Vixen FWF Variables?

[SWeidemann]

I own a Vixen 912ULS with a two piece smooth cowl (builder finished in 2003). I just had my first look at a friend's fairly complete (lots of parts) un-finished Vixen second hand project with the FWF kit for a 912 however the engine mount he has is completely different than mine. It has the 4 round rubber mounts facing forward and the oil tank provision appears to be on the far left side of the engine compartment. The cowl is a three piece (boot cowl plus top & bottom half). One conclusion is this setup could be for the 912 80 HP and not the 912 100 HP ULS. He believes the original builder started this about 1995. My friend also removed the fuel tanks in the partially finished wings because of some quality control issues with the fiberglass. On this, I assume there could have been problems with ethanol laced gasoline. I am considering buying it from him to finish it and my desire would be to power it with the 100 hp so I want to add up the things I would need to buy or change. (I want to know more about what I may be getting myself into.) Anybody have helpful information or at least opinions?

Thanks much, Skot

[desertfox1]

You are describing the model 7 firewall forward (boot cowl and motor mount
designed for Rotax type mount) Several Vixen and model 6 builders have
used it. Just a newer forward then what Vixens were originally shipped.

Phil

[HighWing]

One thing I think might be worth considering. How is the CG on your current vixen and would it be advantageous to have it more forward? I think, the Series 7 FWF moves the engine forward a bit. This will affect W/B.

I built two Model IVs with full gap seals and fairings on the empennage. It added a bit of weight at the aft 11 ft. arm. I found that my first one had a slightly aft CG which limited baggage capacity. I moved my engine forward 2-1/2 inches in the second airplane to compensate for that and it proved to be probably 1/2 inch too much - still within the envelope, but slightly more draggy as with nothing in the baggage sack in cruise, the elevator is slightly up from neutral.