US Navy’s UCLASS / CBARS / MQ-XX / MQ-25 Stingray Program

[AeroFranz]

The concept shown in the last picture differs from the current Avenger in several ways. I can't tell how much bigger it is.

 

[NeilChapman]

Bear with me. I'm trying to work out how this will work.

Assumptions:

Jet fuel = 6.8lbs per gal
SH - Low altitude strike mission profile combat radius - qty 4 1klb bombs & 2 ext tanks
450nmi w/2-480gal external tanks& ~2kgal internal = 450nmi w/6528lbs ext fuel & 14550lbs int. fuel
SH - you want to land with a 2.3-3k lbs of fuel
SH fuel consumption for 900 nmi = ~18,000lbs = 21078-3000=~18,000 lbs
18,000lbs/900nmi = 20lbs per nmi
Steady fuel burn rate
CAW will have qty 5 MQ-25's - 1 or 2 in maintenance & 3-4 operational

===
Objective
The goal is to extend the SH combat radius beyond 700nmi (1400 nmi) from 450 nmi. (900 nmi)
Navy wants some qty of MQ-25's to deliver 15,000 lbs of fuel to 4-6 planes at 500nmi out.
They make it sound like one but it seems it may have to be more than one.

Scenario
Flight of 4 SH's take off w/full load above. ~84k lbs of fuel
Flies out 500nmi, burning 10k lbs of fuel per plane but picks of 15k lbs (84-40+15=59k lbs)
* From 1st MQ-25 - MQ-25 turns back
Flight continues additional 200nmi - releases load - comes back 200nmi - gets 15k more (59-32+15=42k lbs)
* From 2nd MQ-25
Flight doesn't have enough fuel to make it back to the carrier w/any reserve - Needs 40k+12k reserve but has only 42k lbs
* Needs 3rd MQ-25 to get back

I know Navy eluded to the fact that w/magic carpet they need less reserve. But this is assuming a straight flight profile with no maneuvering or avoiding enemy or even time for tanking.

Where am I messing this up? Surely they're not expecting to use all their usable MQ-25's for one strike mission. They're supposed to be doing dozens of sorties per day.

And - the MQ-25 is going to be within 200nmi of the enemy? Doesn't seem like a good idea for a non-stealthy, slow moving tanker.

==

Some options...

- My fuel numbers are way off.
- There will be more than 5 MQ-25's on the carrier so flight can top off on the way out (@ 500nmi out)
* They'd need 3 MQ-25's to top off on way out @500nmi out
* Tankers vulnerable - they'd need an air cap which would require more tankers
* That's a lot of Hornet sized tankers on the carrier

 

[sferrin]

The concept shown in the last picture differs from the current Avenger in several ways. I can't tell how much bigger it is.

It looks like the fuselage is proportionally wider than the current design.

 

[jsport]

blended wing bodies are always going to be better at carrying payloads as well as steath and high dynamic maneuver. Tube and wing is 'Model A' and has been for decades

 

[sferrin]

blended wing bodies are always going to be better at carrying payloads as well as steath and high dynamic maneuver. Tube and wing is 'Model A' and has been for decades

Personally, I think an X-47-ish or LM HWB design, sized for a maximum takeoff of 80,000lbs would be the best.

 

[NeilChapman]

blended wing bodies are always going to be better at carrying payloads as well as steath and high dynamic maneuver. Tube and wing is 'Model A' and has been for decades

Personally, I think an X-47-ish or LM HWB design, sized for a maximum takeoff of 80,000lbs would be the best.

I like the design, the efficiency of it. Perhaps a "scaled" solution for the Navy then, potentially, a full-sized version for KC-Z solution.

-

Just been reading about 91 S-3's in storage. 11k hours of service life left in them and a tanker version was built that can haul 30k lbs of fuel.

Why wouldn't these fit the bill?

 

[red admiral]

blended wing bodies are always going to be better at carrying payloads as well as steath and high dynamic maneuver. Tube and wing is 'Model A' and has been for decades

But probably not for operations on carriers where you need high lift devices and sufficient control power to trim them. You can't do this with a bwb and so have got to massively reduce wing loading, which then significantly impacts your cruise drag.

Just because X-47B managed to take off and land doesn't mean that there weren't significant sacrifices.

 

[AeroFranz]

If you don't need all-aspect stealth, the tailless configuration is not the best choice for bringback capability. Can't trim high lift coefficients, like RA said.

 

[sferrin]

If you don't need all-aspect stealth, the tailless configuration is not the best choice for bringback capability. Can't trim high lift coefficients, like RA said.

LM HWB.

 

[AeroFranz]

The HWB can certainly trim high lift coefficients. It's my personal bias, but i'm still not sure taking a tube and wing and melding it with a BWB is necessarily better than either. Now you don't have the trim problems of a BWB, but you added back so much wetted area that it doesn't have the low drag either.
I have zero evidence to support this, but it smells a lot like a case of picking a certain configuration just because it's different from what other companies are doing. There are oodles of AIAA technical papers produced on the HWB subject, but in the end once you remove the effects of better engines (which can be applied to most of the alternatives), all these configurations end up within 5% of each other - that is, within the error margin of what you can demonstrate short of flying a prototype! I'll be curious to see what happens if and when NASA picks their X-plane demonstrators.

 

[red admiral]

I have zero evidence to support this, but it smells a lot like a case of picking a certain configuration just because it's different from what other companies are doing. There are oodles of AIAA technical papers produced on the HWB subject, but in the end once you remove the effects of better engines (which can be applied to most of the alternatives), all these configurations end up within 5% of each other - that is, within the error margin of what you can demonstrate short of flying a prototype! I'll be curious to see what happens if and when NASA picks their X-plane demonstrators.

Agree. You get funding to look at something different, but almost all gains are due to "technology factors" above the current day, which a conventional tube and wing can use too.

The HWB configuration is nice, but there are small gains over an advanded tube and wing and a lot more risk. Maybe better value putting the money for a HWB demonstrator into additional subsystem technology research.

 

[sferrin]

I have zero evidence to support this, but it smells a lot like a case of picking a certain configuration just because it's different from what other companies are doing. There are oodles of AIAA technical papers produced on the HWB subject, but in the end once you remove the effects of better engines (which can be applied to most of the alternatives), all these configurations end up within 5% of each other - that is, within the error margin of what you can demonstrate short of flying a prototype! I'll be curious to see what happens if and when NASA picks their X-plane demonstrators.

Agree. You get funding to look at something different, but almost all gains are due to "technology factors" above the current day, which a conventional tube and wing can use too.

The HWB configuration is nice, but there are small gains over an advanded tube and wing and a lot more risk. Maybe better value putting the money for a HWB demonstrator into additional subsystem technology research.

A HWB or BWB has a lot more volume than a tube and wing for a given footprint. That's important on a carrier.

 

[bobbymike]

https://news.usni.org/2017/10/10/navy-releases-final-mq-25-stingray-rfp-general-atomics-bid-revealed

 

[jsport]

Claiming H/BWB have trim problems on landing is either design laziness in the 21st century or outright defense of inferior tube and wing designs.

Dipping a H/BWB wing into the wind assists quicker cleaner landing w/ no crosswind rolling effect but rather an accelerated stable landing (Assuming the landing gear works.) while a T & W aircraft have perpendicular crosswinds rolling the tube not in the direction of landing,

Defending T&W is mumbo jumbo.

 

[NeilChapman]

Redid my numbers.

MQ-25 w/15k lbs of give @ 500 nmi. would increase range of a flight of 4 Super Hornets by 400 nmi - 200 out and 200 back when 3-480 gal tanks are carried. W/Block III CFT's you could add an additional 200 nmi to range, opening up a 300 nmi. gap between the bad guys and MQ-25's.

Navy's going to want more than 5 MQ-25's per deck. Have there been any quantities mentioned?

 

[red admiral]

Claiming H/BWB have trim problems on landing is either design laziness in the 21st century or outright defense of inferior tube and wing designs.

Dipping a H/BWB wing into the wind assists quicker cleaner landing w/ no crosswind rolling effect but rather an accelerated stable landing (Assuming the landing gear works.) while a T & W aircraft have perpendicular crosswinds rolling the tube not in the direction of landing,

Defending T&W is mumbo jumbo.

Basic First Order Effects

Deploying flaps on a wing significantly increases Clmax so you can get away with higher wing loading for same Take-Off/Landing Performance. Deploying flaps also gives a large pitching moment, which is trimmed out with a separate control surface. You cannot do this on a configuration that doesn't have a separate pitch control device e.g. a BWB which results in you having to adopt an oversized wing or accept higher take-off/landing speeds to generate more lift.

This isn't anything to do with problems - these are basic design choices

 

[sferrin]

Claiming H/BWB have trim problems on landing is either design laziness in the 21st century or outright defense of inferior tube and wing designs.

Dipping a H/BWB wing into the wind assists quicker cleaner landing w/ no crosswind rolling effect but rather an accelerated stable landing (Assuming the landing gear works.) while a T & W aircraft have perpendicular crosswinds rolling the tube not in the direction of landing,

Defending T&W is mumbo jumbo.

Basic First Order Effects

Deploying flaps on a wing significantly increases Clmax so you can get away with higher wing loading for same Take-Off/Landing Performance. Deploying flaps also gives a large pitching moment, which is trimmed out with a separate control surface. You cannot do this on a configuration that doesn't have a separate pitch control device e.g. a BWB which results in you having to adopt an oversized wing or accept higher take-off/landing speeds to generate more lift.

This isn't anything to do with problems - these are basic design choices

HWB Think of it as a "tube and wing" with built-in CFTs.

 

[jsport]

Claiming H/BWB have trim problems on landing is either design laziness in the 21st century or outright defense of inferior tube and wing designs.

Dipping a H/BWB wing into the wind assists quicker cleaner landing w/ no crosswind rolling effect but rather an accelerated stable landing (Assuming the landing gear works.) while a T & W aircraft have perpendicular crosswinds rolling the tube not in the direction of landing,

Defending T&W is mumbo jumbo.

Basic First Order Effects

Deploying flaps on a wing significantly increases Clmax so you can get away with higher wing loading for same Take-Off/Landing Performance. Deploying flaps also gives a large pitching moment, which is trimmed out with a separate control surface. You cannot do this on a configuration that doesn't have a separate pitch control device e.g. a BWB which results in you having to adopt an oversized wing or accept higher take-off/landing speeds to generate more lift.

This isn't anything to do with problems - these are basic design choices

An unmanned carrier tanker is already projected with lesser wingspan than a manned carrier craft. Catapults speed takeoff and hooks stop/slow craft on deck. Exact flaps are design considerations for carrier and... When the whole craft is maximizing lift while minimizing drag having a time on BWB having to larger than a T&W..

Are we arguing WWI aircraft designs like Raven and Puma are reasonable designs in the 21st century. They are dinosaur's that folks are telling us are BMWs.

 

[red admiral]

What on earth are you on about jsport? Your comments don't even begin to make sense to me. Please could you explain more clearly.

 

[AeroFranz]

??? if bringback capability is something you care about, then trimmed CLmax is definitely something you try to maximize. Regardless of catapults and arresting wires, there is a combination of weights and airspeed limits that you can't exceed. High CLmax helps with both.
The trim power conferred by a horizontal tail acting at a long moment arm is hard to match by something that has little of either.

I'm no tube and wing zealot, i like exotic configurations as much as anyone else on this forum. But there's a reason 98% of all airplanes have that layout. It works. And it's not for lack of trying that other configurations haven't been adopted.

 

[jsport]

??? if bringback capability is something you care about, then trimmed CLmax is definitely something you try to maximize. Regardless of catapults and arresting wires, there is a combination of weights and airspeed limits that you can't exceed. High CLmax helps with both.
The trim power conferred by a horizontal tail acting at a long moment arm is hard to match by something that has little of either.

I'm no tube and wing zealot, i like exotic configurations as much as anyone else on this forum. But there's a reason 98% of all airplanes have that layout. It works. And it's not for lack of trying that other configurations haven't been adopted.

Cl max is defined for a particular airfoil, not for a particular aircraft. Cl max is also affected by Reynolds number. NASA's internet available airfoil design program displays how maximized Reynolds numbers designs are all BWBs.

BWBs UAS are landing on carriers, no problems they have no vertical surfaces unlike the dragging T&W designs. This seems very simple and very proven. Drag surfaces inhibit lift to weight/endurance/payload as well as high dynamic maneuver. T&Ws are antiquated designs used out of personal, non scientific expediency usually because they cheap not because they are better. Indeed, what are we talking about?

 

[red admiral]

@jsport

Despite using some of the correct words its clear you don't have an understanding of the underpinning aerodynamics. I suggest Dan Raymer's Concept Design book as a good start.

Clmax is definitely defined for a whole aircraft. Something like xfoil does 2D aerodynamics, but for a real aeroplane you need to look at 3D. Reynolds number isn't something you can change by changing the aerofoil. Its simply down to size and where in the flight envelope you are flying. Higher Reynolds number isn't "good" - if you want high Reynolds number just look at the Hindenberg.

X-47B is the only BWB or flying wing to have landed on a carrier so far. Its landing speed is about 20kts faster than a Super Hornet despite having a much lower wing loading. This is because it cannot achieve as high a lift coefficient and so needs to fly faster to generate more lift (and probably Vminc is an issue as well but thats separate).

As stated repeatedly, having a horizontal tail or canard as a separate pitch control device can give you much more lift because you can then deploy flaps and get a higher clmax. Moving Clmax from ~1.0 to ~2.0 is quite significant, but it comes with an associated pitching moment that needs to be trimmed out.

 

[TomcatViP]

we have covered already that topic. But BWB is not at stake here. It's a flying wing that have de-facto a blended body since having no... body.

Here is a BWB with a tail and no engine. It fly good as you can see.

https://youtu.be/TnwWxo4T1QA

The problem of the Northrop design, beside its astonishing achievement, is to rely on aerodynamic drag (spit flap) to generate control. Drag is especially at issue on a naval airplane that have wave-off with a low margin of excess power.

 

[AeroFranz]

Ok, let me explain this as clearly as possible.
- in carrier aviation, there's an obvious desire to fly air vehicles heavy as possible while still meeting the limits imposed by catapults and arrestor wires. That means that you must slow down said vehicles as much as possible.
- It's not just slowing them down, they must also be controllable.
-To slow down the airplane, you can use large wing area or increase the amount of lift that the wing can generate per square foot at a given flight speed. This parameter is called the maximum lift coefficient, or "CLmax". Increasing wing area is not as desirable because it increases the drag in cruise.
-Unfortunately, increasing the CLmax, also increase another parameter Cm, the pitching moment coefficient. in practice, the airplane wants to pitch down.
-To prevent this from happening, you need to exert a moment on the vehicle which opposes the nose down.
-A moment is a force applied at a distance from the center of gravity. The bigger the distance and the bigger the force, the more moment you can exert.
- A tail at the end of a fuselage is a very effective way of doing this. You can drop flaps on the wing and use the tail to counter the pitching moment.
-If you drop flaps on a flying wing, or BWB (which does not have a tail), there is no way of generating a countering pitching moment.

If you can come up with an alternate scheme, then PM me and we'll write a nice patent application.

 

[jsport]

Ok, let me explain this as clearly as possible.
- in carrier aviation, there's an obvious desire to fly air vehicles heavy as possible while still meeting the limits imposed by catapults and arrestor wires. That means that you must slow down said vehicles as much as possible.
- It's not just slowing them down, they must also be controllable.
-To slow down the airplane, you can use large wing area or increase the amount of lift that the wing can generate per square foot at a given flight speed. This parameter is called the maximum lift coefficient, or "CLmax". Increasing wing area is not as desirable because it increases the drag in cruise.
-Unfortunately, increasing the CLmax, also increase another parameter Cm, the pitching moment coefficient. in practice, the airplane wants to pitch down.
-To prevent this from happening, you need to exert a moment on the vehicle which opposes the nose down.
-A moment is a force applied at a distance from the center of gravity. The bigger the distance and the bigger the force, the more moment you can exert.
- A tail at the end of a fuselage is a very effective way of doing this. You can drop flaps on the wing and use the tail to counter the pitching moment.
-If you drop flaps on a flying wing, or BWB (which does not have a tail), there is no way of generating a countering pitching moment.

If you can come up with an alternate scheme, then PM me and we'll write a nice patent application.

Thank you for the explanation Aerofranz. High pressure blowing even from near the nose (pressurized internal air tanks) for control comes to mind. NASA work mentioned on this forum.

PS Need to check out the book red admiral recommended
but still seeing a BWB full body wing down toward the crosswind as the nose descends as a quick way to catch the arrestor hook. recalling Cross wind was the original subject

 

[jsport]

Thank you, Red Admiral for reference.

Have learned since most BWBs are designed really Flying wings not true 'airplanes' so there are control problems. A BWB designed as an "airplane" would not have these control problems.

 

[marauder2048]

Forgive the editorializing but what a farce...

Northrop drops out of Navy's MQ-25 competition


October 25, 2017 Lee Hudson

Northrop Grumman will not bid on the Navy's MQ-25 Stingray unmanned tanker program, the company's chief executive said today. During a call with analysts,
Wes Bush said Northrop "could not put forward an attractive offering to the Navy that would represent a reasonable business proposition."
The company was one of four competitors likely to vie to build the MQ-25 unmanned aerial system, which will operate from aircraft carriers.
The remaining potential bidders are Boeing, General Atomics and Lockheed Martin.

https://insidedefense.com/daily-news/northrop-drops-out-navys-mq-25-competition

 

[TomS]

That's the second or third high-profile program that NG has "no-bid" recently (T-X, 3DELRR). Seems like a strategic decision not to spend money on things they think aren't at least 50-50 shots.

 

[sferrin]

From the X-47B performing aerial refueling, carrier landings, and catapult launches, to "no bid". There aren't enough face palms.

 

[TomcatViP]

STill, they are the only ones for long to have landed a tailess stealthy airframe on an aircraft carrier, seen its limitations and spent time finding a solution. Let's be optimistic, that might payoff in the future.

With the lifting of most VLO requirements, there was rationally little room for the extra risks of operating a flying wing that had limited "scalability".

 

[sublight_]

Northrop drops out of Navy's MQ-25 competition

They did the right thing. Does anybody really believe the MQ-25 will make it into production with so many factions hell bent on repeatedly changing its mission requirements?

 

[Mat Parry]

Kelly Johnson's 15th Rule of Management

"Starve before doing business with the damned Navy. They don't know what the hell they want and will drive you up a wall before they break either your heart or a more exposed part of your anatomy."

 

[sferrin]

Northrop drops out of Navy's MQ-25 competition

They did the right thing. Does anybody really believe the MQ-25 will make it into production with so many factions hell bent on repeatedly changing its mission requirements?

Well they did manage to give themselves an all Hornet fleet so I'll have to agree with you. At times it seems they couldn't find their ass with both hands.

 

[_Del_]

Northrop drops out of Navy's MQ-25 competition

They did the right thing. Does anybody really believe the MQ-25 will make it into production with so many factions hell bent on repeatedly changing its mission requirements?

Even if it gets built and the requirements are completely static from now on (big its), the new requirements are heavily at odds with the old. From VLO, strike/ISR to a much larger platform emphasizing offload at range and off-load and lightly weighted signature requirements. It requires a brand new design from everyone involved. Probably with a tail.

"could not put forward an attractive offering to the Navy that would represent a reasonable business proposition."

Northrop also killed their own ATA (A-12) proposal by similarly saying they could easily build a plane to meet the requirements, but it would cost more and they weren't going to lower their pricetag (which made them non compliant). Very similar language here.

 

[Airplane]

Whenever one of the suppliers we work with voluntarily drops out of a competition for business, its always been a case of they had something else more important or lucrative they are working on to consider devoting manpower or plant space to another project.

That could be the case with NG and black projects. Maybe they are spread thin with things we don't know about.

Companies exist to make money, first and foremost. I don't think a company like NG is just cherry picking what they feel like working on.

 

[marauder2048]

That's the second or third high-profile program that NG has "no-bid" recently (T-X, 3DELRR). Seems like a strategic decision not to spend money on things they think aren't at least 50-50 shots.

The common thread is that T-X, 3DELRR and MQ-25 are all fixed price development contracts.

from the earnings calls with NG CEO Wes Bush

We have notified the Navy that Northrop Grumman will not be submitting a bid on the MQ-25 program.
Our assessment of the final RFP, which required a fixed price incentive bid for this development work, was
that we could not put forward an attractive offering to the Navy that would represent a reasonable
business proposition for our company.

 

[_Del_]

Companies exist to make money, first and foremost. I don't think a company like NG is just cherry picking what they feel like working on.

Well, right. The ROI probably looks terrible on a fixed-price contract that has demonstrated constantly shifting goals. Invest that time and energy on other projects.

 

[GeorgeA]

Note that the ATA was fixed-price as well. “Those who refuse to learn from history are doomed to repeat it.”

 

[NeilChapman]

Northrop drops out of Navy's MQ-25 competition

They did the right thing. Does anybody really believe the MQ-25 will make it into production with so many factions hell bent on repeatedly changing its mission requirements?

Well they did manage to give themselves an all Hornet fleet so I'll have to agree with you. At times it seems they couldn't find their ass with both hands.

Recall Northrop designed the YF-17. But yes, Navy management consistently disappoints. I'm sure glad the Marines are in charge for a little while.

I'm also glad NG dropped out. The Navy will want $1.20 of value for $.80. And I think TERN can be a significant program.

Besides, NG needs to integrate Orbital. They've got a lot on their plate.

 

[Moose]

Whenever one of the suppliers we work with voluntarily drops out of a competition for business, its always been a case of they had something else more important or lucrative they are working on to consider devoting manpower or plant space to another project.

That could be the case with NG and black projects. Maybe they are spread thin with things we don't know about.

Companies exist to make money, first and foremost. I don't think a company like NG is just cherry picking what they feel like working on.

There's absolutely something NG is working in: Raider. And while NG has a history of avoiding fixed-price contracts that is probably worth some criticism, in this case it's probably a smart move not to assume extra risk for MQ-25 whime making Raider happen.