pinchflat
03-30-2010, 07:59 PM
I guess I was feeling a bit left out with Clssy and Atis killing their planes.
Today before work I was testing V-4 of my delta (same as v-3 but with a KF4 airfoil). I was seeing how little vertical stabalizer I could get away with. Before sending it off to Wayne.
I had removed the large central vertical and it was tracking great so I was trying spins. After several power off spins I thought I would add a bit of power next spin. I climbed to a few hundred feet and started the spin deadstick I applied full power. Then it rotated about once before I heard a loud "POP" , saw chunks of foam fly and my motor went immediatly silent. The prop in slot design is normally quit lout with a 3 cell and the silence was eerie. I thought that I might have slung a prop since I was using a prop saver. I tried to give it power but had nothing. I was still spinning slowly at about 200 feet so I went to neutral controles and arrested the spin (whew ...still have servoes). I landed deadstick out about 75yards from where I was standing and found this.
2601
2602
The spar had totaly ripped from the structure taking the motor with it. The airframe folded from front to back along the centerline.
I am not sure if there was propstrike that ripped the motor out or if the spars failed and caused prop strike.
My new plane slated to run a 2200KV motor on a 3 cell is under construction. It will be 'glassed at the point where this one failed. Also it has carbon spars not just spruce. It will need too be strong as I am hoping it to bee good to about 90mph.
Today before work I was testing V-4 of my delta (same as v-3 but with a KF4 airfoil). I was seeing how little vertical stabalizer I could get away with. Before sending it off to Wayne.
I had removed the large central vertical and it was tracking great so I was trying spins. After several power off spins I thought I would add a bit of power next spin. I climbed to a few hundred feet and started the spin deadstick I applied full power. Then it rotated about once before I heard a loud "POP" , saw chunks of foam fly and my motor went immediatly silent. The prop in slot design is normally quit lout with a 3 cell and the silence was eerie. I thought that I might have slung a prop since I was using a prop saver. I tried to give it power but had nothing. I was still spinning slowly at about 200 feet so I went to neutral controles and arrested the spin (whew ...still have servoes). I landed deadstick out about 75yards from where I was standing and found this.
2601
2602
The spar had totaly ripped from the structure taking the motor with it. The airframe folded from front to back along the centerline.
I am not sure if there was propstrike that ripped the motor out or if the spars failed and caused prop strike.
My new plane slated to run a 2200KV motor on a 3 cell is under construction. It will be 'glassed at the point where this one failed. Also it has carbon spars not just spruce. It will need too be strong as I am hoping it to bee good to about 90mph.