I just made a small WWII fighter aircraft (wingspan about 7 meters), and for some reason it has a tendency of suddenly roll for a certain degree.
Strangely, this seems to be related to the jettisoned parts (it has a takeoff dolly and booster rockets which would be separated after takeoff), because if I take off from carrier (causing parts to be dropped into the ocean almost immediately), the jerking movement would disappear earlier.
To make things even more strange, the jerking in roll direction occured before I added those parts, but now it seems that they are related...
I've checked all connections and made sure that none of the jettisoned parts are connected.
Any ideas?
Right now there's only two successful resolutions, one can completely remove the problem and the other can largely reduce the effect.
By dropping the takeoff carriage into water, the jerking is eliminated.
By adding LOTS of weight in wingtips, the jerking is largely reduced.
I even tried to fly a version without a takeoff carriage at all and it still jerks around.
@Nickr I checked, the CoM is slightly in front of CoL.
@vcharng check the center of mass and the center of lift
Because it will do something that sounds similar, where the aircraft will suddenly jerk around, sometimes to the extent that it stalls @vcharng
@Avro683Lancaster I flew it and... not even close.
The plane in question is like 3 times the speed and twice the agility.
I mean in terms of flight characteristics. You can see what I mean if you do a trench run in it for long enough @vcharng
@Avro683Lancaster It's even smaller, like 8m length and 7m wingspan.
I tried a lot of thing and it looks like the problem, at least for now, came from the takeoff dolly/carriage. If you drop it into the ocean during takeoff you'll be fine. If you fly all the way out of the render range, it looks like you'll be fine too. (like dropping the carriage at Wright and fly to Krakabloa)
Is it similar to This?