ULPower engines FAQ

What is different about the ULPower engine?

The ULPower engine is a completely new engine. It looks like some of its collegues (it actually is a boxer engine), but the detailled finishing and the electronic injection make it unique.

A lot of engineering has been done to make the engine robust, simple, easily reachable for technical interventions, powerful, economical, ecologically sound and elegant. High quality components and special attention to engineering details puts the ULPower engine in a class of its own.

  • Were these special design details necessary?
    We think so.
  • Doesn't the extra work, material treatments and attention to detail increase the manufacturing price of the engine?
    It certainly does!
  • Why don't other engine manufacturers incorporate the same design details?
    What you don't know you don't miss.
  • Many of the engine components have been designed, and still are, manufactured in-house by our founding partners.
  • You think the ULPower engine is too expensive?
    You have a choice of cheaper aero engines and "auto conversions" but none offer a power plant which has been specially built for aircraft and which is offered standard with electronic engine management, fuel injection, better power to weight ratio (real shaft horsepower), and the quality finishing of the ULPower engine.

The following is a list of the ULPower engine standard design features, all included at no additional cost.

  • Electronic engine management and multi point fuel injection standard - no more danger of carburettor icing and the associated power loss of heating intake air; You get better overall power and efficiency especially if you fly in large variations of weather conditions and altitudes. The pilot doesn't need to make manual adjustments to the fuel mixture to obtain good fuel efficiency. This isn't necessary on your car - why should it be necessary in your aircraft?
  • The Engine Control Unit (ECU) uses high quality electronic components, electrical connections and wiring of the highest aviation quality (Tefzel). The wiring loom conductors are resistant to high temperatures, with each conductor completely and individually shielded in the wiring harness. The ECU has several in-built safety features which will allow the engine to continue to run (possibly with reduced power) even if  some sensors fail, relay false data and/or wiring connections break. (For further information on the ECU see ECU Reliability and ECU Redundancy in the FAQ section.)
  • Automatic altitude and air temperature compensation for optimal fuel and power efficiency - no need to change the fuel mixture settings for a richer or leaner burn depending on your flight condition or altitude.
  • Automatic choke function. The engine has a dedicated oil temperature sensor which measures the temperature of the oil in the main oil gallery. When the engine (oil) is cold, the fuel mixture will be made richer depending on the starting temperature. The colder the engine, the richer the fuel mixture will be. Accidental flooding of the engine is very unlikely and starting in very cold weather conditions will always be much easier than with carburettor engines.
  • Easy starting in hot weather. Since the fuel injection system uses a pressurised fuel flow of a constant 3 bar (43 PSI) with most of the fuel returning to the tank, fuel vapor lock is practically guaranteed to be eliminated even under the most adverse hot starting conditions.
  • Electronic RPM limiter - important to help stop engine and propeller from over speeding in cases of emergencies - e.g. dive, loss of pitch governor in constant speed or variable pitch propellers, accidental engine start without propeller.
  • High security connections between crankshaft and alternator/starter ring gear. The primary load path between the alternator flange and the crankshaft is transferred by the friction caused by the clamping force between the vertical mating surfaces of the inside of the flange and the end of the crankshaft. As a backup we have flat mating surfaces between the back end of the crankshaft and the inside of the alternator flange. The bolt responsible for the clamping force is largely over dimensioned and has thread which is opposite to the direction of the rotation of the engine. In the extremely unlike case that all pretension would be lost, the flat mating surfaces would continue to transfer the rotational motion of the crankshaft to the alternator. The bolt could not loosen itself out of the crankshaft through vibrations because it would have to unscrew faster than the crankshaft speed because of the opposite thread. We haven't used a Nordlock washer for the alternator flange because we feel we have enough security already built in to this fixture.
  • UL Power use a spline connection to mouth the propellor flange to the crankshaft. A large single bolt and a Nordlock washer ensure that the propellor flange is safe connected.



  • Five bearing crankshaft. A sixth additional ball bearing on the nose of the engine casing is used to help offset radial loading forces on the front shell bearing and also acts as the thrust bearing in either tractor or pusher configurations. This thrust bearing can be replaced without the dismantling the engine casing.
  • High quality pistons from a well respected specialist US manufacturer.
  • Over dimensioned H-beam conrods which have been stress relieved, and weight matched.
  • Powerful (ventilated) 3 phase 35 amp alternator with external regulator/rectifier as standard. (The electric current needed for the operation of the electric fuel pump, dual electronic ignition and fuel injection amounts to +/- 16 amps.)
  • Anti-corrosion alkaline zinc plating treatment standard for all steel components.
  • Quality, large dimension lines and connections for air, fuel and oil lines. (Fuel and oil connection kits offered as additional options.)
  • Long lasting, washable air filter included.
  • Stainless steel exhaust and muffler included. - Great aero engine sound.
  • Cylinder heads with very large cooling fin area especially around the exhaust port (larger heads are more expensive to manufacture)
  • Cylinder heads with predrilled holes for bayonet style CHT PT 100 probes which measure temperature inside the head instead of underneath a sparkplug which can be affected by cooling air flow.
  • Cylinder barrel underside baffling to reduce temperature differences and improve heat transfer.
  • Special metal O-ring cylinder head seals. Re-torqueing of cylinder heads has seldom been needed on any of our engines.
  • Even oil lubrication to all rocker boxes. The full oil pressure is kept up to the exit point on top of the rocker/valve stem interface. This helps insure proper lubrication even when the engine is inclined at a angle for long periods - important for a tail dragger waiting for long periods for take-off clearance.

  • Custom made filters to prevent clogging of rocker box lubrication. One custom made filter is fitted into the inlet of each rocker box. This means oil pressure is maintained up to the final outlet in each rocker box ensuring even oil flow to front and back cylinder rocker boxes.
  • Easily accessible large capacity oil pump - oil flow (not pressure) is what lubricates and cools your engine's components! At 2.500 rpm the oil pump pushes 20 l/min (5.3 US gal/min) through the lubricating circuit.
  • A remote oil pressure connection set to be able to locate the oil pressure sensor off the engine casing to isolate it from direct engine vibration and dampen oil pressure pulses. This results in longer life and reliability of the typically used resistive analogue sensors.
  • A filter is incorporated on the bottom of the oil pickup tube in the engine oil sump.
  • A centrifugal Oil/Air separator with return check valve and lines which reduces "oil consumption" through engine "blow-by" to insignificant amounts.
  • Professional finishing and attention to details (click for custom aluminium castings of fuel injection/inlet manifold - starter cap pictures) Integrated fuel pressure regulator
  • Direct drive
  • One electric fuel pump, two fuel filters, fuel pressure regulator and air filter included as standard. (Although the automotive fuel pump is considered extremely reliable, some customers prefer to install an additional fuel pump as a back-up. We offer the second fuel pump and necessary connections as an optional kit)
  • The ECU provides a rpm output signal so that a separate rpm pickup is not necessary. 2 pulses (12V) per rpm.
  • The ECU provides a signal to an optional relay which can turn the electric fuel pump off automatically when the ECU detects the engine is not running. This function has been added as a safety feature so that the ECU will automatically switch off the electric pump in case of an accident/ crash landing. When the ECU is first switched on, the pump will operate for 1-1.5 seconds to build up fuel pressure and if the engine has not been started in the meantime, the pump will be switched off. In the case a pilot prefers to be able to switch the fuel pump(s) on and off manually, the relay is not installed between the ECU and the fuel pump.
  • Turning the engine "backwards" by hand will not damage the engine.

  • Inspection and visual checking of many important components is simple and easy to perform. Providing sufficient access to the engine is available when the top of the cowling has been removed, the starter motor, throttle valve/cables, air filter, fuel injectors and lines, oil dip stick and spark plugs are all visible and accessible on the top of the engine. Not only are they easily accessible, but they can be taken off the engine without the engine being removed from its engine mountings.