- 650 Cubic Inch 60° V-12 Engine -
"Clean Sheet" Design
At the present time (see "Last Update" date above), our engine development program is completely occupied with the three prototype engines for our clean-sheet 650 cubic inch 60° V12 design.
As the various components become better defined, the latest engine simulation work indicates that the normally-aspirated aircraft version will produce about 810 HP at 4800 RPM on Avgas.
Recently, we have received several inquiries about an automotive version of the engine. Some initial design work on that concept indicates that if we re-optimized the intake runners and plenums, the valve springs, the camshaft profiles and a few other items, the engine could easily produce over 1100 HP at 7000 RPM (normally-aspirated).
This engine has provisions for a gear-driven, torsionally-compensated supercharger. In the supercharged configuration, engine simulations predict a power output of approximately 1260 HP at 4800 RPM.
EPI V12 - Starboard - Rear Quarter View
This powerplant can serve a variety of applications including marine, aircraft, and automotive. For aircraft applications, the powerplant includes a version of the Mark-15 PSRU which is optimized for this engine.
The weight of this powerplant, including the integrated Mark-15 PSRU, geared accessory drive system, redundant coolant pumps, redundant alternators, vacuum pump and hydraulic pump, is just over 880 lbs.
This powerplant has been completely designed in 3D-CAD and the critically-loaded components have been exhaustively optimized using contemporary FEA methodology.
As of this update (see upper left corner of this page), we are building three prototype engines for engine development.. There is a video later on this page showing the crankshaft turning in a block assembly with phenominally low effort.
There will be an extensive testing program, as well as an in-depth Spintron evaluation to assure the stability of the valvetrain and the freedom from excitation interactions between the valvesprings and the cam lobe lift and acceleration harmonics.
Most of the major components have been completed, and many of those are pictured below. We are currently working on the cylinder head castings, and expect to have samples for finalizing the 5-axis machining operations that will generate nearly perfect reproductions of the ports and combustion chamber that were developed on rapid prototype models of the head.
Because a complete engine has yet to be assembled and run, we do not have any reliable data on (a) actual performance, (b) actual reliability, and (c) engine cost. Because of the number of custom precision components and the skilled assembly required, it is safe to estimate that the engine cost will be in excess of $100K.
The following five pictures show additional 3D-CAD models of the complete engine.
EPI V12 - Port - Rear Quarter View
EPI V12 - Port - Front Quarter View
EPI V12 - Inside Thunder Mustang Cowl
EPI V12 - With Geared Supercharger
EPI V12 - Powerplant CG Location
The engine block structure is a two-piece design, with the upper and lower block pieces mating at the crankshaft centerline. Both pieces are CNC-machined from premium high-strength aluminum billet and processed in several discrete heat treating / machining operations. Both of the block components (upper and lower) are designed for extreme rigidity and strength, both individually and especially as an assembled set.
The block system includes features found in contemporary top-tier motorsports engines including multiple cooling jets for each piston, bushed lifter bores, replaceable wet cylinder liners, formed (as opposed to cut) internal threads, and an abundance of high strength fasteners.
EPI V12 - Upper Engine Block - CNC-from-Billet - finished - liners and lifter bushings installed
THIS VIDEO shows just a few of the numerous CNC operations required to produce this masterpiece.
EPI V12 - Lower Engine Block
The cylinder liners are a proprietary wet-liner design, made from a steel alloy which has a rich history as a premium cylinder material. The direct contact of the coolant to the (coated) outside surface of the liner, together with turbulent-trip features on the surface, assure an effective transfer of combustion heat away from the hot surfaces. The piston rings and the cylinder finish are specially configured for this liner material.
EPI V12 - Steel Cylinder Liner (wet)
One of the main design criteria has been to make the internals sufficiently robust to sustain operation at high levels of boost in forced induction configurations.
The engine is based on an extremely rigid, premium material billet crankshaft having seven mains and six fully-counterweighted throws optimally spaced at 120° apart and oriented so as to eliminate first and second order forces and couples.
The crankshaft lubrication system has been optimized for this application. The crankshafts are manufacatured by one of the most highly respected crankshaft companies, which also provides crankshafts to top-level NASCAR engine shops and top-level drag race teams.
EPI V12 - Premium Steel Crankshaft (weighs less than a standard BBC V8 crank)
CRANKSHAFT IN BLOCK
Now that the prototype engines are being assembled, we can proudly show some of the subassemblies. The picture below shows a crankshaft installed in one of the upper-lower block assemblies.
To see a demonstration of the immense precision achieved in the manufacture of the upper and lower block components, check out THIS VIDEO, which shows the crankshaft being spun with minimal hand-effort in a fully-torqued block assembly.
This level of operational excellence was achieved with only 0.0022 main bearing clearance (cold). That clearance is intentionally set a bit tight with respect to our main bearing diamater, in order to allow for thermal expansion at operating temperatures. This is the level of precision which is required in the production of engines at the very top levels of motorsport (NASCAR CUP, Indy-Car, F1).
The connecting rods are high precision H-beam productions manufactured by Carrillo. They are machined from AQ-4340 forgings, and heat treated to our required hardness and strength.
EPI V12 - Premium H-Beam Connecting Rod
There are different piston designs for the normally-aspirated and the forced induction versions of the engine. Both designs are very stiff, "boxed-bridge" designs, with different crown configurations to provide the target static compression ratios. These pistons are manufactured in billet 2618 alloy from our drawings by one of the leading high-performance piston suppliers.
EPI V12 - Custom Designed Billet 2618 Piston
The camshafts were manufactured for us by Comp Cams from our drawings, using hydraulic roller lobes specifically designed by Comp to provide modest acceleration rates on the opening ramps and relatively slow closing velocities to extend valve and seat life and to virtually eliminate valve bounce on closing. Several different profiles and lobe separation angles will be tested during development in an effort to find the optimal valve timing events for the intended operating bands.
EPI V12 - Three prototype camshafts
EPI V12 - Camshaft with drivegear and locating plate
The cylinder head is a fresh design which has seen three generations of evolution, resulting in a very rigid design with high-flowing, high-velocity intake and exhaust ports. With a 4.060" bore, a 2.160" intake valve and 1.550" exhaust valve, the ports flow 385 CFM and 270 CFM respectively at 0.600" lift (with 28" H2O test delta-p).
The head also contains specific design features which optimize the proximities and flow rates of coolant around the combustion chambers, valve seats and ports.
These heads are cast from a high-strength heat-treated aluminum alloy, using monolithic printed-cores to minimize internal flash, and carefully designed chills to provide optimal excellent density and grain structure. The design incorporates oil cooling jets spraying on each valve spring.
In late January 2016, we received our first castings of the cylinder head. We are currently working on the programming necessary to machine these extreme-quality castings into the superb cylinder heads that will play a large role in the impressive performance and durability of this engine.
EPI V12 - Cylinder Head Casting
This powerplant was designed with extremely-high-reliability as a primary criterion. With that in mind, we provided an accessory section that is completely gear-driven. It employs several mechanisms which dramatically attenuate the torsional excitations that are rampant on the free end of any crankshaft, assuring that all the driven components, and especially the camshaft, are highly isolated from the crankshaft excitations.
There are standard AN mounting pads for a vacuum pump (for flight instruments) and for a hydraulic pump (for landing gear). The accessory system also incudes two torsionally-isolated alternators, and two torsionally-isolated coolant pumps. And, as an extra option a drive for an air-conditioning compressor is available.
In order to provide a variety of customer options, we included a geared, torsionally-isolated drive for an optimized Vortech centrifugal supercharger. This drive is suitable to supply 150 HP to the supercharger.
The following photos show the features of the accessory section..
EPI V12 - Accessory Drive Geartrain
EPI V12 - Accessory Drive Housing
EPI V12 - Accessory Drive Housing with Gears
Engine control is based on a dual ECU design and redundant sensors for all critical parameters. Each ECU is dedicated to controlling one bank of the engine, which allows for seamless maintenance of partial power in the case of an ECU or sensor failure. Both ECU's have a "limp-home" operational mode which can sustain operation in case of failure of any of the critical sensors. The engine control system is adaptive to actual operating conditions. It has been designed to allow successful operation (at lower power outputs) on 92 octane unleaded fuel.
A large percentage of the internal components for the EPI V12 engine, including the upper and lower block components, cylinder liners, cylinder heads (from castings), rocker covers, accessory case housings, accessory drive gears, as well as nearly everything in the Mark-15 gearbox are manufactured by Burhoe Machine Works (BMW LLC) in Sonora CA.
BMW LLC have also manufactured critical components for several of our drive systems, including shafts and the entire housing set for our AVL Dyno Reduction Gearbox, and for several other dyno adapter systems we have done for clients.