avicom

FREQUANTLY ASKED QUESTIONS

     Q? Why does the 700E have such a high operating RPM? Is this normal for a four-stroke engine?

A.     The 700E was designed to get two-stroke like power output from a four-stroke engine. The way to get      more power from a given size engine is to make it do more work, meaning more RPM. The operating RPM      range of the 700E is normal for an engine using modern motorcycle technology. The Rotax 912 four-
      stroke has a similar operating range.

    Q? Why does the HKS have a gearbox, isn’t direct drive lighter and simpler?

A.     The larger the propeller, the more thrust it will produce, particularly at the relatively slow climb speeds      of light aircraft. More low speed thrust means more climb. As well, there is the great benefit of much      lower propeller noise than direct drive. The 700E gearbox has two ratios available 2.58 and 3.47 to 1.

    Q? Can the gearbox be positioned up or down? Is it a big deal to swap the position? Can the engine be      run inverted?

A. The gearbox can be positioned up or down. To change the position the front cover is removed and      rotated. The HKS 700E cannot be run inverted.

     Q? Why does the HKS have separate oil tank? And what is a “dry sump” engine?

A.          The 700E has a separate oil tank to reduce the package size of the engine. Most conventional aircraft      engines are dry sump for the same reason. A “wet sump” engine has it’s oil supply in the oil pan at the      bottom of the engine. A “dry sump” engine has a separate scavenge pump to take the oil from the bottom      of the mini-sump at the bottom and a supply pump to send oil under pressure through the engine.

     Q?   Can the HKS engine be used in pusher installations?

A.          Yes. As a matter of fact the 700E has been designed to work specifically in both the pusher and tractor      configurations. A majority of the hundreds of engines sold are operating in the pusher configuration.

       Q?   What type of engine mount does the HKS have? Do you sell mounts?

A.             The 700E has a base mount similar to but slightly different than the Rotax. There is also a      requirement      that that the engine mount has a hole for in the center for the sump to fit into. We can      work with you with      the design requirements or send you to an HPower Approved Dealer or OEM for      more help. We have      worked with the many airframe manufacturers to develop mounts. We feel that      this is the best way as they      know their planes requirements.

     Q?    What type of fuel does the HKS require? Can it use 100LL?

A. Automotive Unleaded-high test is best. 92 octane Unleaded is typical. 100LL Avgas can be used during cross countries without worry. Constant use of leaded fuels requires different lubricating oils to be used to avoid lead deposits.

Q? What is the fuel consumption of the HKS?

A. The fuel consumption in typical operation is between 2 gallons and 3 gallons an hour. In our testing, the fuel consumption we have noted is 2.5 gallons an hour @ 75%. The Dyno testing according to the JIS (Japanese Industry Standard) requires the engine to be tested in a manner that does not reflect propeller loading. This makes HKS’s consumption numbers very conservative.

Q? What type of propellers work best for the HKS? Are they readily available?

A. After testing more then 30 different types, mark Beierle, the developer of the EARTHSTAR Ultralights,
found that the best propellor for the HKS on EARTHSTAR AIRCRAFT is the french DUC-Helices, a forget
carbon-fibre ground adjustable pitch 3 blades unit.

Q? What type of exhaust is required? Can you run straight pipes?

A. The 700E was designed as a complete system. There are requirements for back pressure and length of the exhaust manifold as a part of the system. Both the intake and exhaust manifolds are optimized for a flat torque curve.

Q? Are the carburetors used on the HKS altitude compensating? Why don’t they use Fuel injection?

A. The Bing C.V. (Constant Velocity) carburetors are capable of 50% mixture compensation to approximately 10,000 Ft. due to the CV design which uses a diaphragm-slider to vary the mid range mixture. The Rotax 912 four-stroke uses the same carburetors.

Q? How much does a complete engine package cost?

A. HPower sells the 700E as a complete system. We have chosen the best accessory components we could find to match the quality of the engine itself.

Q? What is the warranty on the HKS 700E?

A. The Warranty is one year or 100 hours of engine time.