Hi All, Well the decision has been made (I can sleep tonight, though much poorer now). I'm scrapping the Hirth and replacing it with a 85hp Jabiru engine (the 120hp engine is expensive and too heavy which would require a major rework)
At the same time I'm replacing the retractable under carriage with the Jabiru tail dragger gear, wheels, brakes and wheel spats, all for $2500 Australian. There are 2 reasons to upgrade: 1. My retractable gear is fixed down and looks like two barn doors in the slip stream, 2. I need the extra height and bigger wheels as I'm operating from a grass strip and Jabiru recommends a 60" diameter prop, which brings me to my next question. (remember I know nothing about propping an aircraft) The engine and prop should perform as follows: static run up 2700 to 2900 (2800rpm 74hp 150ft lbs torque) cruise 2750 to 3000 (3000rpm 81hp 140ft lbs torque) any lower rpm and it really sucks fuel max 3300 (85hp 138ft lbs torque) Jabiru props come in the following sizes for their Jabiru aircraft (see http://www.jabiru.net.au ) dia x pitch 60" x 42" recommended for fast climb 60" x 44" recommended for slower climb but 5kts + speed 60" x 48" for their 6 cylinder aircraft 60" x 53" for their 6 cylinder aircraft Which of the above would be best for a standard KR2? Thanks Barry ----- Original Message ----- So I'm thinking of scrapping the Hirth and putting in a Jabiru 85hp @ 60kg or 120hp @ 81kg. My Hirth is/was 92hp @ 52kg. The smaller engine is preferable as the weight will be easier to deal with, But we all want HORSEPOWER.
