Thanks for those pointers guys. I remember reading that the Thermal Hopper used the same crank case casting as the Space Bug so a trip to Martin Hepperle's website revealed the answer. Once removed those tanks must have been a pig to reseal, maybe that's why my dad left it off, must have another rummage amongst the pile of stuff to see if I can find it. Don't fancy my chances of finding one on ebay.



Another engine almost sorted - only 20 more to go!