Ed Cesnalis Posted September 12, 2013 Report Share Posted September 12, 2013 When flying behind a Lycoming, Continental or others the pilot is permitted to lean for economy and performance right up to the service ceiling where you are of course at WOT. Rotax carb engines require full rich at WOT and I thought this is a compromise. Leaning via a diaphram under the needle only leans when the needle jet circuit has control. The crudeness of this system is understandable. Why does the 912i mimic this curve and force full rich upon us when we don't want or need it, namely at high altitude and throttle settings above 92% throttle? 912s especially with fixed props are already quite limited in available power at altitude, why make it worse by motivating the pilot to throttle back even when available power falls below 75%? Link to comment Share on other sites More sharing options...
FlyingMonkey Posted September 12, 2013 Report Share Posted September 12, 2013 The curves on a lot of engines go wicked rich at or near WOT, it's a way to protect against detonation when the engine is most vulnerable to it. Probably never a problem for you, but WOT at sea level on a hot day could put you close to a detonation event if things get too lean. But there seems no reason why, especially for a computer controlled engine that should have knock sensors anyway, they don't allow safe WOT leaning at altitude. Link to comment Share on other sites More sharing options...
Roger Lee Posted September 12, 2013 Report Share Posted September 12, 2013 It's like Andy said. It's for protection and not trying to squeak every ounce of power out. Just like a two stroke is setup. Full power gets more fuel for protection. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted September 12, 2013 Report Share Posted September 12, 2013 Roger, does the 912 fuellie have knock sensors? Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted September 12, 2013 Author Report Share Posted September 12, 2013 It's like Andy said. It's for protection and not trying to squeak every ounce of power out. Just like a two stroke is setup. Full power gets more fuel for protection. That sucks for mountain flying. The 914 needs an adjustable prop but even without is better than a 912 that insists on full rich Link to comment Share on other sites More sharing options...
FlyingMonkey Posted September 12, 2013 Report Share Posted September 12, 2013 That 912 turbo kit would be pretty sweet for you CT, especially if you could set it up to be a turbo normalizer. $16K though. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted September 12, 2013 Report Share Posted September 12, 2013 That 912 turbo kit would be pretty sweet for you CT, especially if you could set it up to be a turbo normalizer. It allegedly makes 130hp. $16K though. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted September 12, 2013 Author Report Share Posted September 12, 2013 That 912 turbo kit would be pretty sweet for you CT, especially if you could set it up to be a turbo normalizer. $16K though. You have no idea, when I fly with Kevin behind a 914 we fly well over the mountains, in my CT I fly between them, big difference. Link to comment Share on other sites More sharing options...
Roger Lee Posted September 12, 2013 Report Share Posted September 12, 2013 "Roger, does the 912 fuel have knock sensors? " It has a place for it on the engine, but is not hooked up on the engine to the computers from Rotax yet and I don't know when that will happen. Link to comment Share on other sites More sharing options...
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