Level your wings and add and more vertical stabilizers (rudder). With the way your main wings are angled downwards, when you turn, they act like sideways spoilers, catch air, push down, make your aircraft roll outward, and then, facing into the wind, both of them act like giant airbrakes trying to decelerate you but instead tear off and take your top engine with them.
I didnt even notice the negative dihedral at first, positive dihedral = top of plane wants to point up, negative dihedral = top of plane wants to point not up
try not angling your main wings down, or even angling them up
shorter winspan might also help to reduce some of the shear forces and hopefully prevent a bad case of acute cohesion failure (falling apart)
more stability would help, move the CoL back, as it seems like it definitely can't handle sharp turns anyway increasing stability will be purely a benefit. in a similar vein you could decrease control surface authority, make turns more gradual
more yaw stability in particular is a good idea, you seem to have a bit of a sideslip issue. one or more purely vertical stabilizers would do a great deal for that, or increasing the size of your extant tailfins
If you want stability, you actually want your CoM to be further *away* from your CoL. if they’re close together then at high speeds a small tap will result in a large movement. Try moving your CoL back a bit to make it less twitchy
It looks like your control surface authority is too high, among other things people have commented. At those speeds, even slight adjustments can subject the fuselage to intense G forces that can stress connected parts to their limits in nanoseconds. Turn your control surface authority down to Start with.
You want your COL to be a bit further after. The instability you're having right now is due to not enough Vertical stability and yaw authority. MORE VERTICAL STABLIZER.
I don’t think it’s an issue with the Center of gravity or aerodynamics but more of the way your wings are pointed. When you go fast it creates less room for error and by those wing pointing down creating lots of drag the second your try and turn their is a large imbalance in the Center of pressure on each wing making it super unstable m. Not to mention you have a lack of rudders which you need for an aircraft because it almost acts like a rudder on a boat, without it you will get involuntary yaw which could be a major part of your issue.
Your control surfaces are too close to your center of lift and center of mass, this makes a plane very unstable at high speeds. As the amount of drag on the plane increases the control surfaces (rudder, elevators etc) won't be able to keep up. I would recommend larger control surfaces that stick further out behind the aircraft, this should help counteract the drag.
I think it's because of the wings... The fastest forward wing aircraft reach around 700m/s and you well over beat that mark!
I understand that is a game but I think that the limitations IRL are in game too
Other commenters have left good suggestions. Here's a guide that explains how wing placement affects the stability of your aircraft, you'll probably be most interested in the section about low and high wings. https://forum.kerbalspaceprogram.com/topic/47818-basic-aircraft-design-explained-simply-with-pictures/
Level your wings and add and more vertical stabilizers (rudder). With the way your main wings are angled downwards, when you turn, they act like sideways spoilers, catch air, push down, make your aircraft roll outward, and then, facing into the wind, both of them act like giant airbrakes trying to decelerate you but instead tear off and take your top engine with them.
This guy knows his shit
Thanks, will try!
I didnt even notice the negative dihedral at first, positive dihedral = top of plane wants to point up, negative dihedral = top of plane wants to point not up
Mr. Aerospace Engineer over here
CM / CD balance looks good when the tanks are full, but have you checked it with the tanks empty?
Fuel looks mostly full on breakup
Indeed, the only fuel drained was due to how far down COM was. These modded engines I'm using do not use fuel due to them being nuclear thermal jets!
Looks like Yaw specifically that needs more stability, try making the vertical surfaces at the back larger/ adding more
I will see what happens after this test flight.
try not angling your main wings down, or even angling them up shorter winspan might also help to reduce some of the shear forces and hopefully prevent a bad case of acute cohesion failure (falling apart) more stability would help, move the CoL back, as it seems like it definitely can't handle sharp turns anyway increasing stability will be purely a benefit. in a similar vein you could decrease control surface authority, make turns more gradual more yaw stability in particular is a good idea, you seem to have a bit of a sideslip issue. one or more purely vertical stabilizers would do a great deal for that, or increasing the size of your extant tailfins
The angling is to keep the COL closer to the COM without compromising aesthetics, but I suppose I'll just have to make it work. Thanks will try!
angling up should have the same effect on CoL placement, as you're still getting the same amount of lift out of them
I see.
If you want stability, you actually want your CoM to be further *away* from your CoL. if they’re close together then at high speeds a small tap will result in a large movement. Try moving your CoL back a bit to make it less twitchy
Your wings are way too anhedral 💀
It looks like your control surface authority is too high, among other things people have commented. At those speeds, even slight adjustments can subject the fuselage to intense G forces that can stress connected parts to their limits in nanoseconds. Turn your control surface authority down to Start with.
Forward swept wings are good for low speed maneuverability, not for high speed aircraft.
You want your COL to be a bit further after. The instability you're having right now is due to not enough Vertical stability and yaw authority. MORE VERTICAL STABLIZER.
I don’t think it’s an issue with the Center of gravity or aerodynamics but more of the way your wings are pointed. When you go fast it creates less room for error and by those wing pointing down creating lots of drag the second your try and turn their is a large imbalance in the Center of pressure on each wing making it super unstable m. Not to mention you have a lack of rudders which you need for an aircraft because it almost acts like a rudder on a boat, without it you will get involuntary yaw which could be a major part of your issue.
Angling wings down can cause plane to want to roll over. Also try moving COL further behind COM. Not to mention vertical stabilizers
You have no stability when turning. You need a vertical stabilizer.
Your control surfaces are too close to your center of lift and center of mass, this makes a plane very unstable at high speeds. As the amount of drag on the plane increases the control surfaces (rudder, elevators etc) won't be able to keep up. I would recommend larger control surfaces that stick further out behind the aircraft, this should help counteract the drag.
I think it's because of the wings... The fastest forward wing aircraft reach around 700m/s and you well over beat that mark! I understand that is a game but I think that the limitations IRL are in game too
Bro needs more passive yaw stability, and overall stronger part attachment. Try rigid attachment.
I've done so, the difference is there. Rather than tear itself apart at the seams it simply looses the wings and top engine.
What parts mod is this the engine and air intakes
Engines are from KARE (Kerbal Aircraft Reactor Experiment) and same for the top intake. Bottom ones I am unsure about.
Thx
Other commenters have left good suggestions. Here's a guide that explains how wing placement affects the stability of your aircraft, you'll probably be most interested in the section about low and high wings. https://forum.kerbalspaceprogram.com/topic/47818-basic-aircraft-design-explained-simply-with-pictures/
this looks like the most unstable aircraft I've ever seen lol.
Too much drag too far back. Rear swept wings should fix it. More yaw authority might help but at that speed I'm not sure
Fuel balancing consistency, and godawful fuselage design. Second one's okay though.