Fair warning, this is a long post!
As some may have noticed, Iíve been interested in other than Lycoming options for my RV-10 build since I started six years ago. My mission, to which Iím building my airplane to achieve, is to have an efficient high performance and luxurious cross country cruiser while having flexibility to still do a sunset treetop flight from time to time. Iíve always been interested in advancement of technology and maximizing performance and efficiency. I am building a four seater to take my wife and friends/family along for the ride, so dependability and reliability is important to me as well. I am not afraid of the ďexperimentalĒ in experimental aviation, so I recognize that there is a middle ground on all of the aforementioned requirements and my middle ground may be different than othersí. With that being said, in the interest of sharing information with others and educating myself along this project, I would like to share my experience with anyone who is interested in following along. I hope this can be an interactive and positive topic and will absolutely avoid anyone trying to slam the concept just because itís not what they would do.
Iíve watched the Turbine Solutions Group, Delta Hawk, Continental, Auto PSRU, Adept Airmotive, and others all with excitement and interest but none have really gone beyond a prototype or a test stand. ACE caught my eye about four years ago with their AX-50 cylinders and ACE-540 engines. The cylinders were a new design tailored to performance and the ability to use MOGAS without all of the problems of the traditional Lycoming design. I liked it because it was enough of new technology and offered great performance / efficiency but still retained the tried and true design from Lycoming at its heart. When I contacted Andy Higgs last spring to discuss options and an order, we got side tracked with a new project he has been working on for some time. I was instantly hooked.
The newly launched Higgs Diesel E330 Hawk by AC Aero is a clean sheet, multi-fuel, spark ignited piston engine. While it is primarily meant to burn Jet A, a variety of fuels may be used with minimal performance degradation and no hardware/software changes required. The V4 design uses a modular architecture which is shown in the development of the larger E1000 V12 Condor design. A V8 version is also planned. The E330 Hawk will produce ~350 horsepower normally aspirated or ~500 HP turbocharged. It uses a unique stepped piston design and interconnected cylinders to help compress the intake air and scavenge exhaust gases. The two stroke cycle is designed to burn cleaner and more efficiently than other traditional diesel engines. This allows for lower parts count, simpler drive systems, and reduces vibrations. The crankcase encompasses the geared prop drive, accessory drive outputs, and uses a traditional pressurized lubrication system. The engine is liquid cooled using a closed loop coolant system as well as an oil cooler. It will be ~350 pounds including cooling system and accessories. Based on scaled test power plants, the Hawk will produce 275 HP at 80% power burning 8.5-9 gallons per hour. Andy is using a custom mapped ECU and closed loop systems to have a power control lever along with a prop control, eliminating any fuel mixture input from the pilot. He anticipates running a three bladed MT propeller on the non-turbo and a five bladed MT-5 on the turbo versions.
Iím working on creating a page on my build log with more information from AC-Aero so folks can learn and follow along, so Iíll update that as I get more information. You can checkout Andy's website at http://www.ac-aero.com/
. I also have a PDF document with a lot of technical information on my buildlog here
. Andy's been posting some updates on his FaceBook
page as well that folks can look at even without a FB account (I believe).
So, back to the story, Andy asked me if I had been following his project and we started talking details. To me, it fits a RV-10 perfectly! It is a bit more powerful than a 540, but not crazy strong. Itís got great performance, fuel flexibility, simple controls, and lightweight design. I see it maximizing the performance, range, and payload of the RV-10 beautifully. As I got more and more details, I fell harder in love with it. We discussed mission, timelines, and expectations and it all seemed like it was a perfect fit. The only question left was will it work???
Thatís a big, unanswered question.
Iíve been working with Andy for over a year now on the integration of the engine and we are making great progress. A few other 10 builders have jumped on board to assist even though their projects are not as far along as mine. With Andyís help, weíve been able to continue our builds with zero modifications needed until an engine is in hand. This was important to me because I already have a quote for a phenomenal 540 engine that will more than meet my needs. I didnít want to get to a point where I was too far committed to an engine that I donít have and is unproven. Iím very happy to say that thus far, itís gone very smoothly. I already had a fuel return line built into my plane and until we need the engine mount and are ready to hang the engine, I wonít stray from Vanís plans to be able to bolt on a 540 should plans change. With that being said, I am fully committed to the Hawk engine and hope to help prepare a firewall forward package for others to add to their aircraft.
While the engine is now formally launched, there are a lot of details still confidential. I can say that the first batch of engines are being assembled now for an OEM customer in the US, with my engine being one of that batch. He has also delivered two of the V12 versions which are undergoing installation on air-frames now. He has been testing a scaled down version of the engine using the same design principles for several years with excellent results. The production version of the E330 should begin dyno testing in the next few weeks, as manufacturing has gone very smoothly with only a few minor component tweaks. Currently, we are working on cooling system and engine mount design with good progress. I already have a Show Planes cowl and will be modeling up the needed modifications with Andyís guidance. We are targeting an April-May delivery of my engine and my goal is to be flying by the end of the year.
So, long post but hopefully entertaining and intriguing for those reading it. Iíll be happy to try and answer questions that are asked and share the information / progress updates as I get them. I will disclaim that I am not a partner, representative, or salesman for Andy or AC Aero, just a customer who is interested in helping and sharing while getting what I want!
Stay tuned as I slug my way through the ďalternate engineĒ story to hopefully a very happy ending!