Marcos_Nieto

Hi guys................In the Funtana 90 instruction manual the ball joint used in the ail push rod is placed on the push rod control horn end. This requires to enlarge to 3/32 one of the connecting holes on the stock control horn to fit the 4-40 ball joint screw. This leaves the apparently weak stock control horn weaker and the extreme surface movement can stress the control horn to its limit. I think this is a mistake and the push rod ball joint should be placed on the push rod servo arm end. I also want to know if you guys are using the stock control hors......
Any comment welcome
Thanks
Marcos

wind junkie

My Feedback: (1)

I did not use the supplied control horns. Instead I used Dubro "giant scale" ones. They are so stiff so It didn't matter which end the ball link goes.

I think guys ARE successfully using the stock horns from what I've read here. I had some high dollar servos in my wings, and didn't want to lose the precision, so I made sure I had a very tight control linkage, and NO twist in the control horns.

I suggest if you do use the supplied horns, that you put the ball link on the servo end as you say, and make sure you use a sturdy servo arm (metal or reinforced pastic). Use just a clevis to the stock horn. That way, the horn will be stronger, and not twist due to an offset ball link.

tande

My Feedback: (48)

Yup!---Flew mine that way all summer---No problem--

famousdave

My Feedback: (61)

The best horns for that plane are the Chip Hyde horns, they are very light (unlike the DuBros) and strong. The stock horns will work, but they are crap. Mine fluttered itself to death due to the combination of the crappy horns, the normal play in ball links, plastic servo arms, and servo gear backlash...


I am sure if the horns were stiffer and I had used metal servo arms I would not have lost the plane.

GS is a lot more fun.. you are forced to use the good stuff by default!
DP

George E.

My Feedback: (16)

I used most of the stock stuff but I put the ball links on the servo arms and the clevis on the control horn. IMO the ball link would apply too much of a twisting force to the control horn since the pushrod is applying its force to the side of the center line of the control horn, ie too much torque on the control horn.

famousdave

My Feedback: (61)

The general rule is to never use ball links at the control horn, so yes, you have that part right. You should not use them on plastic servo arms either for the same reason.

DP

marks90004

Hey Guys,

After reading this thread, I decided to inspect my horns. I'm glad I did.

It's probably my fault, but this was the first time I installed ball linkages and I followed the manual photo.

I had to drill out a bigger hole on the control horn to fit, then I screwed in the ball linkage.

I think I might have screwed it in too tight to the point that the ball and cone parts of the ball linkage mashed the control horn.

The horn was so mashed in that the width from edge of the horn to the hole was the width of a thin wire.

Looking at it today, I'm sure that it would've been just a matter of time before I would've lost the plane.

I'm going with metal servo arms and attaching the ball linkage ends to that.

I least I don't have to worry about squashing the metal arms.

Thanks guys.

Doug Cronkhite

My Feedback: (34)

Balls on the servo, clevis on the horn. This reduces the twisting load on the horn and the possibility of flutter. I used all the stock hardware on my F90 and now have over 230 flights on it without issue.

TOYMAKER

My Feedback: (6)

These are all good ideas.

PUT the ball joint on the servo control arm and take the stand off out of the system. This stand off is not needed and it just puts the ball further away from the control horn contributing to the twisting torque that occurs in this area. If you can or have room or your servo control arm will allow, put the ball on the underside of the control horn.

THROW AWAY the 4-40 metal clevis'. They are junk!!! they are loose and the are prone to vibrating loose even with the lock nut. The first time I
snugged up the lock nut the clevis stripped or moved on the rod. Even when I had a fairly good one there is still slop in the clevis.

DO USE Dubro nylon self threading clevis that has the little lock clip on the side. I have used these on all my 1.40 size ships with never a problem.
The stock control horns are OK if you use this setup. If there is any sideways movement after the clevis is hooked up juse put a #2 washer on the clevis pin and this will tighten it up.

For the ultimate in control horn hookups you could opt to install MK ball bearing clevis. A little pricey but you will never wear one out. They are available through Central Hobbies.

At this point if there is any slop in the linkage it most likely in the servo gears.


WAYNE