Originally Posted by Voyager
I recall a funny little anecdote of a engineer who always beat F-16 pilots in their training simulator, and nobody could figure out what was up. What everyone finally realized was he was pulling 9-10G maneuvers, while the real pilots were only pulling about 4-6, tops. The moral of this story was, people do things in sim that they would never, ever, do in real life.
A WWII fighter is a very different aircraft than a Cessna 172. There's a reason why Air forces need advanced trainers.
The full-back on the stick stall is an accelerated stall or high speed stall, where in one or both wings have exceeded their maximum AoA while under greater than 1G. Most GA planes don't really have the power or elevator authority to do one in a straight pull back. Also recall, the full back haul on the stick is 60-100lbs of stick force, which is non-trivial.
The death spiral does happen if you go into a tight turn near the plane's stall speed. Fighters are less susceptible to it than GA aircraft, because they generally have an order of magnitude more horse power. The P-51 has a stall speed of about 100mph IAS, but it's got about 1,700hp with water injection, cruises at about 200mph IAS, and tops out at 250mph+ IAS. Get into a dive, and you're talking 300mph IAS, with a Vne of about 500mph IAS. The Cessna 172 has a Vne of, what, 187mph, and has all of 170hp? Try flying around in a Mustang with 10% power, and then tell us there's no death spirals. Actually, I'm being a bit unfair with 10%. The Mustang is about 5 times heavier than the 172. Try flying around in the P-51 at 50% engine power, and you'll find that that things gets really tricky. Don't try to take off at that setting, though, or you'll get caught in the drag trap, which is another fun feature unique to aircraft with ridiculous wing loadings.
Torque is also very different on warbirds. ~2000hp with 10-13ft multibladed props tends to produce far more torque than a 6 foot, 30lb pair, driving by a 100-200hp engine. I don't know if you ever read Pelican's Perch, but in the last one Deakin wrote, he went over a Mustang crash on an aborted landing, that was caused by the pilot applying power too quickly. He essentially went from level wings to fully inverted in about ten feet, from torque alone. Deakin wrote a large number of articles on fly warbirds, and how different they are from General Aviation planes.
On WEP. The way you get a Merlin to produce 3000hp+ is very simple: you remove the boost limiter, and apply throttle until the engine reaches the desired HP, or explodes. To get a specific type rating, the engine makers put an engine on a mount, and run it at the desired HP settings until it either blows up, or passes the required run time, but the fact that it doesn't explode is not sufficient to tell you how much power it can really go at before it breaks. For most civilian applications, that's not really a big deal; they just label the thing Xhp, with X being the known safe limit, and that's the end of that, but for military applications, it's more a case of the quick and the dead. There are times when one is less concerned with the possibility of one's engine exploding, than the certainty that the guy behind you intends to administer suppositories with a MK108. As such, many armed forces equip their fighting vehicles with throttle settings that go a bit beyond the rated power, usually 10%, and large quantities of paper to fill out if they ever use it. I'm given to understand, they would typically have a notch wire guard at the 100% setting, that you would have to break in order to get to the 110% setting.
Actually, thinking about it, that was why we have the 110% throttle, WEP is generally referring to the engine modes in which additives are being temporarily added to the fuel/air mix in order to boost max safe power. Most of the time, it is methanol/ethanol/water mix that is being sprayed into the supercharger, which helps delay detonation at very high power settings. On some of the German extreme high altitude fighters, it's also talking about GM-1, which is Nitrous Oxide being dumped into the engine, to help compensate for the lack of oxygen at very high altitudes (as in, 9km+). In all cases, the additives require their own tanks, and generally, there's not enough for more than about 10m or so of operation, so you don't want to use it for routine flight. I don't know if the actual tank limits are modeled in game, however. Calling it WEP is an anachronism in some cases, but having random kanji pop up on screen would be a bit confusing for some.
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10-18-2009, 08:12 PM
Hybrid Mode
