The new metal plates are amazing for perpetual motion flyers based on the rotation feedback thingy I demonstrated numerous times in a variety of patches. The small plates require absolutely zero struts.
So far got it up to 3200m/s, and still going to up that.
I want to see that in action now
Step 1: use the single-kerbal cylinder; the old one in there
Step 2: 8-symmetry plates, radially mounted; add 2 of these, one above the next
Step 3: 8-symmetry small flaps, parallel to the plane of the plates; spam these as much as possible on the plates. When you can't spam any more due to space, keep spamming more, overlapping the existing ones; it works, promise.
Step 4: launch clamp mounted to bottom of kerbal cylinder
Step 5: change craft angle to start out angled partially downwards, then move it high up (to give a little room to fall to gain velocity)
Step 6: launch; do not spin at first, just adjust yaw and pitch angles to level out, you will notice rapidly increasing speed when you use the flaps; aim in a generally upward direction at about 50 m/s, then do very short bursts of spin to accelerate extremely quickly; do not let velocity exceed about 500 m/s below 4k-5k altitude, as the wings will be torn off by floating point errors due to incredibly high spin rates combined with extremely high drag and force vectors. Above about 5k, just hold down spin. Redirecting the direction is a bit shifty, especially at high speeds; a single little tap should do it, but may also just throw you into an uncontrollable spin. Going straight up, you can expect a maximum of a bit under 3km/s by the time you leave atmos, but by going mostly parallel to the ground, you can reach around 3.4km/s with enough flaps, possibly higher.