GGTharos Posted September 6, 2011 Share Posted September 6, 2011 It's not just loud, it shakes the audience, and the ground! :D [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 Link to comment Share on other sites More sharing options...
Bucic Posted September 6, 2011 Share Posted September 6, 2011 From a technical standpoint, the F-100 should in almost every way make more noise than an F404. It has greater pressure ratio, thrust output, and larger nozzle diameter, while having very similar bypass ratio as the F404. They may have a different "pitch" but physics says the F100 is louder. Actually physics says larger diameter => lower noise :) (for similar flow rate ~ thrust) https://akaagar.github.io/briefing-room-for-dcs/ F-5E simpit project https://forum.dcs.world/topic/318106-f-5e-simpit-cockpit-dimensions-and-flight-controls/ Link to comment Share on other sites More sharing options...
-Hammer- Posted September 6, 2011 Share Posted September 6, 2011 I don´t know if this has been posted before but i found a nice video about the A-10C http://www.thedaily.com/page/2011/09/04/090411-news-usaf-pararescue-part2-1-4/ At the end of the article there is a link to Pararescue, which is also very interesting Hammer out! Windows 10 | i7-8700K@5GHz | 2080 Ti | Intel Z370 Chipset | 32GB RAM@1866 MHz | SSD: Samsung 850 EVO 1TB| Thrustmaster Warthog HOTAS w. FSSB R3 Mod | Saitek Switch Panel + Radio Panel + Multi Panel + FIP + Flightpanels Software | MFG_Crosswind | TrackIR5 | TM Cougar MFD Pack | Obutto R3volution | 1 x LG38 | GAMETRIX KW-908 JETSEAT Link to comment Share on other sites More sharing options...
aaron886 Posted September 6, 2011 Share Posted September 6, 2011 Actually physics says larger diameter => lower noise :) (for similar flow rate ~ thrust) As far as I'm aware, the actual volume of a jet engine is determined by total mass-flow. (Thrust.) If the engine can produce greater static thrust while still having a larger diameter nozzle, it will produce more noise. Link to comment Share on other sites More sharing options...
Demokrator Posted September 7, 2011 Share Posted September 7, 2011 Hornet over Michigan Link to comment Share on other sites More sharing options...
nscode Posted September 7, 2011 Share Posted September 7, 2011 That landscape sure does bring back memories from FS :) Never forget that World War III was not Cold for most of us. Link to comment Share on other sites More sharing options...
aaron886 Posted September 7, 2011 Share Posted September 7, 2011 Great video but what a dumb show site! The crowd is so far from the show line. Oh well, the technical aspect is lost on most people there. As long as it's loud and shiny! :D Link to comment Share on other sites More sharing options...
nscode Posted September 7, 2011 Share Posted September 7, 2011 What do you mean far away? Crowd is all below him :) Never forget that World War III was not Cold for most of us. Link to comment Share on other sites More sharing options...
mvsgas Posted September 7, 2011 Share Posted September 7, 2011 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.. Link to comment Share on other sites More sharing options...
winz Posted September 7, 2011 Share Posted September 7, 2011 Russian airliner in fatal crash near Yaroslavl An airliner carrying a major league ice hockey team has crashed in Russia killing 36 people. http://www.bbc.co.uk/news/world-europe-14822582 :no_sad: The Valley A-10C Version Revanche for FC 3 Link to comment Share on other sites More sharing options...
airea Posted September 7, 2011 Share Posted September 7, 2011 Fisrt flight of Turkish attack helicopter, ATAK T-129... http://www.youtube.com/watch?v=NZ8fyqsWd5o&feature=player_embedded Link to comment Share on other sites More sharing options...
vtsgoose1606687932 Posted September 7, 2011 Share Posted September 7, 2011 (edited) Edited September 7, 2011 by vtsgoose [sIGPIC][/sIGPIC] http://virtual-aerobatic-group.nl/ Link to comment Share on other sites More sharing options...
HiJack Posted September 7, 2011 Share Posted September 7, 2011 This was nice :D Link to comment Share on other sites More sharing options...
nscode Posted September 7, 2011 Share Posted September 7, 2011 Fisrt flight of Turkish attack helicopter, ATAK T-129... http://www.youtube.com/watch?v=NZ8fyqsWd5o&feature=player_embedded Don't get it.. I see there were flights of it in 2009 :huh: Maybe this is first serial production flight? 1 Never forget that World War III was not Cold for most of us. Link to comment Share on other sites More sharing options...
Bucic Posted September 7, 2011 Share Posted September 7, 2011 (edited) As far as I'm aware, the actual volume of a jet engine is determined by total mass-flow. (Thrust.) If the engine can produce greater static thrust while still having a larger diameter nozzle, it will produce more noise. What I said. Let's say two design teams have the same goal to design an engine capable of X kN of thrust, where Dmax is max engine diameter constraint. If the team 1 will be granted 1.2 Dmax their engine will most probably emit less noise than the engine the team 2 will come up with. BTW, from the top of my head noise~v^2... An additional hint - airliner jet engines, bypass ratio. Regarding the quoted part of your post - it's to vague. No pun intended. Edited September 7, 2011 by Bucic https://akaagar.github.io/briefing-room-for-dcs/ F-5E simpit project https://forum.dcs.world/topic/318106-f-5e-simpit-cockpit-dimensions-and-flight-controls/ Link to comment Share on other sites More sharing options...
aaron886 Posted September 7, 2011 Share Posted September 7, 2011 Goose - thanks for sharing. Love those RDAF Vipers. Link to comment Share on other sites More sharing options...
aaron886 Posted September 7, 2011 Share Posted September 7, 2011 (edited) Bucic- almost missed your response. Sorry for the volume of BS this is now becoming... suffice to say I had a logic train but in trying to transmit the shortest message, I left it full of holes you are working hard to find. :thumbup: What I said. Let's say two design teams have the same goal to design an engine capable of X kN of thrust, where Dmax is max engine diameter constraint. If the team 1 will be granted 1.2 Dmax their engine will most probably emit less noise than the engine the team 2 will come up with. No need to get into flow rates. Part of the problem here is that I listed off exhaust diameter originally with the intent of noting it as an indication of the engine's output, because that's how I tend to think of it from a pilot standpoint. You say there is "no need to get into flow rates," but that would only be true if both the engines we're comparing had identical output. You said "(for similar flow rate ~ thrust)." Again, true, only if we're talking about similar flow rates. Keeping in mind I'm no engineer: the exhaust diameter will be made as small as it possibly can be, for reasons I can tell you well understand. (Mass-flow theory- we want maximum acceleration.) It can only be so small however, or you'll get back pressure which is unacceptable. (Note how modern jets use variable exhaust vanes to change that diameter... an engine in afterburner requires a greater diameter to avoid that back pressure.) We can reasonably assume that both the F100 and F404 have the smallest exhaust possible without obstructing flow. We can then say that the exhaust diameter is, by design, relative to thrust output and not vice versa. With that in mind, the ratio of flow to diameter should be similar across designs (of similar sophistication, I suppose.) I think that would mean that the diameter of the exhaust can be discounted. (Except perhaps as an indicator of output.) All this is me back-tracking through my understanding of what makes a louder engine, and trying to provide a semi-technical explanation. Usually with aviation knowledge I have to work backwards from application to concept, rather than forwards from concept to application like you do as an engineer. ;) Additional hint - airliner jet engines, bypass ratio. In that case, exhaust diameter has nothing to do with the volume. High-bypass turbofans use a bigger intake to facilitate a larger turbine, which has the effect of imparting an impressive amount of additional thrust while reducing SFC. The reason a high-bypass turbofan is quieter is literally because the N2 exhaust is "wrapped" in the lower-velocity N1 exhaust. (And back on topic, considering the F100 and F404 have similar bypass ratios, I ignored it as a factor.) True, the higher the bypass ratio, the greater the exhaust diameter will usually be (primarily as a factor of the larger intake.) Think of a high-bypass turbofan as like a hybrid between a prop and a jet. A sweet photo, to redeem my off-topic wandering: Edited September 7, 2011 by aaron886 Link to comment Share on other sites More sharing options...
mvsgas Posted September 8, 2011 Share Posted September 8, 2011 F100 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.. Link to comment Share on other sites More sharing options...
mvsgas Posted September 8, 2011 Share Posted September 8, 2011 Did not read the whole thing, but here we go http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050198876_2005199184.pdf 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.. Link to comment Share on other sites More sharing options...
The Flying Goose Posted September 8, 2011 Share Posted September 8, 2011 (edited) Cool wallpaper worthy shot: Edit: these are nice too. Edited September 8, 2011 by The Flying Goose Q6600 @ 2.4 GHz, Sapphire 5870, TM Warthog, 4 GB RAM, Windows 7 Link to comment Share on other sites More sharing options...
combatace Posted September 8, 2011 Share Posted September 8, 2011 F100 Here is something from a book that I have F100 series: Twin spool engine fan rotor assembly 3 stages driven by 2 stage turbine Low by-pass ratio of 0.7:1 at 9600RPM Rear compressor turning at 14,650RPM and is 10 stage driven by 2 stage turbine Total airflow is 228lb/s (103.4Kg/s) Overall pressure ratio 23:1 to 25:1 air cooling for rear-compressor-drive turbine variable vanes at inlet, rear compressor-inlet and 4th and 5th stages of rear compressor annular combustor with 16 nozzles engine's thrust to weight ratio is 8:1 Specific fuel consumption in non-after-burning mode id 0.68lb/lbt/h (69.3g/N/h) and 2.5lb/lbt/h (239.9g/N/h) for after-burning Engine weight is 3036 to 3100 lb and produces 14,375lbt (63,940N) dry and 23,810lbt (105,907N) augmented. For F100-PW-229 Max thrust 29,000lbt (129KN) with TSFC of 2.05lb/lbt/h (209Kg/Kn/h) Dry thrust is 17800lbt (79.8KN) with TSFC of 0.74lb/lbt/h (75.5Kg/KN/h) By-pass ratio is 0.4:1 overall pressure ratio is 32:1 inlet diameter is 34.8in, length is 191in ans weight is 3650 lb or 1655Kg. P.S. I know most of you will be knowing this yet voted myself for posting it. To support my models please donate to paypal ID: hp.2084@gmail.com https://www.turbosquid.com/Search/Artists/hero2084?referral=hero2084 Link to comment Share on other sites More sharing options...
Bucic Posted September 8, 2011 Share Posted September 8, 2011 ... OT Holy *p! You know no restraint! :) I allowed myself for a bit of OT with a careful word count but you just blew me out of the sky! Start a new topic if you'd like to continue the discussion about the engines. https://akaagar.github.io/briefing-room-for-dcs/ F-5E simpit project https://forum.dcs.world/topic/318106-f-5e-simpit-cockpit-dimensions-and-flight-controls/ Link to comment Share on other sites More sharing options...
aaron886 Posted September 8, 2011 Share Posted September 8, 2011 F100 Very nice, I was looking for this exact type of thing but couldn't find it! Would be nice to have it for the F404 as well. Holy *p! Fair enough. I did post a picture though. :D (PS... I don't know what *p! is.) Link to comment Share on other sites More sharing options...
mvsgas Posted September 8, 2011 Share Posted September 8, 2011 (edited) click on photo to enlarge Fire in the sky A brush fire lights up the evening sky behind an F-15SG at Mountain Home Air Force Base, Idaho, Aug. 15, 2011. Flightline activity was stopped and personnel were evacuated from flightline buildings as the fire approached the base. The fire burned approximately 3,000 acres, including five acres on the northwest corner of the base. (U.S. Air Force photo/Staff Sgt. Gina Chiaverotti-Paige) Edited September 8, 2011 by mvsgas 1 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.. Link to comment Share on other sites More sharing options...
mvsgas Posted September 8, 2011 Share Posted September 8, 2011 (edited) Very nice, I was looking for this exact type of thing but couldn't find it! Would be nice to have it for the F404 as well. Fair enough. I did post a picture though. :D (PS... I don't know what *p! is.) Again, I did not read the whole thing, just enjoying Google's search engine :book: http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA527661 http://www.saveourvalleynow.org/F_35_Noise_Measurementsver4_2.pdf http://www.google.com/url?sa=t&source=web&cd=4&sqi=2&ved=0CDUQFjAD&url=http%3A%2F%2Fwww.nmcphc.med.navy.mil%2Fdownloads%2Foccmed%2Ftoolbox%2Fnavair%2520advanced%2520hearing%2520protection.ppt&rct=j&q=JSF%20noise%20test.ppt&ei=YYJoTtrKEKrZiALnw5yABA&usg=AFQjCNFRsoL9uipduS5ixtGL6Ur8YBZImQ&cad=rja Edited September 8, 2011 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.. Link to comment Share on other sites More sharing options...
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