Hover Stability

[p901]

Hirobo Schwiezer 300 3 blade head converted to electric.
2800g Medusa 36mm 810Kv Shulze 32.55
Flightpower 5S 3700mah
MS Composit 515mmCF Headspeed at liftoff 1650rpm 19amps

Question, I see where stiffer blade dampers are sold to increase cyclic
response. Would softer dampers and lower headspeed with a bit more pitch increase the coning angle and therefore lead to greater hover stability?
I understand that too much coning will cause the onset of stability problems in forward flight and windy conditions but I would like to find a way to set the angle on the bench during setup to find a good compromise and improve the hover.
The machine has plenty of cyclic response and authority so a bit more stability in the hover would be preferable.
Servo throws have been changed from 13mm to 16mm and back which only changes the amount of stick throw back at the transmitter, hover sensitivity during flight remains the same.
Anyone have any experience along this line?
Any information will be helpful,
Thank you, andrew

[DarkHorse]

I'm not sure on a heli that size but the tip speed looks a little low for a ~1100mm rotor at 1650 rpm (~200mph tips), can you try a higher head speed? I would think it might have better gyroscopic stability and perform better between 1800 to 1900 rpm (~245mph tips).

I fly a small 560mm 3 blade scale Ecureuil and the hover stability (particularly in a variable breeze) gets a bit hairy at lower rpm's.

[Peter Wales]

Incease the weight of the blades. If you can increase the diameter of the disk as well that will help. The idea is to get as much inertia into the disk as possible to increase the stability.

My much bigger Robbe 300C uses 800mm blades which weigh 300gms each. It flies very nicely with no head gyros.

[p901]

Good evening !

Thanks for the replies!
I modified the damper rubbers by slipping them over a dowel pin which was chucked into the milling machine.
A very light pressure with a cutting bar removed .010" from the outer diameter of the dampers.
Quite interesting to see the amount that the dampers were out of concentric and the amount that they were out of concentric with each other. The dampers originally had .020" interference fit into the blade grips which is now reduced to .010" interference, ( less compression). Tracking is improved.
A bit more pitch to slow the headspeed, (seems contradictory I know), with a bit more coning and the hover is now very stable and predictable with plenty of cyclic authority.
My first point of reference during this setup was with the full diameter damper rubbers, (very hard under compression in the blade grip) and a headspeed of 2,300+. The heli was a handful, very twitchy/sensitive. Got the headspeed to 1,650 and it was much more manageable and even more so with the stock wooden blades, much more gyroscopic intertia apparently.
I have found that the MS Composit, (wider chord) run 1,650 as opposed to the Rotortech which run 1,700, a bit more cyclic response with the higher speed as would be expected.
Now with a bit more pitch, slightly lower headspeed and the slightly increased coning allowed by the reduced diameter dampers the hover is much improved.
Thanks again for the feedback, as I work through these changes I will incorporate the information.
More changes/tweaking, running 1,400 headspeed which has increased the coning a bit, hovers a little nicer now.
Next tweak was to reduce the cyclic servo throw from 16mm to 10mm.
The next move will be to try the 550mm blades to increase the inertia as suggested.
Plenty of cyclic authority.
andrew