P901
Heliman
Location: Southwick,MA
| Hirobo Schweizer conversion
Okay, been trying to improve hover stability/quality.
Took the three blade damper rubbers and slid them onto a dowel pin which was chucked in the milling machine. By applying a very light pressure with the cutting bar I was able to turn .010" off the total diameter of the dampers. Interesting to see the amount that the rubbers were out of concentric and out of concentric with each other.
Dampers still have .010 interference fit into the blade grips instead of very tight .020". A bit more pitch to hold the headspeed back with a bit more coning allowed by the resized dampers and the hover is very smooth and predictable with plenty of cyclic authority.
3800g total weight, (with scale floats), dropped ~150g by machining away excess plastic on the frame and cutting the clutch housing down.
Direct drive, no clutch, Schulze control has soft start
(Saved ~100g by not using clutch)
Medusa 36mm 810Kv Schulze 32.55K Medusa 6v 3.5a regulator
Flightpower 5S 20C Spektrum DX6 JR G500T gyro w/Futaba 3010
(Gyro runs fine on 6v which is not recommended by mfg.)
MS Composit 515mm CF MS Composit 90mm CF
Setup is 3.5+ to 7.5+ pitch for beginner
Headspeed at liftoff 1390 (Skytach Optical)
with 21a (AF Whattmeter) Stock 9.625:1 main ratio
BOCA Ceramic bearings
Fabricated motor mount, 6061 T6 also aids as heat sink
Machined frame to allow movement of pinion bearing location in frame to set gear backlash for quiet transmission.
GER Trv adj. = Gyro gain on DX6 set to 30
All Z-bend linkages changed to ball joints.
Head on photo of rotor plane shows ~2 degrees of cone angle with the reduced diameter dampers at 1400rpm headspeed. Original setup at 1 degree cone angle and 1650 rpm made for a "high strung" hover.
Now the hover is much smoother and overall flight more scale like.
P901
andrew
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