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#1
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1553 bus on the C-130?
Does the C-130 have two 1553 buses onboard? One for flight control
and one for EW/mission systems? Thanks in advance, Dave |
#2
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I thought it was the No.1 via kings cross!!? lol
-- "Fire at will" Which one's will?! Do you know these people???? "David Harper" wrote in message om... Does the C-130 have two 1553 buses onboard? One for flight control and one for EW/mission systems? Thanks in advance, Dave |
#3
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"David Harper" wrote in message
om... Does the C-130 have two 1553 buses onboard? One for flight control and one for EW/mission systems? I don't think 1553 is used for flight control since the latency and speed isn't sufficient. Mission systems may well use it though. I think by nature 1553 is dual-redundant so that's where you might get the idea of two from. Not familiar with the C-130 personally though. Si |
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#5
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In article , "Simon Robbins"
wrote: "David Harper" wrote in message om... Does the C-130 have two 1553 buses onboard? One for flight control and one for EW/mission systems? I don't think 1553 is used for flight control since the latency and speed isn't sufficient. Mission systems may well use it though. I think by nature 1553 is dual-redundant so that's where you might get the idea of two from. Not familiar with the C-130 personally though. 1553 has no inherent connection with dual-redundancy. In fact, 1553 is usually used as a single bus. -- Harry Andreas Engineering raconteur |
#6
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Definitely not used for flight controls. If you have ever been in a 130
and looked up you saw lots of cables that connect to actuators that run the flight controls. Now the MC-130E has a 1553 bus for systems. I suspect the MC-130H has two, for redundant systems. The C-130J might have more than one, because of the FADEC and all the systems. Les Matheson F-4C(WW)/D/E/G(WW), AC-130A, MC-130E WSO/EWO (ret) "Simon Robbins" wrote in message ... "David Harper" wrote in message om... Does the C-130 have two 1553 buses onboard? One for flight control and one for EW/mission systems? I don't think 1553 is used for flight control since the latency and speed isn't sufficient. Mission systems may well use it though. I think by nature 1553 is dual-redundant so that's where you might get the idea of two from. Not familiar with the C-130 personally though. Si --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.703 / Virus Database: 459 - Release Date: 6/10/2004 |
#7
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Simon Robbins wrote:
I don't think 1553 is used for flight control since the latency and speed isn't sufficient. It is sufficient for the B-2 flight control system, which is totally dependent on MIL-STD-1553B data buses for reading the air data ports and commanding the hydraulic actuators. (The stick and pedal position transducers are not on the buses; they are wired directly to the flight control computers.) During ground testing I've transferred 700,000 bps through a 1553 bus from the B-2 cockpit area out to a flight control actuator terminal in one of the wings. That figure is net data throughput, i.e., it doesn't count the command and status words, parity bits, etc. And it's not necessarily the maximum capacity. I never had an opportunity to experiment and find the limits of the bus, though I believe 700,000 bps must be pretty close. That throughput was attained between test sets connected to the bus; I have no idea how much bandwidth the B-2 flight control system uses in normal operation. There are about 32 MIL-STD-1553B data buses on a B-2. Four are dedicated to flight controls. I've never even been aboard a C-130, except maybe at an air show static display, so I can't answer the original poster's question. But I can confirm that the 1553 bus does have enough speed for fly by wire flight controls on a large airplane. -- Paul Hirose To reply by email delete INVALID from address. |
#9
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In message - "Simon Robbins"
writes: "David Harper" wrote in message . com... Does the C-130 have two 1553 buses onboard? One for flight control and one for EW/mission systems? I don't think 1553 is used for flight control since the latency and speed isn't sufficient. Mission systems may well use it though. I think by nature 1553 is dual-redundant so that's where you might get the idea of two from. Not familiar with the C-130 personally though. Si In flight control systems tolerable delays are so large by todays computers standards than it's hardly an issue: for example, such an agile fighter as F-16 feels OK with about 1/2 second delay between the stick input and control surface movement. The fastest type of signal is stabilization augmentation - the control surface can oscilate at frequencies from somewhat below 8Hz in F-4E to something like 20Hz in F-15 (not having F-15 experience the last figure is taken from someone else's words). A delay of the order of 0.1 sec is HUGE by even a modest computer network standard. I don't remember by heart the 1553 standard but I'm sure 0.1 sec delay is well within limits. BTW, one of the replys was dealing with 1553 throughput in B-2. Please note that throughput and delay are not the same and quite often they're contradictory desigh trends: a design optimized for min. delay will have lower throughput and vise virsa (assuming same cost). So, measuring a throughput from one network point to another is irrelevant to FLCS tolerable delay. What should be measured is the worst case max. delay, usually at top throughput and in some particular "pathologic" case of network traffic. ************************************************** **************************** * Arie Kazachin, Israel, e-mail: * ************************************************** **************************** NOTE: before replying, leave only letters in my domain-name. Sorry, SPAM trap. ___ .__/ | | O / _/ / | | I HAVE NOWHERE ELSE TO GO !!! | | | | | | | /O\ | _ \_______[|(.)|]_______/ | * / \ o ++ O ++ o | | | | | \ \_) \ | \ | \ | \ | \ | \ | \ | \_| |
#10
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"Harry Andreas" wrote in message ... In article , "Simon Robbins" wrote: "David Harper" wrote in message om... Does the C-130 have two 1553 buses onboard? One for flight control and one for EW/mission systems? I don't think 1553 is used for flight control since the latency and speed isn't sufficient. Mission systems may well use it though. I think by nature 1553 is dual-redundant so that's where you might get the idea of two from. Not familiar with the C-130 personally though. 1553 has no inherent connection with dual-redundancy. In fact, 1553 is usually used as a single bus. The 1553B bus is, by definition, dual redundant. Each bus has an A and B side. Data is transmitted on one or the other - never both at the same time. Tony S. |
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