![]() This was fixed later in the war with the addition of pressure carbs, however early in the war this gave the German pilots a potential combat advantage: their fuel injected engines didn't have this flaw, meaning they could simply pull negative g to cause a pursuing allied aircraft to lose power. This would rich-cut under negative g as the fuel in the float bowl moved to the top of the carb, forcing the float to move downward and open the fuel valve all the way. Case in point Merlin engines in the early part of WW2 (Spitfires, Hurricanes, etc.) used a simple updraft carburettor. This can be demonstrated easily by bending a paperclip until it snaps: bending it fully one way and then fully the other will cause it to snap faster than simply bending it fully one way, then straightening it and bending again, etc.įuel systems: fully aerobatic aircraft typically have some form of pressurised fuel tank, fuel injection, or similar system to prevent fuel starvation under negative g. The key word here is 'cyclic' a spar which is subjected to loads between (say) -5g/+5g will fail faster than one which is subjected to loads of only -1g/+5g. (Boeing 737 NG FCTM 1.50 General Information)ġ Limits for large aircraft from EASA CS-25:įive short, generic reasons (i.e., not specific to the Weedhopper):įatigue reduction: some highly stressed parts of the airframe (particularly mainspars and engine mounts) are susceptible to fatigue failure from cyclic loading. Provide high/low speed margins in severe turbulent air. Supplementary Procedures chapter of the FCOM. Turbulence is encountered, use the Severe Turbulence procedure listed in the Severe turbulence should be avoided if at all possible. When experiencing strong turbulence, the airspeed should be reduced to turbulent air penetration speed (VB), which reduces the impact of the gusts. This can (for a short amount of time) result in large changes of the load factor, even into negative gs for a strong gust in the vertical direction. Wind gusts: The limiting factor for airliners 1 (which rarely do the maneuver described above) is mostly due to wind gusts and up-/downdrafts. Some aircraft do this intentionally to reduce the g force to exactly zero:īy pushing the control column further forwards, you would get negative gs. Depending on how fast you do this, the load factor can even become negative from this. You can get negative load factors (g forces) in different ways than just flying upside down:Ĭhange in pitch: When you push on the control column, the pitch will start to decrease. ![]()
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