Quote:
Originally Posted by RetiredRacer
Hi NB,
The 0-235 C2C as received (used) weighed in at 245 lb and after re-build and fitment of all the lightest bolt on's weighed in at 217 lb but that was not with engine mounts.
Most of the weight savings was in the interior and under the cowls so everything where possible in the aircraft was moved forward for COG.
This was a quick build kit but nothing was modified on the supplied build.
I studied the RV12 for ideas and cut 45% off the weight of the seats when I constructed them and fitted a D180 EFIS as part of that study.
Moved the battery mount over in line with the starter motor, this meant about 50% less cable was required and this as well as the low compression engine meant a smaller cable as well as a smaller battery could be used.
The cowls are standard fiberglass.
light paint was applied to 25% of the aircraft.
first up there was no wheel pants or intersection fairings fitted to the mains but with some further weight savings else where in the aircraft I was able to fit pants and fairings to the mains and still keep the weight under 900 lbs.
To give you all details of the weight saving build I would need to write a book. But basically never fit anything to the aircraft without studying it first, looking at the job it has to do and trim off all ballast on that piece before fitting even if you think it is not worth the micro weight saving!!
Always, SAFETY MUST COME FIRST!!!
The most important things.... Dedication and stay focused on the end product. Back when I first posted first flight with the weight of the aircraft ( April 2011) I had builders from all over the world wanting advise and guidance to build light but most had lost the plot before they were even half way through their build. this is why I keep saying STAY FOCUSED!!
I'm not too sure how you would go with COG with a Rotax….. may be longer engine mount and this would mean longer cowls etc and that means adding more weight to save weight. From memory the Lycoming 0-233 LSA engine which wasn't released when I built mine is about 5 lb lighter than my 0-235 C2C.
Bob
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The Rotax 912 UL, fitted with a Zipper Big Bore kit should go about 122 # plus engine mounts, prop and such. Find a later model 912 UL built after 2007 and talk to Hal Stockman at Zipper Big Bore kits in Ely, NV, USA, and you could build a very light RV-9A, on a used block Rotax 912 UL. Saving 100# will make what HP you have available more useful.
Most RV-12's go 775 # with paint. A really skinny one with no paint and no interior might go 750#, and they start with a 95 HP Rotax 912 ULS motor, only 95 HP due to dual air filters instead of a single air filter. So I don't see under 900 # with 115 HP being much better or worse. It might be a 140 to 145 MPH bird.
Of course, if built with a 115 HP 914 Turbo, the 9-A will do much better at elevation, where it shines.
The RV-9 will, of course, have more drag than the RV-12, longer wings, and the CG is further aft. In a RV-12, you sit FORWARD of the wing Spars, your butt sits maybe 4 to 5" in front of the leading edge of the wing spars, due to the lightness of the engine.
Myself, I would love to see a RV9 built around a Rotax, 915IS Turbocharged motor making 141 HP. But as you said, the plane would need some sort of redesign, or maybe a RV-15 model or RV-16 model, to make it possible. I think that if it was the first turbocharged powerplant available from Van's, and capable of something a bit above utilitarian G load rating wise, so you don't exceed the "envelope" at 15k, it might fill a nice niche.
But don't quote me on it, Van's knows more than anyone else, what sells and what it's customers want. I am new to the game, and I'm not impressed with a motor that eats a quart of oil every 6 to 10 hour. A Rotax rarely does that, if at all, if run on Mogas and Full Synthetic motor oil. Or at least mine doesn't.