The tails or TVC push the tail down to compensate the nose's downwards moment, rotating it upwards around the CoG.
That is correct, but the tail or engine nozzles weren't developing any lift to begin with... it is just generating a force to maintain aircraft body trim...
The result is an effective reduction of overall available lift as explained.
A couple of problems with this... aircraft lift is not a zero sum game... the consequences of not using tail or engine nozzles to raise the nose will generate a negative angle of attack which will have a much more dramatic effect on lift than any trimming effect they do have to rotate the aircraft on its new cg.
The lift that keeps an aircraft in the air comes from the wing and the fuselage for those aircraft with lifting bodies. The forces applied by control surfaces and moving engine nozzles create very specific forces to turn the aircraft in various ways including roll, yaw, and pitch, and in that sense they often generate a little extra drag, but they are airflow deflectors... not lift generating devices as such.
If your aircraft can only maintain flight with the help of canards lifting at the front you have a shit aircraft design.
Maybe I am missing something, I don't design planes for a living, but as far as I see it is pretty simple.
I don't design them either, but ripping the horizontal tail surfaces or canards off a plane does not lead to loss of lift and rapid descent... it more often leads to loss of control... because that is their primary function.
It is not clear to me what do you mean by "shift angle a few degrees": if you mean shifting "a few degrees" upwards, then it is the situation I am describing and there will be a vertical component of the force pointing downwards, I don't know how to get around that
It goes back to boats and trim. With the propeller horizontal the force it generates pushes the boat horizontally through the water, but water is a very high drag medium. With a very small boat with a big engine, what you can do is angle the propeller so the force does not just push the boat horizontally but it actually pushes down and lifts the boat out of the water. It does not make it fly, but it does make it skim or plane on the surface so there is a lot less drag and returning the prop to horizontal means the boat can go faster for a given amount of power because it does not have to push through as much water.
WTF am I on about... a jet aircraft does not skim water.
You don't design aircraft and neither do I but the shape of an aircraft is absolutely critical to move efficiently through the air. Changing the angle of attack will effect how that aircraft moves through the air... there will be a specific angle of attack for a given speed and altitude where the air flows over the wings and it generates the ideal amount of lift with the minimum level of drag... a 90 degree angle of attack to the flight airflow is essentially being an airbrake... no lift and all drag.
Lets say the ideal AOA for aircraft x flying at airspeed y at altitude z is 8 degrees... you might need a canard deflection of 15 degrees to maintain that, or a tail surface deflection of 15 degrees to do the same. The Canard would be lifting the nose and the tail surface pushing the tail down, but the effect is the same because the engine thrust is angled down 8 degrees and the wing angle of 8 degrees creates the ideal level of lift for that aircraft in that configuration etc etc etc.
As the aircraft approaches and then exceeds the speed of sound the balance of the aircraft changes... the cg moves which causes the nose to drop... if you do nothing you will have problems because you will start to lose altitude for a start... while you are flying through this trans sonic speed range the cg moves but as you keep accelerating it moves back, so the shift and also the countering of the effect is temporary anyway.
During this period of instability you might increase canard deflection to 20 degrees up, or the tail surface to 20 degrees down to maintain the 8 degree aircraft pitch up attitude.
What I am saying is that a 20 degree pitched up or 20 degree pitched down canard or tail surface increases drag and RCS when the aircraft is pitched up a 8 degrees that is an almost 30 degree pitch up angle for the canard, but only a 12 degree pitch down from horizontal for the tail surface, but the nozzles on a thrust vector jet engine have much more control authority than canards and tail surfaces so the ideal low drag angle of attack might not be 8 degrees with TVC... it might only be 4 degrees with the TVC nozzles pitched up 4 degrees in normal flight at that altitude and speed, but the shift in cg it might need a TVC nozzle shift of a further 4 degrees to 8 degrees upwards to counter cg shift until that speed gap is passed through and then it can return to a 4 degree angle up thrust line.
What I am saying is that the engine nozzle pitch angles will be much less to get the same effect but also not really noticeable from the front anyway in terms of IR and RCS factors... and they do their job at any speed including zero forward speed and even negative forward speed in a tail slide.
The canards and tail surfaces can be kept at low drag neutral positions...
It is like talking about super sized HUDs offering the best opportunity for the pilot to keep his eyes outside the plane and not staring at screens in the cockpit, when the obvious solution is really a helmet mounted sight...
Downforce is downforce, a force vector pointing down in the vertical axis, no matter what device created it.
A down force that turns an aerodynamic structure like an aircraft to a nose up attitude increases the lifting performance of the main wing and makes the aircraft climb and not descend... why do you describe it as a loss of lift?
The tails have added drag, the TVC not so much, but drag is not what I am talking about.
Drag and lift are directly related and pretty damn critical if you want efficient long range super cruise.
Having no tail and no canard benefits in terms of drag, but obviously creates risk in terms of loss of control if the TVC fails.
Yes, when I finished with my post I have seen that you two are having an interesting debate, and in my humble opinion both of you have some good and some bad, or should I say somewhat wrong assumptions/conclusions.
Don't hold back
... I have been wrong about plenty of things in the past and I am discussing this not to be right but to compare my view with others to find the truth...
(I am not an engineer so be gentle...)