more maneuverable than the UH-60? Weight, speed pitch rate/roll rate/yaw rate etc.
Thanks.

I havent seen rate, phase delay, etc. data for V-280s maneuverability, just statements that low speed agility testing met level 1 handling qualities. Not sure if thats ADS-33E or more along the lines of the proposed ADS-33F requirements. I suspect the latter. Maybe someone has seen more specific comparisons in a VFS paper or such, but Id be a little surprised data like that would be published during the competition phase.


All times are GMT. The time now is 03:11.


Copyright © 2022 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.