slavik

Hi guys,

In the Quick 30 Learner manual it is suggested to use 18-20 mm servo arms for the swashplate servos.

I have got 16.5 mm servo arms with my Futaba servos (S9001) and I am thinking to use them before I get proper ones.

Is there anything that may go wrong with shorter servo arms? Can I somehow compensate shorter arms by adjusting the length of linkage rods?

Any advice is highly appreciated!

tindra

With short servoarms you will not get an 90 degree angle for the linkages between arms and swash. Short servoarms will work but are not optimal. You will get a shorter lift on the swash, reducing the possible pitchangles. For a beginner and first hovering it will work. Look at my longer arms on this picture. To bad you donīt speak swedish since I have a good site about the Learner. My homepage
Lot of pictures!
Peter

slavik

Yes, it's sad I don't speek Swedish, but I think I can get some useful info anyway!

tindra

Slavik.
Pictures says more than a 1000 words. ... You are welcome to send me an email directly if you have any further questions.
Peter

tindra

Are you using an OS50 engine in your Learner? How does it fit? By the way, you must get the collet to fit properly, or else you can not get the hub and clutch setup perfectly. It is very important that the hub is in perfect alignment. If not the heli will vibrate like crazy.

Peter

slavik

Yes, I have OS.50, but It's not installed yet - currently I have sooooo much work and soooo little time for my heli .
I've noticed, however, that OS.50 fits perfectly on .46 mounting plate. Also, I tried to mount fan hub and it seems to fit OK (despite the fact that the upper collet is little-bit wider, at least it has a bevel on the side that goes to the fan hub)

BTW, is it absolutely necessary to balance the hub with highpoint balancer? It seems to be machined so perfectly that it makes me think it's balanced already (I cannot check it though as I don't have a balancer).

cheers,
slavik

tindra

Balancing is not nessecary. But you have to check that the hub is within 0,05mm when rotating it slowly. See earlier picture. This can be a bit tricky and takes a lot of patience. Assemble, check, disassemble, turn the collet a bit, assemble and check again until the hub is aligned with the crankshaft. After this alignment it is time to check the clutch the same way. 0,05mm i max. If not within limits you will have a lot of microvibrations in the heli.
Peter

slavik

Thanks Peter,

Another question: in the manual it is suggested to use red locktite on the fan hub nut. How it is supposed to use locktite when you work with dial-indicator, meaning that you have to constantly screw and unscrew the nut?

tindra

Between each test of alignment I wipe the thread of and apply new Loctite. The Loctite doesnīt harden that fast. Also check that the swashplate is well Loctited together. I know of three guys who have had "swashplate separations" during flight. Even if the swash seems OK, still check it often during the first 10-15 flights. Another costly problem has been the Tail Pitch Assembly. I have broken three of them till I found a cure. It happened when i slightly touched the ground with the tailrotor. I took the TPA apart and rotated the brass bearing 180 degrees. The nut is now on the tailboom side. Check the pic and I think you will understand!

Also check the pulleys for the beltdrive. Both my pulleys where not perfectly round. The centerhole was drilled OK, but the other small holes where drilled about 0,5mm misaligned to the center. This made the belt to "bounce" on the pulley when rotating.
Peter

slavik

Peter,

I've noticed the tail pitch assembly problem. What I did is to place ~6mm long piece of plastic tube on the tail output shaft before sliding the tail pitch slider. Thus, no collision between the slider and lever is possible.

Regarding belt drive pulley gears - mine are off-center also (both). What is the cure for that? Should I replace them?

tindra

Must be replaced or they will create vibrations!
Peter

tindra

I didnīt first understand about the plastic tube thing. But you might have a point there. Will check on my beloved Quick when I come home from work!
Peter