FlyingWings Venturi FPV Evo II

[Brucey]

Oh I see.

Well I always have it on the inner most hole on the servo and outermost on the elevon.

Hope your testing goes ok

[Coyote]

What's your CG at Brucey ? 185mm ? 

[Brucey]

You mean what was it at! Ha. Yeah I think it was 185 from the leading edge of the wing section, not from the nose

[Coyote]

Cool thanks. Flew miles better today with everything tightened up. By far the best wing I've flown. 

[Brucey]

Good news. Saw your launch video, went off very well.

[iwan_canobi]

Man, that looks like it's packing some serious punch!

[Coyote]

Yeah just a bit :) 100 amps WOT today clocked 110 mph

[Lola]

That is probably the coolest most laid back wing launch I have seen! No stress lol. Nice one.

[Coyote]

After remaking the hinges, stiffening the control linkages, it's still wobbling in pitch. Its really starting to annoy me now as it's spoiling a lot of shots like the one below :

! No longer available

Any idea what is causing it to do this ?

[iwan_canobi]

My Venturi V1 did this and it was one of the reasons I didn't like it, just couldn't get rid of the bobble!

[Billy_boy_2010]

Coyote- can you stick a möbius on the top of the wing facing the elevons and see if you can capture any eleven movement which is causing the bobbing? synch the front and rear cams and you can be certain then.

if it's not the elevons then who knows?! she just seems to be struggling in even slightly turbulent air?!

[Coyote]

It is very odd, looking at iPeels videos of his Venturi his is the same, but Brucey's is not, his is steady and solid in the pitch.

[Loopdreams]

Perhaps some aerodynamic affect that occurs with a particular CG?

[Lola]

Try a touch of downthrust on the motor, you´ll probs need a couple of clicks on the up trim.

[iwan_canobi]

Stumbled across this post from IBCrazy on FPVLab regarding nose bounce, not sure it will help but could be a clue -

"Nose bounce is caused by compression along the CG of the airplane. The foam is quite thin at the CG point and thus if not sparred correctly it will compress. Bowing spars makes the problem worse. This is one thing SBA does that p*sses me off. Bowing a spar is the WORST thing you can do as it causes a torsion in the airframe and weakens it. If you hold and bow a piece of flat carbon and twist it slightly, you will notice it pitches the end up greatly. This is exactly what happens inside the airplane. Since the foam is compromised due to the battery and electronics trays being cut in the center, there is almost nothing to stop this so one it starts to flex along the X axis, the Y-axis begins to oscillate. Adding spars doesn't help since the force is now translated in both axes.

The I-beam style structure works well and is required on the Wyvern and the Chimera or the plane will become unstable (and at high speeds will snap in half). You NEED the I-beam structure. A single spar will flex no matter how thick it is. You need one spar to resist compression and another to resist tension. To do this, they must be stacked with foam in between and plenty of glue to keep them from moving. This is the strongest way to spar a plane."