The USN has a project that's being worked on out there for a CBARS system that based around a drone tanker concept. The big aviation contractors are all hard at work reinventing the wheel as I type this. The question that I have is, why are they reinventing the wheel?

For any system based on a US carrier, it needs to meet very strict size requirements, needs to meet very strict performance requirements, and it has to be easily supportable. Supportability is most easily achieved by having commonality with exsiting airframes, especially when it comes to critical or big ticket parts. Any new system is going to have to bring any of its unique parts onto the carrier, requiring training, inventory of spares, etc. Why torture themselves this way? There is a direct and obvious solution.

The E-2D platform.

According to what I've read, they are still building E-2D hawkeyes for the USN. They are still in use throughout the USN, as well as by many foreign customers. Parts support will not be a problem, both for keeping it on the carrier and finding it when its at sea. Why not just make an optionally piloted E-2 that is filled with fuel tanks instead of AWACS radar systems and computers? The large radome can be removed to save weight. Two hard points can be engineered into the wings between the fuselage and the engines to hold the current USN hose and drogue system (on as primary, the other as backup). A semi-autonomous flight control system can be engineered into the cockpit that can be pulled and replaced with a pilot in the case where it has a problem.

The E-2 has exceptional loiter time capabilities with its current fuel capacity and very efficient turbo-prop engines. It is nearly ideal to circle around the carrier for hours at a time refueling planes that are conducting flight ops. It's fast enough to keep the jets in the air, yet slow enough to be rendevouzed with quickly. Supporting it should be straightforward as it will keep a lot of commonality with the existing E-2 fleet. Since carriers are routinely operating with much smaller air wings than they were designed to, space isn't that much of an issue either.

Why break the bank trying to make something that's essentially all new when you can take an existing, working platform, make minimal changes, and prove the concept? Low observability has been entirely removed from the project as a goal. Even surveilance is a very low priority. If it does become one, there are many hard point mountable surveilance pods that can be used to provide that capability if needed.

Where am I going wrong in all of this?

Because commonality can go the other way as well? Next step could be unmanned AWACS and you're back to one type too.

Tried&Tested or cheaper you say? Where's the fun in that?

LightningZ71 wrote:

Where am I going wrong in all of this?

not really anywhere, it's a pretty reasonable idea.

But if I had to take a stab at red teaming it, I'd say primarily survivability. Even on the USAF side, we are already talking about next gen LO/VLO tankers and transports. CBARS is probably going to be operating on either side of the edge of the battlespace, and therefore will be open to engagement. This is not a simple recovery/top-up tanker as far as I can tell.

Also, cost might appear low for a KC/E-2 proposal, but converting and certifying that legacy platform to be optionally manned is not likely to be easy, nor will re-engineering it to take fuel and pods. Often it's easier and cheaper to design all-new for a new requirement than shoe horn capability into a frame not designed for it.

Cheers

angad84 wrote:

we are already talking about next gen LO/VLO tankers and transports.

Are we talking about it, or already testing it?

angad84 wrote:

not really anywhere, it's a pretty reasonable idea.

But if I had to take a stab at red teaming it, I'd say primarily survivability. Even on the USAF side, we are already talking about next gen LO/VLO tankers and transports. CBARS is probably going to be operating on either side of the edge of the battlespace, and therefore will be open to engagement. This is not a simple recovery/top-up tanker as far as I can tell.

Also, cost might appear low for a KC/E-2 proposal, but converting and certifying that legacy platform to be optionally manned is not likely to be easy, nor will re-engineering it to take fuel and pods. Often it's easier and cheaper to design all-new for a new requirement than shoe horn capability into a frame not designed for it.

Cheers

Agree 100%. Survivability is one key area, functioning as a comms node is probably the other.

I happen to agree with you on making it LO/VLO to start with. If you're going with an all new platform, then I'd definitely design the airframe in such a way that it has an LO/VLO shape, while using cheaper traditional materials for the actual surface of the CBARS vehicle. Then, when the LO/VLO requirement comes into play, you can change the surface material from the cheaper commodity materials to the much more expensive RAM surfaces without the need to re-engineer the entire plane. The problem here is that, for tanking duties, you'd want large internal volume. Most LO drones are essentially miniature flying wings with minimal usable body volume. For a tanker, you'd be better off with a blended wing/body structure that has a more bulbous center section to increase internal fuel capacity to enough of a degree to make it an actually useful platform for refueling. Conversely, instead of that, you can make a traditional LO UAV, but it would need multiple hard-points to mount external fuel tanks in addition to the hose and drogue reel pod that is mandated by the contract. That way, you can just remove the external tanks to convert the thing into a surveillance platform. The Comm node requirement is essentially a freebee. The electronics required for that are tiny as compared to most anything else. Antennas are small, easy to mount, and easy to remove. At the very least, it means that the platform will have an internal electronics bay for mission equipment in addition to the flight control electronics. It could also be cover for additional capabilities that aren't being disclosed.

Either way, if the tactical situation is so dire that an orbiting tanker over a carrier is in danger of being engaged by enemy forces, you've got much bigger problems on your hands than refueling returning aircraft (hint: there probably won't be any returning...) If, on the other hand, you are implying that having a LO tanker could make the strike group harder to detect, you are vastly under estimating our peer states and their ability to locate our fleets. Satellite surveillance systems have come a long way since the cold war days. The IR signature of a supercarrier and its escorts is very difficult to mask, even from long range. When commercial grade survey sats have the ability to detect surface temperature variations in the sub degree range, I dare say that military sats would be easily able to isolate fleet thermals.

The V-22, which will be used for COD, has the capability to be a tanker.

A drone would likely expand capabilities and might save deck space. I see the ROI there.

ssteve wrote:

The V-22, which will be used for COD, has the capability to be a tanker.

Not at the ranges we're talking about here.

ssteve wrote:

A drone would likely expand capabilities and might save deck space. I see the ROI there.

What capabilities? And how would it save space? The primary volume driver is the tanking mission requirement, not crew.

Also let's not forget size. I don't know what the target spot factor for CBARS is, but the X-47 was a 0.9 IIRC (Legacy Hornet as baseline with spot factor = 1). A Rhino is is a fair chunk more than a Bug, and V-22s and E-2s even larger. With most new aircraft larger than the current baseline, carriers are eventually going to face space issues as well.

angad84 wrote:

And how would it save space? The primary volume driver is the tanking mission requirement, not the crew.

I can see the logic here. Space and weight occupied just to keep humans alive are quite extensive. Not speaking of the manpower to maintain this and components stored. Either you could have the same weight a/c and thus more fuel to off load (saving on the number of tankers needed) or the airframe could be smaller and thus saving precious weight. I think it is a logical step. And it could share a platform with an E-2 replacement and/or a COD replacement.

E-2 drone could have a data link to the carrier and the controllers could be relatively safe aboard the ship, no need for humans in the aircraft at all. The same for the COD, perhaps humans might find it uneasy to fly in this craft, so perhaps two versions would be needed.

Worth a read...

http://www.thedrive.com/the-war-zone/13 ... ker-design

Thanks Lightning Z71, very worthwhile read.

I think we are on the cusp of many fundamental changes in carriers ops.

Surviveabilty in contested airspace has made obsolete most current assets and the x47 project is just the tip of the iceberg in what is yet to come to address the need to deal w this

Cheap, easy solution is pulling the S-3s from the desert and having them go back out to the fleet as a tanker. Already proven, carries a lot of gas and it is already paid for. Leaves more money for F/A-18 Block llls and F-35s.

I like the E-2D idea. The hard part is, neither the S-3 or the E-2D is sexy. It is not a "UAV" and therefore isn't a hot topic.

The S-3 would be introducing a "new" type to the fleet (yes, I know it was there before, but it's supporting training and equipment was divested long ago). The E-2 based solution leverages an existing supported airframe that is currently in production. But, I'm with you on the suitability to the role and the usefulness of those airframes. I still consider it a mistake to have not overhauled them for the COBD role instead of using the V-22 platform.

In thinking about the issue a little longer, the E2 proposition seems like a low risk, low investment idea. The pipeline for training and maintenance is already there. You could increase the size of the E2 squadrons and have pilots fly the tankers from time to time just like A-6 or F/A-18E/F squadrons.

Going with the E2 should also decrease the fly away cost of each bird coming off that line.

In reading others comments, I see the "unmanned" platform as high risk, high investment and an end product that is gold plated and doesn't fit the needs of the fleet. This problem shouldn't focus on a "stealth uav tanker/isr" platform. It should be a cost effective bird that hauls fuel. Going UAV is going to provide a platform that is shiny and sexy, cost way too much and in the end gets pulled for isr duties. Buy the turbo prop that has been operating from flat top for years and press on to other needs.

S3 and E2 derivatives would be lower risk until the shooting starts.

The navy's job is to plan to win in contested environments.

Photos have surfaced on the web showing one of the MQ-25 bids having external drop tanks under the wings. In fact, the program calls for the use of existing drop tanks. That negates any "stealth" benefits. It is an unmanned stealth-less platform lugging around external tanks like a KA-6D, S-3 or F/A-18. So about as capable as an E2 when the "shooting starts".

Giving $120 million back out to industry to see if this is viable makes one shake their heads. MAKE US A UAV DANGIT, WE NEED THEM BECAUSE WELL, YOU KNOW, THEY ARE THE HOTNESS. No worries about the extra pilot pipeline, maintenance training and parts availability issues while at sea.

I would love to see what a cost estimate of turning an E-2 into a tanker would cost. I'm betting it is well under $120 mil to see if it works. Same goes for all the Hoovers sitting in the desert. Open bid, E2 vs S-3 vs MQ-25. It's a tanker, don't complicate what a military version of the 767 and A330 will be doing for the next 50+ years.

I'm not sure that the E2 has full (any) fly by wire. That will complicate things.

Can you share how that will complicate things? I'm pretty sure the KA-6D, S-3, KC-135 and KC-10 are not fly by wire designs and they did not have issues.

All in all, this is an interesting discussion but the Navy is going to buy a drone because that's what has been decided.

It has been my impression that fly by wire systems are more amenable to the current systems used for current semi and fully autonomous flight control systems. With FBW, the system will get a lot more feedback about the performance of the various control surfaces than from systems with manual controls. While there are a lot of similarities between a traditional auto-pilot, its not meant to operate without a man in the loop to watch over things and take over if things get out of the expected performance envelope. With an autonomous flight control system, the "auto-pilot" can't simply sound an alarm and keep doing its own thing while waiting for a human to take over. The FBW system already integrates all of the control surface feedback information that the autonomous flight systems would need to recover from those situations. This isn't to say that a non FBW system can be retrofitted with the needed feedback, just that it will take more development work. I've grossly oversimplified a lot of this for both brevity and the fact that I haven't had to handle coding for FBW systems in a very long time (and my own portion of that project was more along system management functions and not in the flight control area).