4 STAR 120- engine Thrust line
03-05-2017, 02:30 PM
#1
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4 STAR 120- engine Thrust line
I just started construction of my 4 Star 120, and when I mounted my Valley View 20 cc engine, I discovered that the centerline of the propshaft is about 1/4 inch abobve the thrust line that is shown on the plans. Should I be concerned enough to make another firewall, or will this amount be acceptable? Thanks for the help
03-05-2017, 08:42 PM
#2
Don't sweat it. A quarter of an inch on a sport plane the size of the 4 star 120 shouldn't be a big deal. At worst it will have the same effect as a smidgin of down thrust. I had a 4 Star 60 with the prop shaft a half inch below the marked thrust line. I lowered the engine to get the spray bar in the carburetor closer to the fuel tank center line. I used the 120 size landing gear to maintain prop clearance. The design of the 4 Star series makes for a very tolerant airframe.
