Super-Hornet
Veteran
Location: Singapore
| I recently purchase a HAC's multibladed (5 bladed) head for my TRex450 scale. It is going to replace/use in my MD500E
The packages comes without any user manual at all. Just bubble wrapped.
It comes with everthing from swash plate and above (except blades of course). Including a compatible main shaft.
Visual inspection looks ok. All linkages are already assembled. All screws appeared to be in loctite (green color I think) except there is one linkage ball at the blade grip came loose. The assembled configuration is in leading edge with main rotor spin Clockwise. The linkage from swash to blade grips angle (or phase angle) is NOT in 90Degree. It is around 45Degree. {See picture}
It come with only one swash plate follower/driver linkage {see picture}. It will be good if it is at least 2 (for stronger holding and as well as balance in weight when spinning)
It is a rigid head design where a M4 (or 4mm Allen screw) is use for the spindle/link for the blade grip to hub. {see picture}
The swash plates that come has its inner swash plate a bit smaller than normal TRex450 size. The swash plate design as a flawed/bad design in such a way that the bottom hole for the main shaft way too small diameter. This restrict the maximum tilting angle of swash plate can go before the bottom hole surrounding hit the main shaft. {See picture}
Not happy with the above flaw, I fix whatever I can.
1. Apply new loctite on each blade grip's linkage ball.
2. Widening up the swash plate bottom hole using pen knife and slowly cut the surrounding to make it bigger diameter hole.
3. Also replace the compatible main shaft to Align main shaft. Don't trust their main shaft
Because I going to use it for my MD500E, I reconfigure it to be leading edge when spinning Counterclockwise. I flip all blade grips to 180 and also flip the swash plate linkages. I readjust the phase offset to be in 90Degree as well.
After adjusting the linkages for proper blade tracking, I spin it up. It appeared everthing is in straight line. The hub looks centered and the blade grip to hub are in perfect 90Degree. They done a good job producing a perfect alignment even though their 30/50size multibladed has been badly reviewed due to poor design/manufacturing.
The stability is also there as well. That mean it is possible to fly using this multibladed head without gyro assist BUT remember that flying multibladed is different from flying flybarred+paddles configuration.
Due to it is rigid head (which I don't like), when spinning, when u apply cyclic, the rotor disc try to tilt BUT it cannot tilt due to rigid head. This causes the whole head to shake/vibrate. When u release cyclic/return to neutral, the vibration is gone. The vibration can be visually seen on the swash plate as well. Using flexible blades (ABS) doesn't help reduce/eliminate the vibration as well.
For me, I prefer to fly with cyclic gyros, I also install 2 gyros as well. It is GWS PG-03 that I have for quite a while.
Do a test hover in living round and it appeared to be stable. Test flight outdoor also appeared to be flyable. Due to it has more blades, it is actually more sensitive to wind. Flying in windy condition can easily cause the heli to sudden and frequent drop or increase in altitute. Again, due to rigid head, each time when I apply cyclic, I can see the heli vibrate a with its blades goes out of track...until I release the cyclics.
No happy with the rigid head, I decided to modify it to have some sort of flapping hinges. Bench test spinning and now, there is no vibration/shake when I apply cyclic. The rotor disc tilt as I want it to when apply cyclics. I still in the process of further testing it. If everything runs good, I will then put it back to my MD500E fuselage.
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. It turn out to be much stable than previous configuration.
