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Tweaking Shuttle Z-TS

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Old 08-08-2007, 10:07 PM
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ByronF
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Default Tweaking Shuttle Z-TS

I have just completed assembling an old Shuttle Z-TS and fired it up a few times but have a couple of issues I am hoping someone can give me some advice on.

1. Although the OS 32 motor is brand new and a little sluggish from a rich setting (lots of smoke) the tail rotor does not spin when the throttle stick is down and the throttle trim is just over half way. With the engine off when I spin the blades clockwise the tail rotor spins ok. Can't understand why it won't move at low speed. Is this normal?
Do I need to adjust the belt tension - tighter or looser?

2. Frequently (but not always) when I get a fast enough idle to start the tail rotor spinning I get a lot of vibration, but once I get to 1/2 throttle and get the heli into a low hover the vibration goes away. Can't decide whether this is a blade balance issue or related to the belt issue noted above.

Would appreciate any advice to help me get this sorted out.

Thanks
ByronF

PS when I spin the blades by hand the tail rotor spins counter clockwise when viewed from the right side or clockwise when viewed from the left side.
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Old 08-08-2007, 10:51 PM
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Default RE: Tweaking Shuttle Z-TS

Which way does the tail spin? If you look straight at the heli from the right side, the tail rotor should spin counter clockwise, that is the top side spins away from the front. Conversely, the main rotor blades should spin clockwise looking from the top down, my tail rotor doesnt spin when I turn the main rotor by hand as it is free wheeling and mine doesnt have a direct drive to the tail, so it isnt driven by the main rotor during auto rotations. It might be if yours doesnt spin like I described, maybe the tail belt is turned the wrong way. I would also check the beft tension. The belt shouldnt rattle around in the tube. Mine doesnt spin till I have some rpm up as well. Did you balance the main blades? Are they tracking correctly? Where is the vibration at mostly, the head or tail. If your tail rotor shaft is bent it will shake so fast it will appear blurry. Same goes for if the main shaft or feathering spindle is bent, the head will blur.
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Old 08-09-2007, 02:44 PM
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Default RE: Tweaking Shuttle Z-TS

Many heli's will have a vibe on the ground until you reach a reasonable head speed and load on the blades. I think this is from the head not having enough speed to get the blades leading and lagging properly. If it is smooth in a hover, you are golden and don't worry to much about it. I've had a few helis that just shake all over the darn place until I get them up to speed enough to hover...


Belt tension should be fairly taunt but you'll need to check it again after you have flown a few tanks of fuel through the machine because the belt will have to wear in.

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Old 08-09-2007, 08:08 PM
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Default RE: Tweaking Shuttle Z-TS

Thanks Mrclueless and b0gh0s for the advice and assurances. I have double checked and the tail rotor does go counter clockwise when viewed from the right and the blades have been balanced and tracked to the best of my ability but I am still kinda new to this. Anyway put 3 more tanks thru it tonite and very little vibration issue
but the tail rotor still is stubborn until I push the throttle trim up past half way. I think I see what you mean about head speed, now that I have about 8 tanks of fuel thru it the engine is now starting to hold a nice idle and the main blades don't move either unless the trim is over halfway and even then they move slow enough I could stop them by hand.
I checked the belt tension and it seems ok. Got a chance to check the belt tension on another Shuttle and his was looser than mine. But I will keep an eye on it as I put more fuel thru it to see if it loosens up at all.
Tonite I also discovered why a small header tank is a good idea. Near the end of each hover flight the engine really came on and the change in head speed was quite noticeable. I mean really noticeable! The old Shuttle must have climbed 15ft in the blink of an eye. My guessing is that the low level in the tank combined with my unsteady back and forth hovering (thank heaven for HH gyros) introduced air which leaned the engine and caused the big boost in rpm. Gotta get me one of them just to stabilize the fuel flow.
Thanks again to both of you for your advice. If you have any other ideas I would appreciate hearing them.
Byron
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Old 08-09-2007, 08:15 PM
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Default RE: Tweaking Shuttle Z-TS

I have a header tank on mine, wouldnt fly without one.
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