durka-durka Posted November 17, 2022 Share Posted November 17, 2022 What's the difference? Why should I use one over the other? Thanks. 492nd Squadron CO (F-15E): JTF-111 - Discord Link Link to comment Share on other sites More sharing options...
ED Team Solution Raptor9 Posted November 17, 2022 ED Team Solution Share Posted November 17, 2022 The Jet Fuel Starter (JFS) is a small turbine engine that spools up the main F110 engine. Hydraulic pressure is routed through a hydraulic starter motor on the Jet Fuel Starter to get the JFS spooled up to speed, which in turn spools the main engine for the start sequence. The hydraulic pressure for starting the JFS is stored in a pair of hydraulic accumulators. When you press the switch to Start 1, you are using one of the accumulators to dump the contained hydraulic pressure into the JFS hydraulic starter to start it. If you use the Start 2 position, you are dumping both of the accumulators to start the JFS. The difference being, if the start sequence fails or is aborted for some reason, you will have the second accumulator to attempt a second start if you use Start 1. If you use Start 2, in theory you only have one attempt to start. Given these facts, as for why you would use Start 2, I'm sure there is a reason. I would imagine it would be determined on the environmental factors or maybe the type of fuel being used, but I don't have any real-world F-16 experience. 2 Afterburners are for wussies...hang around the battlefield and dodge tracers like a man. DCS Rotor-Head Link to comment Share on other sites More sharing options...
Yurgon Posted November 17, 2022 Share Posted November 17, 2022 To add to what Raptor9 wrote, I think I read somewhere that Start 1 indeed requires certain conditions, I would assume outside air temperature, possibly not too much wind or something like that. In essence, pilots mostly don't bother because these conditions are somewhat rare, and there's no real downside to just always using Start 2. Link to comment Share on other sites More sharing options...
ED Team Raptor9 Posted November 17, 2022 ED Team Share Posted November 17, 2022 I forgot to mention that once the main engine is started, the hydraulic accumulators are re-charged (which is important because my understanding is these also power the brakes), so if you shut down the engine following a full and successful engine start, you can still re-start it; even if you used Start 2. 1 Afterburners are for wussies...hang around the battlefield and dodge tracers like a man. DCS Rotor-Head Link to comment Share on other sites More sharing options...
llOPPOTATOll Posted November 17, 2022 Share Posted November 17, 2022 (edited) On 11/16/2022 at 8:28 PM, Raptor9 said: The difference being, if the start sequence fails or is aborted for some reason, you will have the second accumulator to attempt a second start if you use Start 1. If you use Start 2, in theory you only have one attempt to start. Given these facts, as for why you would use Start 2, I'm sure there is a reason. I would imagine it would be determined on the environmental factors or maybe the type of fuel being used, but I don't have any real-world F-16 experience. Start 1 should have a lower chance of working, so always use start 2. Edited November 18, 2022 by llOPPOTATOll Link to comment Share on other sites More sharing options...
Falconeer Posted November 17, 2022 Share Posted November 17, 2022 4 hours ago, Raptor9 said: I forgot to mention that once the main engine is started, the hydraulic accumulators are re-charged (which is important because my understanding is these also power the brakes), so if you shut down the engine following a full and successful engine start, you can still re-start it; even if you used Start 2. Yes, they are also called "JFS-brake" accumulators Planes: Choppers: Maps: Flaming Cliffs 3 Black Shark 2 Syria A-10C Tank killer 2 Black Shark 3 Persian Gulf F/A18C Hornet AH-64 Apache Mariana's F-16C Viper F-15E Strike Eagle Mirage 2000C AJS-37 Viggen JF-17 Thunder F-14 Tomcat Link to comment Share on other sites More sharing options...
Furiz Posted November 17, 2022 Share Posted November 17, 2022 (edited) Well if you think about it, if you use Start1 and it fails you used 1 accumulator, so you are left with 1 again for the second attempt which will most likely result in a fail again, since use of only 1 failed the first time... Therefore there is no logic in using only 1, better to use 2 and you are sure to start the engine, if using 2 fails then its not your fault and using only one in that case again would make no difference. Edited November 17, 2022 by Furiz Link to comment Share on other sites More sharing options...
Dragon1-1 Posted November 17, 2022 Share Posted November 17, 2022 From what I heard, the procedure for at least one non-US operator was to first use Start 1, then kick it into Start 2 if it's not turning fast enough. A single attempt doesn't necessarily use up the whole accumulator, so in practice, you still can do Start 2 if it's taken less than a few minutes of turning the engine over. Failure to ignite might come not only because there's insufficient JFS pressure, but also from, say, ignition problems, so two attempts with one accumulator each are useful, too. 1 Link to comment Share on other sites More sharing options...
LowGlow Posted November 17, 2022 Share Posted November 17, 2022 vor 16 Stunden schrieb llOPPOTATOll: Start 1 has a much lower chance of working in dcs, so always use start 2. Really? It never happened to me that start 1 would fail. Under which condition would that occur to you? Link to comment Share on other sites More sharing options...
durka-durka Posted November 20, 2022 Author Share Posted November 20, 2022 Thanks all for the thorough and easy-to-understand responses. This helps a lot! 492nd Squadron CO (F-15E): JTF-111 - Discord Link Link to comment Share on other sites More sharing options...
DrumminJ219 Posted November 21, 2022 Share Posted November 21, 2022 For US, we use Start 2 all the time. Never met a viper pilot who used start 1, and it's taught to use start 2 from B-course on. 4 Link to comment Share on other sites More sharing options...
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