Precision(er)Paddle alignment.

[aramsdell]

I've been chasing a nagging vibe on my new Swift AP ship. I had everything balanced and the mains pitches the same and I finally discovered that the paddles were ever so slightly out. I had put my pitch guage on them and thought I was good to go.
Tonight I had a brainstorm. I cut a slot in a piece of balsa and slid it on over the paddle until snug, wedging at the front and back, not in the middle. I ran a small strip of 1/8" balsa above the paddle and parrallel to it. I taped a laser pointer in the groove of the balsa strip and main piece of balsa so it is basically parrallel to the paddle. I made a flybar lock/rest so I could consistantly rotate the head and get the flybar exactly in the same position(up/down).
I put the balsa 'level' over the paddle and turned it on.
15 feet away I put a piece of painters' tape on the wall where the laser was hitting. Swapped to the other paddle noticed a big difference. (at this point it is best to make sure one of the paddles is as level to the rest of the head as you can. When you are done at least both paddles are at the same angle.) There may be a little slop in your head so to be consistant, rotate the paddle gently on the fly bar and stop at the end of the slop in one direction.
Make the mark on the wall with the painters' tape. Change paddles. Move the paddle, to get rid of slop, the same way then note what to do to bring the paddle in line with the other. Pliers and gentle twisting.
I test flew immediately after and what a difference. this method amplifies the size of a protractor type level by about a 1000 times ! Depending on how far away the wall is a degree could be quite a few inches.
It took me longer to type this than it did to make it out of scrap balsa.

[RAV50]

I have been using these on every head I assemble for years - they work great!

http://www.heli-world.com/detail.aspx?ID=1945

[Tomas Ahl]

I have a pair of the K&S paddle gauges (http://www.ronlund.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=heli&Product_Code=KSJ624) where I glued a 30 centimeter (approximately one foot) ruler to each. They give high precision but are not for the weak flybar anymore.

[RAV50]

The first paddle alignment gauges I ever owned were the K&S units (still have them).

But I prefer the Century ones because they have a spring system that clamp the paddles firmly to the blades. The screw pressure system on the K&S ones always seemed to need adjusting.

[dave peers]

sounds pretty good m8
do u have any photos of it in use on a heli
cheers

[jackheli]

I've been using these cheap x-acto clamps for years now with great success. And they double-up by holding things...

http://www.misterart.com/grouppix/280x210/6000/g6320.jpg

[aramsdell]

Rav50, now just tape a laser pointer on top of one of those bad boys.

[RAV50]

I agree aramsdell, A laser pointer would work well. I usually align my paddles as the last step in completing the build of a rotor head, BEFORE mounting onto the mainshaft.

I will first align one paddle (I will call it the master paddle) to the flybar control arms or yoke.

Then, using a flat plate of glass, & two identical wood blocks I will align the other paddle to the first (master paddle) .

I stand each block on their sides on the glass at the appropriate distance to rest midway under each paddle. Then I install the paddle gauges on the paddles, and flip the head inverted. Now by resting the flat top of the gauges on the blocks, I can instantly see how much they are out of alignment. I will hold the top flat part of the paddle gauge that is on the master paddle, flat on its' block. If the other is not properly aligned, it will not be resting flat on its block.

This will show me which way to screw the misaligned paddle.

This method also makes it easy to insure the paddles are also properly aligned to the flybar control arms or flybar control yoke. It is of no use having the paddles aligned to each other, if they are not also properly aligned to the control arms or control yoke.

[dave peers]

i do it the same way as rav 50 although i use proper engineers V blocks on glass m8