Atmospheric Flight feels weird

[DragonHalo99]

I swapped tail fin out for another part and used 2 delta deluxe winglets its much more stable that way cant remember name of the part i used for the rudder. The reason why my plane has that much fuel is I had observational surveys over past where you find kerbins badlands. I managed to find a  lake that was badlands for even more badlands science. I wonder if ther is water you can land in for a splashdown in the tundra and ice caps.

[MaxPeck]

10 hours ago, KerikBalm said:

#1) It was claimed that KSP aircraft land much much faster than real aircraft... KSP aircraft can fly much slower than he claimed, countering his complaint (and yes, stuff very similar to them count fly IRL)

#2) the radius of most turns relative to the wingspan is so much greater that a speed differential doesn't cause any noticable asymetry in lift. There's nothin with centrifugal force and yawing here. The yawing it to prevent sideslip. Its not needed if the aircraft has sufficient yaw stability.

It turns in the direction of the bank due to the lift vector not being vertical... well the craft's velocity vector moves to the side anyway. The sideslide that results will impart a yaw moment if it is yaw stable, which will cause the nose to point in the direction of the turn.

The case of lift asymmetry and a need to counter with yawinput only occurs when a roll is initiated.. due ot a higher and lower effective AoA of the wings, causing adverse yaw

https://en.wikipedia.org/wiki/Adverse_yaw

Thats not applicable to a "steady state" bank... merely a response to a roll input

Ach.  Here we go. Nitpickers at 12 o'clock, 5 miles.

1. Aircraft in KSP generally rotate, operate and land well above normal aircraft operating speeds.  Your particular outliers are exceptions.  I didn't say it was impossible, I said it's not generally done.  Congratulations on designing aircraft that land at subsonic speeds, I don't think most people land under 100 m/s.  I could be wrong.  Also, I know 100m/s is subsonic, I was being deliberately hyperbolic, so relax.

2. The main force acting in opposition to the horizontal component of lift in a turn is centrifugal force.  Yes, adverse yaw is a thing.  Adverse yaw will tend to point the aircraft's nose away from the turn, but it is the balance between an aircraft's HCL and centrifugal force that creates a coordinated turn.  Too much yaw control will cause the aircraft's HCL to be less than it's inertial force, resulting in a skid, not enough will create more HCL than inertia, resulting in a slip.  Regardless of what causes the imbalance between HCL and centrifugal force, it is centrifugal force that you're working against in a turn. Refer to https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/media/FAA-H-8083-15B.pdf page 4-11 for more details.  So what I said remains true... you're using yaw control to keep HCL and centrifugal force in balance.  If you just bank an airplane and take your hands and feet off the controls, you're stupid, but also the airplane will react by raising the nose slightly and yawing away from the bank (due to adverse yaw, as you astutely pointed out).  It will slip, and that's due to an imbalance between HCL and centrifugal force, which is caused by adverse yaw left uncorrected.  There are other factors too, wing blocking in a slip or a skid reduces the available lifting area, and the aircraft's slipstream will also play a minor role.  Regardless, it's inertia that you're working against, and inertia that creates the offset g-forces that enable a turn-and-back indicator to work.

 

Interestingly, this is also what leads to inertial coupling, which is where the total inertia of an aircraft overcomes the authority of the control surfaces.  Since almost all of our speeds in KSP are a hair shy of ridiculous, that's a lot of what you're contending with.  Most people, I would hazard to say, don't bother at all with coordinated turns, they just roll 90 degrees, pull back on the stick to convert the aircraft's VCL to HCL, and let the wings do all the work.

As for asymmetric lift, I stand by what I said. refer to https://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/airplane_handbook/media/FAA-H-8083-3B.pdf  In particular, turn to chapter 11-1, which says:

"Deflection of trailing edge control surfaces, such as the aileron, alters both lift and drag. With aileron deflection, there is asymmetrical lift (rolling moment) and drag (adverse yaw). "

It's also this asymmetric lift during a turn that can lead to spin entry.  Again, in the FAA-H-8083-3B, refer to page 4-12.  If the angle of attack of one wing becomes critical during a turn and it stalls, you get a spin.  Why would that happen?  Say it with me: asymmetrical lift in a turn.  At low speed, we also refer to this is a "cross control stall" and it's one of the leading causes of traffic pattern accidents.  If you're in an uncoordinated turn at low speed, the lower wing will stall before the higher one, resulting in a spin.  If it happens at low altitude, you just bought yourself a farm.

3.  In addition to being a pilot for over 20 years, I'm a full-time college aviation professor.  I might have an idea or two how aircraft work.

Edited May 29, 2016 by JJE64

[KerikBalm]

I've found that a lot of people who know how to fly, don't actually know the physics behind flying...

They know the "algorithm", they know what to  do, but their understanding of why is seriously flawed.

#1) I don't think its an outlier for any reason other than piloting or what people can get away with... pretty much all my designs land lower than 100 m/s... even this monster landsat around 80 when it comes back without fuel and payload:

#2) "is centrifugal force" *sigh* centrifugal force... is not a force. Its just inertia. Inertia acts in opposition to any force. And you don't counter "centrifugal force" by "apply[ing] yaw correction in the direction of the turn"

Even using a rotating coordinate system centered on the aircraft, the "centrifugal force"is not corrected with yaw, its corrected with the proper use of roll and pitch, to modify the horizontal component of lift. The yaw input is just to keep the nose tracking the velocity vector to avoid slip. If the aircraft has enough yaw stability, this is un-needed, as evidenced by the large numbers of aircraft which lack a rudder completely... There are many many many 2-axis (mostly roll and pitch) control RC models as well as ultralight aircraft...

"yawing away from the bank (due to adverse yaw, as you astutely pointed out)" - except when you first initiate the roll, the yawing is not due to adverse yaw, but due to sideslip

"It will slip, and that's due to an imbalance between HCL and centrifugal force, which is caused by adverse yaw left uncorrected."

That is *not* due to adverse yaw. Adverse yaw occurs only when there is input from the ailerons. and again... centrifugal force... ughhhhhhhhhhhhhhhhh

And again... asymetric lift... a lack of understanding. It is not being banked that causes a lift asymetry... it is one aileron deflecting up, and one deflecting down. An aircraft with neutral roll stability can hold a turn without any significant aileron deflection.

As you quote: "With aileron deflection, there is asymmetrical lift (rolling moment) and drag (adverse yaw)." Its the control surface *deflection* not "the direction of the bank" You can be banked at 60 degrees and turning without further aileron deflection.

Again, from what you cite: "Any time ailerons are used, adverse yaw is produced. Adverse yaw is caused when the ailerons are deflected" - it is deflecting the ailerons, not the mere condition of being banked that is causing adverse yaw.

As to its citing of centrifugal force... that's just bad physics, and not the first time a handbook is wrong. You'll get different explanations from an aeronautical engineer vs a pilots handbook... guess which one is more accurate and which one is dumbed down?

Edited May 29, 2016 by KerikBalm

[Green Baron]

Pls., guys, stop that joking on a serious subject :-)

 

Engineer or not, F=m*v²/r describe a force, it's just Newton. Centrifugal force (cf) is not countered (rather caused :-)) by the pilot directly, that's right, but by the lift vector (partially). I don't understand what you @KerikBalm are trying to convince us of and what kind of problem you have with the cf. The degree of bank determines the centrifugal force in a coordinated turn (60° being roughly 2G).

It's not that difficult and i'm neglecting other forces that act on the plane or special constructions of ailerons: centrifugal force, gravitational force and the lift force are (should be) in equilibrium in the coordinated turn. If not the aircraft slips (which can be fun). The adverse yaw you guys are battling about is (to be precise) caused by the higher induced drag at the tip of the wing with higher lift (a paraglider turns in "wrong" direction compared to a fixed wing because the force from induced drag is higher than that from the increased lift when braking one side for a turn, moreover, if you overdo it it turns "negative", one half flying forward the other backward, which can be fun).

Concerning slip and adverse yaw: an aircraft can actively be slipped by applying rudder and aileron in the opposite direction. That's applied adverse yaw, one wing is highly obscured from the airstream by the hull, the other one points forward to some degree. It's a stable state of flying, controlled with the ailerons, used in cross wind landings or when landing over an obstacle.

With a glider however, you can enter a slip unintentionally during a turn (if you don't counter the beloved adverse yaw) if you don't coordinate the turn correctly. Don't underestimate these forces !

 

Edit:

I'm glad others helped the op with his problem ;-)

Edited May 29, 2016 by Green Baron
conclusion

[KerikBalm]

4 minutes ago, Green Baron said:

Pls., guys, stop that joking on a serious subject :-)

 

Engineer or not, F=m*v²/r describe a force, it's just Newton. Centrifugal force (cf) is not countered (rather caused :-)) by the pilot directly, that's right, but by the lift vector (partially). I don't understand what you @KerikBalm are trying to convince us of and what kind of problem you have with the cf. The degree of bank determines the centrifugal force in a coordinated turn (60° being roughly 2G).

It's not that difficult and i'm neglecting other forces that act on the plane or special constructions of ailerons: centrifugal force, gravitational force and the lift force are (should be) in equilibrium in the coordinated turn. If not the aircraft slips (which can be fun). The adverse yaw you guys are battling about is caused by the higher induced drag at the tip of the wing with higher lift (a paraglider turns in "wrong" direction compared to a fixed wing because the force from induced drag is higher than that from the increased lift when braking one side for a turn, moreover, if you overdo it it turns "negative", one half flying forward the other backward, which can be fun).

Concerning slip and adverse yaw: an aircraft can actively be slipped by applying full rudder and aileron in the opposite direction. That's applied adverse yaw, one wing is highly obscured from the airstream by the hull, the other one points forward to some degree. It's a stable state of flying, controlled with the ailerons, used in cross wind landings or when landing over an obstacle.

With a glider however, you can enter a slip unintentionally during a turn (if you don't counter the beloved adverse yaw) if you don't coordinate the turn correctly. Don't underestimate these forces !

 

 

* "F=m*v²/r describe a force" Centripetal, not centrifugal. Centrifugal force doesn't exist in an inertial reference frame.

You don't counter it with yaw... which is what he said

* paraglider steering is quite different, weightshift can also apply, and the brakes act more like.. well... brakes than airlerons... more like the "rudders" on a B2

"an aircraft can actively be slipped by applying full rudder and aileron in the opposite direction" Yes, a forward slip for example.

"when landing over an obstacle." More like when overshooting your intended landing... as famously used on the "gimli glider"

https://en.wikipedia.org/wiki/Gimli_Glider#Landing_at_Gimli

What is important to note in many of these cases, is the aircraft has a certain passive stability built into it that often needs to be counteracted. If a player doesn't design that into their aircraft (like no dihedral), then many things don't apply, because much of what is taught assumes an aircraft designed with certain properties.

"With a glider however, you can enter a slip unintentionally during a turn (if you don't counter the beloved adverse yaw"

*you don't see to know what adverse yaw is, and you conflate it with other things. That's not adverse yaw... thats preventing sideslip. When the aircraft's velocity vectory starts to get a horizontal component, the nose should be yawed in coordination... that isn't adverse yaw.

Just deflecting the ailerons... without executing a turn (rolling and yawing aren't turning, they don't change the velocity vector on their own, only the orientation of the craft) will cause a yaw force due to the higher and lower effective AoA on each wing causing a difference in induced drag.

Roll right -> it yaws left : that is adverse yaw... when you yaw at a steady bank angle, its to counter sideslip, not because of adverse yaw.

[MaxPeck]

Sigh. I give up. You're seriously arguing just to argue and you literally just presented yourself as being more knowledgeable about flight than actual pilots, a college professor who teaches it *and the FAA*. If I can literally quote to you from the Pilots Handbook (published by the FAA and used by actual pilots and flight instructors) and the Instrument Flying Handbook, and you can sit there with a straight face and say they're wrong and you know better... then there's no place left to go with this. I'm out. I concede. 

Edited May 29, 2016 by JJE64

[KerikBalm]

Completely ignoring the parts where the FAA book disagrees with you.

[The_Rocketeer]

I'm amazed you guys managed to talk so much and still not help at all to solve this guy's issue. Nice one.

[KerikBalm]

19 hours ago, JJE64 said:

When you bank a real airplane, centrifugal force will try to push the airplane to the outside of the turn unless you apply yaw correction in the direction of the turn.  The aircraft will still turn in the direction of the bank due to asymmetric lift,

...

As for asymmetric lift, I stand by what I said. refer to https://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/airplane_handbook/media/FAA-H-8083-3B.pdf  In particular, turn to chapter 11-1, which says:

"Deflection of trailing edge control surfaces, such as the aileron, alters both lift and drag. With aileron deflection, there is asymmetrical lift (rolling moment) and drag (adverse yaw). "

Lets give you the non-inertial reference frame needed for "centrifugal force" to exist... these statements are still contradicted by the very things you linked.
FAA says: "the upward acting lift together with the opposing weight becomes the vertical lift component. The horizontally acting lift and its opposing centrifugal force ... This horizontal lift component is the sideward force that causes an aircraft to turn. The equal and opposite reaction to this sideward force is centrifugal force, which is merely an apparent force as a result of inertia. ... As the aircraft banks to enter a turn, a portion of the wing’s vertical lift becomes the horizontal component"

You say: "centrifugal force will try to push the airplane to the outside of the turn unless you apply yaw correction in the direction of the turn"

* They get it right that its merely Inertia, as I said, but go on with the "apparent" force to dumb it down.

* They say that the horizontal component opposes this "centrifugal force", which is cause by bank. In contrast you talk about yaw.

The FAA does not agree with you.

 

FAA says:

"Deflection of trailing edge control surfaces, such as the aileron, alters both lift and drag. With aileron deflection, there is asymmetrical lift (rolling moment) and drag (adverse yaw).

...

Lift is increased on the left side and reduced on the right, resulting in a bank to the right. However, as a result of producing lift on the left, induced drag is also increased on the left side. The drag causes the left wing to slow down, in turn causing the nose of the aircraft to initially move (left) in the diretion opposite of the turn."

You say:

"The aircraft will still turn in the direction of the bank due to asymmetric lift" and cite the above

* this conflates bank and roll (rate of change of bank). Being banked is not the same as deflecting ailerons to roll.

* Adverse yaw is away from the direction of the turn.

Conclusion: The FAA does not agree with you. Your citation of the FAA handbook to back up your statements is simply wrong.

 

"being more knowledgeable about flight than actual pilots" - I am an actual pilot

"*and the FAA*" the FAA handbook is agreeing with me, not you

"a college professor" - I'd have no trouble finding other college proffessors, particularly of those that design aircraft, not just fly them. What college are you teaching at anyway?

[The_Rocketeer]

8 hours ago, DragonHalo99 said:

I swapped tail fin out for another part and used 2 delta deluxe winglets its much more stable that way cant remember name of the part i used for the rudder. The reason why my plane has that much fuel is I had observational surveys over past where you find kerbins badlands. I managed to find a  lake that was badlands for even more badlands science. I wonder if ther is water you can land in for a splashdown in the tundra and ice caps.

If you're comfortable with mods (which IMHO you should be  ), there's a contract pack (I think it's Field Research?) with many contracts specifically for gathering science from rare biome situations. I don't recall if there are water landings in tundra/ice-caps, but as for the rest it will eventually point you to them all.

Regarding fuel, I wasn't really remarking on the amount of fuel. It's just that because nearly all of the fuel is behind the CoM, when the tanks get low you'll have a plane that tends to pitch down again. You could easily change this by changing the stack to put one of the centre-fuselage tanks in front of the CoM.

[Green Baron]

6 minutes ago, The_Rocketeer said:

I'm amazed you guys managed to talk so much and still not help at all to solve this guy's issue. Nice one.

You are right, sir.

I thought yourself, Pecan and others had answered the issue.

What i do to deal with the weirdness is i make simple planes. A hull/fuel tank, cockpit, 3 wheels, a single engine (mostly the wheesly), intake, two wings and canards, airbrakes, (v-shaped) rudder. That flies easy and long ranges, lands almost everywhere (i mean in one piece). I switch off any reaction wheels but use sas to stabilize the course, just because i don't manage to trim the contraption so that it flies level (may be my own inability). To turn i bank steeply and use elevator pulses to do the turn. I fly at 250m/s (throttle down the wheesly).

But i'm no ksp aircraft specialist, i just like plain straightforward designs.

btw.: i'm using the keyboard, that means digital control surfaces ...

Maybe using a joystick would give a better ability to steer in a graded manner ? Joystick-trim could partly solve the problem with the level flight, turning would become smoother as well. Could help with the weirdness ...

 

[MaxPeck]

No.

"Lift is increased on the left side and reduced on the right, resulting in a bank to the right. However, as a result of producing lift on the left, induced drag is also increased on the left side. The drag causes the left wing to slow down, in turn causing the nose of the aircraft to initially move (left) in the diretion opposite of the turn."

...lift is increased on the left side and reduced on the right.  Increased on one side, reduced on the other.  Almost as though the lift has become... asymmetrical.  I never said yaw counters inertia (which for the layman, is the same as centrifugal force).  I said inertia, centrifugal force, angular momentum, The Force, whatever you want to call it, will try to push the aircraft to the outside of the turn.  If you don't apply some rudder correction in the direction of the turn, the HCL and The Force will be out of balance, resulting in a slip.  In an uncoordinated turn, there is absolutely asymmetrical lift being generated, which is why at low speeds you're at risk of entering a spin.  The lower wing in a turn has a lower relative wind across it than the raised wing, which will cause it to stall first.  Yes, everything you've said about adverse yaw is correct.  But adverse yaw is not the force pushing the aircraft to the outside of the turn, inertia is.  Adverse yaw will push the nose slightly away from the turn, but the asymmetrical lift generated by the wings in the turn will still keep the aircraft banked into the turn and the HCL created from the bank will turn the aircraft, albeit in a slipping condition.  This can be addressed by introducing a positive dihedral to the wings, but how many people do that in KSP?  I'd be willing to bet that most KSP wings are symmetrical and flat.  Did I simplify the interactions for the sake of explanation?  Guilty.  If you just bank, which is what most new folks are probably doing in KSP, without adding additional control inputs like yaw and pitch correction, The Force will try to push you to the outside of the turn, but the aircraft will still turn.  You don't see it in real life, because in real life, turning is more than just banking, which is what my original post was trying to impart, which is possibly why turns seem weird to the OP.   

At this point, like I said, this is argument for the sake of argument, and we're arguing apples and baseballs.

As a postscript - and I'm sure you'll howl about this, I am a college aviation professor.  I cannot, unfortunately, name my institution.  We had an instance two years ago where another professor was answering questions from student pilots on a Facebook page, and using his title and our school in his answers.  We got smacked down for that, and the standing orders from our Department Chair was that we're free to discus things online and say what we do, but we're not allowed to name the school unless we get clearance from the school first.  I'm not really interested in getting institutional clearance so that I can bicker on an internet forum about private pilot ground school stuff.  Knowing my chair, I already know what his answer will be.  Take that for what its worth, have fun with it.

 

 

Edited May 29, 2016 by JJE64
completely forgot a prepositional phrase

[KerikBalm]

Well, I'll try to get back on topic, and summarize/recap some of the advice

On 5/28/2016 at 10:25 AM, BebopRebop said:

Are you using a joystick?

Flying in KSP feels really wonky because apparently joysticks have an issue with input lag, which I could see causing oscillations and difficulty turning. The advanced fly-by-wire mod worked to fix this for me, but tends to crash KSP when I try to tweak its settings.

 

Control input might be an issue as noted above. A keyboard is not smooth at all, and ifthere are input delays... its not good either (my game often runs so slow, there are click and keyboard input delays...)

20 hours ago, JJE64 said:

 Speed is indicated in a scale you're not used to...  We're used to measuring altitude in feet, not meters.  The upper limit of most non-turbocharged piston aircraft is around 12,000' MSL, which is only 3,658 meters.  10,000 meters is about 32,000 feet MSL.  20,000 meters is pretty much in the stratosphere.  And that's on Earth, Kerbin probably has smaller atmospheric layers.

Indeed, if you are thinking in feet, and see 3,000, you're being mislead greatly. 3km is nearly 10,000 feet. Kerbin's radius is roughly 1/10th that of earth, but its atmosphere's scale seems to be about 1/3 of Earth's... so 3km is like 30,000 feet on Earth. The air gets thinner much faster than you probably expect based on flying (simulations of?) real aircraft. The atmospheric flight model is pretty much accurate at 69 km... wouldn't you agree? So if 3km is more like 30,000 feet on Earth, we should be comparing the aircraft to airliners at cruising altitude... which have very narrow margins and are not maneuverable at all.

19 hours ago, DragonHalo99 said:

The plane I made Flies at 501ms cruise speed when 1/4 of the fuel is left. when it does that the whole aircraft is glowing red and the engines are close to overheating but never overheat completly.

Yea... 501 m/s is 1806 km/h.... thats blisteringly fast... thats a lot of momentum to change.How long do oyu think it takes a SR-71 to turn when its flying at altitude?

18 hours ago, KerikBalm said:

A lot of it has to do with the face that we're building planes out of lego parts. No washout in almost every plane, for example

Another issue is the ridiculous OP reaction wheels which can have your nose pointing in ways that can't be sustained... flying with reaction wheels disabled tends to be much smoother IMO.

Them of course, there's the binary input of a keyboard (unless you use a joystick) which will make things not smooth at all

#3) "here's a fair amount of inertial coupling going on "

Indeed, KSP stuff is generally quite heavy, and they have a lot of roll/pitch/yaw inertia. I find the SAS can often make things worse as you end up fighting it... I miss the old mode where it just tried to stop all rotation, but not hold any heading... its been gone since... 0.21 I think? I used to use that mode a lot on landers. I want it back

Also, you probably expect your aircraft's wings to produce lift in level flight... without having to hold up the nose. KSP wings have symetrical airfoils... they won't produce lift unless they have positive AoA.. I find it helpful to give the main wings some incidence.
 If you expect it to fly like a real aircraft, it must be designed like a real aircraft, with all the little things that go into it, not just overall look. Have you arranged your craft so that it has positive pitch stability? - you can crudely test this by seeing how the blue CoL changes as you rotate your entire craft in the VAB - do you have any dihedral? Have you looked at what your control surfaces are doing? is your rudder responding to roll commands?

Are reaction wheels imparting angular momentum to your craft causing it to point in directions that can't be sustained by aerodynamic forces (this causes a lot of oscilation, planes tend to fly smoother with reaction wheels disabled). Are you flying a brick (ie high wingloading) - keeping in mind that many parts in KSP are unrealistically heavy (and thus more momentum, which couples with flying in air much thinner than normal aircraft) in part to balance the low dV requirements of the catoon KSP system.

 

18 hours ago, Pecan said:

1. It is not desirable to depend on SAS for stability but it probably is normal for most people.  Better by far (pun intended) to use trim: ...
2. ... The whole point of SAS is to keep the vehicle pointing the same way so, yes it WILL make turning hard(er).

 

15 hours ago, cantab said:

Lots of people do fly planes with SAS, but it is indeed what's making turning weird. SAS attempts to hold the craft in a particular orientation in space. That means that if you bank your aircraft, SAS fights the turn and puts you into a slip, the plane flying slightly sideways through the air. You have to wrench the plane around with manual control inputs to turn effectively when SAS is on.

I prefer to fly stable planes without SAS, and instead use trim, which is set by Alt+WASDQE, or RShift+WASDQE on Linux.

...

Setting up a joypad or flightstick can let you fly more smoothly, but simple flights on Kerbin or spaceplanes to orbit are doable with the keyboard.

As above, SAS is probably fighting you, and keyboard input is not great

[KerikBalm]

"lift is increased on the left side and reduced on the right.  Increased on one side, reduced on the other.  Almost as though the lift has become... asymmetrical"

I have to seriously doubt you're reading comprehension if you can't tell the difference betwene control surface deflection and bank angle. The part you are quoting there is about control surface deflection.

"If you don't apply some rudder correction in the direction of the turn, the HCL and The Force will be out of balance, resulting in a slip."

No, you need to increase AoA to increase the vertical component of the lift... then as the plane turns, you need the nose to track with it, which is where the yaw input comes in.

This "centrifugal force" is only resisting the turn, it is not "trying to push it to the outside of the turn" to cause forces to "be out of balance". The "centrifugal" force is always proportional to the horizontal component of lift... because its just inertia. What is happening is that the angle of the velocity vector is changing *due only to the horizontal component of the lift - not inertia* and the aircrafts' orientation should change with it if there won't be a sideslip, so you use the rudder to track the aircrafts heading... not to somehow balance inertia.

"In an uncoordinated turn, there is absolutely asymmetrical lift being generated, which is why at low speeds you're at risk of entering a spin."

There are many variables here that render your use of "absolutely" inappropriate when the real case is "not neccessarily". And a large factor here only occurs right at stall, and thats when the aircraft's nose starts to rotate towards the ground, which at that point, but not before that point, will cause differential speeds at the wingtips, and resulting asymetrical lift. Dihedral, if present can also contribute. Also the turn radius matters. While the speed difference will never be zero.... a turn of a radius of 5km won't have much significant difference if the aircraft's wingspan is <5 meters.. there'd be less than 0.1% difference in speed.. this is particularly true as bank angle increases (as in a steeply banked, but very high speed turn).

None of that contributes to a yaw in the direction of flight - is that what you meant by "turn in the direction of the bank due to asymmetric lift"? that would just come from the vertical stabilizer providing yaw stability. Or if you mean turn by actually changing the velocity vector of the aircraft... again thats due to the horizontal component of lift. Any asymetry of lift is only a reason to use continuous aileron input to balance it and remove the asymetry (otherwise the plane will roll and not hold its bank). If there's a lift asymmetry, the plane starts rolling...

"Adverse yaw will push the nose slightly away from the turn, but the asymmetrical lift generated by the wings in the turn will still keep the aircraft banked into the turn and the HCL created from the bank will turn the aircraft, albeit in a slipping condition."

* the asymetrical lift is caused by the deflection of the ailerons, and causes a roll, to hold a bank angle, the lift must become symetrical again, or it will continue to roll. The adverse yaw occurs only at the start of the roll, not throughout the bank.

"I'd be willing to bet that most KSP wings are symmetrical and flat."

I believe all are

[cantab]

Aeroplanes were invented over a hundred years ago. We have here an argument between a pilot and an aerospace professor about how they fly.

Think about this the next time you're booking a flight.

On topic, yes KSP wings behave like symmetric airfoils. There's a reason for this - "mirror" symmetry doesn't actually mirror the object, which you can see when you try and place Science Jrs in mirror symmetry. So an asymmetric airfoil would end up upside-down on one side.

Edited May 29, 2016 by cantab

[Green Baron]

If KerikBalm is the aerospace professor he is in grave danger of ending up on the roof in the first turn cause he wouldn't want to counter The Force(tm) .... "but it worked in KSP and Wikipedia said it would, too !"

 

Sorry couldn't resist, don't take it too serious, don't want any trouble with noone, ok ? If you need revenge make a fool out of me ...

 

[MaxPeck]

I give up. You win. I just don't have the energy to keep this up.

Everyone, he won.

[Green Baron]

22 minutes ago, cantab said:

Aeroplanes were invented over a hundred years ago. We have here an argument between a pilot and an aerospace professor about how they fly.

Think about this the next time you're booking a flight.

On topic, yes KSP wings behave like symmetric airfoils. There's a reason for this - "mirror" symmetry doesn't actually mirror the object, which you can see when you try and place Science Jrs in mirror symmetry. So an asymmetric airfoil would end up upside-down on one side.

I see, thanx. So 0 AoA means 0 lift ? (Have no ksp installed here so cannot try)

[KerikBalm]

19 minutes ago, Green Baron said:

If KerikBalm is the aerospace professor he is in grave danger of ending up on the roof in the first turn cause he wouldn't want to counter The Force(tm) .... "but it worked in KSP and Wikipedia said it would, too !"

 

Sorry couldn't resist, don't take it too serious, don't want any trouble with noone, ok ? If you need revenge make a fool out of me ...

 

Well... considering I do fly (unpowered ultralights for 16 years, used to fly powered and unpowered RCs).. don't worry about me ending up on your roof.

To be clear I'm not disputing what actions one should take... we both agree that one should yaw in the direction of the turn... its a dispute over the terminology, the forces, and the reason for doing so.

[Green Baron]

Not on my roof, the roof of your plane ... i mean upside down :-)

No more disputes, you have won.

And i got cantab totally wrong ... sorry jje64.

 

[MaxPeck]

@Green Baron no worries, mate.. I know when I've met my match. 

Edit: FWIW, I've been flying powered airplanes with an actual pilot certificate since 1993 and have a degree in aeronautics, so I probably won't be on your roof anytime soon, either. 

Edited May 29, 2016 by JJE64

[The_Rocketeer]

I'm totally unqualified as an aeronaut in all respects. You will definitely not be seeing me on your roof ever.

[Pecan]

12 hours ago, DragonHalo99 said:

ok so I took what you guys said to change into consideration and I gotta say this aircraft is performing twice as better it even got 3x farther than it could reach before. Tell me what you think! ... Thanks for the advice guys!

Understanding, accepting and applying other peoples' advice so quickly is an uncommon skill in itself :-)  You posted a perfect picture to illustrate your design, which is not too bad in the first place, as illustrated by the detailed comments from @The_Rocketeer particularly.  It is then very nice to see how your plane has benefitted from the changes you decided to make and how much happier you are with everything.  Thank you for the thread.

[Adelaar]

This was probably the KSP equivalent of a barfight, caused by two men squabbling over a trivial matter in how to help the damsel in distress. Been good fun reading this 

[MrChittyChad]

the issue that everyone seems to miss is that turning in ksp is completely unrealistic even with FAR. bank a plane 45 degrees and it should be turning, but still flies striaght. people think that it's normal to just pitch up but that just adds more drag.