scorpioflyer,
The main problem is tracking down useful documents as the average bookshop is not well stocked with this sort of thing. Probably your best bet is to see if Genghis has any CAA-specific requirements to meet - they might well have recommended light aircraft performance methods manuals as does, for instance, the Australian CASA.
Otherwise, I would check out a local (reasonably large) library or, especially, a local university engineering (preferably aero) library and see what books are on the shelves.
The sorts of documents you might look for in the library include
(a) the Boeing Performance Engineers' Manual - I don't have my copy with me at the moment but I seem to recall that the doc number is D-1620 ?
(b) AGARD Flight Test Manual
(c) any other flight test manuals which the library has scrounged over the years.
In your local technical bookshop, you might find books such as (memory scratching now) Mair and Dunstall (Cambridge series) - a very readable engineering text on performance. Stinton's book probably has plenty of guidance material as well.
Have fun ...
[ 05 October 2001: Message edited by: john_tullamarine ]