David Paule
Well Known Member
The one I flew was new, having just flown off its 40 hours. It is not in an RV-12. The focus of this will be the engine and things to consider for adapting it to an RV-12.
This engine has an AeroVee throttle body fuel metering device. I hesitate to call it a carb and it's not a fuel injector. It took most of the 40 hours to get the AeroVee set up to deliver roughly the correct fuel-air mixture.
Even now when the throttle is changed, the pilot must adjust the mixture as well.
The engine started very easily and quickly. It idled well and ran smoothly the entire range of rpm. It was one of the smoother engines I've flown behind and it wasn't very noisy in the cockpit, at least compared to the Lycomings and Continentals I more often fly.
The prop was a fixed-pitch Sensenich, and gave a powerful acceleration when the throttle was pushed forward. The plane probably weighed around 1,240 pounds, more or less, and the acceleration was remarkable. At one point while flying we accelerated from about 100 to about 140 mph IAS and I could feel the acceleration.
Climb speeds were necessarily fast due to the need to provide cooling. This engine runs on the hot side. With some tweaking by the builder, there's enough air to keep the oil cool, but the cylinder heads need speed to cool them. The builder is still working on that.
We flew up to about 9,000 feet (with a field elevation of around 5,000') and there was sufficient mixture range to handle that altitude. Our speed range during the flight was from about 45 mph to about 155 mph true. We spent a lot of time at about 100 mph IAS, with good cooling and loafing along at around 2,800 or 2,850 rpm. Above about 3,000 rpm, even in level flight, cooling becomes an issue.
While cylinder head cooling is definitely an issue, the EGT was unusually consistent for all the cylinders, at any power setting or speed.
We seemed to burn roughly 7.3 gallons per hour fuel for the flight.
The only installation issue that I'm aware of is that the oil drain plug is in an awkward location, and the exhaust pipes are adjacent to it.
The impression I had, having flown the Rotax RV-12, is that this engine would make a suitable powerplant for the RV-12. But some good engineering would have to go into designing the cooling system. If a different fuel metering device other than an AeroVee is used, and personally I'd hope that the AeroVee is not used, then some of the issues might differ.
I'd expect that the higher prop rpm would somewhat reduce the prop efficiency compared to the Rotax, but that the extra power would make up for that.
Dave
This engine has an AeroVee throttle body fuel metering device. I hesitate to call it a carb and it's not a fuel injector. It took most of the 40 hours to get the AeroVee set up to deliver roughly the correct fuel-air mixture.
Even now when the throttle is changed, the pilot must adjust the mixture as well.
The engine started very easily and quickly. It idled well and ran smoothly the entire range of rpm. It was one of the smoother engines I've flown behind and it wasn't very noisy in the cockpit, at least compared to the Lycomings and Continentals I more often fly.
The prop was a fixed-pitch Sensenich, and gave a powerful acceleration when the throttle was pushed forward. The plane probably weighed around 1,240 pounds, more or less, and the acceleration was remarkable. At one point while flying we accelerated from about 100 to about 140 mph IAS and I could feel the acceleration.
Climb speeds were necessarily fast due to the need to provide cooling. This engine runs on the hot side. With some tweaking by the builder, there's enough air to keep the oil cool, but the cylinder heads need speed to cool them. The builder is still working on that.
We flew up to about 9,000 feet (with a field elevation of around 5,000') and there was sufficient mixture range to handle that altitude. Our speed range during the flight was from about 45 mph to about 155 mph true. We spent a lot of time at about 100 mph IAS, with good cooling and loafing along at around 2,800 or 2,850 rpm. Above about 3,000 rpm, even in level flight, cooling becomes an issue.
While cylinder head cooling is definitely an issue, the EGT was unusually consistent for all the cylinders, at any power setting or speed.
We seemed to burn roughly 7.3 gallons per hour fuel for the flight.
The only installation issue that I'm aware of is that the oil drain plug is in an awkward location, and the exhaust pipes are adjacent to it.
The impression I had, having flown the Rotax RV-12, is that this engine would make a suitable powerplant for the RV-12. But some good engineering would have to go into designing the cooling system. If a different fuel metering device other than an AeroVee is used, and personally I'd hope that the AeroVee is not used, then some of the issues might differ.
I'd expect that the higher prop rpm would somewhat reduce the prop efficiency compared to the Rotax, but that the extra power would make up for that.
Dave
