I was reviewing that in the AAF manual and on page 13 it talks about linking the throttle with 100 grade fuel, but to unlink it below 7000 ft when using 91 grade fuel. So perhaps that 7k rule is based on octane level and with 100 octane or better, it can be used or linked at any altitude. Then there is the question of if DCS models that behavior and what grade fuel are they modeling the aircraft. Maybe I need to RTFM.
That make sense, because I lost an engine recently following my element lead while he was working the vertical. The engine made king of a grinding noise, then stopped after about another minute. All of my gauges were in the green, so I thought it was fuel starvation. I had 100 gallons in the main remaining so was confused.
Yeah, I think that I remember my CFI preaching the RPM/inches rule of thumb many years ago. Sort of rings a distant bell
This is taught wrongly in real aviation but with an opposite variation: Never have RPM/100<MP. Both rules of thumb have no mechanical basis to be useful.
Do you think this causes ED to model some things incorrectly as well? It seems like a lot of people are having mechanical failures in the Jug by flying with low MP and high RPM. I haven’t flown it recently so can’t say first-hand, but I’m about to start training on it for some Liberation campaigns.
when I fly I simply fly at 2550 and keep it there. I interconnect the boost and throttle and keep them connected. I fly at 50” and keep it there for as ling as altitude permits. At 200 mph I close the cowl flaps and keep it closed until on the ground. I now put the oil cooler and intercooler at neutral. But I am not sure doing that matters because previously I never touched them and flew for hours with no adverse results. I do not feel that there is anything at all complex about managing this tough old Pratt other than to be careful not to overboost it. I do know why I (underlined) was having failures: because I forgot to lock the primer and the engine was flooding during climb.
The engine doesn’t care what combination of RPM and MP you are flying if the power output (torque) is equivalent. If 75% power is 42”/2300 and 39”/2500 the engine is equally happy with either. (I made those numbers up for illustration). It’s best not to overthink this. Stay inside the red lines and don’t exceed any temperature limits. As long as it has fuel and oil, and is in the green, it will not quit. On takeoff, advance the throttle slowly and only use as much power as you think you’ll need to clear the trees. Almost certainly 50” will be more than enough.
IRL underboosting will adversely affect the seating of the piston seals and cause higher than normal wear of the piston liner. There’s advisable boost ranges for a given RPM for a reason. I don’t own the DCS Jug myself, so I don’t know how this translates to the sim.
