I used 4 of the small bearings from the plastic mixing arms.
8 2mm flat washers.
2 2mm x 16mm socket head cap screws.
2 2mm nuts.
Bearings and washers weigh the same as the steal ball links.

Looks clean, however I'm still not entirely sure I understand the concept behind adding weight to the grips in order to get a better holding tail.
Anyone care to explain the physics behind it?
-Eric

Someone correct me if I am wrong ! The high speed of the rotor creates a great amount of centrifical force which is placed on the blades themselves. This requires the tail servo to use alot of force to change the pitch of the tail blades. By adding the weights, the weights absorb much of that force and allow the servo to more easily move the pitch of the tail blades. This should allow your servo to work more efficient, therefor creating a better holding tail.

10-8

That should increase the load, not decrease it. I thought I read something about it essentially turning the system into a sphere instead of a plane, which is easier to rotate. But it still doesn't make sense.
-Eric

I guess I understand what it is doing, but I am not real good at explaining it! I do know that it works very well!

10-8

So tell us how the flying is different...

Faster tail slides, hurricanes ect.
At least with your version of the mod you don't have to buy a drilling jig as was mentioned on the other forum.

Having my heli: Cool, Having a working heli: Awesome, Having a day to fly: PRICELESS!

wow no drilling needed........

- Let's Fly Guys.....!!!!!

My mod was like KFILLOON's. I did not do any drilling just added some anodized blue lock nuts. I have noticed a great increase in the tail holding. Keep in mind, I am using an align gyro with a 9650 tail servo. The tail had always flown decent, but nothing compared to after I completed the mod.

10-8

[

Here is the mod I did !!

10-8

Experiment on this...... Then it might start to clear up the picture....

Remove the main blades, also the tail blades..... Disconnect the tail control rod from the tail servo.

Now try to spool up, but not too fast yet...... You will notice that the tail grip pitch arm will try to line up with or track the tail rotor plane of rotation, which is also the 0* position of the tail blades. The centrifetal force is slinging the pitch arm of the tail blade grip far as posible from the center of the circular plane of rotation. Move the tail slider so the pitch arm is away again from the plane of rotation, and let it go. The pitch arm will once again track the plane of rotation. Speed up the rotation and play with the tail slider control lever again..... You will notice that the amount of pressure you will feel will be much more the faster the speed of the rotation......

Now this explains why adding weight perpendicular to the pitch arm counteracts the centrifetal force acting on the pitch arm. The "chinese weight" being added will also have its own centrifetal force acting on it. Remember the pitch arm and the chinese weight rotates on the same axis. If the chinese weight will have more force than the pitch arm, as it tries to track the plane of rotation of the tail rotor, the grip will tend to angle towards 90* pitch instead of 0*.

Now if the centrifetal force between the two are balanced now matter what angle of these two opposing forces are from the plane of rotation. The "grip angle" will retain its orientation until you reposition it by moving the tail slider control lever, if this is a perfect world..... Now since none of these, pitch arm or chinese weight, could outdo each other to try to track the plane of rotation, changing the angle of the grip requires less force..... This translates to less torque required an the servo to change the pitch angle of the grip....

It might still be confusing. I know my explanation was still rather vague at its best..... But just try to read it through and it might sink in. You might then be able to explain it much better and concise....

Well I did this mod.... And I could well attest, having done so, I installed s3153 as well and my tail is rock solid as if I had the 9650 on..... But my version is the drill and tap. Well, I drilled and let the link ball screw do the tapping. So no extra spending for drill and tap set tool. It's aluminium, so the screw wouldn't have any problem tapping in........

Anyways there is another centrifetal force resulting from these weight added.... And that is actually a burden being shouldered by tail grip bearing.... That's why I elected to used the drill and tap method..... The further away these added weight from the center of the tail rotor plane of rotation, the faster it travels through space, resulting in greater centrifetal force produced, as the tail rotor rpm increases.......

Bump,

I updated with pictures. Scroll up...

Very nice.

Tail_BoomStrike

Good job.

If the wings are traveling faster than the fuselage, it's probably a helicopter.

Now how mph are the blade tips traveling at 3000 rpm of 325mm blades?

Ignorance is the absence of facts.Stupid is lacking the intellectual capacity to comprehend the fact

250 mph

hi all....
sorry.. i have a question to ask...
are there any diffrent from 2 application that i read above....
1. drill
2. put in the tail blade screw....

thx a lot.....
beacause to drill it very precision.... is very hard for me... hehehehe

- Let's Fly Guys.....!!!!!

I Finally had the chance to test fly the Trex with tail mod today. Unfortunately I only made it out to my back yard for some hovering tests.
The tail now holds very well during fast pitch pumps and full collective climbs.
Also the pirouette rate seems to be slightly quicker in both directions. Using 401 9257.
So far so good.

hi all....
sorry.. i have a question to ask...
are there any diffrent from 2 application that i read above....
1. drill
2. put in the tail blade screw....

thx a lot.....
beacause to drill it very precision.... is very hard for me... hehehehe

Let's Fly Guys...!!!

It doesn't matter what your choice is.... Both will work... You still need to do trial and error BTW. To see how much weight you need..... Honestly, I didn't have any trouble drilling it, using regular hand drill and without using the alignment jig. I did it all freehand.....

so I did the mod using a longer 2mm bolt and some balls on both sides. After I give the tail an imput and it stops it seems to bounce back and forth for a second. Is this what other peoples tails are doing also or should it stop solid? Using a 401 with the 9650. It does feel more solid in the wind but just curious about when it comes to a stop.

Thanks

Tail_BoomStrike - Excellent post. Thanks!