Cheers MIHC – interesting little puzzle. Soundly cursing the bump of curiosity, I went digging about for Jab information. Must say the POH is very good and the Jab folks seem honest enough about engine cooling. Most informative –
Engine Cooling – blurb was worth the few moments it took to read, Jabba is onto it. It's refreshing to see an issue being tackled openly, it's no wonder the little beasties are popular.
Hunted down the speed range – the POH I looked at placed max glide at 65 KIAS and engine out landing at 60 KIAS, which is comparable with similar aircraft. There are some interesting 'cautions' regarding in flight restart though:-
In the event that the engine is stopped during flight, it may be restarted by application of fuel & ignition, provided that the propeller is still windmilling. The propeller may stop windmilling below 50 KIAS.
Now, I've scratched that itch – well done Jabiru; nice to see that someone cares.