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

[Sundog]

With regard to tailed versus not tailed aircraft, Raymer (I think it was Raymer) did a very nice comparison of the B-47 (High aspect ratio) versus the Vulcan bomber (Low aspect ratio) and shows how they're performance was quite similar given their different approaches to the same problem in his aircraft design book.

A couple of other things to note:
1) Just having to build a wing could have a very good cost advantage compared to the competing designs, which all have fuselages and tails.
2) Endurance for a jet powered aircraft occurs when flying at the velocity that delivers the maximum lift to drag ratio; i.e, it's a direct function of (L/D)max. Endurance as a function of (CL3/2/CD)max only applies to propeller driven (Turbo-prop and recip) aircraft and is a function of air density; i.e.-it occurs at sea level for propeller driven aircraft.

 

[AeroFranz]

SD is right - my bad. Been working on recips too long, i forgot the difference with thrust-type powerplants :-[
I almost brought up the Raymer comparison between the B-47 and the Vulcan but did not want get too deep; in a nutshell the interesting point there is the importance of wetted aspect ratio as opposed top just span or aspect ratio, which explains how a low aspect ratio vehicle as the Vulcan can have as good an L/Dmax as the high-aspect ratio B-47.

I still think that in the absence of signature requirements a flying wing is not worth it. Not a lot of CG range for a vehicle where a large fraction of TOGW is expendable. Can it be made to work? Sure, but why make things complicated?

 

[Sundog]

I still think that in the absence of signature requirements a flying wing is not worth it. Not a lot of CG range for a vehicle where a large fraction of TOGW is expendable. Can it be made to work? Sure, but why make things complicated?

Yeah, I agree, but I think it will definitely make for an interesting competition, based on which way the Navy goes on the trade-offs.

 

[kcran567]

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

The Navy didn't like the X-32a, and practically forced a re-design causing Boeing to lose the contract and yet this pure flying wing is perfectly fine for carrier take-off and landings?
Makes me nervous about crosswinds, gusts, weather, pitching deck at night...only so much the software can do. But then again hasn't been a problem so far.

 

[marauder2048]

Don't flying wings tend to do well on spot factor/geometric packing?

At the risk of damning the current program, A-12 and X-47B seemed to excel on these points

* and if memory serves, Northrop's ATA entry folded into a nicely packable hexagon.

 

[Flyaway]

If correct these all seem like good reasons given at the end of this article for why LM only went with a ‘paper design’ for the MQ-25.

http://www.thedrive.com/the-war-zone/19635/lockheeds-mq-25-tanker-drone-is-impressive-but-its-still-just-a-paper-plane

 

[VTOLicious]

Is it just my impression or does the exhaust of the LM design suggest the use of a low bypass engine?

As a reference: The Cobham Buddy store has a diameter of 79cm

And remember: "On Feb. 12, 2018, General Atomics revealed the partnership with Boeing in a press release that also named a half dozen other companies that it would be working with on its MQ-25 bid. Pratt & Whitney will supply its PW815 high bypass turbofan engine,..."

The PW800 has a diameter of 130cm

 

[TomcatViP]

the engine exhaust don't have to be the jet exhaust outlet. You may have a nozzle to dilute or mask the hot air and backend engine just like most other stealth aircraft.

Given the geometry of the bulbous center fuselage with a drastic v-shaped section as seen from above I don't see why we can't have a short 130cm Ø engine in the mid section.

Also the numerous camera windows in the front-end are probably there for a sense&avoid passive sensor. The existence of such system was hinted for the for the RQ4 in the past and would seem a mandatory system for a refueling aircraft able to use civilian flight regulation...

And last but not least the presence of such similar window on the X-44A, the aspect of the landing gear (rugged and broken as it seems on the pictures) would converge with a system test for carrier landing and approach [obviously speculative]

 

[VTOLicious]

the engine exhaust don't have to be the jet exhaust outlet. You may have a nozzle to dilute or mask the hot air and backend engine just like most other stealth aircraft.

I agree, exhaust gas mixers are used on "unstealthy" aircraft as well and exhaust ducts are usually convergent. However, the exhaust on the LM concept still seems small to my eyes...I might be wrong :

*Global Hawk engine installation

 

[litzj]

Engine inlet, and exhaust part look very strict;(for my eyes) they did not choose s-shape duct and mixed-external-air-exhaust, usual features of stealth aircraft.

For cruise/endurance efficiency, strict design is better option for pressure recovery and flow distortion of duct.

I could agree that this platform has potential for LO ISR aircraft in further development, however, this prototype is not legitimate stealth aircraft.

 

[TomcatViP]

Absolutely. Probably simply some LO features (as opposed to a VLO aircraft) with emphasis put on L-Band or surveillance radar and in the IR spectrum.

Notice also that although the photo appeared to be truncated without showing clearly the wing tips there is no split-flap apparent during the recovery sequence. As I noted previously, LM might have chosen to go with another aero trick (where the engine could have some importance? ). Thick wing might help there.

 

[fightingirish]

And here the next one...
Just a teaser, again at Aviation Leak. More next week on Monday, April 2nd.
Twitter: https://twitter.com/JamesDrewNews/status/978665003959160832?s=19

 

[Sundog]

Absolutely. Probably simply some LO features (as opposed to a VLO aircraft) with emphasis put on L-Band or surveillance radar and in the IR spectrum.

Notice also that although the photo appeared to be truncated without showing clearly the wing tips there is no split-flap apparent during the recovery sequence. As I noted previously, LM might have chosen to go with another aero trick (where the engine could have some importance? ). Thick wing might help there.

You don't have to have split ailerons to control yaw. Many tailless designs simply use opposite deflection on the outboard control surface and the inner one next to it (I hesitate to call them ailerons or elevons, etc, since they tend to be multi-use flight control surfaces), to create a drag force without creating a pitching moment or net lift increase.

 

[TomcatViP]

yes. That's what I referred to "aero-tricks".
But Split flaps are also used for yaw control on FW (see Northrop for ex.). This dual usage generates a fair amount of drag in landing configuration. And LM apparently choose not to use them here.

 

[marauder2048]

I thought the split arrangements were typically motivated by engine-out scenarios in a multi-engine configuration.

 

[TomcatViP]

https://youtu.be/_zC8diFd5O8

 

[VTOLicious]

Notice also that although the photo appeared to be truncated without showing clearly the wing tips there is no split-flap apparent during the recovery sequence. As I noted previously, LM might have chosen to go with another aero trick (where the engine could have some importance? ). Thick wing might help there.

On one of the images, a control surface on the leading edge of the wing tip is visible

 

[TomcatViP]

Well done!

I really want to rebound on this but we gonna enter the grey world of... hyper-speculation.

 

[litzj]

Well done!

I really want to rebound on this but we gonna enter the grey world of... hyper-speculation.

that is why we are here

 

[VTOLicious]

Btw, it seems LM has abandoned the air brakes that were apparent on the UCLASS design concept.

 

[TomcatViP]

Probably that differential aileron/flap bracking will do the trick

 

[litzj]

Btw, it seems LM has abandoned the air brakes that were apparent on the UCLASS design concept.

nozzle become more simplified one.

wing planform is also simplified while number of control surfaces are also reduced.

 

[Archibald]

https://www.popularmechanics.com/military/aviation/a19600045/lockheed-martin-unveils-mq-25-stingray-tanker-drone-design-for-the-navy/

thanks for sharing. Took me a while to realize that the picture of the drone refueling the F-35 had not happened yet / that the drone was not real. Pretty good CGI (even more when you are a litle misinformed about drones, because they are a little boring)

 

[VTOLicious]

Is it just my impression or does the exhaust of the LM design suggest the use of a low bypass engine?

As a reference: The Cobham Buddy store has a diameter of 79cm

And remember: "On Feb. 12, 2018, General Atomics revealed the partnership with Boeing in a press release that also named a half dozen other companies that it would be working with on its MQ-25 bid. Pratt & Whitney will supply its PW815 high bypass turbofan engine,..."

The PW800 has a diameter of 130cm

That's what I'm talking about...

 

[overscan (PaulMM)]

Is it just my impression or does the exhaust of the LM design suggest the use of a low bypass engine?

As a reference: The Cobham Buddy store has a diameter of 79cm

And remember: "On Feb. 12, 2018, General Atomics revealed the partnership with Boeing in a press release that also named a half dozen other companies that it would be working with on its MQ-25 bid. Pratt & Whitney will supply its PW815 high bypass turbofan engine,..."

The PW800 has a diameter of 130cm

That's what I'm talking about...

That was my thought when I saw it. Not enough mass flow for a high bypass ratio engine.

 

[TomcatViP]

correction: for a [large] High bypass ratio engine. Something small can also have a large ratio

 

[litzj]

Is it just my impression or does the exhaust of the LM design suggest the use of a low bypass engine?

As a reference: The Cobham Buddy store has a diameter of 79cm

And remember: "On Feb. 12, 2018, General Atomics revealed the partnership with Boeing in a press release that also named a half dozen other companies that it would be working with on its MQ-25 bid. Pratt & Whitney will supply its PW815 high bypass turbofan engine,..."

The PW800 has a diameter of 130cm

That's what I'm talking about...

That was my thought when I saw it. Not enough mass flow for a high bypass ratio engine.

Inlet of Boeing’s seems to be more smaller than even LM’s

 

[overscan (PaulMM)]

correction: for a [large] High bypass ratio engine. Something small can also have a large ratio

True, but that would make it rather underpowered.

 

[overscan (PaulMM)]

1 x F414 would make sense in some respects. Fuel burn will be much higher than the PW815 though.

 

[fightingirish]

And here the next one...
Just a teaser, again at Aviation Leak. More next week on Monday, April 2nd.
Twitter: https://twitter.com/JamesDrewNews/status/978665003959160832?s=19

Another teaser by James Drew at AW&St.

Remember Sea Avenger? This ain't it. "It's the most fuel, for the most range, within the given spot factor. It’s the best bang for the spot," says GA-ASI President David Alexander. See @AviationWeek's in-depth article on @GenAtomics_ASI's MQ-25 Stingray design on Monday, April 2.

Twitter: https://twitter.com/JamesDrewNews/status/979736805112152066?s=19

 

[aim9xray]

Deep voice:: "Indy, why is the insignia upside down?"

(And with that, back to the Fortress of Solitude)

 

[AeroFranz]

Never underestimate how much the graphics department can mess things up without adult supervision. Once my company sent out a CAD model of an airplane to a graphic designer, wanting a cover picture for a proposal. The picture we got was showing the vehicle flying backwards...

 

[LowObservable]

Didn't someone produce a helpful plan-view sketch of the DarkStar showing direction of flight - with the arrows pointing the wrong way?

I am fairly sure that one of the air show news magazines got the picture upside-down. But then, in the days of hot metal printing it was always risky using a photo of an aircraft flying inverted. No matter what instructions you gave or how many proofs you checked, some compositor would look at it at the last moment and think "what w***er got that photo upside down?" and flip it over.

 

[VTOLicious]

And here the next one...
Just a teaser, again at Aviation Leak. More next week on Monday, April 2nd.
Twitter: https://twitter.com/JamesDrewNews/status/978665003959160832?s=19

https://twitter.com/AviationWeek/status/980731682352484354?s=08

 

[fightingirish]

...
Twitter: https://twitter.com/JamesDrewNews

 

[bring_it_on]

In an exclusive interview with Aviation Week in mid-March, GA-ASI President David Alexander expressed confidence that the company’s proposal for MQ-25 will exceed the Navy’s performance requirement for fuel offload and range, as well as the objective delivery schedule. To validate this claim, the company is ready to fire up the full-scale engine test stand at Gray Butte, which incorporates GA-ASI’s customized MQ-25 engine inlet and exhaust duct.

http://aviationweek.com/defense/general-atomics-claims-huge-advantage-over-big-rivals-mq-25

 

[litzj]

it seems very very very low risk, technically cheap solution for TANKER...

other candidates still have potential as LO UCAV as further variants.

however this one try to fit tanker mission by using conventional design used by reaper, predater, and avenger c

 

[Mach42]

Looks like the lovechild of the Avenger and the Global Hawk.

 

[aero-engineer]

What will be interesting to see in the end if Boeing wins, will they spit out warmed over UCLASS vehicles or go back to the drawing board with with a purpose built MQ-25 tanker.

Lockheed has publicly stated they dropped their UCLASS Sea Ghost for a clean sheet MQ-25.

This will be interesting to watch unfold.

To summarize th state of affairs:
1. Boeing offered their already built UCLASS from years ago, can apparently be in the air first but at what capability? How close is MQ-25 to UCLASS and does that work to Boeing's advantage overall even if the air vehicle isn't a tanker design?
2. GA used their UCLASS as a point of departure for a bulked out MQ-25 designed tanker, claims to be the experts of quick turnaround but has no airplane and need's Boeing's help for "systems integration, aircraft test and evaluation, and carrier suitability" and a large production space. (In other words-GA has inherent capability to build small run UAV airframes and that's about it) Can GA manage Boeing (especially after beating them)?
3. LM clean sheet designed/used their UCLASS as a more radical point of departure for a flying wing MQ-25 designed tanker, has the historical reputation of being the experts of quick turnaround and (presumably) has everything Boeing brings to GA. Has been coy about what they actually may have.

Orange, Banana, Apple - which will the US Navy choose?

If it were a Wing Body Tail, my money would be on LM. The flying wings throws a wrench into it. However, did NG and the USN already boil down all the risk of a CVN based flying wing during X-47B UCAS-D and LM has the strongest technical compliant offering and offers the USN the best chance of success?

I'll bring the popcorn, someone else bring the pizza.

 

[TomcatViP]

It will all come down to carrier suitability. At the end, the USN discarded MQ-25 UCLASS because of it. Their primary objective might be simply to build a solid castle out of any play-cards. Stealth and survavibility come as and add-on, something that can be added to lower cost of the total system. (This is why it comes as a surprise that no outsider came up with a cheap remotely piloted regenerated platform like the old S-3 or something similar).

At one time or another in your life, you always need to start with the basis.