thanks Dave, I do not hold break and open power, I slowly gain speed and with this plane I would only go to 75% power and it would lift off easily. My very first flight it did sudden nose up and when I reduced the elevator travel it wouldn't do it after that. However I reset the elevator to factory for other reasons. Hence I am going to set it back to 20mm as recommended here. However, the nose strut is just as it comes, no changes were made to it. Does it need to be moodified? do I need to change springs? do I need to make sure it stays fully open? and do I need spacers? how much?
Any comments regarding the vent?

Thanks
Jason