Performance/Flight Evaluation
Well we've taken the Mac Daddy up for it's first few flights and all I can say is "what a sweety!" All in all, this is the best flying plane I have and fully lives up to all the stories I was told before building it. It's easy to see why it's probably the most popular model at our field and you can see one out there almost any day you go out to fly. Everyone told me it's a very stable and forgiving plane that can really perform high-end aerobatics when called upon, and they were right. It flies slower than my trainer and lands easier than any plane I've flown.
First off, let me say that I think many of the forgiving characteristics are due to building this plane to a reasonable weight, which includes choosing the right power plant. I used an OS 91 FS in mine and the plane came in at 9 lbs even. This includes the heavier aluminum gear, fiberglass cowl, aluminum TrueTurn spinner, and pants a good bit of structural enhancements and even a fully sheeted (1/32") fuselage. This great power to weight ratio and a strong pulling APC 14 x 6 prop gives the plane great slow flight capablilites while still having plenty of vertical pulling power.
No it's not a rocket and no it does not have unlimited vertical, but it has plenty of speed and power in my opinion. Five out of the last five CG Extras I have seen at our field are running the OS 91 FS engine and everyone loves the combination. I've read about so many people putting 120's and even G23's in this plane but it really doesn't need it unless you plan on doing torque rolls or want to fly at screaming eagle speeds (not me).
I've come to the conclusion that putting a larger motor in this plane usually brings it to 11 to 12 pounds, making it less forgiving and much hotter landing. It also explains why these guys are often blowing the tail apart on the Extra or getting into flutter problems. I just don't think the plane was designed for that much weight/speed without adding significant structural modifications (adding weight). Personally I would rather have a great performing aerobatic plane with very respectable vertical but maintain hands-off stability and cakewalk slow landings... What more could you ask for?
I set mine up per plans and the COG came up on the money. You can't deviate from the plans much at all without getting int COG problems. I used a 12oz Sullivan Tank and the OS 91 will get a good 12 minutes out of that tank with plenty of throttling. I did not have to add any weight to balance fore/aft or left/right at all, which also helped keep the weight down. I only added one click of right aileron trim, but had to add about 4 clicks of up elevator trim... not sure why cause it's definitely not nose heavy... may have the horizontal stab incindence off just a tad. I may experiment in the future with moving the COG back slightly to reduce the amount of up-elevator trim, just a little at a time, test-flying it as I go.
I set up my throws as per the kit supplied throw guides. They seemed very modest until I flew the plan, which proved them to be more than enough... I even backed them back off a tiny bit after flying. I have dual rates set up for AIL/ELE but not rudder. Just throw as much rudder throw in as you can get, you'll need it. I also set up all 3 control surfaces with 40% exponential, which seems about right for me on this plane.
The only slightly bad flying characteristic I found on this plane is that if you go too high on your elevator rate/throw it will tend to roll/snap a little to the right. Use the suggested throws and you won't run into problems with this coupling issue. Or, you can computer mix a little aileron in to compensate when on high elevator rate I suppose?
All in all this plane is a definite winner and I hope to enjoy many a flight with it in the days to come! Thanks again to Pat, Bill and Roger for all their advice on building this plane, choosing the right motor and letting me try out their Extras before building mine.