gorish, I had that concern. I went and looked and it happens to be exactly 2 3/4. Hopefully that will work for me.
I had called TBM, but when I went to their website, I couldn't locate anything. Probably because I'm not familiar with the correct nomenclature of things. Will have to try elsewhere hoping some site is easier to find things.
I called RC Showcase, but they are either done for the day, or just busy. Guess I will try again on monday. Caley

Edwin, Need to answer you about the ducted fans stuff. Sorry for forgetting. I love jets, but have come to the conclusion that I am not skilled enough to fly anything over 60mph, and then I am a bundle of nerves. I've just started flying EDFs with a Banana Hobby A-10 Wartlehog. And for its size, it seems plenty fast, probably around 50mph full throttle. I read a lot on fuel powered ducted fans, and decided that I was not skilled enough with engines to even attempt such. Can't tune things worth a darn. When I had a couple of glow type models, I always had to rely on the expert flyers to come over and tune my models engine, so I could fly it. I'm tone deaf, which may be one reason for not being able to tune an engine. Caley