Hi Jamiechip

I have thrust tube dimensions given to me by Martin Lambert, you are welcome to a copy if you want.
I have been flying a Lambert for about 2 years on a foam Twinjet...The engine has performed flawlessly in this time. I have taken it to a few jet meetings over the years as well. They are a great hassle free easy to transport engine/airframe combo for sunday flying.
PM me if you want any more help or maybe come and see mine fly one day.

Kind Regards, Craig