The turbines themselves are fairly simple to make, but getting them adequate fuel is another thing entirely. Automating the production of jet fuel can be a real headache, lemme tell ya. You also have trouble with creating auto-shutoff systems with the jet engines since they take time (and fuel) to spin up to maximum output. Besides, are blaze rods even that useful? I mean, they might've been back in the 1.5 days to power solid-fuel boilers in Railcraft, but I honestly can't think of a single, non-crafting use for them outside producing jet fuel and maybe XU generators. However, for the latter, its much, much easier to just make a charcoal farm to feed them than it is t make a blaze farm, at least, it is in my experience. Then again, I prefer farming to mob harvesting, so I'm a little biased in that area...