Yaw and pitch control surfaces just fall off.

[Vaporized Steel]

Thus far I created some nice SSTO spacecraft designs. Especially the smaller versions. I'm undertaking the voyage of creating a v1.03 SSTO spacecraft capable of launching a Jumbo tank with docking port with a mainsail attached to LKO.

Everything goes fine up until I reach 800-1100m/s between 15-20km altitude. The problems occurs pretty varied in between those speed and altitude ranges as I tested proper flight profiles.

What happens is that the pitch elevons (attached to steel beams as seen in the picture below) just fall of. Including the Yaw control surface which is directly attached to the tail connector. Both the yaw and the steel beams with the elevons attached are strutted. Both at the base and at the tip.

I don't think the problem is caused by structural stress. Because the plane is pretty balanced. Meaning it maintains AoA without control input at the specified speeds and altitudes. So during a few of the tests I didn't even hit a button and then suddenly they just fell of the aircraft.

Even although I don't know for sure, but does the new heating simulation induce heat from the engines on parts positioned in the wake of the engine exhaust?

If so then it explains why the pitch elevons on the tail fail.

But it doesn't explain why the Yaw control surface also falls off. It isn't positioned in the wake of any engine exhaust.

More notably they always fail at exactly the same time. Which I find very very odd.

Yet it might have something to do with heat anyway, maybe not related to the engines perse.

However it still puzzles me why only those specific control surfaces fail at exactly the same moment and not other parts due to heating damage.

One final note is that when I spoke of the failing pitch elevons on the tail, I exactly mean those on the tail.

The Elevon on the wingtips next to the outer rapier engines does not fail.

Anyway, here is the picture.

[TheMoonRover]

Possible simple solution:

Try turning on the heat and aerodynamics overlays (F11 and F12 respectively in 1.0.2). Any parts highlighted in a bright yellow are on the verge of overheating. Is there a sudden increase in drag (i.e. do the red lines suddenly get longer) when the wings disappear?

Is there anything odd in the flight info screen (F3) or in the debug log?

[Vaporized Steel]

Didn't knew about those usefull info overlays.

It definetely answered my question. The pitch elevons were indicated as bright yellow prior to failure. As for the yaw I cannot understand why it also fails. In the heat readout overlay it just shows red. But I think it's somehow related to the pitch elevon failure. I'll just use more on the wingtips and remove the tail elevons completely and see if that solves the problem.

Thanks for the usefull information.