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Main Forum - Helicopter Talk R/C Helicopters and the people who fly them. VENDOR TOPICS DO NOT GO HERE. Full Scale Heli threads go in OT please |
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08-19-2008, 10:06 AM | #1 (permalink) |
Join Date: May 2007
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Tail rotor direction - CW vs CCW
450SE rex, 401/9650, DX7, etc.
I'm being told that my tail rotor is rotating the wrong direction (clockwise.) The belt doesn't care, it's half a turn one way or the other. Everything is setup right otherwise w/ gyro and whatnot. I've had 'pros' inspect my setup and no one has ever commented on this. It flys pretty nicely. My skills are improving and I'm flying more aggressively, that and I broke the V1.5 arm on the linkage and 'upgraded' to the V2 tail linkage system. I do have a fairly violent tail wag when the heli gets upset (wind or move or pilot induced) which I'm trying to get out. I've improved it by changing the arm on the tail servo (increased the C-C by 1.75mm, from 7.25 to 9mm) and reducing the gain (85% down to 60% DX7&401) but haven't solved it yet... Does the direction of tail rotor rotation really matter? and if so, why? I want to understand why it would make a difference if it does. |
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08-19-2008, 10:08 AM | #2 (permalink) |
Registered Users
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The tail blades need to turn into the air coming down off of the main blades. It should help get rid of your tail problem.
If the tail is to the left and the canopy is to the right, the tail blades need to turn counter clockwise. |
08-19-2008, 10:15 AM | #3 (permalink) |
Thread Starter
Join Date: May 2007
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So I will need to flip the belt, flip the blades and reverse the gyro, leave the radio alone?
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08-19-2008, 10:26 AM | #4 (permalink) | |
Registered Users
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Quote:
I've never believed this as being the reason, so I played around with it one week. It didn't seem to make a difference on my heli. I was using a 401/9650 combo and I skipped setting up the rate mode and just centered the pitch slider with the servo arm at 90 degrees. I would fly a couple of batteries with it going clockwise, fine tune the gain, and just fly around in my usual style. Then I would pull the tail, twist the belt to turn the blades in the opposite direction, flip the blades around, and then go fly. The only things I ever noticed different was that the gain was never the same in both directions and the pirouette rate would be different in both directions. I'm sure there is a valid reason why they are supposed to go the direction the manufacturers intended them to go, but I don't think it has much to do with prop wash. If you're thinking that your wag might be caused by this, then by all means change it and see what happens. If it fixes it, great. My bets are on a mechanical setup of a different type.
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08-19-2008, 10:27 AM | #5 (permalink) |
Registered Users
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You need to change the belt, but you can leave the tail blades in the grips and just flip the grips, that way they are leading edge.
Leading edge is where the ball link of the grip is on the side of the leading edge of the blades. That is supposed to help also. Not sure about your gyro. I think you can leave that alone, but you might need to turn your servo around. |
08-19-2008, 10:41 AM | #6 (permalink) |
Thread Starter
Join Date: May 2007
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I did the flips, had to reverse the gyro and radio.
seems my grips were 'trailing', and are now 'leading'. Hovers normally, will take it to the field this afternoon and try it. Thanks for the help. I'll update this thread with the results. on another similar note, how important is the 'Chinese weight mod'? |
08-19-2008, 11:09 AM | #7 (permalink) |
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Not sure yet. I'm about to purchase a set of extra tail grips to try the mod. It seems completely sound in theory. I've seen a video somewhere of a guy demonstrating the tail blades moving with and without the mod. He said it was night and day difference between the force it took to move the pitch slider while the tail was spinning.
Anything to save a servo. Or to even extend its life a little. |
08-19-2008, 11:24 AM | #8 (permalink) |
Registered Users
Join Date: Mar 2007
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My 450 and 600s fly really nice inverted. But there is a difference in how well they fly as opposed to upright. It gets alittle more exasperated doing backwards inverted flight. My helis hold very well either way but I'm saying there is a difference and it's not just me on the sticks.
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