F-35A versus Saab Gripen NG

[ricnunes]

The business jet based AEW does have some advantages compared to the single aisle jets in terms of fuel efficiencies and cost. However I think the gulfstreams have an advantage in both vs the bombadiers that the Swedes use, in thrust, range fuel efficiencies and basic TW. The Bizjets can operate at higher altitudes (51k ft service ceiling) and with the advantage that higher altitudes bring. The 737 based platforms are ~40k ft max?

You made a very interesting point above about biz jets vs single aisle jet aircraft.

However your Gulfstream (GV and G550) versus Bombardier (Global Express 6000) assessment isn't accurate in terms of range. The Global Express 6000 actually has more range than the Gulfstream GV and G550 (and not otherwise). Yes, if you read the wikipedia entries about these aircraft it seems that the Gulfstreams have more range than the Bombardiers but that's not the case because the range figures for the Gulfstreams are while flying at Mach 0.8 while the range figures for the Bombardiers are while flying at Mach 0.85 (higher speed). Flying at the same speed and altitude the Bombardiers have more range than the Gulfstreams.

Sources:
https://www.flightglobal.com/bombardier ... 00.article

https://www.businessinsider.com/bombard ... ns-seat-25

BTW, the Global Express 6000 is used by the US Air Force as the E-11A and by the RAF as the Sentinel R1.

[weasel1962]

Ric, agree with you comparing B-6000 vs G-550. However the current offerings for gulfstream include the G-650 and the G-650ER which should stand better against the B-6000.

[loke]

Bombardier has also the Global 6500, which has 10% longer range than the 6000 (6600 nautical miles compared to 6000 miles for the Global 6000). Presumably it should be quite straighforward for Saab to replace the Global 6000 with Global 6500 and get an endurance of 12 hours.

Erieye was integrated on a number of platforms. If a customer wants to integrate Erieye ER onto a bigger platform like the Airbus A330 then that would not be a problem for Saab. This has already been proposed to some potential customers. Of course such a solution would be more expensive than Globaleye, in particular for the first customer (unless that customer happened to have some A330s already).

[magitsu]

Saab told a year ago that new GlobalEye orders will be based on Global 6500.

"Yes, we offer Global 6500 aircraft to Finland #GlobalEye platform. #hx" (Jun 17, 2019)
https://twitter.com/SaabFI/status/1140611572232052736

Another mention here (Jan 30, 2020):
http://www.lentoposti.fi/uutiset/saab_t ... ntakonetta

It's in part due to Global 6000 phase out, not just performance. Interestingly Luftwaffe sprung to buy Global 6000s (they already had some) before they ran out. They have that need which they weren't able to fulfill with Triton/EuroHawk.

https://www.bombardier.com/en/media/new ... ercom.html?

[ricnunes]

Bombardier has also the Global 6500, which has 10% longer range than the 6000 (6600 nautical miles compared to 6000 miles for the Global 6000).

Exactly. And on top of that Bombardier also has the Global 7500 and Global 8000 which have a range of 7700 and 7900 nautical miles respectively while flying at Mach 0.85

[loke]

Saab just announced that their new GaN radar has started flight tests in a Gripen D.

I wonder what their plans are for this new radar? To my knowledge the Gripen E/F for Sweden and Brazil will have the Raven GaS AESA developed with Leonardo. Perhaps future Gripen E/F customers will be offered the new radar as an option?

Since they bother to develop it I assume it is a significant improvement over the Raven AESA...

[magitsu]

Doesn't really make sense to start swapping out radars at less than 100 units sold, none delivered. It would just add to more testing time, testing costs.

Only if there was a sucker like the Middle Eastern buyers tend to be with them wanting to fund special variants. But Sweden won't be allowed to win a fighter procurement in the ME.

It's probably to keep C/D competitive (Thai MLU?, Swedish MLU - imagine if they suckered Sweden to pay for another C/D upgrade since 60 E won't be enough), not anything specifically to E/F.

GaN radar is also an interesting tech transfer bait, especially towards India. They've already proven their prowess in the naval side, but like Brazil India is looking for a leg-up for their domestic aerospace industry / fighter projects instead of just buying foreign planes.

For now it's just another solution looking for a problem (1st paying customer).

[weasel1962]

Any idea when the bombardier 8000 will start production?

[loke]

More info on the new radar:

Saab has flown its active electronically scanned array (AESA) X-band radar in a Gripen fighter for the first time, the company announced on April 24. The flight took place at Saab’s Linköping airfield on April 8. During the 90-minute sortie undertaken by a JAS 39D trials aircraft (serial 800), the radar was successfully tested against aerial targets of opportunity and a range of ground targets. Speaking to AIN, Anders Carp, senior vice president and head of Saab's Surveillance business area, noted that the radar demonstrated good capability and stability throughout the test mission.

“This is an important step in the development of our new fighter AESA radar,” said Carp in a company statement. “We see great possibilities for the radar, and its modular, adaptable and scalable design means it can also be used for a range of other applications.”

Under current plans, Saab expects to continue initial radar trials for around three to four months, with Gripen 800 due to fly around 15 times with the new sensor. As part of the evaluation, the radar will be employed against fighter targets.

What is now currently known simply as the “Saab AESA fighter radar” comprises the GaN array married to the back end of the PS-05/A Mk 4 mechanically-scanned radar that is the current option for the Gripen C/D. Saab has built virtually all of the elements of the radar itself, including the TRMs that are manufactured in a foundry at the company’s primary radar design and production facility, the former Ericsson plant in Gothenburg. The company began ground-testing of the array well over a year ago.

In the Gripen installation, the array is fixed with Saab opting for this configuration due to its simplicity and reliability. The concept of using a repositioner was initially discarded as advanced digital processing can overcome most of the problems associated with radar performance at the outer edges of the scanning volume without adding the internal space required to accommodate a repositioning system. However, Carp commented that a repositioning system could be employed if trials showed that it was necessary.

The array is essentially the same as that which was ordered in late September 2018 for what Saab describes as an "undisclosed U.S. government customer". At the same time, however, the Pentagon announced the award of an $8.2 million contract to Saab USA for the research and development of an "active aperture array". The contracting agency was Naval Air Systems Command, with the array being intended for the Office of Naval Research and Office of the Secretary of Defense Foreign Comparative Testing Program. Saab has already flight-tested this array on another testbed in support of the U.S. program and delivered it to the customer earlier this year.

Saab claims that its new ITAR-free array is ready to go to market, and would take between 12 and 18 months to deliver given the need to complete development and testing, and to establish production. The radar has an obvious application as a retrofit for Gripen C/Ds, and could also be included as an option instead of the PS-05/A Mk 4 for new C/D sales, with the potential of revitalizing that aircraft’s sales prospects. Other opportunities include other fighter types, particularly as an upgrade option.

The company sees opportunities for the X-band radar beyond fighters, including installation in advanced trainer and aggressor aircraft. Moreover, the radar has been designed in a modular fashion, and is scalable. This opens up a wide range of applications, including scaled-up radars of almost Erieye ER size for X-band surveillance. Ship- and UAV-based opportunities are also being studied.

For now there are no plans to equip the new-generation Gripen E/F with the GaN radar as the GaAs-based Leonardo ES-05 Raven is fully integrated for that requirement, but it could be substituted if a customer specified it. Saab also points out that the work being performed by the company on an AESA radar for the KF-X fighter in collaboration with South Korean industry is a separate project.

https://www.ainonline.com/aviation-news ... hter-radar

Hmm, last sentence is interesting, I did not know that it was Saab that was helping South Korea with the radar for their KF-X project.

[operaaperta]

Is it possible to simply bolt an AESA front end onto a radar that was designed for a planar array and Travelling Wave Tube?

[ricnunes]

Any idea when the bombardier 8000 will start production?

Nope.

Official word seems to be that Bombardier is still committed to the 8000 but design modifications will be implemented due to the diference in range between the 7500 and 8000 being relativity small (7700nmi for the 7500 versus 7900nmi for the 8000). So and by reading the source below it seems that Bombardier is implementing or planning to implement changes on the 8000 to make it worthwhile.

https://www.flightglobal.com/business-a ... 15.article

[marauder2048]

The business jet based AEW does have some advantages compared to the single aisle jets in terms of fuel efficiencies and cost. However I think the gulfstreams have an advantage in both vs the bombadiers that the Swedes use, in thrust, range fuel efficiencies and basic TW. The Bizjets can operate at higher altitudes (51k ft service ceiling) and with the advantage that higher altitudes bring. The 737 based platforms are ~40k ft max?

The smaller bizjet engines really can't match the electrical power generation of the single aisle turbofans.
It's easily a 2X difference. And the extra altitude translates to a pretty minor difference in two-way
atmospheric losses.

[weasel1962]

I agree on APU power difference. Nevertheless, I do note the G550's APU has enough power to run the EL/W2085 radar. Credit honeywell for making a decent APU (RE220/HGT400). Also, a significant chunk of the APU is needed to run a bigger plane so how much of it is really available to run other subsystems is not easily that verifiable. Add that the kva drops as the altitude goes up which contributes to why the bizjet can operate higher? The question is how much of the excess power actually translates into useable radar effectiveness, factoring in horizon limits esp against low level targets is not so clear cut from where I stand but these are just my thoughts, not claiming this to be fact.

[hornetfinn]

Is it possible to simply bolt an AESA front end onto a radar that was designed for a planar array and Travelling Wave Tube?

Yes it is. Here is a picture of what's "back-end" and what's "front-end" of pretty much any modern radar system.



So the back-end is just the data processing part and that doesn't differ much whether it's AESA, PESA or MSA radar. The main problem I can see is that back-end designed to fulfill the needs of MSA radar might not be powerful enough to get the best out of an AESA front-end. Without additional development it will also likely not be able to do more advanced stuff like multiple simultaneous beams or acting as communications system.

[mixelflick]

https://hushkit.net/ has an interesting piece recently about cancelled Swedish military aircraft and... the road to Gripen. Stated in the article was SAAB's goal of creating an aircraft more capable than the Viggen, but half the size. On that score, they apparently succeeded.

But when looking outside of Sweden to be competitive... it starts to make sense now why they're not. If those were in fact the design criteria, it's no wonder it can't even compete with older, 4th gen designs. To me, it appears the Gripen E/F is an attempt to take a step beyond Viggen, which it has but still comes up short (woefully, in some cases) vs. the F-16, Super Hornet and other foreign models.

There's also an A-10 like attack aircraft they toyed with, it's very interesting to look at. Much smaller with only 5 hardpoints, but it had the 30mm cannon of Viggen supposedly firing the same size/type of shell the A-10 did. I'm sort of skeptical about that claim, as those shells are MASSIVE. Had a training round gifted to me by a gentleman who owned the place that made them. I'll never forget how heavy the actual round was.

Anyway, I thought it was interesting to see how they arrived at Gripen...