99

Air-to-Air guided missiles are little airplanes. If there are only fins at the tail, it's a ballistic rocket, basically a fin stabilized artillery shell accelerated by a rocket motor instead of an explosion in a pipe. On missile like AMRAAM, Sidewinder, or Sparrow, the vanes are wings and the missile is a rocket powered aircraft that can climb, descend and ...


78

The small wings make it fly like a brick. Without the wings it would fly like a stone. Seriously, you are taking the expression too literally. The Space Shuttle is landing like a glider plane with a (not so good) glide ratio of about 4.5:1 (see What was the Space Shuttle's glide ratio?). No brick would be able to achieve that. Designing the Space ...


60

Special mention for Raúl Pateras Pescara de Castelluccio (good article) who was fond of lots and lots of rotor blades, settling on sixteen for most of his designs, although his Model 3 had twenty. Pescara's helicopters may look a little comical (and dangerous!) but they are an important part of early helicopter evolution, pioneers in the first fully ...


54

1) Airspeed, 2) Forward motion, 3) Size constraints. Just to begin with. Household fan blades are extremely slow, so they need more chord to push a meaningful amount of air. Aircraft propellers approach the speed of sound at their tips, and low drag is critical. All things equal, more span and less chord is more efficient. Reducing the airspeed for props ...


44

This podcast with one of the pilots answers just about every question on the shuttle carrier you could have and it's worth a full listen. But to cover the flight dynamics, I would skip to 50:33 minutes, where the pilot states (please note there is no official transcript of the podcast and I typed this as I listened to it, please see the official podcast for ...


41

The most blades I've seen are 8 on the Mi-26. Source But the highest theoretical lifting efficiency is achieved with the fewest blades and experiments have been done with single blade rotors (with a counterweight - there were vibration problems that couldn't be resolved). So in practical terms, the most lift for the least power is achieved with a 2 blade ...


41

This effect is likely caused by something called the "boundary layer," first defined by German engineer Ludwig Prandtl in a paper he presented in 1904 at the third International Congress of Mathematicians in Heidelberg, Germany. From Wikipedia: The effect of the paper was so great that Prandtl became director of the Institute for Technical Physics at the ...


40

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: ...


40

Yes it's called a Deep Stall, and is mostly a problem with T Tail aircraft, especially jets with Supercritical Airfoil wings (like the CRJ Regional Jet line). Such wings stall from the leading edge and the stall's flow separation spreads rapidly and completely across the entire wing all at once, so there is very little residual nose down pitching moment. ...


38

As everyone has pointed out, it's a joke. Others have answered the lifting-body question (it didn't meet design requirements), so I just wanted to expand some thoughts on the spirit of the "flying brick" nickname. I suspect whoever came up with the term didn't spend a lot of time analyzing it. However, I think it's significant that the nickname is flying ...


28

I would not follow the advice in the forum. While the reasoning that a windmilling prop does create more drag is sound, I have seen no empirical evidence that says how much it actually translates to in Feet Per Minute. The only studies I have seen have been inconclusive on the subject, and say there's a number of factors that you can't really control in that ...


28

This PDF indicates an increase by ~10 dB for an F-8K in afterburner versus the same aircraft in 100% dry thrust. This PDF indicates smaller increases: +5 dB for an F-15 +4 dB for F-22 and F-35


27

The first possibility is that that the CFD in your cad isn't as sophisticated as the software used by boeing's engineers. Which means that your design may have flaws that don't show up in your software but do in Boeing's (or not even in there but do in a windtunnel). Second is that I only saw one flight configuration being tested. Airplanes do more than ...


27

First off, awesome question and great investigation! This kind of let's-see-what-happens inquiry will take you far should you decide to pursue aerodynamics at an advanced level (and, of course, in other pursuits). Not so long ago, I had to write a similar report: lacking the resources and knowledge of the aerospace giants, I, too, wondered why I could ...


27

The autopilot pitches to hold the flight level when it captures the level at the top of the climb, so later on as the aircraft gets lighter and wants to climb further, the A/P will lower the nose as required to hold the flight level (the A/P is able to move the elevator through its servo's link to the elevator controls; it can also work the trim if the servo ...


26

At the same size and rpm, a 4-bladed prop will require twice the horsepower to drive, approximately. Due to blade interference, it will always generate less than twice the thrust. So lbs thrust per hp will generally slightly decrease, as long as the propeller is in its optimal tip airspeed band. If the propeller was overly fast initially, slowing it down ...


24

It has been around 20 years since I've been on a carrier deck, but I recall that it wasn't as dramatic of an increase as you might think. It may have gotten a little bit louder, but what I remember more is that the tone changed. The sound was more "full" when the afterburner was engaged. I realize this is a rather subjective answer.


22

The missile's wings are very large for it's mass, and produce a great deal more lift than the wings of the aircraft firing the missile. One thing to note from the OP's linked video is that the F-35 and the chase plane are traveling at the same speed, so the F-35 appears stationary. However, that aircraft is likely traveling in excess of 0.8 Mach. Therefore, ...


22

Some household fans are shaped like airplane propellers, the ones that need to move a lot of air at the highest speed. For a given motor, they have the highest efficiency, but the tip effect makes them noisy. They are best suited for industrial applications. For inside the family home there are other considerations: Silence. Best if we don’t hear the fan ...


22

No, flaps are never used during a nose dive. We need to distinguish between two scenarios: Intentional nose dive: this is actually called a rapid descent maneuver. The FCTM (Flight Crew Training Manual) has a whole section dedicated to it. The general procedure looks like this: From the Boeing 737 NG FCTM (7.5 Maneuvers - Rapid Descent - Level Change (LVL ...


21

The moisture stays at the surface because the air speed at the surface is essentially zero. (No-slip condition) A solid body moving through a fluid develops a boundary layer around it, which is caused by friction between the surface and the air. A boundary layer is a region of slow moving air relative to the body it surrounds. The closer you get to the ...


21

I have never heard of an ionization device being used on an aircraft, but when I searched Google for "Northrop B-2 ionization", I actually found a reference for this: Microwave frequencies emitted along the leading edge would readily ionize the approaching air and allow the B-2's high-voltage electric field to discharge a greater flux of positive ions. ...


21

In addition to its poor glide ratio the shuttles name also stems from the materials its made from as much as it does its poor glide performance. The Space Shuttle's heat shield was made out of LI-900 Silica tiles that strongly resemble bricks and thus the shuttle was sometimes called the "Flying Brickyard". If you would like to know why NASA chose a wing ...


21

Most twin-engine aircraft with counter-rotating propellers have the rotation set up so that the propellers are rotating inward towards the center at the tops of the propeller arc. This configuration reduces the P-Factor effect at slow speed high angles of attack, and eliminates the "critical" engine that is present on multi-engine aircraft where both ...


20

In the video you posted, the missile appears to continue falling even after the motor ignites -- you can see the missile start to overtake the aircraft even as it continues to drop: By the last frame, it appears to have taken a slight nose-up attitude to maintain altitude:


20

Surfaces sticking out ahead of the Centre of Gravity act in an unstabilising manner: any dissymmetry will want to amplify itself. A dart thrown with the feathers first is in an unstable equilibrium and will very quickly turn around 180º. Surfaces behind the CoG act as stabilisers, keeping the nose pointing forward. An aeroplane has vertical and horizontal ...


17

I can give you two theories. One is it's a very very mild case of "overcontrolling" of the autopilot roll servo as it chases a perfectly wings level condition and continuously applies a teeny bit too much left, ooops, then a teeny bit too much right, oops, and back and forth. The aileron control circuit is cables running to hydraulics at the ailerons, ...


17

The scientific definition of a stall is as you state in the first line, however in the cockpit that definition isn't actually that useful. Practically there's 2 parts of stalls a pilot needs to be aware of because they are things a pilot experiences, and impact the flying characteristics of the airplane: Stall buffet: this isn't a stall, but it happens when ...


17

This is not conceptually correct, for the following reason: Doubling the number of blades on your prop will not double the thrust unless your engine is powerful enough to drive the prop at the same speed as the 2-bladed case. For small planes with fixed-pitch props, a prop and engine combination is chosen for a given aircraft so that when the engine is ...


16

It turns like an airplane by tilting the lift vector. Watch carefully in this video, especially about 50 seconds in, and you can see the craft is turning by banking. It just can't bank very hard unless it climbs a little higher. This is one of the problems of GE aircraft; they aren't very maneuverable because they can only make gentle turns at the normal ...


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