Guess 10 years ago I made a mould from Dave Goldsmith s 2400 h36 done by koff and co Germany. . It was a section under Muffler which pushed air down guess 2 inches and exhausted.
It was made by friend Todd Clark in bright yellow gel cote and was thick and heavy I loaned it to somebody and could well have been Allan McMaster or John Viney both if which who have left us regretfully. It may have been to a grob 109 owner as well. If you have any recollection of same please advise me. I have done same to G109 bottom cowl and also really improved the cooling. I learnt from Col Critiden the other day this works even better if you extend this a distance of 75 mm to 100.mm behind the firewall and works even better. Makes total sense as this is a high pressure area and unless extended back air can curl back. I saw demo of what he mentioned. Col used to fly an LS4 but in past 25 years has built 34 aircraft and mostly RVs of some type and the 35 is in the shed ready to start. All are air-cooled and one I saw was a rv10. His ideas make total sense sense. With Jabiru he has discarded the ducts and gone back to the plenum chamber but shells that curl the air under the cylinders as per Limbach tech bull 41. Rod stiff never had it right it seems. Ian McPhee 0428847642 Box 657 Byron Bay NSW 2481
