Building and Flying Related Boards › miniMax, Hi-Max, and AirBike General Discussions
MickvdsSeptember 22, 2020, 7:01am
Upon joining circuit after a local flight I noticed something flapping in the breeze over my left shoulder and to my surprise I saw my Aileron Connecting Tube disconnected. This certainly raised my heart rate a bit. The plane still had good roll response on the one Aileron and I landed without incident.
Has anyone else experienced this? It's certainly something to be aware off.
LSaupeSeptember 22, 2020, 10:05am
Without a closer examination it kinda looks like cyclic loading failure. How is rotation handled at the base (fuselage mount)? Does the cable have torsional motion in the base bracket?
radfordcSeptember 22, 2020, 10:13pm
The way your system is designed it's almost guaranteed to fail sooner than later. The bending loads on that connection are significant. It would be much better to have the Teleflex cable terminated close to the control surface.
flydogSeptember 23, 2020, 1:10am
Yikes! Or is it crikey?.
Radford,it looks to be per plans and I have heard of no other failures like this.
Mcvids, how many hours on that part? Did you use a torque wrench on the jamb nut? Cable supplied by TEAM?
MickvdsSeptember 23, 2020, 5:28am
The plane has only got 16 hrs on it so shouldn't be fatigue related.
This extension did seem like a possible point where the check nut may vibrate loose so I might have put a bit of extra TQ on the nut but I don't think excessive TQ. In saying that I didn't use a TQ wrench and couldn't tell you what the correct TQ should be.
In the UK they fit a 1/4" cable vs the smaller one (3/16 that comes with the kit. As far as I know my kit was shipped with TEAM cables back in 1993. David Cooper said there is something in the Flight Manual about what to replace them with. I can't seem to find anything though and have asked him to send me the info.
A member on the UK Minimax FB page sent me a photo of his HiMax with the larger cable mounted direct to the aileron without an extension piece. That looks to me to be the way to go other than making a push/pull rod system.
LSaupeSeptember 23, 2020, 9:57am
Still seems like an excessive amount of unsupported length in the flow stream. Aerodynamic vibration also could be a concern.
PUFFSeptember 23, 2020, 11:21am
lo0ked per plans to me. my guess is a bit overtorqued on one end or the other. I believe it's aluminum, so doesn't take much to break it. mine was the same way, I just had to be extremely careful. ask team about a torque spec, but I think just snug is enough, along with your pre-flight to see it doesn't back off.
Another thing to look for is making sure that when you snug it, the rod-end on the aileron isn't cocked sideways.
