Single engine Cessna tailplane lift

[photofly]

Since this is a flight training forum how about a post on how you think I, a working part time instructor, should teach "what the tail does" to a PPL, a CPL ?

I'm reluctant to give advice to instructors because I hate giving advice and I don't consider instruction to be within my area of knowledge. I'm also reluctant to provide "simplified" explanations here because someone (usually it's me, in fact) starts bleating about how the details are all wrong, something important has been missed out etc. So this is not what I'd suggest you teach. But it is what I would teach myself, to an interested person, if they asked me:

The horizontal stabilizer does exactly what its name suggests: it provides whatever force is required to keep the pitch angle stable.

Much of the time, in smooth stable flight, that force involves pushing the tail of the aircraft down. Some of the time, it might involve lifting the tail of the aircraft up. Whether it's one or the other depends on various things including, how fast you fly, what the weight of the aircraft is, and where the centre of gravity is.

If the aircraft is disturbed from stable flight - either nose up or nose down - the force provided by the horizontal stabilizer changes automatically so as to direct the pitch back towards equilibrium. The fact that a stabilizer can be designed to make that happen makes fixed wing flight possible and is quite an astonishing discovery. But that's for another thread perhaps.

[Strega]

Again, I have no idea whether it is even possible for an aircraft like a 182 to lift up on the tail, but when you see aircraft like the Quickee and a zillion canard aircraft that have lift over all of their surfaces, it makes it hard for me to believe that it is impossible.

The quickie and canard aircraft do have both surfaces lifting (fYI front or rear engine has no effect,, another FYI the piaggio jet prop jobby is NOT a canard.)... Where do you think the cofg is in the quickie or other canard aircraft? I can give you a hint,, its not centered or even close to any center of pressure... If you have ever flown a canard aircraft, you would immediately observe the difference in handling caused by both surfaces being lifting surfaces. I have NEVER flown a conventional aircraft that has had the tailplane lifting, and I hope I never do

There are a lot of non trained people on this forum that like to baffle people with their bs (IE the balsa wood glider wing rotates this way so all wings do the same) ... If I get the time, I will show with real math, and correct principles of flight that in a 182 or 72, in no stage of normal flight in the approved envelope, the tailplane exhibits lift in the same direction of the main wing.. The only issue is, most of the people reading this forum, will not understand the explanation, as it is beyond their comprehension.

S

[Shiny Side Up]

I have NEVER flown a conventional aircraft that has had the tailplane lifting, and I hope I never do

Unfortunate, since both of these would be pretty neat to fly.

[iflyforpie]

Where do you think the cofg is in the quickie or other canard aircraft? I can give you a hint,, its not centered or even close to any center of pressure...

Yes... but it is behind the center of pressure of the front wing.... At what point does a tandem aircraft become a conventional aircraft?


You see... the difference between you and CS and PilotDAR and other 'educated' individuals is that you make no attempt to explain your position. You offer sentence fragments as your sole method of argument, then copypasta from some wikipedia article you may or may not understand, then the inevitable cop out 'you won't understand it'.

The real measure of a person's intelligence is the ability to break down complex ideas and have them understood by laymen. It's a sad individual that uses knowledge to intimidate and scoff.

Until you figure that out, you have nothing of value to add to these forums Strega...

[photofly]

[If I get the time, I will show with real math, and correct principles of flight that in a 182 or 72, in no stage of normal flight in the approved envelope, the tailplane exhibits lift in the same direction of the main wing.. The only issue is, most of the people reading this forum, will not understand the explanation, as it is beyond their comprehension.

S

I hope you do get the time; I'd like to see what you come up with. I don't think you could come up with something (correct) that I couldn't understand.

Until then, I'm afraid I have to call BS on that one.

[photofly]

I just wanted to add: unfortunately people round here treat it as some kind of crime to change one's opinion about something. There's nothing dishonourable about believing something to be true and arguing that it is true; then at some point seeing an error and changing your mind. It's the best way to learn. Maybe a bit less ego around here would make it a more pleasant place to do that learning.

[PilotDAR]

I remain unconvinced. But I will allow that I am less unconvinced than I was before. I have conferred with One very experienced aerodynamicist, and two very experienced test pilots, and they affirm my being unconvinced. According to them, tails of conventional aircraft create lift down only, during stable flight. But one of those discussions did illuminate something I need to understand more about this.

Test flying I do is intentionally at the edges of the approved limitations, particularly C of G and weight. During this I am evaluating control forces, and the possibility that there is way more trim than their needs to be - why is it there? Would it allow a pilot to trim out a configuration which instead should be ringing alarm bells?

In addition to the two non compliant aircraft I have mentioned in the foregoing, I have flown another, which due to a maintenance error on the pitch trim, seriously tried to kill me. I have also test flown and spun a modified 185, which was later found to have had a loading error in the ballast. The detail of that is not for here but its poor handling became rapidly apparent. On the basis of this, I am reassured that Cessna has chosen the C of G limits for their aircraft well!

The highly in depth substantiations of an unconventional way of thinking are certainly entitled to be presented, though I believe that in being here, they may have been in a poorly chosen forum. A flight test forum would be a better choice. The notion that someone might read this, take it to heart, and start to teach it, worries me. Some new instructors are still to impressionable to be fed these "way out" ideas. They might take them seriously, and try to teach them!

I think of how atoms are depicted in chemistry class. Is that really exactly what they're like? Perhaps not. But the format established for their presentation, makes teaching about atoms workable. Similarly, the concept that a conventional tail provides a down force, is a simple and effective way to teach how planes fly. Conflicting viewpoints to be discussed among the mathgods, are out of place on a training forum.

Impressionable people read these forums. We, who know better, have a responsibility to keep the posts somewhat in harmony with established training methods, and general safe ways of doing things. Yes, there are things I have done with I would never describe here, lest the impressionable try them. I opine that trying to get a 182 tail to light in flight would be one of those foolish things that no one should attempt, other than within the limitations.

So as long as you actually assure that your flight is within the limitations of the aircraft, the certified plane will reward you with well proven handling, and performance you've come to depend upon.

[Trematode]

Apparantly we are not the only ones discussing it: http://www.av8n.com/how/htm/aoastab.html

Good contribution, digits. Enjoyed this link the most. I think it illustrates best why what photofly is saying makes sense.

Thanks be to DENKER.

Frankly, I applaud the fact that photofly is not just taking some of these old ground school axioms at face value. To be honest guys, I think some of you are too quick to attack without actually reading what he has to say. I enjoy his posts, and the controversy and discussion they promote. If it does happen, he is always the first to correct himself and/or admit he made an error. This is a hallmark of someone who is truly trying to understand something, and not just trying to prove a point -- contributions of this nature and the people that make them should be welcomed and encouraged on a forum that's so important to Canadian aviation.

And also:

Glory be to DENKER.

[Strega]

Until you figure that out, you have nothing of value to add to these forums Strega..

So does the balsa wing still "rotate backwards"?


PF... I'll try and get some time to sit down.. Ive been busy the last few days.. we have been td ing a well for the last 5 days...

[digits_]

I remain unconvinced. But I will allow that I am less unconvinced than I was before. I have conferred with One very experienced aerodynamicist, and two very experienced test pilots, and they affirm my being unconvinced.

Did they find an error in photofly's math ?

The highly in depth substantiations of an unconventional way of thinking are certainly entitled to be presented, though I believe that in being here, they may have been in a poorly chosen forum. A flight test forum would be a better choice. The notion that someone might read this, take it to heart, and start to teach it, worries me. Some new instructors are still to impressionable to be fed these "way out" ideas. They might take them seriously, and try to teach them!

I think of how atoms are depicted in chemistry class. Is that really exactly what they're like? Perhaps not. But the format established for their presentation, makes teaching about atoms workable. Similarly, the concept that a conventional tail provides a down force, is a simple and effective way to teach how planes fly. Conflicting viewpoints to be discussed among the mathgods, are out of place on a training forum.

For your information, the "Oxford Aviation Academy" CPL/ATPL books explain the whole equilibrium of forces and stability chapters wih a lifting tailplane. It is a widely used book in Europe, and one of the more "fancy" aviation schools. That doesn't mean they are always right, and they do over simplify some things, however, their whole stability chapter does make sense.

So they explain everything with

(nose) LIFT UP CoL ---- Gravity down CoG ----- Tailplane LIFT UP

(see attachement)

It's really not that unconventional.

By the way, what's wrong with photofly's explanation on top of this page ? I think it's clear (even without math) and correct. Again, it doesn't matter a bit to fly the airplane, that's where are all your certification rules come into play, but if you want to understand the theory behind it (which is the purpose of teachting the theory I believe ), it would be a shame not to mention that a tailplane can lift up as well.

[Colonel Sanders]

Normally C of G is well ahead of C of P, and the tail pushes down.

People seem concerned with C of G aft of the C of P.

Dumb question: is there anyone here who has ever
intentionally configured a (non-canard, conventional
tail) aircraft with the C of G perfectly aligned with the
C of P in straight and level flight, and actually taken
off and gone flying?

This seems to be a reasonable question. What were
the flying characteristics like? Did you stall it? Did you
spin it? What were the recovery characteristics?

Again, I know Denker is God, praise be to Denker, but
as I said before, some combination of chalk and stick
might be best.

I know a woman called Kathy Jaffe that did some
experimentation with this, and she died on her first
flight. I'm interested in hearing about other people's
experiences.

[photofly]

I've been through all the equations and maths that are used to determine when an airplane is in balance, and when an airplane will be stable. From several authoritative sources, university aerodynamics textbooks and course notes both in print and online. This is the mathematics that people who learn to design aircraft study. Including how check in theory whether an aircraft can maintain trim, how big the control forces are and in which direction. As PilotDAR knows, it's not a fluke that a certified aircraft is "flyable" and it's easy to get it wrong, with scary consequences in the air.

There's nothing in any text or theory to suggest that a lifting tail isn't possible. None of the equations actually care which direction the tail force goes; which is why I had to derive my own expression for it. If it was a significant parameter I'd expect it to be mentioned in the authoritative works.

So if it's not actually forbidden, does it happen?

Sure: canard aircraft are subject to exactly the same set of stability equations as a conventional airplanes: it's just that the wing at the back is now bigger than the wing at the front. I note Strega's claim that canard aircraft handle differently but it's the first time I've heard that claim, in respect of stable flight, (not in ground effect or other special circumstances). As far as I know, if an aircraft has a canard it's still trimmable, exhibits pitch stability while the cg is in bounds, pitches up when you pull on the yoke etc. If he can say more about the differences I'd like to hear.

Does it happen in the C182?

I think so. If some strings on the tail plane will give a definitive answer I'll be able to check.

Does it matter what we teach (or are taught)?

In my opinion, kind-of. Clearly it doesn't make any practical difference; half the pilots in the world seem to believe one thing, and half the other. As far as I know, no TSB accident report cites the pilot's ignorance as to the direction of his or her tail force as a contributing factor. But I'd like to think that when I learn something, if its not the full technical detail then at least it's not actually wrong. As far as I can determine, a belief that an airplane is unstable if the tail lifts is just incorrect.

[photofly]

Normally C of G is well ahead of C of P, and the tail pushes down.

People seem concerned with C of G aft of the C of P.

Dumb question: is there anyone here who has ever
intentionally configured a (non-canard, conventional
tail) aircraft with the C of G perfectly aligned with the
C of P in straight and level flight, and actually taken
off and gone flying?

This seems to be a reasonable question. What were
the flying characteristics like? Did you stall it? Did you
spin it? What were the recovery characteristics?

Given that the cp wanders about as the airspeed varies, and to find the predicted position you have to do exactly the maths I did above (which is not complex, but not included in any pilot training that I know of) I think it's unlikely anyone has cared to check.

There's no change in handling or stall characteristics associated with it and no reason to know or care. In fact the centre of pressure isn't really mentioned in any serious aerodynamics textbook or course note that I can find. It's just not important.

The points we are actually interested in knowing about, with respect to the cg (even if we don't know it) are called the stick-fixed and stick-free neutral points. Run the cg past the stick fixed neutral point and you are unlikely to live. A great deal of attention is paid to the neutral points in the literature, and by test pilots. There are special methods to measure their location (in the air) by adjust the cg towards them but without exceeding them. Nobody gives a hoot about the cp.

[Colonel Sanders]

if an aircraft has a canard it's still trimmable, exhibits pitch stability while the cg is in bounds, pitches up when you pull on the yoke etc

A few years back, canard aircraft were very fashionable
with homebuilt aircraft (and have since nearly disappeared).

Anyways, the idea was that as the AOA increase, the canard
was rigged to stall before the wing, so that the nose would
drop, and you could recover nicely from the stall.

Except it didn't work out that way. Canard aircraft - I remember
on in particular, the Velocity - occasionally suffered from what
was referred to as a "deep stall". No comment on the technical
correctness of the name - that's just what it was called. The
canard aircraft would stall and could not be recovered. They
came down like a manhole cover. All sorts of discusssion worthy
of AvCan ensued, people bolted aircraft to the roofs of their
cars at different AOA and drove around town, etc. What
the resolution was, I can't really recall. Might be around 20
years ago, thinking about it.

the direction of his or her tail force

I posted a couple of long-forgotten pictures a few pages
back. I don't think there were any errors. It showed that
under positive G in straight and level flight, with a forward
C of G, the tail was pushing down (relative to the pilot).
And under negative G, in straight and level flight, the same
airraft with the same C of G, the tail was pushing up (relative
to the pilot).

Absent of any errors, I believe that shows that a conventional
tail can either push "down" or "up" relative to the pilot's
frame of reference.

What I am interested in, is people flying around with the C of G
perfectly balanced with the C of P. Should be a pretty fast way
of getting someplace, because the tail is incurring minimum drag.
And, if C of G is allowed to be either ahead or behind of the C
of P, then it's a perfectly valid configuration.

[photofly]

What I am interested in, is people flying around with the C of G
perfectly balanced with the C of P. Should be a pretty fast way
of getting someplace, because the tail is incurring minimum drag.

A simple symmetry argument will tell you that the minimum overall drag is actually with the cg some distance aft of the cp, not at the cp. Do you want me to make the case?

[Colonel Sanders]

Sure, but I'd really like to hear from people that have
intentionally loaded their aircraft with a C of G aligned
with their C of P, and then gone flying.

I think it's a valid configuration and hence question, even
if no one is interested in the location of the C of P any more.

Last person I know that tried this died on her first
flight. I'm really interested in hearing about other
people's experiences.

[photofly]

Sure, but I'd really like to hear from people that have
intentionally loaded their aircraft with a C of G aligned
with their C of P, and then gone flying.

Well, for a given aircraft loading you could only achieve it at a single airspeed: and here's how you'd do it: Merely go flying with a relatively rearward cg then fly slow and trim back until the tailplane is flying with zero angle of attack. To move your cp back and forth just fly faster and slower. If you want to judge it just right, put tufts on the tailplane and trim forwards until the tail vortices stop. You won't notice any difference in the flying characteristics.

As for someone dying trying this: if the aircraft approved cg envelope doesn't permit the cg to go rearwards of the cp for any airspeed then you can't do the experiment without loading the aircraft out of limits.

EDIT: had this the wrong way round to start with

[photofly]

A simple symmetry argument will tell you that the minimum overall drag is actually with the cg some distance aft of the cp, not at the cp. Do you want me to make the case?

I have a sneaky suspicion that (under certain circumstances) the condition for minimum total induced drag is actually the same condition for neutral pitch stability. i.e. cg at the neutral point. Not something you want to achieve. That would be a neat result. I'll check later.

[Big Pistons Forever]

Early in my flying career I flew a Freighter short body Ho for a courier company. One day the airplane was miss loaded due to some incorrect weight numbers on some heavy boxes. Those boxes wound up in the back of the aircraft. The result was the aircraft was in a totally stick free state. If required effectively no pressure to move the elevator and the pitch attitude would not stay steady on its own and I had to continually adjust the elevator with small slow movements to hold the aircraft in a steady attitude. I declared an emergency, completed a very careful circuit and landed flaps up. A post flight calculation of the C of G showed it was about 2 inches aft of the aft limit. I figure if it was an inch further aft I would not be here today.

From a flight training perspective I don't really care whether the tail pushes up or down but understanding the relationship between C of G and stability and to know the expected changes in aircraft handling characteristics with changes in C of G is a very important thing for students to know.

[LousyFisherman]

PF... I'll try and get some time to sit down.. Ive been busy the last few days.. we have been td ing a well for the last 5 days...

Your jiggy must be loving it

LF

[crazy_aviator]

The deep stall that you mentionrd CS is actually the main wing entering into a stall . All canard aircraft are designed so that the fwd canard stalls well before the main wing nears stalling angle. when the canard stalls , the nose drops, the canard unstalls and life is back to normal. the main wing looses lift and it feels like it is stalling when the canard stalls but that is NOT the case. I demonstrated this canard stall bobble in a full circuit by using full power and pulling near full aft stick, thereby stalling the "aircraft" all the way around the circuit, this was in a quickie ,,, i suggest you test at altitude first
Full and abrupt stick pull on a test flt with parachute demonstrates that i could not bring the main wing into stall before the canard lift loss and c of g reduced the aoa on the main wing.

[crazy_aviator]

Ive had the misfortune of demonstrating a C-185 with an excessive aft c of g Controllability was marginal and turbulence would induce pio due to overcontrol, and large pitch control movements. i credit this to the tailplane transitioning from tail down force to tail up force. Dont do this at home folks stay within the c of g range ( remember as you transition there is NO control effectiveness ) The last 2 examples were well into my past and i dont do the test pilot stuff anymore

[photofly]

i credit this to the tailplane transitioning from tail down force to tail up force.

You'd be wrong if you did.

The result was the aircraft was in a totally stick free state. If required effectively no pressure to move the elevator and the pitch attitude would not stay steady on its own and I had to continually adjust the elevator with small slow movements to hold the aircraft in a steady attitude.

You had a cg that was approaching the stick-free neutral point. Your stick-free static margin was zero, or close to it. That means that the control force gradient goes to zero, and if you take your hands off the stick the aircraft won't maintain a pitch attitude, which is exactly what you're describing.

But note that if you were able to hold the yoke in a fixed position, the aircraft would maintain a fixed pitch. And small adjustments to the yoke position enabled you to make small adjustments to the attitude. The aircraft was still flyable, albeit requiring continous concentration.

Aft of the stick-free neutral point is the stick-fixed neutral point. If the cg goes aft of the stick-fixed neutral point the airplane is no longer stable under any circumstances. Even small adjustments to the yoke position will cause the nose to pitch up or down in an uncontrollable manner.

None of which has anything whatsoever to do with the direction of the force provided by the tail.

Here's a professor from the IIT Madras on the subject of stability.
http://www.youtube.com/watch?v=LLPtUTQOqYg - from about 15 minutes in.

The whole analysis is done from the point of view of having positive lift on the tail.

What's fascinating is that towards the end of the lecture, he looks at the forward limit of the cg. He explains that as the cg goes forward the lift on the tail goes negative and explains why having negative lift on the tail is undesirable. He says, (37:25) "Would you want such an airplane?" (38:07) "The performance of the aircraft will go down... negative lift ... [the wing] has to compensate for it.... And what is the problem that is going to come...? (38:39) High wing loading. And that's going to have a bad effect on the health of the wing."

[PilotDAR]

So in my effort to either understand or refute this really hard to accept concept, I'm trying to relate it to the real world of flying planes. It does not relate for me yet...

Leaving for the moment the non compliant aircraft I measured and charted, I'm considering all of the flying boats, and most of the floatplanes I have flown. Let's say I'm beginning a takeoff at the aft C of G limit. It is optimum to begin the takeoff with the control full pitch up, to get on the step. I'm sure that everyone would agree that the tail is pushing down at that point.

At some point along the way, I'm going to push the controls well or full forward. This application of controls is resulting in the tail lifting - no doubt. I am so certain of this, because my Taildragger requires a nose down control input to lift the tail off the runway during takeoff, so it's lifting.

So the plane is accelerating on the water, with the control being held full nose down for a short time. Obviously, this cannot go on for long, or the floatplane is going nose over. So, I relax the push force. Now, the tail is not lifting anymore.

Now, so far, I'm not talking about hinge moments, or stick fixed or free forces, I'm talking about which way the plane is pitching because of which way the tail is forcing it. I'm using the pitch control to lower or lift the tail as I require, to manage the pitch attitude, and thus the takeoff.

But now, I have a plane splashing along the water in the desired pitch attitude. I also have no pitch control force applied or fed back - everything seems to be balanced. I'm prepared to believe that the tail is neither lifting or downforcing at this point, because, with control inputs, I can make it do either. I don't have numbers or formulas to describe this condition, you're just going to have to believe me - this is the way it is.

Now because of the changing balance point under the hull (the water center of pressure moving back and forth a little), the plane is going to pitch. It is certainly negatively stable now, and will go divergent with very bad results. A careless pilot will aggravate it with PIO. So the pilot is going to have to apply control to maintain the required pitch attitude. This is GOING to require a pull force, though could require a quick "check forward" before that point. In between the necessary pull force, and the possibly necessary check forward push force, there is a very definite "null zone" of control force.

It IS this null zone with is to a large degree a causal factor in PIO. The pilot applies a control input, expecting to both "feel" the build up of force, and "see" the resulting pitch change. But the pilot's patience waiting for these feedbacks is inadequate and the pilot applies more control input to get a reaction. Then, it's too much, and the pilot corrects - again, through the null zone, and over corrects the opposite direction. The PIO is underway.

During all of this, neither the trim, or C of G has changed, and the angle of incidence of the tail (negative 3 degrees to the fuselage, and even more to the wing) assures that if the elevator is trailing, the whole tail IS providing a down force.

So if I check forward, I'm going to lift the tail momentarily to maintain pitch attitude. Tail lifting load, I'm sure. But, a pull force will thereafter be required to maintain pitch attitude, and a greater pull to lift off.

So I think that an elevator trimmed for trail, on a horizontal stab with a 3 degree negative angle of incidence, will not be applying a lifting force on the tail - ever. Yes, with full nose down control input, the tail is lifting. I know it is during a runway takeoff when I lift the tail well before flying speed. I know that there is a null zone between tail lifting, and tail downloading. I pass through that null zone very quickly during a runway takeoff, and much less crisply during a water takeoff.

I believe that I can tell (assuming the trim selected to the "takeoff" mid point position) if the tail is generally lifting, or applying a down force, based on the control force which may be being applied. No control force (null zone) means very slight tail downforce, due to negative angle of incidence, and no elevator displacement to overcome it. Pull force will always mean more downforce - never a lift of the tail, and a push force will transition from a slight downforce to an upforce at some point of displacement, which the pilot will not know. The pilot just knows that with "lots" of nose down control, the tail chordline has overcome its negative angle of incidence, and is now lifting.

I believe that a null zone in flight control force is non compliant, and therefore not a feature of a certified plane. It conflicts with the control force slope vs speed requirements. But, again, I cannot cite math to support my point, only flying experience, and the concurrence of two test pilots and a retired aerodynamicist.

My observations about the handling of a 182 floatplane are extremely similar o what I have described in the foregoing. It is these observations I have made over the years, which causes me to be confident that in stable flight, conventional tails don't lift.

Though I'll be darned if I can find it, I know that I did have a paper copy of Cessna's stated angle of incidence of all 100 and 200 series fixed stabilizers, and they were all negative, ranging form 1.5 negative degrees to more. If I find that page, I will certainly post it.

I will be interested in a possible alternate consideration of the pitch forces and tail loads associate with water and taildragger takeoffs...

[Colonel Sanders]

taildragger takeoffs

I think that it's pretty obvious that during a taildragger
takeoff with the mains supporting the weight of the
aircraft, with sufficient power and forward stick you
can raise the tail before you even start moving.

Obviously the tail is providing "upwards" lift - relative
to the pilot's frame of reference - at that point.

Watch this video and try to tell me that the tail isn't
providing upwards lift during both takeoff and landing:



As you may have surmised from my previous posts,
it is the transition between the two that interests me,
because I really don't think the aircraft would have
very good flight characteristics with the tail providing
NO up down or up force.

Since nobody notices that, therefore it must occur
rapidly (or not at all).

I keep dropping hint after hint but ...

I have provided pictures with vectors of an aircraft
in upright straight and level flight, where the tail is
pushing "down" relative to the pilot.

And where the aircraft is in inverted straight and level
flight, where the tail is pushing "up" relative to the pilot.


Now I want to to consider something theoretically
impossible, according to some people: sustained
knife edge flight. I will happily demonstrate that it
is indeed possible (a little more stick than chalk).
Biggest problem is oil pressure with the crappy 801
wet sump system.

During sustained knife edge flight, the wings are
providing NO lift:

http://i.imgur.com/rZtOXMx.jpg

Similarly, the horizontal stab and elevator is not used
to produce an "upwards" or "downwards" force in
the conventional sense. You can use to move "right"
or "left", viewed from above, and that's about all.

Obviously the vertical fin and rudder is providing
either "up" or "down" lift, and I can assure you that
you have a bootful up top rudder in, trying to keep
the nose up. Pretty clearly to me in this configuration,
the "tail" as you might call it, is providing downforce,
relative to an external frame of reference - just as
in normal straight and level flight!

Given that the C of G hasn't changed (why would it),
what does that say about the C of P and the production
of lift? Talk to me about the wing area involved, and
the associated coefficient of lift, and the "clean wing"
concept.