I have less than 5 gallons of fuel through mine and until yesterday it has ran like a champ. On my first flight saturday about 3 minutes in to my flight it dead sticked got it back on the ground safely and I had almost no compression. I took off the muffler and from what I can see the cylinder looks good and the plug is tight, but still no compression. Any ideas anybody else had this happen?

greyhound man,
I can only think of three things that would cause the problem. First pull the plug and make sure the piston crown is ok. Try a spare plug. I have seen plugs leak before. You can apply some oil to the plug insullator and turn it over to see if it bubbles. Also the adapter should be checked. If it isn't this, it has to be a ring issue. Good luck.

Dave

Just pulled the jug off and the ring is broken. What could cause this?