Daniel Reese
Senior Heliman
Location: Urbana OH
My Posts This: Topic Forum | Like you, I object to electronic stabilization. For me, it's purely stubborn (ego driven, im sure) belief that if I can fly the real thing with no stabilization, than I can fly the scale thing just the same.
So here's what I got: Trex600E with a Century diamond 30-50 sized 5-blade head. This is my third head by the way. Got the lightning heli V2- piece of crap. Had one custom made for me but it was poorly balanced and proved unfliable too, so now I'm back to a trusted brand name. Go figger.
Anyway, back to gear- I've set this heli up for counter-clockwise rotation (just like the big kids do) and the tail rotor is on the left side (just like the big kids) but other than that, it's a stock TRex...well, there's another change but we'll get to that in a minute.
Phasing is a heck of a lot simpler than the voodoo magic it's sometimes made out to be! All you need to know is 2 things: Concept One and Concept Two.
Concept One: Your swash has two axis' (ax-eez) One is ELEVATOR, the other is AILERON. The ELEVATOR axis pivots the swash forward or backward- the sides dont move. AILERON axis pivots the swash left and right- the front & back dont move.
Concept Two: Whatever input you apply to a rotor blade will cause the rotor disc to react 90* later. If you want the disk to tilt forward, say, down at the 12 O'clock position and up at the 6 O'clock position, the blades will have to change their pitch at the 3 and 9 O'clock positions. That's a toughie and will take a bit to wrap your mind around. It's called gyroscopic precession but dont worry 'bout fancy words or physics. You can prove it by looking at your old 2-blade setup. With a blade over the tail boom, if you give forward cyclic, the front & back of the swash move (up or down depending) which pushes on two links connected to two arms connected to two other arms and eventually to the blades but the blades dont move! Now rotate them around to the sides and give the same input- blades move. That's mechanical phasing for a 2 blade head accomplished with a combination of linkages to washout asseblies and flybar gizmos. We need not bother with proper names for all that junk since you've already swapped it out for the much simpler direct links to a 5-blade head. Cool huh?!
Setting phasing is as simple as connecting the blade you want to move with the part of the swash that is moving. Easy right?
I could tell you exactly how to do the phasing on your bird but I'd have to ask you a bunch of questions first and I dont want to belabor this post too much longer so I'll just give you an example and hope it makes sense.
For the sake of examples, lets assume clockwise rotation, leading edge control of the blade grips (blade grip ball link is in "front" of the blade as it rotates around the axis of the mainmast) and that a FORWARD input from the TX causes the swash plate to tilt down in the front, while a RIGHT input from the TX causes the swash plate to tilt down on the right. A lot of assumptions I know but we need to start somewhere eh'
So, we want the helicopter to go forward when we tell it to- a forward input from the TX causes the front of the swash to drop. Since the blades are spinning clockwise, the blade at the 9 O'clock position is on it's way to the front. So we need to connect it to the front of the swash, to a ball at the 12 O'clock position. To do that you could connect that 9 O'clock blade to any swash ball and loosen the swash follower, twist it til it's at the 12 O'clock position and lock it down. Double check that with a blade at 9 O'clock, with a forward input, that blade's pitch decreases. Now rotate that blade around to 12 O'clock and give that same forward input- the blade should not move at all. If so, the phasing is set! It's that simple. Of course, now you'll have to set all the other grips to the swash in sequence and then fiddle with pitch link length to get the tracking and pitch throws right but the phasing wont change much at all- just fine tune it at that point.
Now, if any one of those assumptions is wrong, let me know and I'll "draw" you a more accurate picture. On second thought, this would be a great subject for a quick YouTube video....
Did this help your phasing confustion at all? |
