gmcullan Veteran Location: Southbridge, MA
| Hot off the presses!I should have done this ages ago.
I had the HDX flying like a champ yet again. When, and I swear! All I did was charge the LiPo for another flight. On spool-up the whole heli shook uncontrolably. I couldn't even lift off. I checked everything. All shafts were true, all blades were tracking, and everything was balanced.
Like I've said, when it's right, it's great. But it goes from right to a pile of crap in the blink of an eye.
So I'm sitting there, staring at the darn thing, when it hits me. I have three helis flying with the MicroHeli aluminum main rotor head. Hmmmmmm! So once again I tear down the HDX300. After making a couple of measurements, I made a 92 mm long main shaft. I used injector rod material for this shaft. A 1.5 mm hole was drilled as appropriate to allow the MicroHeli head to be cross-bolted in place. Pitch was adjusted as appropriate. If you've been running the V3 head, remember to reverse the sign of your CCPM collective pitch mix. Raising the swash with the V3 head increases the main blade pitch. With the MicroHeli head, lowering the swash raises the main blade pitch.
So how does it fly? Like an absolute charm. Cyclic response with the MicroHeli is slower than with the V3 head. But it is smooth and stable in flight.
Even though I've experimented with several main shaft configurations, I'm beginning to think that the 3mm shaft is just too long and flexible to adequately handle the mass and rotational forces of the larger V3 head. I've experimented with the V3 head on shafts as short as 95mm. This length restricts the amount of collective and cyclic pitch you can input. About 100mm is about as short as you can go.
I've tried very hard to make the V3 head work consistently. It is so similar to the T-Rex head. Since I've enjoyed such a high level of performance from my T-Rexes, I was hoping for the same out the HDX300 with the V3 head. I might just get there. But right now I just want to fly and I'm tired of chasing problems.
Some of you might wonder how goes the composite main shaft project. Still working on it, the challenge is getting the right alloy tubing. It's a challenge getting seamless tubing of the correct alloy, hardness, and surface finish. I'll get there with it.
Anyway, back to flying!
I'll try to get some photos up by this weekend.
Gerry Cullan, Blade CP, HoneyBee CP2, T-Rex 450 SE & SA, HDX300, MicroHeli Monster |