nscode Posted June 14, 2007 Posted June 14, 2007 Why doesn't the 25T's altimeter work when electrics are turned off? Isn't it a simple barometer? Never forget that World War III was not Cold for most of us.
ED Team Groove Posted June 14, 2007 ED Team Posted June 14, 2007 I think the gauge is powered with electricity Our Forum Rules: http://forums.eagle.ru/rules.php#en
Allochtoon Posted June 14, 2007 Posted June 14, 2007 i thought for redundancy they should work without electricity.
3Sqn_Vulcan Posted June 14, 2007 Posted June 14, 2007 Barometrically corrected altitude from an air data computer (hence you need power)
RvETito Posted June 14, 2007 Posted June 14, 2007 Air data computer on Su-25? I don't think so. It's an UVID or VEM electro-mechanical altimeter. It's still picks up the barometric pressure like the pure mechanical alitemeter (with aneroids) but transform it to electrical signal which drives the pointer. "See, to me that's a stupid instrument. It tells what your angle of attack is. If you don't know you shouldn't be flying." - Chuck Yeager, from the back seat of F-15D at age 89. =RvE=
3Sqn_Vulcan Posted June 14, 2007 Posted June 14, 2007 No air data computer? Really? ....my mistake. :doh: What does the "SVS-1-72-18 air data system" do on the su-25? Always thought this was the ADC. Leaves me wondering where the hud symbology comes from, overspeed info, AoA info etc etc.
RvETito Posted June 14, 2007 Posted June 14, 2007 There's a diference between air data system and air data computer. While the computer is part of the system I doubt that the Su-25T has one (computer). The point is what type of altimeter it supplies. The SVS (which is abreviation for Air Data System) of all russian a/c supplies all gauges with static and/or full pressure. On most aircraft there are two types of barometric altimeters- one is purely mechanical(the sensor is one or more aneroids) and it needs no power supply, the other is electro-mechanical- the static pressure data is converted to electrical signal by separate unit which sends the signal to the gauge and drives the needle. When power is off the second one will fail. "See, to me that's a stupid instrument. It tells what your angle of attack is. If you don't know you shouldn't be flying." - Chuck Yeager, from the back seat of F-15D at age 89. =RvE=
egaRim Posted June 14, 2007 Posted June 14, 2007 Russians would possibly raise their head and look out of the cockpit window to estimate altitude :D (hoping visual conditions are appropiate)
RvETito Posted June 14, 2007 Posted June 14, 2007 So, Russian planes don't have a pneumatic standby for their servo-driven altimeters? Its a requirement in American aircraft. This I can't tell :) It's going a bit far of my area. May be there's such things on some systems (newer) but I haven't worked with something like that. The Kamov helicopter I'm working on has in total 2 indicators of the radioaltimeter, 2 indipendant machanical barometric altimeters and one electromachanical UVID-30-15 which fully relies on AC power. "See, to me that's a stupid instrument. It tells what your angle of attack is. If you don't know you shouldn't be flying." - Chuck Yeager, from the back seat of F-15D at age 89. =RvE=
S77th-konkussion Posted June 14, 2007 Posted June 14, 2007 Russians would possibly raise their head and look out of the cockpit window to estimate altitude :D (hoping visual conditions are appropiate) I'm sure they are for at least 10 to 15 days a year...:D [sIGPIC]http://forums.eagle.ru/attachment.php?attachmentid=43337&d=1287169113[/sIGPIC]
3Sqn_Vulcan Posted June 14, 2007 Posted June 14, 2007 On most aircraft there are two types of barometric altimeters- one is purely mechanical(the sensor is one or more aneroids) and it needs no power supply, the other is electro-mechanical You might want to add a third...The last two types of aircraft I have earned a living on have been connected to the ADC (As per engineering manual) and will not read until power is supplied to the ADC. I take it you haven't worked on these yet? There's a diference between air data system and air data computer. While the computer is part of the system I doubt that the Su-25T has one (computer). Clear as mud.... Cool. So what work do you do on aircraft and what types are you endorsed on?
3Sqn_Vulcan Posted June 15, 2007 Posted June 15, 2007 Nah western. Don't work on them, just fly them. Eastern and Western aircraft are very different in how they approach certain things avionics-wise. Thanks for the tip :thumbup: Hope I don't come across as aggressive! Just curious how the T can have these systems and not have an ADC. What feeds the HUD for starters? Perhaps I digress! I would of thought the "simple" Altimeters would be more prone to errors in the faster higher flying jets (yeah I know we're talking about the T). Would be great to see a schematic though. :book:
nscode Posted June 15, 2007 Author Posted June 15, 2007 You thump it with your finger... and the accuracy is back ;) Never forget that World War III was not Cold for most of us.
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