What do you guys make of this?

[Sunde]

My Spitfire kinda got a life of its own after i lost half my elevator. Usually when i take this kind of damage as long as the other half is still functional i can fly. But here it just felt like any elevator input was completely worthless. Even when my remaining surface was responding to my input as it should (you can see me verifying in outside view). The plane almost felt "locked" in its pitch movements, and would not at all respond even if i went from full negative pitch, to fullly positive, the attitude of the machine would be completely unpredictable, and very random. 
Any ideas? 

Recording in the link. 
https://www.youtube.com/watch?v=qVxklsgZSgM&feature=youtu.be

Edited June 1, 2018 by EAF331_Sunde

[danielprates]

I know this is off topic but anyway... seeing your crash at the end of the video reminds me how lenient this simulation is regarding crash injury to the pilot. I forgot how many times I collided with the ground going at least over 200kph and the pilot survived without injuries. That can't be right! The way you crashed right there should have been an instant kill right there,  a massive head trauma or something, regardless of seatbelts (and the eventual gunsight cushing recently discussed elsewhere ?)

Edited June 1, 2018 by danielprates

[Sunde]

5 minutes ago, danielprates said:

I know this is off topic but anyway... seeing your crash at the end of the video reminds me how lenient this simulation is regarding crash injury to the pilot. I forgot how many times I collided with the ground going at least over 200kph and the pilot survived without injuries. That can't be right! The way you crashed right there should have been an instant kill right there,  a massive head trauma or something, regardless of seatbelts (and the eventual gunsight cushing recently discussed elsewhere ?)

My Spitfire was equipped with a premium airbag.

?

[303_Bies]

12 minutes ago, danielprates said:

and the pilot survived without injuries

 

[-TBC-AeroAce]

The spit is very close to having neutral stability in the pitch axis so I suspect loosing half of it could make it unstable. 

 

Btw just to clarify aircraft have three types of pitch stability. 

 

When disturbed by a gust or by pilot control  inputs the plane will:

 

1) If stable react with an opposite force to the disturbance making the plane want to go back to its initial state.

 

2) if neutrally stable the plane will keep its new attitude after the disturbance not getting any better or worse.

 

3) if unstable after the disturbance it will increasingly divert from the initial state getting worse.

 

I suspect a serious case of number three is happening!!!!!!

[-SF-Disarray]

In my brief time in the Spit 9 I have noticed that it does not seem to tolerate damage well, especially to the wings. I've had it lose basically all control with some light MG damage to one wingtip, this was on the clipped wing variant for what it is worth. On the other hand I had an AA gun shoot the entire vertical stab away and was able to fly for some kilometers before the plane lost stability and crashed. This is all anecdotal, though, and these are only my initial impressions.

[SCG_Space_Ghost]

Devs clearly have a pro-German bias.

 

/s

Edited June 1, 2018 by Space_Ghost

[Chief_Mouser]

1 minute ago, Space_Ghost said:

Devs clearly have a pro-German bias.

 

Ooooh you tease...

[RedKestrel]

6 minutes ago, Disarray said:

In my brief time in the Spit 9 I have noticed that it does not seem to tolerate damage well, especially to the wings. I've had it lose basically all control with some light MG damage to one wingtip, this was on the clipped wing variant for what it is worth. On the other hand I had an AA gun shoot the entire vertical stab away and was able to fly for some kilometers before the plane lost stability and crashed. This is all anecdotal, though, and these are only my initial impressions.

My understanding is that the Spit has a pretty unstable flight regime. That makes it wonderful to fly and very maneuverable, but maybe it makes it a little more vulnerable to damage...

[DD_Perfesser]

I had one half or more of my right wing missing from AAA and i think i would have been able to limp back to base and belly in.

[danielprates]

3 hours ago, bies said:

 

 

Very cool video! Lucky guy, that one. 

 

You can see though he managed to land "gently" on the ground. My guys survive headons, crashing on trees etc. 

[-TBC-AeroAce]

1 hour ago, DD_Perfesser said:

I had one half or more of my right wing missing from AAA and i think i would have been able to limp back to base and belly in.

 

I have landed a mk 9 with half a wing missing.  It was not a pretty landing but it ended upright on its wheels with the engine running. 

 

3 hours ago, Disarray said:

In my brief time in the Spit 9 I have noticed that it does not seem to tolerate damage well, especially to the wings. I've had it lose basically all control with some light MG damage to one wingtip, this was on the clipped wing variant for what it is worth.

 

I have flown it a lot and the wings are just as strong if not stronger than other ac in the sim.

 

The tail on the other hand is made of glass.

[-SF-Disarray]

I don't mean that the wings come off easier than other planes. Just that the flight performance seems to be affected more severely by damage to the wings. There could be other damage that has gone unnoticed when I have observed this phenomenon, I have not made a rigorous study of the plane's damage model just yet. It could also be the case that this behavior is entirely inline with it's real world counterpart. Perhaps someone knows about that last bit, but I don't know all that much about British war time aviation.

[Talon_]

Losing half the tail will move the CoL forward - depending on fuel load this could well put it slightly forward of the CoG leading to divergent behaviour.

[unreasonable]

6 hours ago, Talon_ said:

Losing half the tail will move the CoL forward - depending on fuel load this could well put it slightly forward of the CoG leading to divergent behaviour.

 

I need someone to explain that to me: as I was thinking the opposite:

 

If you take a piece off the stab or elevator you remove weight from the back of the plane. That must move the CoG forwards.

The forces on the tail in level flight are downwards - ie negative lift. Taking a piece off should reduce that negative lift, ie making the tail rise, ceteris paribus. That is equivalent to moving the CoL backwards.

 

I am perfectly prepared to believe that is back to front, but why?

 

[[TWB]Sauerkraut-]

12 hours ago, AeroAce said:

The spit is very close to having neutral stability in the pitch axis so I suspect loosing half of it could make it unstable. 

 

Btw just to clarify aircraft have three types of pitch stability. 

 

When disturbed by a gust or by pilot control  inputs the plane will:

 

1) If stable react with an opposite force to the disturbance making the plane want to go back to its initial state.

 

2) if neutrally stable the plane will keep its new attitude after the disturbance not getting any better or worse.

 

3) if unstable after the disturbance it will increasingly divert from the initial state getting worse.

 

I suspect a serious case of number three is happening!!!!!!

 

 

This is a link to a Kerbal Space program post explaining the very basics of airplane design, which explains this phenomenon.

 

https://forum.kerbalspaceprogram.com/index.php?/topic/47818-basic-aircraft-design-explained-simply-with-pictures/

 

As someone who used to play KSP quite a lot (and with the "realism overhaul" for quite a bit of it) before I became interested in WW2 aerial combat, which led me to flight simming, learning stuff like this will really make you stop and think about why an airplane is designed a certain way, and will give you insights about its handling and the general design philosophy just by looking at it.

[Talon_]

8 hours ago, unreasonable said:

 

I need someone to explain that to me: as I was thinking the opposite:

 

If you take a piece off the stab or elevator you remove weight from the back of the plane. That must move the CoG forwards.

The forces on the tail in level flight are downwards - ie negative lift. Taking a piece off should reduce that negative lift, ie making the tail rise, ceteris paribus. That is equivalent to moving the CoL backwards.

 

I am perfectly prepared to believe that is back to front, but why?

 

 

All wing area contributes lift, so when you remove wing area from the back of the plane the center of lift moves forwards. It's not the tail applying downwards force so much as the entire wing-plan applying balanced force behind the center of mass - it's kinda hard to explain. Also, tailplanes don't weigh much!

 

 

 

Edited June 2, 2018 by Talon_

[unreasonable]

My understanding is that most of the time (eg in level flight) the horizontal tail surfaces are not producing positive lift, but negative lift.

 

If you are at very high AoA you might get positive lift, but in level flight you do not: the horizontal stabilizer usually has a zero AoA and is subject to the downwash of airflow over the top of the wing. It produces negative lift.

 

The net lift is balanced at one point - but this consists of the components from the wing  and from the tail. Reduce the downwards component on the tail and you will get a nose down movement. 

 

This is where I get that from... http://avstop.com/ac/flighttrainghandbook/longitudinalstability.html

[Talon_]

I can't find the term "negative lift" anywhere on that page. Negative lift e.g. lift below zero is called "downforce" and is not necessarily a good thing to have on your tailplane.

Edited June 2, 2018 by Talon_
added the word "necessarily"

[DD_Perfesser]

Yeah sorry but to my understanding the tailplane is an inverted airfoil. Faster you go the more down force you have.

 

In any fighter the loss of this much flying surface(half a wing or one side of horizontal stab) is going to mean a hole in the ground.  That you can fly at all should point to a simplified flight model and all talk of real world comparisons isn't relevant.

Edited June 2, 2018 by DD_Perfesser

[Talon_]

1 minute ago, DD_Perfesser said:

Yeah sorry but to my understanding the tailplane is an inverted airfoil. Faster you go the more down force you have.

3

 

I am constantly shocked by the ignorance of people who claim to know enough to call IL-2's flight model "simplified"

 

[unreasonable]

14 minutes ago, Talon_ said:

I can't find the term "negative lift" anywhere on that page. Negative lift e.g. lift below zero is called "downforce" and is not a good thing to have on your tailplane.

 

You can call it whatever you like - look at diagram 17-24:  the force on the wing is "upforce" ie "lift", the force on the tail is "downforce" ie "negative lift".  Together, they balance the CoG. 

 

Downforce is absolutely required to have on your aeroplane's tail anytime the CoG is in front of the CoL of the wing if you do not want to be pitching nose down: including in level flight with the elevator at a neutral position in most aeroplanes. 

 

Never mind, if you do not want to believe the U.S. Department of Transportation that is entirely a matter for you.

 

 

[DD_Perfesser]

LOL  OK.  I suppose in the interest of clarity I oversimplified

 

Quote

Regardless of the airfoil shape, nose-heavy airplanes like WWII fighters will almost always have downforce on the horizontal stabilizer.

Even if the airfoil is not inverted, it will be attached at a negative angle of attack.

https://aviation.stackexchange.com/questions/36934/did-wwii-fighters-have-inverted-airfoils-for-horizontal-stabilizers

 

It entirely possible that the airflow over the wing is curved down enough that it's pushing down on the tail but looking at everything sitting on the ground it appears the opposite.

Edited June 2, 2018 by DD_Perfesser

[Talon_]

4 minutes ago, unreasonable said:

 

You can call it whatever you like - look at diagram 17-24:  the force on the wing is "upforce" ie "lift", the force on the tail is "downforce" ie "negative lift".  Together, they balance the CoG. 

 

Downforce is absolutely required to have on your aeroplane's tail anytime the CoG is in front of the CoL of the wing if you do not want to be pitching nose down: including in level flight with the elevator at a neutral position in most aeroplanes. 

 

Never mind, if you do not want to believe the U.S. Department of Transportation that is entirely a matter for you.

 

 

 

Just look around at various aircraft tails. Lots use semi-symmetric, normal or symmetrical airfoils.

@unreasonable even with the downward pointed elevator, it's not as simple as +lift here and -lift there as you might like to think.

 

By way of example, here's a simple aircraft of normal weight/ift distribution I put together with a downward pointing elevator:

 

 

And here's that same aircraft with a downward pointing elevator on only one side:

 

 

Despite the constant downforce applied by the tail the center of lift still moves forwards.

[DD_Perfesser]

Sorry, no cheating with swept wings.

T- tails don't have the horizontal stab in the prop wash either.

[Talon_]

5 minutes ago, DD_Perfesser said:

Sorry, no cheating with swept wings.

T- tails don't have the horizontal stab in the prop wash either.

 

So what are you trying to say by stating this? The main wing's lift is still far ahead of the tail's leading edges regardless of wing sweep.

 

Please post supportive counter-examples of CoM/CoL shown on an airframe with two horizontal stabilisers vs it's single horizontal stabiliser equivalent if you think you are right.

[Holtzauge]

You can think of it this way: Even if you have a positive or negative contribution from the tail at any given flight condition, if your aircraft is statically stable or not depends on the relationship between the CG and the neutral point NP. While it’s a bit more complicated than the below explanation, you can basically think of the NP as the balance point: So if you take the area of the wing times the distance from its aerodynamic centre AC to the NP this is balanced by the tail area multiplied by its AC’s distance to the NP. For a stable plane the CG is typically 5-15% forward of the NP. However, let’s assume we have a statically neutrally or slightly stable plane like the Spitfire, the CG and NP are very close. Now remove half of the stabilizer and presto your NP is now in front of your CG meaning you are now statically unstable and will diverge unless you are very quick on the elevator because any disturbance either up or down in aoa will be amplified. Regarding the lost weight of half the tail assembly this of course moves the CG forward but that movement is much smaller than the movement of the NP.

 

Disclaimer: This is a simplified explanation and power on/off, stick free and stick fixed stability, mach effects etc. etc complicate the picture but hopefully it goes some ways to explain the basic phenomena anyways.

[EAF19_Marsh]

Quote

All wing area contributes lift, so when you remove wing area from the back of the plane the center of lift moves forwards. It's not the tail applying downwards force so much as the entire wing-plan applying balanced force behind the center of mass - it's kinda hard to explain. Also, tailplanes don't weigh much!

 

The tailplane is lift neutral on these aircraft (non lift generating with elevator neutral) unless the elevator is moved by the stick or damage locks it in a certain position Otherwise, there is no lift generated so CoL cannot really move forward owing to loss of the elevator. However, when commanding nose up (for instance) and higher alpha of the wing, the CoL may move forward to a degree. Same as flaps tend to move CoL aft, so you can maintain same lift with the nose down.

 

The Spitfire has static stability in pitch, so does not return to neutral with elevator input but will continue in its new attitude unless you consciously apply control in the other direction. That is why it is very responsive to elevator and it is easy to pull the nose up to fast. It is positively stable in aileron and rudder, so one comment / mild criticism of the aircraft is that elevator is relatively unbalanced compared to the other control inputs (light on the elevator, heavier on aileron and rudder in which the aircraft does tend to return to level flight) which required some getting used to. The Fw. was praised for the controls being very well harmonized (positively stable) so the stick and rudder are more 'in tune'.

 

As far as I understand it, anyway.

 

 

[Talon_]

 

3 minutes ago, EAF19_Marsh said:

Same as flaps tend to move CoL aft

 

Spitfire flight testing actually consided the Spitfire unstable with flaps deployed, meaning they apparently move the CoL forward, closer to the CoM. I believe this was another handling aspect that was improved by the clipped wingtips, as the wingspan reduction moved the CoL back further slightly.

[EAF19_Marsh]

Quote

Spitfire flight testing actually consided the Spitfire unstable with flaps deployed, meaning they apparently move the CoL forward, closer to the CoM. I believe this was another handling aspect that was improved by the clipped wingtips, as the wingspan reduction moved the CoL back further slightly.

 

Sure, might well have been in the Spitfire case (not sure why that might have been, maybe if the gear were down as well?) but flaps in general move CoL backward.

 

However, taill-plane is lift neutral so its absence  - while problematic - does not specifically affect CoL in terms of removing a lifting surface aft of the CoG.

[Holtzauge]

BTW: Here is an example that the tail load can be both positive and negative for a stable aircraft: The attached picture is of the motorized glider W1100 and shows the tail loads as a function of CG position and flap angles. Note that with deflected flap the tail load is always negative but that with flap retracted, the tail load is positive at xcg=0.25 and for aoa’s larger than about 3 degrees.

[EAF19_Marsh]

Quote

Note that with deflected flap the tail load is always negative but that with flap retracted, the tail load is positive at xcg=0.25 and for aoa’s larger than about 3 degrees.

 

But under [undamaged] neutral flight conditions they should have no load at all, right? Unless that is a particular design. The little aircraft I used to fly had no load on the horizontal stabiliser under general flight conditions and elevator. Unless I am missing / forgetting something...

[Holtzauge]

Well I think you can take that figure as pretty representative for a stable aircraft in terms of general principles. And if you look at it the tailplane is only at zero load at xcg=0.25 and an aoa of about 2 degrees. Other than that you either need an up- or downforce. You can however see the effects of different stability margins: Notice that for xcg=0.15 you need to move the elevator more than for xcg=0.25 when going from the depicted 0 to 12 degrees aoa. Going the other way, if you move the xcg back further, you will angle the drawn lines in the diagram until they become paralell to the delta_e lines. This is when you become neutrally stable: You don't need to move the stick anymore to change aoa.

[69th_chuter]

Interesting discussion.  My experience, however, is that stabilizers always produce some downforce, the old school rule of thumb is up to 10% or more of the aircraft weight.  That is what makes canards more efficient than the conventional layout, they carry the nose with lift instead of downforce that the wing ultimately has to carry.  If your plane weighs 125,000 lbs you could see 1,250 lbs down on the stab and a consequent ultimate lift load of 126,250 lbs.  That's why loading to the aft CG limit gives faster speeds than loading to the fwd limit.  Most of the planes I work on have cambered stabilizers so they can produce the downforce more efficiently.  The DC-10 used a (massive) symmetrical stab like a lot of WW2 planes, though, which produced its downforce by local AoA*.  The 747-400 had a clever way of getting around this by converting a portion of the stab box to a fuel tank so when the aircraft was in cruise the crew could pump fuel back there to physically move the CG behind the normal aft CG limit (much less static stability is needed at high speed than slow) thereby virtually eliminating the required stab downforce.  Even flying wings have to hold their noses up which is done by sweeping the wings and washing the wing out until the wingtips have a quite noticeable negative AoA so the CL is ahead of the CG and the wingtips, which are behind the the CG, produce the downforce to hold the nose up.  An example of a WW2 combat plane with a cambered stab is the P-61.

 

 

*The MD-11 went with a smaller, cambered stab in its bid for range relevance.

[unreasonable]

I take on board Holtzauge's points about the Neutral Point, and how it's position relative to the CoG will change and potentially affect stability, which answers the OP's question.  Seeing chuter's post reassures me that I am not completely bonkers.

 

In my simple minded way I see it like this: forces exerted at any point other than the CoG induce a moment: ie a tendency to rotate around the CoG.  If the lift force produced by the wing is aft of the CoG - as is normal in our sim kites - there is a nose down rotating moment equal to force times distance.

 

To keep the aircraft level this has to be balanced by a moment in the opposite direction. This is done by the tail as a whole - stabilizer, elevator, stabilator, or a man hanging on the end with a blow drier. Since it is much further away from the CoG than the wing lift, the force required is much smaller. But force times distance must be the same.

 

So if you are flying level the moment of the wing must by definition be equal but opposite to the moment of the tail. (Assuming no other bits exert up or down force).  If both are on the same side of the CoG, arithmetic dictates that the forces on tail and wing have opposite signs (ie directions), hence "negative lift". 

 

 

[Guest deleted@134347]

On 6/1/2018 at 11:55 AM, EAF331_Sunde said:

My Spitfire kinda got a life of its own after i lost half my elevator. Usually when i take this kind of damage as long as the other half is still functional i can fly. But here it just felt like any elevator input was completely worthless. Even when my remaining surface was responding to my input as it should (you can see me verifying in outside view). The plane almost felt "locked" in its pitch movements, and would not at all respond even if i went from full negative pitch, to fullly positive, the attitude of the machine would be completely unpredictable, and very random. 
Any ideas? 

Recording in the link. 
https://www.youtube.com/watch?v=qVxklsgZSgM&feature=youtu.be

 

ahem.. at 0:19-0:21 I see that the elevator is locked/blocked in a "pitch down" position and it doesn't respond to your stick movements. So the other half wasn't functioning at all.

 

[Sunde]

1 hour ago, moosya said:

 

ahem.. at 0:19-0:21 I see that the elevator is locked/blocked in a "pitch down" position and it doesn't respond to your stick movements. So the other half wasn't functioning at all.

 

Wrong, that was me trying to push the nose down, look at where the aircraft is going in relation to the elevator's position. 
It was fully functional, i checked it multiple times while trying to regain controle. 

Edited June 3, 2018 by EAF331_Sunde

[-SF-Disarray]

I can corroborate the elevators function in this situation. I took the Spit into Berloga with some friends and found, sure enough, as soon as the plane lost part of the elevator it would go nuts as seen in that video. Once we had the fight way up high and I had plenty of time to right the craft. The elevator would respond and would affect the attitude of the plane. Though I could get the plane under control it wouldn't last but a second or so and then it would go right back to spinning. The thing that has me a little confused on this that no other plane in the game behaves this way. Shoot the elevator and stab off a 190? It will still fly more or less ok. Shoot half the tail off a PE-2, A-20 or a 110? It will keep on keeping on. But take the elevator off a Spit 9 and it is a complete wright off.

 

The other thing I noticed was a disproportionate loss of lift when light damage was applied to the wings of the Spit 9, both the clipped and full winged variants. I don't know if this is an aberration of the visual damage modeling or something in the flight/damage model of the plane, but as soon as a wing gets raked by a few MG rounds the plane becomes sluggish and it is a fight to keep it maneuvering at all. I'd understand this handling if the damage were substantial but it appears to be minor.

[Holtzauge]

8 hours ago, unreasonable said:

I take on board Holtzauge's points about the Neutral Point, and how it's position relative to the CoG will change and potentially affect stability, which answers the OP's question.  Seeing chuter's post reassures me that I am not completely bonkers.

 

In my simple minded way I see it like this: forces exerted at any point other than the CoG induce a moment: ie a tendency to rotate around the CoG.  If the lift force produced by the wing is aft of the CoG - as is normal in our sim kites - there is a nose down rotating moment equal to force times distance.

 

To keep the aircraft level this has to be balanced by a moment in the opposite direction. This is done by the tail as a whole - stabilizer, elevator, stabilator, or a man hanging on the end with a blow drier. Since it is much further away from the CoG than the wing lift, the force required is much smaller. But force times distance must be the same.

 

So if you are flying level the moment of the wing must by definition be equal but opposite to the moment of the tail. (Assuming no other bits exert up or down force).  If both are on the same side of the CoG, arithmetic dictates that the forces on tail and wing have opposite signs (ie directions), hence "negative lift". 

 

 

 

9 hours ago, chuter said:

Interesting discussion.  My experience, however, is that stabilizers always produce some downforce, the old school rule of thumb is up to 10% or more of the aircraft weight.  That is what makes canards more efficient than the conventional layout, they carry the nose with lift instead of downforce that the wing ultimately has to carry.  If your plane weighs 125,000 lbs you could see 1,250 lbs down on the stab and a consequent ultimate lift load of 126,250 lbs.  That's why loading to the aft CG limit gives faster speeds than loading to the fwd limit.  Most of the planes I work on have cambered stabilizers so they can produce the downforce more efficiently.  The DC-10 used a (massive) symmetrical stab like a lot of WW2 planes, though, which produced its downforce by local AoA*.  The 747-400 had a clever way of getting around this by converting a portion of the stab box to a fuel tank so when the aircraft was in cruise the crew could pump fuel back there to physically move the CG behind the normal aft CG limit (much less static stability is needed at high speed than slow) thereby virtually eliminating the required stab downforce.  Even flying wings have to hold their noses up which is done by sweeping the wings and washing the wing out until the wingtips have a quite noticeable negative AoA so the CL is ahead of the CG and the wingtips, which are behind the the CG, produce the downforce to hold the nose up.  An example of a WW2 combat plane with a cambered stab is the P-61.

 

 

*The MD-11 went with a smaller, cambered stab in its bid for range relevance.

 

Well FWIW I agree with what both of you are saying about a conventional configuration (i.e. wing with tail) that in general you have a downforce on the tail. As you can see in the figure I posted this holds true in most cases. However, as always, there are exceptions to the rule and that was what I wanted to show. Note that in the example I posted, it is only at high aoa that the tail starts producing a little lift. But really what is going on is quite complex, with the main wings centre of pressure and pitching moment characteristics changing with aoa as is the downwash on the tail. But if we limit ourselves to “normal” relatively low aoa flight like at cruise then sure, the tail will carry a small downforce.

 

Now that brings us to the canard and the idea that this is a good design because the canard produces lift and not a downforce. On paper and in theory this looks good but in reality the canard comes up short: If we limit the discussion to subsonic flight there are three main drawbacks: One is that in order for the plane to be statically stable you need to have a high wing loading on the canard surface so you get a lot of induced drag. Two: the canard sits in front of the main wing and this causes a downwash on the main wing behind the canard so you basically loose on the wing what you gained on the canard: Three: The speed of your plane is to the largest extent (if we assume parity in other design aspects like power, weight, sleekness etc.) determined by your wing area. Your wing area needed is in turn determined by your design landing speed which in turn is determined by your trimmable Clmax. Now the best way to gain Clmax is by flaps and with a conventional design your added lift from the flaps comes close to the CG and is easy to balance with the tail which has a long arm of moment so only a small force needed. On a canard however, your flap lift comes far behind the CG which puts a great load on the canard which is already highly loaded due to the static stability requirement and on top of that has a shorter moment of arm. What all this boils down to is that your trimmable Clmax is lower and you are left with a bigger wing which produces more drag. There are many other things as well to consider but these are just some of the main ones and a final clue can be had just by looking at all the designs that are out there, both our own and in mother nature: If a canard was such a good idea, why are there so few of them out there?

 

32 minutes ago, Disarray said:

I can corroborate the elevators function in this situation. I took the Spit into Berloga with some friends and found, sure enough, as soon as the plane lost part of the elevator it would go nuts as seen in that video. Once we had the fight way up high and I had plenty of time to right the craft. The elevator would respond and would affect the attitude of the plane. Though I could get the plane under control it wouldn't last but a second or so and then it would go right back to spinning. The thing that has me a little confused on this that no other plane in the game behaves this way. Shoot the elevator and stab off a 190? It will still fly more or less ok. Shoot half the tail off a PE-2, A-20 or a 110? It will keep on keeping on. But take the elevator off a Spit 9 and it is a complete wright off.

 

The other thing I noticed was a disproportionate loss of lift when light damage was applied to the wings of the Spit 9, both the clipped and full winged variants. I don't know if this is an aberration of the visual damage modeling or something in the flight/damage model of the plane, but as soon as a wing gets raked by a few MG rounds the plane becomes sluggish and it is a fight to keep it maneuvering at all. I'd understand this handling if the damage were substantial but it appears to be minor.

 

This is because the Spitfire is close to statically unstable even with the complete tail. However when you loose a part of it it becomes unstable meaning it will go off and either pitch up or down. Other aircraft that have a larger stability margin remain stable in pitch (GG in front of NP) so you will still be able to control then. I don't see any problem with this difference between the in-game Spitfire modeling and the others: It is just a result from the Spitfire's marginal static stability which it also had IRL.

 

BTW: Is there any way to get rid of this automerge function? It's really bugging me that the system keeps automerging my posts all the time......

Edited June 3, 2018 by Holtzauge

[EAF19_Marsh]

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There are many other things as well to consider but these are just some of the main ones and a final clue can be had just by looking at all the designs that are out there, both our own and in mother nature: If a canard was such a good idea, why are there so few of them out there?

 

Well, it needs a decent FBW system which is the preserve of a few countries . companies and it is a way of working but not the only. Note it tends to be coupled with deltas, which IIRC get a significant forward CoL movement that further improved turn rate (initially). It is not without a price, though

 

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So if you are flying level the moment of the wing must by definition be equal but opposite to the moment of the tail. (Assuming no other bits exert up or down force).  If both are on the same side of the CoG, arithmetic dictates that the forces on tail and wing have opposite signs (ie directions), hence "negative lift". 

 

But this will depend heavily on airspeed, so my understanding was that - for a Spitfire - the tail is net zero lift but has to be trimmed at various speeds to maintain the aircraft in level flight owing to the lift force  and centre being variable but the CoG not (of course it is but not 'really' for our discussion purposes).

 

Sunde, this happened also to me also the other day when one elevator was lost - Spit went nuts and totally unrecoverable.