Kusch Posted August 5, 2008 Author Posted August 5, 2008 New Hi-Res pics: http://pilot.strizhi.info/2008/08/04/5572#more-5572 Give me "flying telephone pole" (SA-2)!
mikoyan Posted August 8, 2008 Posted August 8, 2008 Please...everybody resist the temptation ok? :lol: we should have an r-27 EA in lock-on su-27 and su-33 !
nscode Posted August 8, 2008 Posted August 8, 2008 PESA - Passive Electronically Steered Array or passive phased array radar PRO's: ... CON's: ... Single frequency beam, as opposed to multiple simultaneous frequencies. Not as expensive as AESA Not as many problems with heat dissipation ... Firstly, how are the last two points I quoted cons? :) Now for the single beam/freq. thing. It's true that there can only be one beam at one time. That is an disadvantage over several beams that can be put out by AESA. BUT, that single PESA beam is by no means limited to a single frequency. You can still do frequency hopping and/or spread spectrum. (I base this only on theory; I have no knowledge if any actual radars do that) It should also be noted that use of multiple frequencies, regardless of radar type, create their own set of problems and challenges that must be pondered through by the designers :) Never forget that World War III was not Cold for most of us.
GGTharos Posted August 8, 2008 Posted August 8, 2008 I read some patents/papers which gave me the impression that while you can frequency-hop using a TWT (heck, the S-300 does it) - the means for doing so are less convenient and less efficient than using an AESA's T/R modules - this means miniaturization hurts, AFAIK. Also I think you can more easily jam a TWT since it has a natural propensity to propagate certain frequencies and possibly waveforms. I think that Rhen might be referring to an ability to hit the same target with multiple frequencies simultaneously. [sIGPIC][/sIGPIC] Reminder: SAM = Speed Bump :D I used to play flight sims like you, but then I took a slammer to the knee - Yoda
nscode Posted August 8, 2008 Posted August 8, 2008 I think that Rhen might be referring to an ability to hit the same target with multiple frequencies simultaneously. Hmm.. yeah:doh: Never forget that World War III was not Cold for most of us.
GGTharos Posted August 8, 2008 Posted August 8, 2008 I just read something that suggests AESA has far more bandwidth available for frequency agility ... could it be that MSA/PESA cannot cross bands due to the TWT, while the AESA can? [sIGPIC][/sIGPIC] Reminder: SAM = Speed Bump :D I used to play flight sims like you, but then I took a slammer to the knee - Yoda
nscode Posted August 9, 2008 Posted August 9, 2008 (edited) I'd guess that it's not that it cannot cross bands, it's that it has several (a limited number of) operating bands where it achieves necessary gain, and them having different efficiency. It's interesting that probably if you know one of them you could determine others :) R/T elements on the other hand should have equally bad performance over a wider continual spectrum. But since they get their strength in numbers that's no problem. But who knows what some pesa freak thought of, maybe managing to fine tune those tubes :D That's where the "Classified" thingy comes in ;) Edited August 9, 2008 by nscode Never forget that World War III was not Cold for most of us.
mvsgas Posted August 9, 2008 Posted August 9, 2008 (edited) Looks like the F-35 is having more issues. Crazy to think that now even environmental issues like noise, may affect development or procurement of a Fighter aircraft. http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=defense&id=news/aw081108p2.xml Edited I just realize I posted this in the wrong thread, sorry Edited August 12, 2008 by mvsgas To whom it may concern, I am an idiot, unfortunately for the world, I have a internet connection and a fondness for beer....apologies for that. Thank you for you patience. Many people don't want the truth, they want constant reassurance that whatever misconception/fallacies they believe in are true..
GGTharos Posted August 9, 2008 Posted August 9, 2008 According to spec it can form 2800 beams/sec. Somehow I don't see tracking 50 targets simultaneously with a very high update rate as a problem in this case. That's well... up to speculation, but possible, I guess, not sure on the true capabilties meself. Then again it's not like JDAMs need constant correction, feed them the coordinates, and drop them and then move on to the A2A portion. [sIGPIC][/sIGPIC] Reminder: SAM = Speed Bump :D I used to play flight sims like you, but then I took a slammer to the knee - Yoda
Weta43 Posted August 9, 2008 Posted August 9, 2008 Coming late to the discussion & I've only skim read it, but from this & other reading seems to me that this is where the discussin has arrived at (no?): While technically AESA is more elegant & a technological wonder, in terms of actual tracking ability on a co-operative (not employing ECM) target/targets, fielded PESA & AESA are pretty much on a par, with PESA having an advantage in terms of raw power & therefore theoretical detection range. Where EASA probably holds an advantage is in terms of ECM / ECCM, having more frequency hopping ability for a non-cooperative target. The beam splitting tracking/multiple targets without interleaving ability is technically impressive & obviously there, but given that each time the beam is split the power of the beams goes down, & therefore so does the range at which a return is received, this seems to me to be of limited (though probably not zero) practical usefulness given that scanning the beam at a high enough frequency to in all meaningfull terms eliminate target movement between scans, allows full beam strength & therefore range for tracking, without any real loss of ability to track multiple targets / interleave with other modes. Being able to reduce the strength of specific beams to remove information regarding emitter range may be a genuine advantage against a single or multiple targets separated by a small angle, but if multiple spatially separated targets are being tracked, triangulation across data-links by those being scanned would be fairly simple & removes that advantage. Which again brings the situation back to being the significant advantage of AESA over PESA being its better Hz & waveform hopping ability, and therefore its ECM/ECCM ability, Which is an undoubted advantage right up untill the oppositions software can deal with it. While on the other hand the PESA has more range, and mounted in the manner of the Su-35, an ability to maintain tracking of targets/ guidance at much greater off bore angles that exisiting AESA (yes, you could mount AESA arrays on other parts of the aircraft & get 180 degree coverage, but this is true of any radar type, & I was thinking more of existing, not theoretical, aircraft). Provided it can maintain tracking/lock in the face of ECM. Cheers.
DarkWanderer Posted August 10, 2008 Posted August 10, 2008 (edited) could it be that MSA/PESA cannot cross bands due to the TWT, while the AESA can? Don't know about AESA, but PESA's are usually built on klystrons or magnetrons, which are strongly limited in frequency bands. but given that each time the beam is split the power of the beams goes down, & therefore so does the range at which a return is received You're wrong in that. Yes, AESA can split beams, just like the Fly-By-Wire system on F-22 theoretically allows to incline thrust vectors and ailerons in opposite directions, but why do so in conventional flight, or (for radar) if it allows fast scanning just like PESA? The actual splitting is needed only when handling really large number of targets. Therefore, NO range decrease of AESA in comparison to PESA, except ones to enchance LPI capabilities or due to less desing experience (like for russian ones). The only advantages of PESA are less heat, less expensive production and slightly larger FOV. Edited August 10, 2008 by DarkWanderer You want the best? Here i am...
Weta43 Posted August 12, 2008 Posted August 12, 2008 Am I ? I'm aware that either type can electronicallly scan - that's why the last 3 letters of each acronym are the same :-) What I said was, that if beam splitting is used by an ASEA radar, detection range for each beam goes down, limiting the usefulness of this ability. In an AESA array there are a fixed number of elements, each with a finite power output. Broadly speaking total available output from the array = number of elements x power from each element. If half the elements are used to form a beam directed in a direction different to that of the rest of the array's beam direction, the energy available to that beam is half that of that available to a single beam - as the first element in the total available power equation has been halved. Lower beam energy means lower return signal strength, means shorter detection range... I don't think I suggested either type suffers from this problem if they "simply" use their extremely high speed "*ESA" capabilities. NO range decrease of AESA in comparison to PESA True - if both have the same power output - and the EASA uses a unified beam. Not true if the PESA has a higher power output, and because one of the advantages of PESA are less heat, current PESA radars have higher output power when compared to AESA radar - & all other things being equal, power = range. 1 Cheers.
DarkWanderer Posted August 12, 2008 Posted August 12, 2008 and because advantages of PESA are less heat the current PESA radars have higher output power when compared to AESA radar Ok, sorry, misread you. Just seen too much guys saying that AESA is less powerful because of beam splitting. My bad. You want the best? Here i am...
Alfa Posted August 12, 2008 Posted August 12, 2008 What Weta said :) . Ok, sorry, misread you. Just seen too much guys saying that AESA is less powerful because of beam splitting. My bad Keep in mind that this thread concerns the new Su-35 version and therefore much of the radar talk here takes outset in the PESA radar of this(Irbis-E) versus the AESA of the F-22(APG-77). Comparing these two particular sets, the PESA is by far the most powerful......peak output of 21 Kw vs. 12 Kw of the APG-77. JJ
Pilotasso Posted August 12, 2008 Posted August 12, 2008 One other thing to take in account is signal processor. When you add background noise things are not so linear. .
GGTharos Posted August 12, 2008 Posted August 12, 2008 Yep ... twice the power output doesn't give you that much - and you're really asking for bigger sidelobes as well. Also recall that the MiG-25 had a very powerful radar, but its increase in peak power didn't really obey the radar equation for a commensurate increase in detection range, IIRC. Even if you go by the radar equation, twice the power nets you maybe a 20% increase in detection and tracking range, IIRC ... yes, 20% can be significant, no doubt - but not the ridiculous ranges that some are claiming, IMO ;) It's all about what's 'inside'. When I was working somewhere near a certain classified sonar suite, it was the processing algorithms that were classified - more so than the DSP's or hydrophones. It was those algorithms that did wonders to improve the signal to noise ratio. [sIGPIC][/sIGPIC] Reminder: SAM = Speed Bump :D I used to play flight sims like you, but then I took a slammer to the knee - Yoda
nscode Posted August 12, 2008 Posted August 12, 2008 One other thing to take in account is signal processor. When you add background noise things are not so linear. Increasing the output power gives you better SNR. It's not like increasing receive gain where you boost both signal and noise. Never forget that World War III was not Cold for most of us.
Kusch Posted October 3, 2008 Author Posted October 3, 2008 Second prototype Su-35 (902) first flight ( 03.10.2008 ): http://www.knaapo.ru/rus/gallery/events/combat/su-35/2nd_su-35_flight.wbp 2 Give me "flying telephone pole" (SA-2)!
Pilotasso Posted October 3, 2008 Posted October 3, 2008 I does lokm pretty. But I Hope they never get used :D .
Case Posted October 3, 2008 Posted October 3, 2008 With the design over 30 years old now, I still find this the best looking fighter around. ;) Great find Kusch! There are only 10 types of people in the world: Those who understand binary, and those who don't.
UWBuRn Posted October 10, 2008 Posted October 10, 2008 A little OT, are there any other photos or videos of the second prototype? That paint scheme is awesome, i would like to make a skin for the Su-27 based on it.
SuperKungFu Posted October 10, 2008 Posted October 10, 2008 Yea the paint scheme looks awesome, however IMHO, I don't like the black outline around the canopy. Its the same with the india Su-30 MKI. [sIGPIC][/sIGPIC]
Weta43 Posted October 11, 2008 Posted October 11, 2008 It does look pretty. But I Hope they never get used You and me both :-) Cheers.
mikoyan Posted October 12, 2008 Posted October 12, 2008 Yea the paint scheme looks awesome, however IMHO, I don't like the black outline around the canopy. Its the same with the india Su-30 MKI. that may not be there just for looks, it is to prevent glare from the light hitting the nose of the airplane. Some animals especially predators have dark shades around their eyes for the same purpose.
RedTiger Posted October 12, 2008 Posted October 12, 2008 Yea the paint scheme looks awesome, however IMHO, I don't like the black outline around the canopy. Its the same with the india Su-30 MKI. that may not be there just for looks, it is to prevent glare from the light hitting the nose of the airplane. Some animals especially predators have dark shades around their eyes for the same purpose. Reminds me of some MiG-29 schemes you see. I bet the glare is the reason for it. Here's one where it just looks crudely spray painted on!
Recommended Posts