F-35 vs Su-30/35

The F-35 compared with other modern jets.
  • Author
  • Message
Offline

SpudmanWP

Elite 5K

Elite 5K

  • Posts: 8408
  • Joined: 12 Oct 2006, 19:18
  • Location: California

Unread post07 Apr 2015, 17:59

popcorn wrote:@hornetfinn,
can you talk to the reliability of AESA vs legacy radars? How robust are T/R modules and what kind of MTBFs can we expect with new GaN tech?


Considering that the radome of the F-35 was designed to never be opened throughout the lifetime of the F-35.. I would say the T&Rs are VERY robust.
"The early bird gets the worm but the second mouse gets the cheese."
Offline

sergei

Banned

  • Posts: 984
  • Joined: 24 Sep 2014, 22:56

Unread post07 Apr 2015, 22:31

Nothing surprising some of my opponents know less than me and often have problems with logic.
Offline

munny

Forum Veteran

Forum Veteran

  • Posts: 631
  • Joined: 13 Jan 2010, 01:39

Unread post07 Apr 2015, 22:49

Read an article on GaN on Diamond a few days ago. In the test in which amplifiers were run at the same high temperature, GAN transistors ran for 5,000 hours before degrading. TEGaN for 10,000.
Offline
User avatar

KamenRiderBlade

Elite 2K

Elite 2K

  • Posts: 2679
  • Joined: 24 Nov 2012, 02:20
  • Location: USA

Unread post08 Apr 2015, 02:37

sergei wrote:Nothing surprising some of my opponents know less than me and often have problems with logic.


LOL, you have proven nothing while on this board Sergei.

Your reputation here isn't as high as you would like to think.
Offline

mrigdon

Senior member

Senior member

  • Posts: 403
  • Joined: 04 Feb 2015, 22:03

Unread post08 Apr 2015, 02:41

KamenRiderBlade wrote:
sergei wrote:Nothing surprising some of my opponents know less than me and often have problems with logic.


LOL, you have proven nothing while on this board Sergei.

Your reputation here isn't as high as you would like to think.


What? No. Sergei is many-splendored inhibiter of truth on this board. Is strong bulwark against anti-Russian many who promote false notions.
Offline
User avatar

popcorn

Elite 5K

Elite 5K

  • Posts: 7724
  • Joined: 24 Sep 2008, 08:55

Unread post08 Apr 2015, 03:47

munny wrote:Read an article on GaN on Diamond a few days ago. In the test in which amplifiers were run at the same high temperature, GAN transistors ran for 5,000 hours before degrading. TEGaN for 10,000.

Amazing stats. AESA radars already setting the performance and reliability standards with GaAs and GaN will set the bar even higher still.
"When a fifth-generation fighter meets a fourth-generation fighter—the [latter] dies,”
CSAF Gen. Mark Welsh
Online

hornetfinn

Elite 3K

Elite 3K

  • Posts: 3773
  • Joined: 13 Mar 2013, 08:31
  • Location: Finland

Unread post08 Apr 2015, 07:46

SpudmanWP wrote:
popcorn wrote:@hornetfinn,
can you talk to the reliability of AESA vs legacy radars? How robust are T/R modules and what kind of MTBFs can we expect with new GaN tech?


Considering that the radome of the F-35 was designed to never be opened throughout the lifetime of the F-35.. I would say the T&Rs are VERY robust.


I agree, T/R modules have proven to be extremely robust and reliable. IIRC, modern AESA radars have something like tens of thousands of hours between T/R module failure. Of course even if some modules fail, the radar performance will not degrade much. It's usually stated that up to 10 percent of the modules can fail before performance will be noticeably degraded. I think T/R modules very likely are the most reliable part of the whole aircraft.
Online

hornetfinn

Elite 3K

Elite 3K

  • Posts: 3773
  • Joined: 13 Mar 2013, 08:31
  • Location: Finland

Unread post08 Apr 2015, 09:38

sergei wrote:The problem is that before turn on the radar you do not know what is near, is it large RCS target like bomber? or it may be small fighter very far away? To track large RCS target do not need many power it is true, but to that would be confident in discovering new targets at maximum range you must use the maximum power.


There is really no problem. If you are flying at 10,000m or about 33,000ft, then any threat +/- 5 degrees is closer than 100 km away and +/- 10 degrees is closer than 50 km away. So multiple simultaneous beams could very safely be used below and above those elevations. This means if scanning from +20 degrees to -20 degrees (top down) with 2 degree beams, a PESA would require about 20 beams. A modern AESA would use about 5 full power beams (to scan near horizon to long range) and use simultaneous beams to scan the high and low elevation parts. The rest would require equal of say 5 full power beams (like 2 full beams split into 2 equaling 4 beams, 1 full beam split into 4 beams and 2 full beams split into 6 beams equaling 12 beams). So AESA could easily scan at least twice the search area without sacrificing detection range at all.

With tracking taken into account, things seem even better for AESA. Let's say there are 20 targets detected by the radar. A PESA would require 20 beams to track each target while AESA would usually require only about equal of 3-5 full beams. This means it saves a lot of time to scan other targets while tracking targets already detected. Combined with the above mentioned optimized beam patterns, AESA has rather huge search and tracking advantages compared to PESA and MSA radars.

One caveat is that simultaneous beams really require the use of digital beamforming to be possible. Analog beamforming can not practically do it. Of course pretty much all (at least Western) AESA radars use digital beamforming as it offers a lot of other advantages compared to analog systems besides simultaneous beams.
Offline

eloise

Elite 2K

Elite 2K

  • Posts: 2015
  • Joined: 27 Mar 2015, 16:05

Unread post08 Apr 2015, 13:21

SpudmanWP wrote:
Considering that the radome of the F-35 was designed to never be opened throughout the lifetime of the F-35.. I would say the T&Rs are VERY robust.

wait, does that mean F-35 willnot be upgrade for it entire life time?
Offline

eloise

Elite 2K

Elite 2K

  • Posts: 2015
  • Joined: 27 Mar 2015, 16:05

Unread post08 Apr 2015, 13:25

btw not very related, but here a graph of Su-27 RCS with and without RAM
Attachments
EMScatteringofSu-27.jpg
Online

hornetfinn

Elite 3K

Elite 3K

  • Posts: 3773
  • Joined: 13 Mar 2013, 08:31
  • Location: Finland

Unread post08 Apr 2015, 14:01

Another interesting thing about that AN/APG-81 test video is that it fully tracks several receding targets, some over 80 nm (150 km) away. For example Bars radar for Su-30 can detect a receding MiG-29 target 60 km away according to manufacturer. Bars would be able to track the MiG-29 somewhere between 35-50 km away.
Offline
User avatar

spazsinbad

Elite 5K

Elite 5K

  • Posts: 26639
  • Joined: 05 May 2009, 21:31
  • Location: ɐıןɐɹʇsn∀¯\_(ツ)_/¯
  • Warnings: -2

Unread post08 Apr 2015, 14:27

but wait yourself 'eloise' [who said above: "wait, does that mean F-35 willnot be upgrade for it entire life time?"] just today or whenever your time we read this:

viewtopic.php?f=54&t=27171&p=288743&hilit=radar#p288743
"...said potential [F35] upgrades could include new avionics systems, radar, laser weapons and a new more fuel-efficient engine...."

And here is a recent otherworldly account of how a modern AESA radar is upgraded (replace 'wedgie' with 'stubby'):
Australia, Happy With Boeing E-7 Wedgetail, Plans Upgrades
08 Apr 2015 Bradley Perrrett Aviation Week & Space Technology

"...Now the Wedgetail is about to be fully operational—but not finally operational. The latter status will probably be reached the day before it is retired, says Carpenter, because the type will always be subject to upgrades. Already, “we still have a huge shopping list of things that still need to go in there, . . . lots more features to work on.”

Upgrades are easier now that signals processing in modern systems is changed by software, not necessarily by switching hardware. “There is an enormous amount of potential in that Mesa radar that is waiting to be unlocked by a whole bunch of ones and zeros,” Carpenter told reporters at the Australian International Airshow at Avalon near Melbourne in February. There are clear paths to upgrading the radar, he adds, giving no details.

Turkey and South Korea also operate the E-7. Although the three countries’ aircraft are not identical, they all feature the Mesa, the active, electronically scanned array of which is mounted on a dorsal fin on the fuselage of the E-7...."

Source: http://aviationweek.com/defense/austral ... s-upgrades
A4G Skyhawk: www.faaaa.asn.au/spazsinbad-a4g/ & www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/videos?view_as=subscriber
Offline

sprstdlyscottsmn

Elite 5K

Elite 5K

  • Posts: 5210
  • Joined: 10 Mar 2006, 01:24
  • Location: Nashua NH USA

Unread post08 Apr 2015, 17:26

eloise wrote:btw not very related, but here a graph of Su-27 RCS with and without RAM

So it's between 10 and 30 dB in the front area?
"Spurts"

-Pilot
-Aerospace Engineer
-Army Medic
-FMS Systems Engineer
-PFD Systems Engineer
-PATRIOT Systems Engineer
Offline

SpudmanWP

Elite 5K

Elite 5K

  • Posts: 8408
  • Joined: 12 Oct 2006, 19:18
  • Location: California

Unread post08 Apr 2015, 17:32

eloise wrote:
SpudmanWP wrote:
Considering that the radome of the F-35 was designed to never be opened throughout the lifetime of the F-35.. I would say the T&Rs are VERY robust.

wait, does that mean F-35 willnot be upgrade for it entire life time?


No

It just means that the radome only needs to be opened to upgrade the T&Rs if they ever decide to. All the computers that drive the AESA T&Rs are accessible from within the front wheelwell and that there are more T&Rs installed than are needed to meet spec. These extra T&Rs are there so that when the occasional T&R fails, the dish will still perform within spec.
"The early bird gets the worm but the second mouse gets the cheese."
Offline

sergei

Banned

  • Posts: 984
  • Joined: 24 Sep 2014, 22:56

Unread post08 Apr 2015, 17:43

KamenRiderBlade wrote:
sergei wrote:Nothing surprising some of my opponents know less than me and often have problems with logic.


LOL, you have proven nothing while on this board Sergei.

Your reputation here isn't as high as you would like to think.

I did not even try,the purpose of my staying there is not in the set of reputation and not propaganda- it is education itself.
PreviousNext

Return to F-35 versus XYZ

Who is online

Users browsing this forum: No registered users and 7 guests