SlipHavoc Posted February 8 Posted February 8 There's a related bug for the A-10C and A-10C II here, but I've found it also affects the A-10A: In testing, I've narrowed it down more and was able to replicate it reliably. The A-10A starts the left engine fine, but fails to start the right engine if the outside temperature (as set in the Mission Editor) is 7 deg C or below. If the temperature is 8 deg C or above, the right engine starts just fine. However for the A-10C and A-10C II, it fails if the temperature is 4 deg C or below, and works if it's 5 deg C or above. In the A-10C, I think the problem is because the engine idle speed is just under 56% at that temperature, and so the ENG START CYCLE light stays on (manual page 582 says the light will be on if the RPM is below 56%), and the other engine won't start until that light goes out. (Note: This also affects manual startup, not just the auto start. The other engine will not start if that light is on.) I think the same thing is happening internally in the A-10A, but with slightly different temperatures. Workaround for all A-10 models is to advance the throttle a small amount so the idle speed when it starts up is just over 56%, that allows the second engine to start. Please let me know if you need example tracks or scenario files, but it was very easy to replicate once I figured out it was temperature related. @Yurgon for visibility as well. 2
Yurgon Posted February 9 Posted February 9 17 hours ago, SlipHavoc said: @Yurgon for visibility as well. Thanks, good report! I had tested and included the A-10A in my internal report. I wasn't aware that there's a slight difference in the exact temperatures that triggers the issue between the A and C models, but don't think that it actually matters for the report. Still good to know, thanks for checking it out! 17 hours ago, SlipHavoc said: Workaround for all A-10 models is to advance the throttle a small amount so the idle speed when it starts up is just over 56%, that allows the second engine to start. In the C model (both modules), I find that it takes quite a lot of throttle to get the engine start cycle light to go out - and as soon as the throttle is pulled back towards idle, the issue will reappear. I haven't checked if this remains the case after takeoff though. 1
SlipHavoc Posted February 9 Author Posted February 9 5 hours ago, Yurgon said: In the C model (both modules), I find that it takes quite a lot of throttle to get the engine start cycle light to go out - and as soon as the throttle is pulled back towards idle, the issue will reappear. I haven't checked if this remains the case after takeoff though. I had thought that it took a lot of throttle as well, but I found that once the RPM is over 56%, it takes about 8-9 seconds for the light to go out, and that was throwing me off. I am able to get the light to go off reliably by advancing the throttle just enough to get it over 56%, and then waiting. I also tried in the air, but was never able to get the RPMs under 56%. Not sure if that's because my forward speed was always enough to windmill the engine up past that RPM, or if there's some difference in the engine system that accounts for weight-on-wheels somehow. I even tried doing a vertical climb and turning on active pause just as I started to tailslide so my airspeed was almost zero, and the RPM never dropped below about 61%. I also tried a hot start on the ramp with a 100+ kt headwind to see if that would windmill the engines up, but it didn't, and I was still able to get the ENG START CYCLE light to come on in the A-10C at least. So there's something odd going on under the hood. At least there's an easy workaround by just advancing the throttles a bit. Anyway, thanks! Hopefully this is enough to troubleshoot. 2
Yurgon Posted February 9 Posted February 9 I take any opportunity I get to bump the report, and this was one of those. 1 1
Baz000 Posted March 21 Posted March 21 I am experiencing the same problem with engine startup, doesn't matter if I start the left engine first or the right engine... It seems like the APU gets hung up or something as it does not shut off after individual engine start. This happens to me on the A-10A Cold Start instant action mission on Caucuses map. You can reproduce by playing that particular mission. Also, the default view in the A-10A is messed up. I fixed this by using user snap view to move the head further aft to try to match the full fidelity A-10C position.
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