Looks like transverse failure to me, loose weights acting as hammer load with every turn? No hours on airframe provided. Is it an SLSA IFR trainer with the VOR antenna installed? Or an EAB/ELSA flown in IMC that got rough? Be fun to see what the engineers come up with. Clearly not a weld failure. Imagine someone would like to look at that counter balance arm under a microscope.
I wonder how the airplane flies when the weight falls off in-flight? Apparently controllable... as witnessed by photo above where airplane appears intact.
I bet a SB to be issued soonest....
It looks like there are pieces of tubing or something RTV'd to the edge of the stringer, probably to protect the cable where it's cable tied in place. Dried blood would be darker.BTW, is that blood I see next to that nylon zip-tie holding an antenna cable to a longeron/stiffener?
God help me if I have to crawl into the back of that tailcone again....
BTW, is that blood I see next to that nylon zip-tie holding an antenna cable to a longeron/stiffener?
That depends on how flexible you are. Chase washers and bolts or have trouble walking for 3 days....I’d rather crawl back there than have to remove the stabilator
The break appears to be broke in the horizonal direction. (small neutral access)
Engine vibration and the length of the tube transmit it to an inertia stable counterweight.
A rubber isolator may solve this problem. (Harmonic balancer)
My view
My guess is that the plane was parked outside without a control lock on the stabilator and it banged up and down in the wind until the weight attach bracket fractured.
This problem has been on my mind since my pervious my post.
I believe this failure is caused from a frequency-based metal fatigue from harmonic vibration. (Over the maximum number of cycles allowed)
Also, the kip frequency caused by the engine balance and the prop balance when in alinement? (caused by the gear box ratio)
The engine Ballance and the prop balance and the gear box move the force in changing degrees from a horizonal plane.
The engine is the on the front end of a teeter totter (so to speak) inertia stable.
The center mass is at the spar, balance point (so to speak), The spar the fuel tank and the occupants. Note full fuel tanks in the wings would help dampen the vibration.
The counterbalance is on the longer arm of the teeter totter (so to speak)
Note my background is in engineering (I am not a wordsmith)
A good prop balance and pitch match would mitigate this problem.
My view
From my pervious post
I think it’s red RTV, used to hold the abrasion protection in place. Or a lot of blood!
I'll jump in on this one even though it's serious thread drift...I'm sure I'm misremembering things but I very vaguely recall a warning not to use Red RTV on aluminum. I think it was when I was building my RV-7A rudder or elevators and the instructions called for a dab of RV inside the stiffeners at the trailing edge. Now I don't remember if it was in the instructions where the caution was made or if it was in an issue of the RVator (which is how we got our RV news from the factory way back when).
Am I dreaming this? Because I've made sure to always use blue RTV where it's called for on the airframe since.