...what if Van had taken that mindset. Lots of successful low-wing singles out there; why reinvent the wheel?...
Here's one thing to consider regarding that line of thinking: Van has always taken a very measured approach to sizing and configuring his airplanes.
Where we see this most directly is in the way they are designed for decently sized engines. All of the RVs are designed from the get-go to accommodate somewhere between a reasonable amount of power and lots of power, and still balance reasonably well. They may not accommodate the great gobs of raw brawn that the Rocket crowd demands, and they may not balance as well as someone with an RV7 and light prop would like, but they've all been in the ballpark.
What we haven't seen is a new RV design that comes out with a small engine, and then goes back to the drawing board for a power upgrade just to give it decent performance. Many airplane projects, the Wing Derringer included, have been there and done that.
I think that if Van were to dabble in a twin engine airplane, it would have a lot more horsepower on a side than the airplane we're talking about here. What I'd sort of guess at is that he'd start with the RV10 airframe, and mount 200 hp IO360s on a side. But that is a speculation for a different thread, and maybe a different forum.
For the twin we're talking about here, I think we will see that 2x110hp won't really be enough. According to
www.flycorvair.com, the installed weight for a single 110 hp corvair motor ready to fly is 215 lbs or so. So for 220 horsepower worth of them, it is 430 lbs of weight, versus the single IO360s 300 lbs or so for 200 hp. And let's not forget that it has two engine mounts, two sets of fuel plumbing, two cowlings, two propellers, two sets of engine controls (cables, wires, etc). It also has about half again as much frontal area as an RV6. What it adds up to is an airplane with a bit more power than an IO360-powered RV6, but a lot more empty weight and a handful more drag. It will require greater workload to fly, but won't reward that workload with better performance or better handling.
And let's not forget that the usual selling point of the light twin is the improved safety of having an extra engine. At least that's what the brochures say, it too often does not work out that way. But anyhow, I don't see this airplane holding altitude very far above sea level on one 110 hp engine. I guess you can say that the extra engine gives you a lot more landing options, but I don't think that is worth the trouble.
Thanks, Bob K.