Actually, the RV3 stall speed is quoted as 51 mph which is just what it needs to
be for light sport. The weight is okay too - 1100 pound gross. When I went
down the list of requirements, the only item that stood out was the top speed.
I think you can get around that with a fixed pitch (or ground adjustable prop)
wherein the pitch is probably going to work to be something on the order of 58"
to 60" - the theory being the airplane will never go faster than the prop.

The Rotax is an interesting motor - but like the Lycomings, I'm old too.
Perhaps irrational, but preferences being what they are, if I had a choice I'd
like something closer to what I know. As to relative cost, I think I could
overhaul a O-235 and come up with a good motor at a reasonable cost.

Anyway, there is chatter here and there about people wanting to do something
other than Rotax in the 12, and they seem to keep bumping into the engineering
difficulty of making such a change. So, the thought was whether this was a
workable solution when that conversation comes up.

I think you could build it as EAB and, as originally inspected and given an
airworthiness certificate, it would meet light sport requirements. Anyone,
later, wanting to put in a larger motor or different prop could do that with
just a little additional Phase I testing.

FWIW - thanks for the feedback.

Dan

--- In RV7A@yahoogroups.com, RV7 builder <mcsophie@...> wrote:
>
> On 10/11/2010 10:42 AM, danbaier wrote:
> >
> > Saw the RV-12 this weekend. A beautiful aircraft - but I can't get
> > past the Rotax engine.
> >
> > Then - in a blinding flash of the obvious - what about a RV-3 where
> > you use the O-235 engine with a fixed pitch prop pitched no more than
> > 55" (to keep your speed below 120 knots). With that setup, the
> > aircraft would meet all the LSA requirements and could be built E-AB
> > (any panel you want). Since the aircraft, when inspected would meet
> > the requirements for LSA, it would take no special paperwork to
> > operate it that way.
> >
> > The only downsides I can see are
> > - more construction time than a 12
> > - the repairman certificate can only be issued in the builder's name
> > and no LSA courses or certification for successor owners would be
> > possible, and
> > - single seat (no one gets to go with you).
> >
> > Thoughts? Do I have this right?
> >
> > Dan
> >
> Additional downsides:
>
> Lyc O-235 :-)
> Parts for an O-235
> Too high a stall speed (probable deal-killer)
>
> FWIW, there are some RV-9's flying as light sport. According to the guys
> who sell the Carbon Cub (180 HP), you can solve the overspeed problem by
> just placarding the max continuous power allowed.
>
> You could build a -4 & meet the light sport numbers, but you'd probably
> need a decent engine (now we are back to the Rotax...). If flown single
> seat, the -4 could be certificated with a low enough gross weight to
> meet light sport even with a Lyc, but the stall would probably still be
> a problem.
>
> What's your issue with the Rotax, the cost? Everything else about it
> kicks the Lyc's butt.
>
> Charlie
> (No, I've never owned a Rotax. But I've owned a few Lycs...)
>