Stratus Strut bolts .. constantly breaking

[bkervaski]

Anyone else having problems with their Stratus strut bolts constantly breaking? If so, what are you doing to solve it (if anything)

I'm not landing hard, I loose about two a weekend. Easy enough to just pop another in but it's getting old and I'm looking for a solution.

I thought about just drilling the holes a size bigger ...

[WayneBrown]

which end? the ones I've broken were all at the horizontal fin bracket, and I drilled them out to accept a 4mm bolt.

[bkervaski]

I meant landing struts... It seems to be just the forward-right bolt every time... Weird.. I just replace it and go on about my business ... It happens on both of my Stratai/Stratuses, lol

[Dr.Ben]

What kind of motor?

Ben Minor

[bkervaski]

OS91SZ-H PS

Why?

[DavidH]

Been flying the Stratus since August. I have yet to break a 3mm bolt that holds the struts on. I don't do anything special. None of the Team pilots are having bolts breaking that I have seen or heard. . I would be looking for the source of high frequency vibration. The base plate the bolts go thru is about 1/8 inch thick. So I don't believe the base plate is cutting the bolts.

David

[Zilly]

Tim at MA said that most of the team pilots are running 4mm bolts in the landing gear of the Stratus especially when running the SZH he recommended that I do the upgrade anyway even if it was not a problem for me.

z

[heliroller]

I replaced all of mine with 4mm bolts. I broke 2 and decided it was time to switch them out. Also broke a canopy stand off bolt as well. This only happened early on with a new motor during the first 2-3 gallons of break-in. This was with an SZ. After the motor started running better, the heli smoothed out and no more broken bolts. That eliminated the possibility of an out of balance fan..Also, what head speed are you running. That makes a difference as well. Higher head speed was better in my case. 1900ish!

[bkervaski]

Were you able to find 4mm bolts that the cap didn't rub the new tank? If so, do you have a part number and/or vendor?

Thanks. I broke two of them again yesterday. I installed two new motors and made sure my fan runout was less than 2 thou and the fan was nice and balanced. My models have almost no vibration. Really smooth.

[heliroller]

Just stand 4mm bolts. You could grind the edges off to make button head type bolts since you must have the new tank. I did not have that problem as i run the older tank. I don't like the new tank.. What headspeed are you running?

[wjvail]

If I were to guess, I'd say that some stress and miss-alignment has crept into your frames/heli/setup.

I know this is a lot of work but I'd suggest removing the boom, skids and head. Then loosen EVERY bolt holding the frames together. You don't have to take them out, just loosten them. Having done this you should be able to flex and move the chunk of heli in your hand. Now set what's left of the heli on something really flat. I use a Starrett surface plate but anything really flat will do. Now alternately snug up the frame bolts. Start with the engine mounts and bearing blocks then the little stuff. Put it all back together and see if it doesn't run better.

It really isn't as much work as it sounds. I've done it several times over the years and it seems to cure a wide assortment of undetermined problems. Broken bolts, fuel foaming, eating dampers....

Bill Vail

[wjvail]

Any progress here? Still breaking bolts?

Bill Vail

[bkervaski]

I called MA, they said to make sure my tail rotor was balanced. I haven't had a chance to test the theory, I'll rebalance it this week and fly it this weekend and post the results.

[Dr.Ben]

Under 0.002" on the fan isn't really where you should be if that means more than 0.001". While you're working on the model, redial your fan and get the runout to well under 0.001". Just because you can't see the vibration doesn't mean it's not there. I won't bolt an engine in a model unless the fan runout is under 1/2 thou, but then I'm seriously anal (but not breaking any bolts <g>).

Ben Minor

[heliroller]

If MA says to check or re-balance the tail, then I would first look for a vibrating tail unit or see it bobbing a bit. Frankly, I've had run out on my Stratus more than .002 and it is un-detectable in the heli and no ill after effects. I still say, make sure the engine is running as smooth as possible. How is it running. Are you breaking the bolts under heavy loading such as tic tocs, etc? There are still several things that could break bolts. Not to contradict what these folks are saying, but I've chased things like this before and most of the time it comes back to the motor. Especially the SZ. It's as bad as an out of balance fan.

[EricLarson]

I run the stock 3mm.... No issues.

[Wayne]

I started breaking strut bolts when I switched to the OS-SZH engines from the YS-91's. My machines are balanced, and the fuel does not foam or any of that... If everything is balanced, etc, just put in 4 mm bolts. I made mine into "round heads" by putting them in the chuck of my drill press and rounding them off with a dremal grinder when the drill press was on. The other solution which might have been easier would have been to get some from Min Air.

Good luck

wayne hillenbrand