On Fri, Jun 14, 2013 at 9:27 PM, Mark Steitle <msteitle@gmail.com> wrote: Sorry for the bad news, but good thing it happened on the ground. As for the possibility of detonation, it doesn't sound like it to me. If it was detonation, I would expect to find a broken apex seal or two. Sounds like maybe an o-ring blew. It could have even been a defective iron. Pictures would help. MarkOn Fri, Jun 14, 2013 at 7:38 PM, <shipchief@aol.com> wrote: N89SE received it's Airworthiness Certificate June 13, 2013! Yay! So I put the covers on it an pulled it out of the hangar for a start up and taxi test. I have not run it this year while finishing the airframe. So I started it up, a bit behind the curve on the EC-2, chasing the mixture around etc, then settled in to a nice smooth high idle and taxi'd down to the far end of the runway where I ran it up to 4400 +RPM, checked the water & oil temps, (158 & 167) pulled out on the runway, and fed the power to it for a 2 or 3 second burst, to be pulled off to prevent flight. Well the thing started well enough, I pushed the throttle slowly to about 2/3, and as the plane gained some speed, the CATTO 68x74 prop unloaded a bit and the RPMs went up. The acceleration was profound for about 2 seconds followed by a POP! as or just before I started to pull the throttle back. Then came the grey smoke as I shut down the fuel pump and glided off the runway to the taxiway. A few guys came running to help. One asked 'How ya doin'?" Medium I replied. (I'm OK and nothing is burning). Yada Yada, The plane is back @ the hangar, and the oil leak (spew) is a cracked block at the last oil tap fitting on the top gallery, by the distributor pulse counter. (1986 type) Today I stripped the engine and pulled it off the airframe. Looking in the ports, all the tip seals move and are springy, but I think I detonated it, some damage is visible. Maybe in a previous tethered run (to 40" manifold press), and this time it let go. compression was down (prop pull method) I wonder if detonation under boost will crack the block (end irons)? What a letdown after your AW certificate.........Curious what type of fitting you have in that oil galley........As I recall from my1988 13B front housing the side walls may be a little thin after threading.............If a tapered pipe thread fitting was used the pressure from the tapered thread can crack the hsg.......I would suggest using straight threaded fittings (US or Metric) withalum , copper or "O" ring for sealing.............FWIW -- Kelly TroyerDyke Delta_"Eventually"13B_RD1C_EC2_EM2
Sorry for the bad news, but good thing it happened on the ground. As for the possibility of detonation, it doesn't sound like it to me. If it was detonation, I would expect to find a broken apex seal or two. Sounds like maybe an o-ring blew. It could have even been a defective iron. Pictures would help. MarkOn Fri, Jun 14, 2013 at 7:38 PM, <shipchief@aol.com> wrote: N89SE received it's Airworthiness Certificate June 13, 2013! Yay! So I put the covers on it an pulled it out of the hangar for a start up and taxi test. I have not run it this year while finishing the airframe. So I started it up, a bit behind the curve on the EC-2, chasing the mixture around etc, then settled in to a nice smooth high idle and taxi'd down to the far end of the runway where I ran it up to 4400 +RPM, checked the water & oil temps, (158 & 167) pulled out on the runway, and fed the power to it for a 2 or 3 second burst, to be pulled off to prevent flight. Well the thing started well enough, I pushed the throttle slowly to about 2/3, and as the plane gained some speed, the CATTO 68x74 prop unloaded a bit and the RPMs went up. The acceleration was profound for about 2 seconds followed by a POP! as or just before I started to pull the throttle back. Then came the grey smoke as I shut down the fuel pump and glided off the runway to the taxiway. A few guys came running to help. One asked 'How ya doin'?" Medium I replied. (I'm OK and nothing is burning). Yada Yada, The plane is back @ the hangar, and the oil leak (spew) is a cracked block at the last oil tap fitting on the top gallery, by the distributor pulse counter. (1986 type) Today I stripped the engine and pulled it off the airframe. Looking in the ports, all the tip seals move and are springy, but I think I detonated it, some damage is visible. Maybe in a previous tethered run (to 40" manifold press), and this time it let go. compression was down (prop pull method) I wonder if detonation under boost will crack the block (end irons)?
N89SE received it's Airworthiness Certificate June 13, 2013! Yay! So I put the covers on it an pulled it out of the hangar for a start up and taxi test. I have not run it this year while finishing the airframe. So I started it up, a bit behind the curve on the EC-2, chasing the mixture around etc, then settled in to a nice smooth high idle and taxi'd down to the far end of the runway where I ran it up to 4400 +RPM, checked the water & oil temps, (158 & 167) pulled out on the runway, and fed the power to it for a 2 or 3 second burst, to be pulled off to prevent flight. Well the thing started well enough, I pushed the throttle slowly to about 2/3, and as the plane gained some speed, the CATTO 68x74 prop unloaded a bit and the RPMs went up. The acceleration was profound for about 2 seconds followed by a POP! as or just before I started to pull the throttle back. Then came the grey smoke as I shut down the fuel pump and glided off the runway to the taxiway. A few guys came running to help. One asked 'How ya doin'?" Medium I replied. (I'm OK and nothing is burning). Yada Yada, The plane is back @ the hangar, and the oil leak (spew) is a cracked block at the last oil tap fitting on the top gallery, by the distributor pulse counter. (1986 type) Today I stripped the engine and pulled it off the airframe. Looking in the ports, all the tip seals move and are springy, but I think I detonated it, some damage is visible. Maybe in a previous tethered run (to 40" manifold press), and this time it let go. compression was down (prop pull method) I wonder if detonation under boost will crack the block (end irons)?