The flying monkeys got me...

Helis and fixed wing

AMA 957918
IRCHA 4345
AMA Intro Pilot Instructor

Sunday, May 4, 2014

Another death in the family...

It started out well. I went out solo this morning, first on the field and had it all to myself. Virtually no winds, occasionally a brisk crosswind gust, but never threatening. A quiet Sunday morning at MCRCC. I got out there around 10am, ready to go.

I took Aidan's Alpha 450 up, and ran it through its paces. She flew great with her extra nose weight, and I practiced short and cross wind landings as well as work on orientation. She is tight in control, predictable and rugged, everything you want in a trainer. She's a keeper, and I am glad Aidan and I each have one to keep our basic flight skills honed, and to share this hobby with others. I flew a couple of packs, but then that clicking noise came back when she tipped over her feet in the thick grass despite bigger tires. The rotor was on the move again. I tweaked her up and she flew fine. After 4 packs I put her away for the day. That'll do girl, that'll do.

 

When I got her home I took the prop off and realized there are cut out flat spots on the motor shaft, so I worked to get the lock screw to set in there with some locktite and gorilla snugged it into place. Hope that's the end of it.

 

After that I took the Pulse up and ran her through some aerobatics, getting mentally in place to follow up those aerobatics on the Sbach. She is so well built and tuned, not a vibration anywhere. her motor ran true and silent. I flew her for one pack, sweet, high powered high altitude work, a couple of touch and goes in the northerly crosswind, and decided I was ready to take the Sbach up.

 

The Sbach flew like a dream... Sweet smooth effortless takeoff, into some high altitude, high speed, high G, high torque aerobatics. I put her through the wringer. I noticed a final set of loops and Cuban 8's that were less round, a little uncommanded roll as she came around. I swung her hard into a final loop to pull out into final from the south. She took off skyward like the rocket she is, a bit of un commanded roll, I pulled her back into a loop, and realized I wasn't flying her anymore. I tried to correct, no repsonse, then zeroed the controls, nothing. She waffled out of the top of the loop in a slow shuddering spin, powered her off and called out that I had no control. She was high as she came down, twisting, screaming, and slammed into the ground nose first. She hit so hard she bounced up scattering pieces all over, a wing cast off across the runway, and came to a rest in a crumpled heap about 6 feet away from the impact site. No chute, no fire... The pilot was surely dead...

 

The tan colored crater in the right foreground is the initial impact site, a hole about 7-8 inches deep. This was my walk-up to the crash site at the south end of our runway. Dick Clark came out to post-crash with me. The electronics were still live and everything worked. None of the servos were apparently damaged, all the linkages were in place. but we noticed that the CA hinges on the right aileron and elevator were separated from the aircraft. There was no external damage to the wings or the elevators otherwise (the wing that came of suffered some internal damage where the wing tube broke). The hinges pulled clean. Despite my CA work there looked to be no glue on them at all. We suspect that the hinges were weakened by the poor glue work (I really tried hard to get them to set in.., recall I had to redo the rudder hinges on the field on her maiden day), and worked loose by the aerobatic maneuvers, evidenced in flight by the dirty loops and the sudden loss of control during a maneuver at altitude with intact electronics. The rudder wires had also stretched during those maneuvers. I check them before each flight and they had been snug, but now visibly slightly sagged. None of the wire linkages separated and they showed no wear. The freed elevator did not move with the main elevator but slightly.
 

 

 

Curiously, neither the prop, motor, electronics, landing gear nor the wings and tail, for the most part, had any significant damage. The fuse was powdered, but that was it.

When I got home a visibly shocked Aidan helped me recover the electronics. I tested the motor and it worked fine. I had to work the prop screw loose and then cut the adapter rotor off to get the prop off. The impact smashed the aluminum prop adapter shaft and the steel screw together and totally smashed the screw so that it locked and stripped. The spinner was oddly totally fine, albeit muddied. Further evidence of the altitude and energy of the crash. Still shocking how little the rest of the plane suffered.
 

I wasn't sure what I would do... I recovered all the electronics and they all seem to function well. I ordered a replacement SK3-5055 prop adapter, but am not sure I will replace the plane right now. Surely I will.

UPDATE: I was looking at the HobbyKing version, but after an hour dicking around with their website issues, I learned it would cost an additional $73 to ship their version from the USA warehouse. Great price for the plane, but the shipping killed. Since the General Hobby Skyline version was a good plane really, and on sale for two more days with $25 shipping, still way under the HobbyKing cost, I opted to go ahead and replace it from General Hobby. Since I was leery of the supplied hinges and they failed, I have also ordered nylon and metal hinges from Hobbylinc for cheap. The new plane will have reliable hinges.

When. I come back from a business trip this week all the parts and the plane should be here. Should be a quick build.

 

1 comment :

  1. uffff hard but this is rc plane hobby, and between is electronic :)

    ReplyDelete