@ChiChiWerx Well, i still make them) Just because they do still affect the game (for example drag increase is really noticeable) and because they make models look a lot better. Here s the latest for example: https://www.simpleplanes.com/a/E3O7xD/017-cv-880-0-4

i would have done with flaps.

X-plane is a hardcore flightsim, a competitor for MSFS. it's very realistic and instead of having the statistical model of a plane aerodynamics, it takes it as a body and actually dynamically calculate the airflow around the model, like a virtual wingtunnel, it actually gives the realistic effect of flaps and slats. Unity which is the engine simple planes use, can do the same by default. But this is not used in game, the calculate the wing's lift as a simple function of area, angle of attack and speed, thats it.

I've tried connecting flaps and stab, but it is very difficult to tune ingame, because the relation is not linear, it debends on at least the airspeed, not mentioning angle of attack and thrust. In real planes that is calculated by a flight computer or at least some kind of analog calculator

@vonhubert yes, totally agree. In fact, I'm trying to decide whether or not to add flaps to my current build (the one you helped me with), I'm not sure it's worth the effort even though the real-life counterpart had them, what do you think? Also, if what mean when you say "X-plane", you mean real life aircraft undergoing flight testing, If you are correct, experimental and prototype aircraft these days undergo extensive computer and wind tunnel testing, even after all the design calculations, gone are the bad old days when the pilot wasn't sure if the machine would actually fly or not and the spectacular accidents which sometimes resulted.

@ChiChiWerx it is still of no practical use ingame unfortunately. The planes still lift of almost just as good without flaps (at most i've seen 5-10 mph difference in take off speed). I've made lots of tests - both on a flying boat and on my normal tu-124 plane. The latter case - i've used Gyrococpit on high power settings to hold my plane always on the same angle of attack on the take off, gyro cockpit eliminated the difference in that how easy it is to pitch the nose up. And yes, flaps add a bit of a lift. But definitely less than real slotted flaps. They simply omit that sloted flaps normalise the air flow behing the flap and curve the whole airflow of the wing down, which not only increase lift, but also delays stall. Obviously, flaps that are just small separate wings, as they are seen by the game, have no effect on stall, at least the positive one. I wish that the dev switch to the real airflow calculations, as Unity actually allows... BTW, X-plane works that way, they really calculate the airflow around the whole plane regarding its shape and current configuration

@vonhubert even flaps on straight wing aircraft (the U-2 has a very noticeable nose down pitch movement when extending the flaps) can cause pitch changes; considering the flap-slab interconnect systems on newer aircraft, yeah, the T-38 has that system (the U-2 does not, lots of manual trim change required), in fact failure of that system with flaps extended causes an abrupt pitch up which must be arrested with aggressive full forward stick "within 3 seconds" is what the Dash-1 states. I've noticed the pitch change, but not the lift increase...but that's interesting that you've noticed it. I will have to re-attempt a flapped build to see if I can reproduce the lift increase...up to this point, I had decided it just wasn't worth the effort. Now that you ALSO have me thinking about the whole pitch change thing, I'm going to have to build something with a flap-slab interconnect system...hmmm....

@ChiChiWerx Well, Flaps actually do cause lift increase in SP, but less then real due to simplified calculations (they treat flaps as a small separate wing at high angle of attack, omiting the overall aerodynamic effects.) I've noticed that when playing with my flying boat, when you deploy flaps it notisably rises from the water and start gaining speed. And flaps on real planes, especially with high swept angle, do really pitch the plane down at the same time. That is usually corrected by stabiliser adjustment on most planes even from 1960s

Here ya go)
https://www.simpleplanes.com/a/eyd2jU/Aircraft66EdvH

i think i can. Despite increasing lift, flaps actually pitch down the plane in real life. this works here too. To make it take off easer - you can move CoG back to make it pitch up easier. Also, your horisontal stabiliser is obviously too small, thus it is possible that it is not effective enough to pitch up on the ground, when CoG is too far forward of main landing gear. is it adjustae? Also you can lenthen the front gear to make it stay slightly up forward on the ground. Or i can fix it this weekend. I've already been through that problem with my tu-134)

The tail (horizontal stab) appears to be too small, increasing its size, and that of the elevator, would help get the nose up on takeoff at lower speeds. Also, flaps don't work the same way in SP as they work in real life...they don't really cause a lift increase, but they do cause a pitch change, often nose down. But...yeah...I would try and make the horizontal stab larger because it definitely looks too small. Hope that works because it's a really nice looking build so far.

Remove all fuel and deadweight from the fuselage blocks, then when you get to 350mph push the VTOL down. Use a long runway, preferably Yeager Airport.

Heavy cause it hard to lift up, Lighten your front airplane it may help you out.