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Old 11-18-2012, 08:10 PM
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combatpigg
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Default RE: OS 91 VRDF experts wanted

ORIGINAL: freakingfast

I first discovered how well they ran is when I'd run the engine through at the end of the day with FAI fuel. I would do this for DF and Marine engines. If you don't do this, the bearings wont last. The engine was down on power a tad and you really had to lean it. I used a clip on rolling IV clamp so I didn't have to mess with my flight needle setting. One day I was out of 30% and too lazy and didn't want to spend the gas money to get some more so I pulled all the gaskets and hoped the piston wouldn't hit the head....what the heck, roll the dice. Well it ran fine, but it was visibly down on power and the engine easier to fall off the needle setting. Perhaps It would have ran better with the pipe re-tuned for the low nitro, but it doesn't matter any more as the plane flew away from home some weeks later.

As you know, you need a clean plane (dart) and flight time is limited by tank size, however before you even consider this, make sure you have a nice selection/candidates of CF props actually in your paws, not on order, not shown in stock and not promised, just in your hands and good luck with that. Cut down and thinned wood props work, but they are very fragile and time consuming.

Thanks for the "low down" on this engine FF.
Having an assortment of props and a way to quickly adjust compression is really a must.
It sounds like a 9x9 [or similar load] would be a good "default" size to start out with on a 36 inch span delta.
I'd look at something like this as like a Big Block Vega bracket racer that the driver "short shifts" to easy 10 second runs.