Bob

Do a search on Vectorflight and you will find a ton of information here on RCU. There are some people who have used the ST 90 on the extra and edge. Read the threads and you will find a lot of useful information about vectorfligths planes. I had the 66 inch extra with a 91 4 stroke on it and it was great. I recently lost it due to the rx battery dying in flight. I will get another one soon. I like the ST 75 and if I already had one I would use it. If I had to buy another engine I would get the 90 instead just because it can be used on a larger variety of planes in the future. ST engines are great and I have 7 of them in lots of different sizes.

Rick