Help! Power Pack C linkage stoppers don't fit servo arms

[Flyingshark]

A couple of days ago I started building the FT Spitfire (my second FT plane, and hopefully the first one to fly for more than 10 seconds), and quickly ran into a problem. I thought I'd install the linkage stoppers on the servo arms before I glued the servos in the wing, but I couldn't get the linkage stoppers that came with power pack C to fit in the holes on the servo arms.

It looks to me like the diameter of the stopper (minus the threads) is about 1 1/2 to 2 times the diameter of the hole it needs to fit through.

My questions are:
1) Are there any other servo arms that might fit both the FT 9 gram servos and the linkage stoppers?
2) Will drilling out the hole break the arm?
3) Are there different linkage stoppers I could get that would fit the holes in the servo arm better? (In the build video, David uses some spring-style linkage stoppers, maybe those might work better?)

I'd rather not ditch the idea of linkage stoppers entirely, since on my FT Long-EZ it took me multiple tries to bend the control rods to the right length to be even remotely close to working.

 

[JasonK]

1. don't know
2. When I did this with my 5gram servos from my A pack, it did fine
3. don't know
4. Did you consider putting the linkage stoppers on the control horns instead (you only need them on 1 end - and the control horn end tends to be easier to work with)

 

[dap35]

I carefully drilled out the holes in the servo arm.

 

[Flyingshark]

1. don't know
2. When I did this with my 5gram servos from my A pack, it did fine
3. don't know
4. Did you consider putting the linkage stoppers on the control horns instead (you only need them on 1 end - and the control horn end tends to be easier to work with)

That's good to know that the A pack arms still worked. The two different types of servo arms are probably the same type of plastic, so it also out to work for the power pack C servos.

I'll investigate putting them on the control horns. When I did that on my Long-EZ, it needed a little squeezing to get it in, but that certainly would work better then on the servo arms (without drilling the holes out). I was just trying to do it how Josh and David did in the build video.

 

[sh0sey]

I regularly use drill bits and drill the holes larger to fit. From what I’ve seen of other Flite Testers this seems to be a pretty common practice. Out of a dozen or so servo arms I have yet to break one. I usually start with the smaller drill bits and work my way up to the size the fits the linkage stopper. That way I’m not putting too much strain on the plastic. The plastic seems pretty strong and yet still flexible to accommodate drilling. If you want to practice, use one of the more off shaped servo arms (like the cross) that you wouldn’t ordinarily be using and use it to test drill.

 

[CorsaiRC]

Me too!

 

[CorsaiRC]

Get the drill bit that fits and then smaller ones

 

[Flyingshark]

When I did this with my 5gram servos from my A pack, it did fine

I carefully drilled out the holes in the servo arm.

I regularly use drill bits and drill the holes larger to fit. From what I’ve seen of other Flite Testers this seems to be a pretty common practice. Out of a dozen or so servo arms I have yet to break one. I usually start with the smaller drill bits and work my way up to the size the fits the linkage stopper. That way I’m not putting too much strain on the plastic. The plastic seems pretty strong and yet still flexible to accommodate drilling. If you want to practice, use one of the more off shaped servo arms (like the cross) that you wouldn’t ordinarily be using and use it to test drill.

Get the drill bit that fits and then smaller ones

Sounds like the consensus is to drill the holes out. Any suggestions on how much larger the drill bits should be than the previous one? Or is it just a "use what you have" situation?

 

[sh0sey]

2-3 drill bits total should get the job done, you just want to avoid trying to take all that plastic out at once. You’ll notice at this size if you’re using a good size drill bit, you’ll break through with relative ease. If it’s too big you’ll have some difficulty (especially given the size of the pieces you’re working with). You can literally twist the drill bit using your fingertips to break through. Once I did that and realized I was using the right bit sizes, I moved on to the power drill to speed things up.

Sounds like the consensus is to drill the holes out. Any suggestions on how much larger the drill bits should be than the previous one? Or is it just a "use what you have" situation?

 

[Merv]

+1 on drilling. I’ve used a piece of wire for a drill bit, cut a sharp, pointy, bevel. A proper drill bit works much better, if your bit is slightly to small, use the wire to widen the hole.

I find it much easier to put the linkage on the control surface and a Z bend on the servo.

 

[CorsaiRC]

Z-bends are common and work well!

 

[Flyingshark]

Z-bends are common and work well!

Z-bends do work well, but I had a hard time bending them accurately enough on my Long-EZ. The elevons tended to be slightly up or slightly down in the neutral position. After a couple of tries I had used up most of the wire from the SBK and gave up trying to make it perfect. With a linkage stopper, I'm hoping I will be able to avoid that issue on my Spitfire.

 

[skymaster]

i will have to say mmmm yea just make the hold bigger with a drill bit. do not be afraid to experiment. use your imagination let it fly .