Hi,, I have a Hummelbird with a 1/2 vw scott castler 37 hp engine with 160 hours on it. In early summer it quit at 2,000 ft between Lyons N.Y and Sodus Bay. I was able to make a successful landing in a corn field without any damage to the airplane. When I got the Hummelbird back to the hangar and remover the cowl part of the crankshaft and connecting rod had gone through the case. I tore the engine down and found the crankshaft was broken into 3 pieces, 2 fractures right at where the counterweights were welded on to the crankshaft. I called Scott Castler about it and he said mine was the only 37 hp engine that he knew of where the crankshaft broke, however there were many 45 hp engines with the cast crank that have broken, he offered to sell me a new FORGED crank and case at his cost. I accepted the offer understanding that the new crank would be Forged, not cast like the original.
After receiving the parts I put the engine back together and have about 50 hrs on it, but it vibrates as bad as the old one. I had the prop dynamically balanced, but the vibration is still bad.
I saw an earlier post where the question was asked, How many IPS is acceptable with this engine when a dynamic balance is preformed, but there was no answer, .
I also saw a link to an Ipad app for vibration and ordered it and mounted the Iphone to the instrument panel with Velcro or just pressed it against the instrument panel when I was flying.
My results on the x and y axis between 3,000 and 3,500 rpm has been in the 1.7 to 2 g range.
I would be interested in finding out if any one else has used the app to get a relative indication of vibration so we all could compare what is dangerous and what is not,,,Thanks a lot Mike Heckler,, N607SN
