Servo to swash link gave up....

[tony stevens]

Is there a chance you have too much travel on your servos, binding up the swash and bending the links?

[Procrastinator]

That was my initial thought, but its set at 12.5+\- which is pretty docile....the servos do not fit the posts cleanly, meaning, the mounts are slightly longer than the servo tabs. My thought is, maybe with these servos, and the 17mm horn, they are at a weird angle...and at full deflection maybe the link is giving up. Compared to other 700 size ball links, avants are rather small, but it doesn't seem to be some widespread problem. I don't want to make it seem like it is, I am just letting people know, that with my setup, and a mechanically perfect helicopter, the ball links are giving up.

[vburge]

It is feasible that different servo’s speed, torque, and geometry along with varying flying styles and environments could cause this issue for only a subset of Mostro owners. My Mostro was pre-owned so I don’t know the exact history, but the links were straight, and before I could maiden it one of the ball links bent. I assume it happened when I powered up the vbar and the servos jumped to position. Lately I have been trying to make sure the collective position is relative to the swash location so there is very little jump at power on. When these very same servos and vbar were on my Trex I had the swash jump occasionally and onetime even popped off a link. However, it never bent one. There are so many outstanding design elements to this heli that I feel ecstatic about this purchase even though I will be substituting the ball links. I definitely don’t want to propagate misinformation about the ball link design. The concept is great and it may not be an issue for most Mostro owners, but my paranoia will not allow me to fly those with confidence and I don’t want to spend a lot of money to prove whether they hold up to my setup and flying style. I won’t “procrastinate” and will get these swopped out pronto.

[helicraze]

It does to me sound like binding somehow. A hardened steel rod needs a lot of force
To snap. If this were an issue across the board we would see this issue constantly

[Procrastinator]

Originally Posted by vburge

It is feasible that different servo’s speed, torque, and geometry along with varying flying styles and environments could cause this issue for only a subset of Mostro owners. My Mostro was pre-owned so I don’t know the exact history, but the links were straight, and before I could maiden it one of the ball links bent. I assume it happened when I powered up the vbar and the servos jumped to position. Lately I have been trying to make sure the collective position is relative to the swash location so there is very little jump at power on. When these very same servos and vbar were on my Trex I had the swash jump occasionally and onetime even popped off a link. However, it never bent one. There are so many outstanding design elements to this heli that I feel ecstatic about this purchase even though I will be substituting the ball links. I definitely don’t want to propagate misinformation about the ball link design. The concept is great and it may not be an issue for most Mostro owners, but my paranoia will not allow me to fly those with confidence and I don’t want to spend a lot of money to prove whether they hold up to my setup and flying style. I won’t “procrastinate” and will get these swopped out pronto.

Haha I let my screen name get the best of me I guess. I orginially had tried to find metal follower arms for it, and never found one I was happy with. On top of it, avant uses a smaller ball joint than some other manufacturers, and didnt want to buy a bunch of different ones only to have them not fit or work right. To be clear to one of the posts before, it was not the threaded rod that bent, it was the actual ball link plastic.

To comment on your issue, I too center the servos before powering up. I run BD units, with a kosmik and ultraguard, and have to center them because kosmik only puts out 5.6v at startup. When running spek sats, sometimes it can be a pain to get it initialized due the Kosmiks low startup voltage. I say this because during startup and preflight checks, everything was fine. I literally spend a minute visually inspecting the heli, as well as function testing the controls. That is why it was surprising to have a failure, as I am super particular about the way things go together, I also think you are right about certain setups, and this not being a widespread problem. The new savox have similiar specs to the mks x8, which are monster servos. I think there is some kind of issue, specific to my setup, which was causing the failures.

[Procrastinator]

Originally Posted by helicraze

It does to me sound like binding somehow. A hardened steel rod needs a lot of force
To snap. If this were an issue across the board we would see this issue constantly

I said it above, but the threaded rod is straight as an arrow.....the link gave at the plastic on the ball joint. I posted a pic earlier in the thread, and have more images of it on the aircraft and after. I have posted them on HF elsewhere, and it won't let me repost again...

[frito169]

Do you have 17 mm between the ball and center of the servo horn?

[Procrastinator]

Originally Posted by frito169

Do you have 17 mm between the ball and center of the servo horn?

Yes, I am using the secraft arms. I did measure the output shaft of the savox servo, and it is 1-2mm closer to the edge of the casing than most of my other servos. In turn, that may make the angle slightly greater at center, but at full deflection it wouldn't make a real difference I would guess as it would mean its more straight up and down?

[jrwalte]

I'm about to finish my build. There has been talk of replacing the ball links with another brand? I am interested in doing this. A few bucks or so isn't worth a small chance of boom strike. What would be a brand that would work?

[frito169]

Quick uk makes excellent links.

[s car go]

I used Mikado and they were perfect. There was no metal rod exposed and they came out to the right length.

[jrwalte]

The logo 600 or 700 ball links? I've measured and don't have a match to either.

Sent from my SCH-I545 using Tapatalk

[s car go]

I used the 600 links. They are longer than the Avant links. They seem stronger than the Avant links.

[Alex M K]

Procrastinator,

thank you for the heads up with this issue, sorry about the troubles you are having.

I am sure these issues will be polished with time, and these are normal things that happen, especially when a new design comes out.

Eventually, we, the end users start coming up with more and more issues, and it is by relaying them to the manufacturer and by posting on forums that the designs improve. I'm in awe by the design and features of this heli. I'm from Europe, and could easily get a SAB, but decided on Avant., so there.

I fully understand your intention of showing what can happen, so it does not happen to others, and I am also fully aware of what you mean when you say "in my configuration".

Other people with other configurations may not have any issues at all, and I can clearly see you that you are not trying to blame Avant for this..that Sir, is a good thing and I take my hat off to you for it.

Its relatively easy to bad mouth a brand, (especially on a forum, where the bravery of being out of range kicks in), and make things can go ugly from there. So your intentions are good in my book.

Now, when I built my other Avant heli, the Aurora90E, (and I know yours is a Mostro), one thing I noticed right away, was how far better than the average the ball links from Avant were, so I was happy with them.

Having said that, as I started building the Aurora, and when I looked at the length of some of the Ridgidcore rods and servo rods push/pull rods on that heli design, I decided to play on the safe side and after talking to Jason Bell, I decided to go with the thick thread rods from Avant (part number AV000127), so I replaced everything with thicker ball links. I know the Mostro does not have any of the long rods the Aurora has, so this is a plus.

not that I care much with what links people use, and fully understand the use of other brands and understand other recommendations for ball links, but why don't you try the thick threaded ones form Avant? I personally find them fas better than everything else, but again...these are choices and tastes and we all are different with regards to that

Thanks and again well done

Alex

[Kepstang]

I noticed that the Avant links formulation has some elasticity to them which is probably desirable within reason at the ball/link connection but at the same time might contribute to a few specific failures at the area between the ball and the end of the threaded rods engagement. I am sure that the heavy links recommendation would make the difference.

I love the Mostro. Being a ME, I can appreciate what has gone into this heli and it will be my next purchase as soon as I sell a couple of Rush 750s that I have. Heck, I might not even wait ..............................

[vburge]

I just got the Mikado 2.5mm ball links #01567 and the ball and threads are too small on the avant. It looks like #0156 are the same size just a fewer quantity. S car go do you have a part number for the ball links you are using?

[frito169]

is it possible 2 or that you may have threaded the one side in so far that it's stressed the plastic causing it to bend more easily?

[vburge]

Just ordered the thick body Avant ball links AV000127. I hope these are as described, just a thicker body with the same thread diameter. Trying to order alternative parts that don't fit is giving me bad Trex flashbacks! It will be great if these thicker Avant links do the trick.

[Procrastinator]

Originally Posted by frito169

is it possible 2 or that you may have threaded the one side in so far that it's stressed the plastic causing it to bend more easily?

The first time? Maybe anything is possible, but with a 14-15mm rod, I had 6mm exposed, and 4mm on one side with 4-5mm on the other. Most of my rods were 16mm, but I had two that were not....one was a little more than 14mm, and the other was 15mm. I personally think the rod should be longer....that way it can fully support the rod instead of sitting in the middle of the plastic. Plus, the last two rebuilds I made sure I took extreme care with the links, making sure I had 16mm rods, and making sure both were threaded in 5mm.

[byter182]

Originally Posted by s car go

I used the 600 links. They are longer than the Avant links. They seem stronger than the Avant links.

There're like 3 or 4 options of Logo 600 parts (http://shop.mikadousa.com/Mikado-Helicopters_c_7.html). Anyway you could provide a part # or a link? Also... Are you using the Logo 600 metal control rod too or did you use the Avant Mostro stock metal control rod w/the Logo 600 plastic ball links?