Hi All

I really wanted more airtime before I posted on the forum just in case it was me that was missing the big picture. But since the weatherman promises nothing but rain, I decided to try my luck.

My MiniMax seems to have a nasty habit of pulling right. I was prepared on take off, from all the taxi training. But even in level flight it seems to need some left pedal? Now I have been looking trough the plans. And I can’t seem to find any indication of the engine needing offset mounting to counter prop wash?
Have any of you experienced this or made any modifications to avoid it?
I’m using a 447 with a 60” GSC 2 bladed prop.

Just for info. What would your normal Cruise speed and RPM be with this kind of engine?

And compared to a closed cockpit version how much slower should my open cockpit be?

Thanks
Thomas.

With a gearbox some left rudder is normal.  A lot of people put a trim tab on the rudder to eliminate this at cruise. My 1600R cruises about 70mph at 5800 rpm with a 58x40 wooden 2 blade. Open cockpit could slow you down 5-10 mph or more.

I have not yet mounted my big Suzuki, but have pondered this issue. Thinking I might introduce one or two degrees (if I can measure it that finely) of left offset to counter the potential problem, though it's impossible to say how much would actually be correct without trying it. Problem is, once I drill those big holes through my mounting surface it would be very difficult to re-drill or adjust things again by a small amount. I have raised this issue previously with no good responses. My thinking though, is that a bit of offset would be preferrable to the constant drag of having the rudder offset by a trim tab. With 70+ HP maybe that would be a non-issue for me though.

I don't use a trim tab as there isn't enough force on the rudder pedals to even notice. Even on long flights with a crampy leg it's easy enough to just switch feet on the pedals. Personally I would mount the engine straight up. Remember VNE isn't all that high!