X50 - servo fitting

[sargan]

Now starting to put electrics into my X50 (first build) ... and as usual Q's crop up.

As per reccomendations here - I'm using:
3 x DS610 servo for swash
S3152 for Throttle
DS650 Tail

Firstly - The TT X50 manual show all servos fitted with a straight bar - not what comes with servos, I have option of 4 spoke or 6 spoke arms .... is the 4 spoke the choice to use.?


Secondly the manual shows the fitting of servos that does not make immediate sense ... it shows they are mounted by
... screw --> plate --metal bush/rubber mount --- into carbon frame.
http://i771.photobucket.com/albums/x...servomount.jpg
holes in carbon frame are clearance holes ? or do they all lkine up with plastic spacres between the 2 halves of frame ... and they are in fact fitted as per manual shows

[Heliblerk]

Hi

Using Futaba servos, I used the disc as you get a bit more support rather than using arms but arms should be OK. As long as you have opposing arms of the right length you will be OK.
The balls on mine are about 12mm out on each side on the cyclics.

The servo screws thread into the servo mounts built into the model - page 16 on the manual known as servo frame A +B - try putting a screw in and you will see what I mean.

Andy

[Mark_T]

You'll find the horns with 4 arms have holes in the right places.

Don't forget to centre the servos and then rotate the horns and try each of the 4 positions until you find the one that is closest to correct to avoid needing too much sub-trim.

[sargan]

You'll find the horns with 4 arms have holes in the right places.

Don't forget to centre the servos and then rotate the horns and try each of the 4 positions until you find the one that is closest to correct to avoid needing too much sub-trim.

Is there a simple way of knowing where to fit them ? ... or do I just center them now and adjust arm position on servo once I try to fit the links ?

[Mark_T]

Is there a simple way of knowing where to fit them ? ... or do I just center them now and adjust arm position on servo once I try to fit the links ?

No point in fitting the horns until you are fitting the links.

Set a 50% pitch curve on the radio and you'll ensure the collective servos are centred.

[sargan]

OK ... so fit Servos .. but leave off arms for now ?

BTW - is there a knack for fixing the ball mount screws to the arms .... jeez this is fidly

[Mark_T]

BTW - is there a knack for fixing the ball mount screws to the arms .... jeez this is fidly

Yes, use a drill to enlarge the hole just a little so you don't stress the plastic by trying to screw through it. You can get ones just the right size with a knurled top to them for hand use from most model stores.

http://www.fast-lad.co.uk/store/hobb...98-p-5062.html

Next point is you can't fit the balls until you have the arms lined up right as you don't know which arms to fit them to yet ...

[sargan]

Thanks for that I was starting to fit as per the positions down in manual.

BTW ... Do you know diam of that drill, I have loads of drill sets so could use an existing bit

[Mark_T]

I believe it is a #48 size which has no exact metric or imperial equivalent being a little smaller than either 2mm or 5/64ths

[sargan]

I have sets of drills in standard number sizes .. and also Metric in 0.1mm increments.

Anybody out therer got one of these drills and can measure with a vernier ?
a #54 would be 0.055" (1.397mm) betweeen 3/64" and 1/16"

[Mark_T]

A size 48 drill is 0.076 in/1.930 mm

The aim here is to remove enough material from the horn to avoid stressing the plastic while still leaving enough that the screw is not loose in the hole. If you have a 1.9mm drill then I'd suggest using that.

[sargan]

Yep .. have 1.9 .... thnx , I'll use that in a tap wrench ... on less thing to buy .... tool & parts count so far is high, and kit still to go.

Just to look at sequence, is this correct approach:- ...
# fit servo without 'horns'
# create all links to lengths set in maual - but don't fit to servo end
# power up & centre all servos
# fit horn in position that aligns with link end 'hole'
# fit ball to appropriate hole


Will it be obvious what angle the links should be at ? when servos is centre ?

[Mark_T]

The aim is to get the links at 90 degrees to the arms, you may find the links need slight adjustment to fit as not all servos are the same, but you should still have both links equal, do not adjust just one to make it fit.

One trick you can use is to place a set square so it is aligned with the arms on the servo and pointing towards the control arm at the other end of the links, if you have it right, the set square will be pointing directly at the pivot point on the arm.

You may not be able to get the horn exactly spot on so you may need a little sub-trim, but it really should be just a very small amount.