Peter,
To your Post#9:
In Derek Pickard's test of the PAW 40TBR, in
Stunt News several years ago, he said much the same as is repeated here. They can be set to an RPM and it doesn't seem to matter uphill, downhill or lingering up top. (In my experience, you can hear a subtle increase in "stress" in prolonged figures up top, but well within the engine's compass.)
A factor explaining both the economy and rev limiting in medium-large sport diesels is that their port passages are quite small. They don't flush vast amounts of air through, as is needed to burn methanol-based fuels. The diesel's power comes more from a higher heat energy basic fuel component - kerosene, than from a higher quantity of a lower heat energy fuel component - methanol. Setting a diesel is trickier than setting a glow, because of methanol's tolerance to a slightly 'off' needle since you're still going to burn quite a bit of it.
For the deodorized among us Yank fliers, the objectionable times are starting and launching, unless you use a really rank kerosene in the fuel. With a clean kerosene, the exhaust is nearly odorless, or more like the steam smell of an old-fashioned neighborhood hand laundry - if you're old enough to recall that...
But, for starting, launching and recovery, we have to impose upon other greasy-rag types if available, or beg the indulgence of one of our white-shoes/pants/airplanes buddies...
The only negative I've heard, once you get past the smell matter, anyway: A British flier who was discussing diesels in stunt answered a simple question: "How do you tank to get a consistent stopping time?" He answered, "You can't, really. You just do as best you can on that."
A 'click' on the needle could mean an extra 30 seconds of power, I guess. It's not so bad in the USA with the 8-minute flight limit, but I can see that would be of concern for FAI's 7-minute limit.
Also, I think on on RC Universe's CL forum, there's a thread on a modeller starting out with diesel. Good first steps stuff, and he sounds quite pleased, now. ...After a frustrating beginning...