Originally Posted by OrbitalGolem

Alternatively, you can get BenMLee's slipper clutch. I bought it and am very impressed with its build quality. That being said, it's still in the box - I've been slipper clutch-free ever since I got my first D02S five months ago. I've only had to replace the tail gears or "A" gear three times. Learning how and when to apply throttle hold is very key with this heli. Last night throttle hold is what saved the gears when I got her upside down and applied too little negative pitch, shooting her straight into the grass upside down. I couldn't believe the servos survived too. Throttle hold was applied maybe 10-15 feet above the ground.

Though my luck will likely change when I get that Turbo Ace 815. I doubt throttle hold will allow the blades to slow down enough - I'll be installing the slipper clutch then.

But I wouldn't trust the advice of someone that thinks only having had to replace the "A" gear 3 times is OK when there have been ways to not have any tail gear problems for years now.

My use of slipper clutches go way back to my first 4#6 and 4G6 days. When I was replacing the "A" gear 3 times a night, dam lace curtains kept grabbing the tail.. And replacement gears where getting hard to come by. So had to come up with something..

The LB V2 adjustable one didn't come out till the V120D02 where more control of the slippage was needed.

first crash today.
First flight this morning, during stunt flight mode, the tail boom partially slipped out of the body, pushing the beveled tail gear out of the drive shaft. Lost (NO) tail control.
- lost the tail servo linkage (pushrod), & the tail rocker arm's metal ball link, which probably, still attached to the pushrod.
- But found the tiny tail gear that was keyed to the drive shaft on the runway.
- Everything else are OK & all servos are fine...

Originally Posted by Spyro37

first crash today.
First flight this morning, during stunt flight mode, the tail boom partially slipped out of the body, pushing the beveled tail gear out of the drive shaft. Lost (NO) tail control.
- lost the tail servo linkage (pushrod), & the tail rocker arm's metal ball link, which probably, still attached to the pushrod.
- But found the tiny tail gear that was keyed to the drive shaft on the runway.
- Everything else are OK & all servos are fine...

I have lost 3 or 4 tail servo links with balls on the driveway and have yet to find any of them..

On my maiden flight i put the V120D02S down from about 2 feet into soft grass by turning off the engine. I broke off the lead on the rotorhead, one of the links flew off and one of the balls broke of the swashplate and the little tail gear in the gearhouse lost 5-6 teeth.
I then ordered A LOT of parts as I expected the worst. But since then nothing has broken, and I have crashed it a lot of times and from far higher altitudes and speeds..

(Knock three times on the table )

It was pretty far away when it went in. I got TH just a few feet before it hit the ground. All that grass & it goes down on the hard packed desert. I popped the ail servo loose & lost a link. The slipper clutch seemed to do it's job.

V120D02S Inverted tail in crash (2 min 58 sec)

Rocker arm.
Has anyone used this, looks like it's for 120D02S CNC upgrade?
http://www.wowhobbies.com/hm-4g6-z-0...p-1-1-1-2.aspx

Originally Posted by livonia bob

I have lost 3 or 4 tail servo links with balls on the driveway and have yet to find any of them..

I found a v450 canopy mounting pin in my driveway the other day i was SURE i lost in the field. I don't fly the 450 in the driveway so... weird. but i still have not found any of my rudder rods or ball links either! lol. I'm with you about that 3 tail gears thing too. In the fall all i have to do is fly the v120 in my yard and either by taking off, landing or just flying and a random leaf blows by. I've totally gone though 3 tails gears in a day myself! Granted one oak leaf isn't always enough to do it in. But one oak leaf every other flight will sure have you spinning out quick enough.

Funny enough, i always find lost parts out in the field though.. I crash and walk past a blade grip there, a stopper cap here. My favorite was a WHOLE helicopter i though i lost on a lake bank! The landscapers found it and returned it to me when they saw me flying! lol.

Originally Posted by Spyro37

Rocker arm.
Has anyone used this, looks like it's for 120D02S CNC upgrade?
http://www.wowhobbies.com/hm-4g6-z-0...p-1-1-1-2.aspx

Just my opinion. But don't waste your time on CNC "upgrades" for the v120. For this size and weight plastic actually tends to be a better material because it will bend but return to shape, unlike CNC aluminum. These parts are too small and will probably just bend. Some people have enjoyed the Extreme tail boxes though because of the mounting method used on the boom. But the slipper clutches don't fit exactly the same in those.

I just replaced a main gear, "A" gear, and turned the elevator servo gear 180 degrees after a tooth broke off during a front flip (eerily similar to TucsonFlyer's mishap on 8/13, also leading to my first heli-injury when the little bastard shot at my right arm - scary how sharp these little blades are).

Everything is smooth again and the servo is working well on its "second life". What is baffling me is when I checked the tail adjustment mechanically with 20% rate-hold gyro on the test flight. The tail had been dialed in prior to the repairs with a tiny amount of CCW rotation. I didn't expect the quick CCW spin though after the work was done and I switched to rate hold. I had to tighten the tail rod several turns to get it dialed in again. What is this indicative of? Do I now have more or less main rotor torque/power than before? Can these new parts really have that much of an effect on the mechanical tail adjustment? I'm assuming that I may need to re-check the adjustment as the parts "break in"?

• The original main gear had a few worn teeth
• All gears are fine - no rounding or slipping that I see or feel
• Everything sounds good and she's really smooth when hovering at 100% throttle

Check that your tail servo did not slide back on the boom.

Originally Posted by OrbitalGolem

I just replaced a main gear, "A" gear, and turned the elevator servo gear 180 degrees after a tooth broke off during a front flip (eerily similar to TucsonFlyer's mishap on 8/13, also leading to my first heli-injury when the little bastard shot at my right arm - scary how sharp these little blades are).

Everything is smooth again and the servo is working well on its "second life". What is baffling me is when I checked the tail adjustment mechanically with 20% rate-hold gyro on the test flight. The tail had been dialed in prior to the repairs with a tiny amount of CCW rotation. I didn't expect the quick CCW spin though after the work was done and I switched to rate hold. I had to tighten the tail rod several turns to get it dialed in again. What is this indicative of? Do I now have more or less main rotor torque/power than before? Can these new parts really have that much of an effect on the mechanical tail adjustment? I'm assuming that I may need to re-check the adjustment as the parts "break in"?

• The original main gear had a few worn teeth
• All gears are fine - no rounding or slipping that I see or feel
• Everything sounds good and she's really smooth when hovering at 100% throttle

Originally Posted by dgibbons

Check that your tail servo did not slide back on the boom.

No slippage and the tail servo mounting is still nice and tight. Could the few worn teeth on the original main gear have caused main rotor power loss? Do I have more main rotor power now than before?

OK, thanks.
I just then ordered the stock rocker & tail pushrod from here: http://www.nitroplanes.com/walkerahe...7-rtf-24g.html
I also added a feathering shaft & mainshaft, just in case...

This (U.S.) store have it in stock as well http://helircstore.com/shop/index.ph...product_id=405 , but Nitroplanes is local & I usually get them in 2 days. WOW is out of stock...
- Spyro

Originally Posted by IntegrityHndywrk

Just my opinion. But don't waste your time on CNC "upgrades" for the v120. For this size and weight plastic actually tends to be a better material because it will bend but return to shape, unlike CNC aluminum. These parts are too small and will probably just bend. Some people have enjoyed the Extreme tail boxes though because of the mounting method used on the boom. But the slipper clutches don't fit exactly the same in those.

Finally figured out why I was going through a silly number of tail shaft gears, and always the hard-to-replace one under the main gear:

I had the tail shaft in the wrong way around! It has a longer 'notch' on the end which is supposed to be under the main gear. It seems to fit fine if reversed, but it doesn't go the full length into the gear, making it strip (notched->round) a lot more easily. (yes, I know... I need a slipper clutch!)

Had to replace my rotor head today for the first time... that's a fairly nasty job, isn't it... especially when the screws holding the blade grips strip extremely easily, and the only way to save the blade grips is to cut your way through the old rotor head, so you can grip the shaft with pliers...

Anyway, after a few more repairs my heli is flying smoothly again

The biggest problem that I've got with this heli is that you need a very smooth surface for take-off - smooth enough for the tail fin to slide over and not get stuck in. If the heli is unable to rotate freely (e.g. tail fin digs into carpet), the heli gets very confused, tries to overcompensate, and spins all over the place when the tail fin leaves the ground...

Originally Posted by bluescrn

Finally figured out why I was going through a silly number of tail shaft gears, and always the hard-to-replace one under the main gear:

I had the tail shaft in the wrong way around! It has a longer 'notch' on the end which is supposed to be under the main gear. It seems to fit fine if reversed, but it doesn't go the full length into the gear, making it strip (notched->round) a lot more easily. (yes, I know... I need a slipper clutch!)

Had to replace my rotor head today for the first time... that's a fairly nasty job, isn't it... especially when the screws holding the blade grips strip extremely easily, and the only way to save the blade grips is to cut your way through the old rotor head, so you can grip the shaft with pliers...

Anyway, after a few more repairs my heli is flying smoothly again

The biggest problem that I've got with this heli is that you need a very smooth surface for take-off - smooth enough for the tail fin to slide over and not get stuck in. If the heli is unable to rotate freely (e.g. tail fin digs into carpet), the heli gets very confused, tries to overcompensate, and spins all over the place when the tail fin leaves the ground...

Try punching the throttle a bit more when you lift off so that it lifts off quickly. My landing pad at home is a throw rug and I never have trouble with it lifting off straight and facing the right way. I get a little disoriented if I launch it from a hard surface and it starts spinning

Originally Posted by OrbitalGolem

No slippage and the tail servo mounting is still nice and tight. Could the few worn teeth on the original main gear have caused main rotor power loss? Do I have more main rotor power now than before?

Yes, missing teeth and main gear slipping can cause loss of power to your tail. After replacing them you might get a increase in head speed. Since the tail speed is multiplied by about 4x the head speed, the difference could be very noticeable if the main gear was slipping. I also always keep my tail boom screws loose, so i ALWAYS have to check that the tail box is fully seated on the boom. The servo mounting could slide too but i keep that pressed right up against the air frame so that i just have to shove it forward to check that it's in the right spot. Those screws i keep a little tighter though.

Originally Posted by bluescrn

Finally figured out why I was going through a silly number of tail shaft gears, and always the hard-to-replace one under the main gear:

I had the tail shaft in the wrong way around! It has a longer 'notch' on the end which is supposed to be under the main gear. It seems to fit fine if reversed, but it doesn't go the full length into the gear, making it strip (notched->round) a lot more easily. (yes, I know... I need a slipper clutch!)

Had to replace my rotor head today for the first time... that's a fairly nasty job, isn't it... especially when the screws holding the blade grips strip extremely easily, and the only way to save the blade grips is to cut your way through the old rotor head, so you can grip the shaft with pliers...

Anyway, after a few more repairs my heli is flying smoothly again

The biggest problem that I've got with this heli is that you need a very smooth surface for take-off - smooth enough for the tail fin to slide over and not get stuck in. If the heli is unable to rotate freely (e.g. tail fin digs into carpet), the heli gets very confused, tries to overcompensate, and spins all over the place when the tail fin leaves the ground...

If your stripping screws regularly, It sounds like to me you are not using the right size or a hard enough screw driver. I would get a hardened steel set of 0, 00, and 000 size phillips screw drivers. The little jewlers screw drivers work okay too. But not having a good screw driver handle on them makes it hard to apply down pressure and torque at the same time. I always use thread lock on the metal-on-metal threads and only lightly tighten. YES, even with the v120. But don't use thread lock on the plastic parts, its not needed and could ruin the plastic.

Patients is a virtue. Something i typically have none of. But if you have that problem again. Bust out a soldering iron and let it get hot. Touch the tip to the screw head being careful not to touch the plastic! Let the screw get hot for a second (be mindful it's connected to plastic!) and then try to loosen it. The heat will loosen any thread lock on there and thermal expansion also aids in removal of tightly threaded screws too sometimes.

Also, As orbital mentioned. You should be lifting off rather rapidly once you get your head speed up. Leaving a 3 axis gyro sitting on the ground will give odd feedbacks to the gyro. "Scale" lift offs are not usually recommended. You want to slowly spool the rotor up to get the head speed up and avoid kicking the tail around right off the bat! But once the head speed is up you want to kind of "pop" off the launch pad. WITHOUT using cyclic!!!! This is why it is very important to have your mechanics setup correctly! Because using cyclic before the heli is in the air will also confuse the gyro because there is no motion going on besides the feedback resonance from the landing skids touching the ground. So once you "pop" into the air. All your controls should feel and work normally. If you set up your mechanics right the heli should just lift straight up into the air.

Originally Posted by IntegrityHndywrk

Also, As orbital mentioned. You should be lifting off rather rapidly once you get your head speed up. Leaving a 3 axis gyro sitting on the ground will give odd feedbacks to the gyro. "Scale" lift offs are not usually recommended. You want to slowly spool the rotor up to get the head speed up and avoid kicking the tail around right off the bat! But once the head speed is up you want to kind of "pop" off the launch pad. WITHOUT using cyclic!!!! This is why it is very important to have your mechanics setup correctly! Because using cyclic before the heli is in the air will also confuse the gyro because there is no motion going on besides the feedback resonance from the landing skids touching the ground. So once you "pop" into the air. All your controls should feel and work normally. If you set up your mechanics right the heli should just lift straight up into the air.

Interesting...

I typically take off from my driveway.

I spool up the heli which I have set to not take off in spool-up mode.
Once the blades have reached speed, I roll the cyclic and also give it a left & right move of the rudder before lift-off. I've found doing this "sets" the gyro.
Note that I do all this in perhaps 2-3 seconds, it doesn't take long.

I then throw the switch for flight and give it a bit more throttle and it lifts off nice and smooth, no tilting, rotating, nothing.

Just how I found to do it and it works well for me. YMMV...