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You can get negative load factors (g forces) in different ways than just flying upside down: Change in pitch: When you push on the control column, the pitch will start to decrease. Depending on how fast you do this, the load factor can even become negative from this. Some aircraft do this intentionally to reduce the g force to exactly zero: (image source: ...


8

Five short, generic reasons (i.e., not specific to the Weedhopper): Fatigue reduction: some highly stressed parts of the airframe (particularly mainspars and engine mounts) are susceptible to fatigue failure from cyclic loading. The key word here is 'cyclic'; a spar which is subjected to loads between (say) -5g/+5g will fail faster than one which is ...


5

Recent discussion with friends who work or worked for one major US airline, say they never witnessed such a thing. One of them points out that on Navy P3 flights, they would do it to newbies. Not often, but sometimes to recalibrate newbies. With respect to commercial flights, all pointed out that flight attendants are at high risk for injury, and would ...


4

As it was pointed out in the other thread, the ball just rolls around inside a curved glass tube. It doesn't know what the angle of bank is, or anything other than what direction gravity, and/or centrifugal force is moving it. Therefore: At 90 deg AOB in coordinated flight at positive G, the ball would be centered. The aircraft in this case would be in a ...


3

Here's what the Cessna 172S POH says. If you attempt any aerobatics outside of this, you are pretty much a test pilot. Nothing here about loops. UTILITY CATEGORY SECTION 2 LIMITATIONS This airplane is not designed for purely aerobatic flight. However, in the acquisition of various certificates such as commercial pilot and flight instructor, certain ...


3

If you are serious about designing an airplane that will one day fly and certify, you should, to the very least, read up Raymer, Aircraft Design: A Conceptual Approach. It has a chapter on stability & control, and would be a good introduction to the lingos. More in depth coverage can be found in Etkins, Dynamics of Flight. It's pretty much the bible for ...


2

The farther forward the center of mass is from the neutral point, the more stable the airplane is in pitch. When the two coincide, the airplane becomes pitch-unstable. When center of mass is behind, human reflexes are insufficient to maintain controlled flight. As far as designing goes, center of mass and AoA are different beasts. Center of mass stays ...


2

Here is a video of a stolen Q400 Dash-8 doing a barrel roll. That's not quite as large as a B737, but I think it's close enough for the purposes of the question, especially given it was accomplished by an amateur. It's fair to assume that a trained pilot could do at least as well in a much larger plane--if they were willing to risk their job/license.


1

First, I would like to point out the question was about limit load on airplane wings, which is different that load limits for the entire aircraft. Therefore, this sounds like an airframe question, not propulsion. Let's look from the wing frame of reference: it does not care if aircraft is going level, up, down, sideways, or upside down. All it cares is ...


1

Stuff you quoted in your question seems to provide the answer you're after: 2.6 Approved manoeuvres Category „Utility“: The glider is certified for normal gliding in the "Utility" category. Simple aerobatics are approved but only without waterballast and with the weight of the rear pilot compensated by ballast in the ballast box in the fin see section 6.8....


1

As noted in the question, the flight manual for the German-made DG-1000S sailplane specifically states that loops are permitted in the "utility" category. More advanced maneuvers are permitted at a lighter loading, when the glider is in the "utility" category. In "The Handbook of Glider Aerobatics", downloadable here , table 2 on page 31 lists 9 different ...


1

Well, classic lawyer response here: It depends. Barrel roll is an aerobatic maneuver which, at a minimum, requires the PIC comply with the legal limitations on aerobatic flight per 91.303 and 91.307. Like any other risk management procedure on a proposed maneuver or mission, ask yourself: is it safe? Is it legal? Is it reasonable? You are PIC - Directly ...


1

This answer is for the US. A parachute is required of everyone when the aircraft is carrying someone who is not a crew member. The maneuver must not be prohibited by the aircraft flight manual. (Or must it be specifically permitted?) (Future edit needed.) And of course you must not exceed the permitted airspeed and G-load parameters. There is no ...


1

The key is that you qualified the turn as coordinated. If the turn continues coordinated after the application of more power, then the aircraft will climb due to increased energy being converted to altitude. Unless you decide to "lower the nose" and turn at a faster airspeed.


1

Sort of amusing F-16s were used here, instead of older vintage aircraft. One must realize those little turns would involve high Gs that may incapacitate the pilots. Also, any "yo-yo" would bleed off a lot of energy and make B an easy target for wingman of A. One "oldie but goodie" would be for A and its wingman (person) to weave and have B turn right into ...


1

So two things you need for a spin entry, as you mentioned, are a stalled wing and large enough yaw rate. If you stall the wing inverted (meaning pushing the control column forward, instead of pulling in a classic upright stall) it really doesn’t matter at what attitude you achieved this two requirements. But the method used in trainings is as @Wirewrap ...


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