Tompa,
Methinks that you just read Matt's (Diablo Kid) comments?? If you really have read much of the thread you would have picked up on a lot of tips on building and flying these models. There have been many photos of modifications that have been made by Joe, David and Roger that helped me build my first UCD. I lost part of my home to Hurricane Charley and my UCD to Hurricane Jeanne. The other guys have been somewhat affected by the storms as well except for David in the UK, be he has some other issues. All have been busy with their jobs and of course other projects. We have lately, I'm afraid drifted away from the issue of the UCD on the thread. Strange as it may seem with everyone's problems we have all remained friends and have used this very medium to communuicate. I can't really help you with your question as mine had a Saito four stroke. Joe used the same engine and later changed to a YS 110FZ for more power. Roger used an OS .91 four stroke as did David with the exception of David's being pumped. Stick around and I am sure that someone will answer your question for you. From what I understand, you really have to wind the two strokes up to get them to hover for very long at all and then they have a difficult time pulling out. A fellow at my club had one with an OS 91 FX and from what I observed, that seemed to be the case. On the other hand, he was not the best pilot in the world either. I can assure you that we all think alot of this airframe and will probably always have one. Later this fall I hope to have the time to get to it with #2 and if I'm not mistaken I think Joe is on #4 right now.