New answers tagged

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No, the 737 NG stabilizer trim system does not feedback from AOA. My source of information comes from this LinkedIn Slide Share and corroborated by this online FCOM. There are several ways through which the stabilizer can be commanded: Manually via the trim switches. Manually via the trim wheels. Automatically via the Speed Trim System (STS). A helpful ...


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As Jeffrey points out, when that plane is at cruise conditions, it will be in a very slightly nose-up pitch attitude. the thrust line from the props will then be in the direction of travel.


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TL;DR: Maybe. Maybe not. It depends on the particular fighter jet, and how it's loaded, and the effect will, in any case, be very small. An increase in thrust causes an airplane to pitch up via two mechanisms (more details in this PDF):1 An increase in thrust causes an increase in speed; for airplanes with positive speed stability (which is true for all ...


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The engines do create some thrust (exhaust gasses), but it is of little significance. Most of the energy from the turbine engine is harvested to turn the propeller as explained on NASA website (for example): NASA: Turboprop Thrust The exhaust of Osprey engine has actually proven to be quite problematic, as it damages the take-off platform: Wikipedia: Bell ...


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The lift is provided by the rotors only. The rotors are powered by Rolls-Royce T406 engines, which are turboshafts: all useful generated turbine power is converted into shaft power for the rotors. Note that turboprops do convert some of the exhaust energy directly into propulsion thrust, turboshafts do not. All helicopters can provide enough rotor thrust to ...


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As in all turboprops, some thrust is derived from the turbine exhaust, but it's very little, compared with the big thrust of those enormous propellers...


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Aerodynamic heating will damage or destroy the composite wing of the F-22, especially around the leading edge where compression heating is highest. See here for the temperatures which supersonic flight causes. Therefore, the F-22 has been restricted to Mach 1.8 for short duration and Mach 1.6 for prolonged flight. More speed will not be needed, anyway. The ...


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Well, $C_D = C_{D,0} + k_1 C_L^2 + k_2 C_L$ according to Brandt et al's "Introduction to Aeronautics: A Design Perspective," so the parasite drag coefficient is $C_{D,0}$ or 0.038. (Also, $k_1 = 0.0458$ and $k_2 = 0$.)


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There is really some useful information in all answers. Two design choices really make me wonder how hard engineers worked to create that aircraft. First; ventral strakes or tail fins. They are canted 45 degrees. Which means they provide both pitch and directional stability. I also think they provide little bit of dihedral effect. Actually that maybe the ...


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Surface 1 is a horizontal stabilizer with elevator, just the same as on any other aircraft with a T tail arrangement. Surface 2 is called a rear strake or a tail fin. There is one on each side of the fuselage. They provide extra stability during operation at high angles of attack when the fuselage is disturbing the airflow to the vertical tail. They are ...


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No. 2 is a ventral strake and No. 3 is a canard. Neither have actuated control surfaces on the P.180. The ventral strakes are there to provide additional directional stability and the canards provide a more direct longitudinal balance and control, alleviating tailplane loads, and improving low speed handling. The Avanti was built for speed (400 KTAS in a ...


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Why there so many pitch control surfaces on the Piaggio P180 Avanti? You mark 3 surfaces, but only one is movable, i.e. there is only one pitch control surface on the P180, not "so many". what is that device (number 2 in the picture), what is that name, and what is that for? Don't know the name myself, but it is there to guide the airflow around the ...


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When you fly gliders you discover it's quite common to run into air that's descending at 1-200 fpm, or "sink" in soaring-talk. Descending air next to a thermal, or air descending due to downsloping terrain. It's a lot more than that at times, but a couple hundred fpm is typical. On a day where there's any convection (with rising air, there is always ...


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Why was the Cessna 150 changed to tricycle landing gear from the "old school" tail wheel? According to my old-time teacher, the accident rate in flying school changed dramatically when changing to tricycle gear. Ground loops used to be common and potentially expensive with tail-wheels. That seems to be enough of reason for a flight school to stop buying ...


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Already some excellent answers here, but to add to Peter's response, in spite of the challenges, some folks prefer tail wheel planes because they are better for back country type flying - landing on unpaved surfaces, etc. If you take a look at any of the short take off and landing (STOL) contests around the country, you see almost exclusively tail wheel ...


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A tailwheel aircraft is particularly susceptible to a dynamic instability during landing which causes the plane to violently spin around, point backwards, and skid off the runway. This is called a ground loop and is one of the leading causes of landing accidents in tailwheel aircraft. Avoiding ground loops requires good reflexes, good training, and lots of ...


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A tailwheel is a good choice for operation on unprepared surfaces with aircraft that have low wing loading and need to be as light as possible. Two main wheels and a small tail wheel weigh less and cause less drag than a tricycle gear, especially if they cannot be retracted. On the Bo-209 Monsun only the nose gear was made retractable because, being ...


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Others have answered that the boats are so far outboard because they hang from the hardpoints designed for ordnance. The reason the hardpoints themselves are so far outboard is twofold: the ordnance is clear of the propwash to reduce drag, and when it drops, it won't hit the struts. Both reasons apply to the boats, too.


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As you note - as altitude increases, air density decreases. The work done by the compressor stages therefore also decreases at any given rotational speed. If we assume constant power applied to the compressor stages (not entirely correctly) then the speed will increase until the work done matches the power input. The overall work done by the engine will ...


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Your first statement is correct, look at the lift vs AOA chart. You go faster by pitching down (reducing lift and drag) and speeding up above Vbg(lift recovered now more drag), which effectively changes your trim and lowers AOA. Why? Because best gliding "Vbg" is all about covering the most distance per unit altitude, NOT time in the air. In the most ...


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We went to an FAA seminar on the emergency turn back to the airport, and 45 degrees was given as the best bank angle after testing by an experienced pilot. Also, taking off and climbing while turning to 45 degrees away from the runway, so that if one had to turn back, the 180 would get you better lined up with the end of the runway, vs taking off, doing a ...


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Asked and answered, since a any plane without a functioning engine is basicly a glider: What is the optimal bank angle to accomplish a given turn in a glide? Assuming the question refers to an engine failure after takeoff, there is a lot more to the stunt than just turning with the least amount of altitude loss. In any case, before attempting "the ...


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To complement previous answer, vanes on nacelles create vortex on high angle-of-attack, which then goes over the wing. This effectively acts as an boundary layer fence reducing span-wise flow over the wing thus improving lift and lowering stall speed at high AoA (is. low speed). The energized flow also improves down-wash in the area of the wing where there ...


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