ORIGINAL: cmoulder
The lightened metering diaphragm cover (Walbro's term - I was wondering what they actually call it) won't reduce the weight more than 3-4 grams perhaps, but as I learned from doing this model ''the right way'' - trying to keep it light at every step - every gram counts. It occurred to me that the standard Tygon tube I routed inside the fuse is heavier and longer than necessary, so I have already come up with a lighter alternative, reducing the weight by yet another few grams.
My tail gear is far more robust - and therefore several grams heavier - than most, but that is by choice because of my experience flying off rough grass fields. This thing really absorbs a lot of shock and complements the main gear to reduce stress on the airframe. I make my own tail gear (sometimes using the stock bracket) from 5/64'' piano and one of those cheapo wire bending tools I got from Tower. Better than any straight commercial tail gear I have used yet. My model's weight is still comfortably under 5 kg, so it is a small weight penalty I can afford.
At some point, there has to be a balance between light weight and durability.
Bob,
Here's a snap of the gear I fashioned from .078 music wire for the Extra. Used the a portion of the stock bracket which was very light and stiff carbon. The tiller arm is a 1/2" 4-40 bolt with a piece of nitrile tubing, which will get pinned to the rudder. It saved 40% the weight of the original gear, (around 8 grams....doesn't sound like much but it is).
I have the engine just about mounted. I'll take a pic of the final assembly when it's ready