David Lior Interviewed by Sander Olson

Here is the David Lior interview by Sander Olson. Dr. Lior served in the Israeli airforce for 17 years and now heads an israeli startup company called R-JET Engineering. R-JET has designed a new type of gas turbine engine that is simpler, more efficient, more reliable, and less polluting than current gas turbine engines. This engine could be used to power jets, for distributed electrical power generation, and even for solar driven turbogenerators.

The Economist recently ran an article on R-JETs technology

Question: R-Jet has developed an engine (gas turbine) that is different than standard engines. What benefits does this engine have over conventional engine ?

Answer: Our engine is simpler than conventional jet engines. It is substantially more fuel efficient, has fewer parts, is more environmentally benign, and is more reliable than conventional jet engines. So it is in virtually every respect superior to conventional gas turbines technology.

Question: How does an R-Jet Engine work?

Answer: With conventional engines the air-flow changes directions from rotational (vortex) out of the compressor to axial into the combustion chamber, and from axial to vortex at the entry to the turbine. This results in expensive components and a loss of efficiency. In the OCN (Orbiting Combustion Nozzle) engine , the vortex created by the compressor is maintained through the combustor and the turbine. The efficiency gain is 20-25% over that of a conventional jet engine.

Question: How many components are in an R-Jet engine? How many components are in a standard turbojet?

Answer: In both engines there are hundreds of parts. However, the OCN engine has 75% less hot parts which are the high cost parts. As a result, we have an engine with fewer parts, which directly translates into greater efficiency, reliability, and performance. Moreover, our engines would be only half the size of a conventional engine of comparable power.

Question: How would an R-Jet compare with a conventional jet regarding efficiency, reliability, and environmental emissions?

Answer: The Efficiency advantage is in the 20-25% range. The environmental
emissions are only a quarter of that of a conventional gas turbines . The
reliability should be superior to that of a conventional engine, due to the fewer high-temperature components

Question: How much continuous thrust could a scaled R-Jet engine produce? Could it compete with large turbojet engines, such as the GP7000 or the Rolls Royce Trent 900?

Answer:There is no limit on thrust – we can make OCN’s as large as any other turbofans. Currently our target size is around 500 kW.

Question: R-Jet has built a prototype engine. How much testing has this engine undergone? Has testing revealed any design flaws?

Answer: R-Jet has built a “technology demonstrator” and tested it for 50 hours.

Following is a summary of test results:

Question: The R-Jet engines could be used to produce electricity. How should the efficiency compare to that of conventional generators?

Answer: Electric generation efficiency is slightly lower than in piston engines. However, the overall efficiency, including generation of useable heat in CHP (Combined Heat and Power) applications – is ~ 90%. This overall greater energy efficiency is due to its low installed cost $510 /KW vs. 1,015 $/kW for low pollution IC (internal combustion) engines. It is superior economically in terms of payback and cost per kWh, as shown below.

Question: How would the cost of an R-Jet compare with that of a conventional engine?

Answer: The OCN Cost is approximately 50% the cost of conventional engines. There are fewer moving parts with our design, which results in a simpler, less-expensive engine..

Question: How many electricity generators do you anticipate that you can sell?

Answer: We believe that centralized power generation is starting to become largely obsolete. The market for decentralized energy generation is growing rapidly and we plan on selling thousands of generators per year within a decade, with each turbo-generator in the 500-1200 kilowatt range.

Question: It would seem that this technology would be ideal for Unmanned Aerial Vehicles (UAVs)

Answer: Yes, our first priority is in the decentralized generation market, but after that we plan on concentrating on the UAV market. The UAV market is supposed to double within the next decade, and UAVs spend considerably more time airborne than manned planes. So this would be an excellent proving ground for our engines.

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