Alternative Power Options For Experimental Aircraft
The alternative power “movement” is taking firm root. It will very likely blossom and grow for several reasons. First, we cannot reasonably expect any newly designed, up-to-date aircraft engines from established manufacturers in the power range we need; the homebuilt market at the present time is too fragmented for the development of new factory designs.
Second, conservative engine certification rules and a harsh product liability environment preclude any commercial adaption of existing auto power plants. Lets explore the possibilities. The entire idea of adapting alternative engines to a propeller has been scoffed at – at least as much as the rotary engine itself. Let us then further address misguided comments concerning modern high revving auto engines in general.
The physics of relative piston speeds in feet per minute, bearing loads, oil pressures, mass inertias of moving parts, the advantages of electronic ignition and liquid cooling somehow escape the analytical power of the “experts”. When will they recognize that today’s auto engines are built to zero mass and dimensional tolerances?
When will they recognize that today’s auto power-plants which are extensively tested at wide open throttle (WOT) are more durable than those powering our aviation fleet? Can we honestly confront our problem? As we see it, the lack of progress towards improved and affordable flying power is the collective responsibility of the homebuilder community.
The Mazda rotary engine is but one good example of the alternative” powerplant solution. The engine has compactness combined with excellent power producing capability and also extreme smoothness. The RX-7 has achieved some enviable racing milestones.
One can speculate why it hasn’t happened when considering the widespread interest generated by the Wankel invention and by the General Motors entry in the rotary race. Ross Aero is of the opinion that at the time we began looking at that engine (1979) there were at least 1,000 people in the experimental movement looking at the engine, intrigued by its potential.
Some of these people had some degree of engineering and manufacturing ability. Still many others could understand the potential of such an engine. Based on the comments posed today from our customers it is evident that several factors are working against the acceptance of the rotary engine or all automobile engines in general.
Probably the greatest single obstacle was and still is a position/attitude based or? familiarity and mental comfort (why would anyone want to challenge known engines when these were proven by long experience?).
Another detraction and a serious one could be labeled the “parrot” complex; misinformation is repeated verbatim irrespective of facts or additional study. Peer pressure by “experts” causes further misinformation to be disseminated to still other groups of people.
The rotary engine has been an outstanding example of this version of slander. Try this out on your airport pals. Ask them about rotary power for airplanes and, chances are, you will hear some or all of the following, “They make tons of power, but they don’t hold up well and they really swill gas!”, “They are noisy”, “They are heavy”, “They seize up”.
Then speak to people who own a Mazda rotary, except those with the first introductory year models (1972). You will get a more accurate picture. To be fair, first impressions may have contributed to these mis-statements; the original Mazda engines did have some problems.
Mr Yamamoto (now its president) and his team stuck behind the engine and turned it into a truly successful engine in a twenty year period fully comparable to the best four cycle reciprocating engine with its 100 year developmental history. Ross Aero is the latest star in the unique and interesting career of Louis Ross. Not content to rest on the many laurels earned during his 76 years.
Lou has energetically applied his vast and unique experience to the development of automobile engine conversions for custom built airplanes in the Experimental Category. Lou takes great pride keeping up with the latest engine trends and in sharing his knowledge with others. He loves the challenge of new concepts.
The design of engines and things mechanical are the life-blood of his enthusiasm for life. If one word could define a man’s industrial attributes Lou’s would be chosen from the following short list: creative, inventive, inquisitive, original.
He has accomplished much in his 50 years of work in the world of design, engineering and manufacturing. Not a graduate of any college he has. nevertheless, accumulated a wealth of knowledge of engineering principles, materials, and manufacturing methods equal to that of any degree holding engineer.
Lou is rightfully proud of his wartime effort. At Fairchild Ranger, as a newly hired grinder operator Lou was told to produce 28 Ranger engine cylinders a day. He produced 32 in no time and was reprimanded. Not to be cowed he re-profiled the wheel to grind the main and flange diameters producing 231 units in line day.
Disciplined and reassigned to finish grinding Packard Merlin connecting rod bolts, once again, Lou increased production eliminating the need for two other workers. This are a of the plant was not your typical cost plus ten percent arrangement. His wife being suspicious of Lou’s problems called the FBI.
They came in disguised as workers and arrested the foreman. They were later identified as members of the German American Bund and were sabotaging defense production. Lou then transferred to Bendix Marine, Brooklyn Division, where he increased production in many areas earning several government “E” Merit ‘Awards.
Promised but not paid a company incentive cash award, he quit and went into private business doing subcontractor defense work. Quality and high production of engine components led to Lycoming relocating their special machinery in his plant.
After the war, Lou was one of the few people chosen to help the U.S. Government catalog and identify war surplus machinery. He also built diesel engines for world export under the Marshall Plan and performed engine testing using the generator and resistance coil technique to measure power (1.0 HP = .746 kW).
The early postwar years were devoted to the design and manufacture of world class Ross model airplane engines of various configurations and displacements. The model airplane engines were built to high standards which contributed to their high price.
Not to be satisfied with the status quo. Lou also designed and marketed a precision part holding chuck for the machine tool industry. Later, a specialty designed Ross engine producing 10 hp with 5.25 cubic inch displacement was chosen over giants McCulloch and Continental for use in n McDonnel Douglas RPV aircraft.
Lou’s first involvement with the experimental aircraft movement occurred when the Ross R-1000 90 horsepower 61 cubic inch air-cooled engine was designed, built, and tested for Jim Bede. It featured the first use of the Ross planetary gear reduction unit. Unfortunately, the liming of this development coincided with the financial demise of the BD-5 program.
Ross Aero of Tucson. Arizona, (then Ross and Sons’) essentially began in 1979 when I joined my dad in the machine shop as a 19 year old high school graduate. A year earlier Lou’s friend and fellow EAAer, John Thomplon, became excited about the potential of the Mazda rotary engine like the one he had in his pickup truck.
That in itself was not novel; most everyone in this country was caught up in rotary engine fever during this period. John particularly was impressed by the rotary engine’s smoothness, power, size and other desirable features. He decided an aircraft conversion was in order for his nearly completed BD-4. They decided to work together.
A Model 12A engine was acquired, the R-1000 gear reduction unit was installed, and necessary modifications for cooling were incorporated in the BD-4. Although the airplane did fly, the flight test results were disappointing. Further development was obviously necessary.
Meanwhile, John’s retractable gear Mustang II modifications, Lou’s bike riding injury and other events would contribute to the cessation of the Mazda BD-5 project without any resolution. I mention the above involvement to emphasize that auto engine conversion is not a project to be underestimated.
A liquid cooled engine system that is not specifically engineered into a given airframe like the Prowler and the Pulsar designs will require an investment in additional study, time, patience, and motivation over and above that needed for the original air cooled configuration.
Having said that, Ross Aero believes the advantages of liquid cooled auto engines outweigh the obstacles. While engaged in related manufacturing work (to support family needs) Ross continued its keen interest in automobile conversions.
Added to the list of viable candidates was the General Motors 215 cubic inch engine, originally installed in 1961-63 Oldsmobile and Buick “Y” bodied cars. Reliable power in the neighborhood of 185 horsepower could be obtained within the proper gearing. Several conversions were built and flown.
By 1983 it was evident that the supply of used GM engines was growing smaller and that demand for auto conversions would grow in the future. A decision was made at Ross Aero to concentrate on the business of developing auto engine conversions for aircraft covering a wide selection of auto manufacturer offerings in addition to the Mazda rotary and GM aluminum 215.
Ross’ early work on the drone and model airplane engines pointed to the utility of reduction gearing. The numerical reduction of crankshaft rpm of high output smaller engines was the key to extracting maximum efficiency and usefulness. Early Ross tests with the model airplane engines showed propeller thrust was increased 100 percent through the use of reduction gear units.
The Ross drone engine was built in both direct and geared versions. Flying RPV (remotely piloted vehicles) trials of both versions were conducted by McDonnel Douglas. The Air Force chose the more efficient geared power-plants. More recent experience is reported in Sport Aviation.
In the February 1990 issue builder Bob Vasey describes his results using a gear reduction unit. The propeller efficiency factor when I applying actual figures to the conventional formula is over 100 percent. Everett Hatch’s work on a modified and geared Mazda engine was documented in the June 1989 issue.
We at Ross Aero conclude that the old propeller efficiency factors developed from tests on golden age high drag airplanes do not square with the results being obtained with today’s slippery designs. Today’s high performance planes can take advantage of geared engines putting out maximum torque to large blade area, slower turning propellers.
While the ground run during takeoff will be slightly longer, the appreciable increase in climb and cruise performance due to optimum torque multiplication cannot be denied. We keep a supply of engines which we use for gear reduction fitment. Factory block and flywheel tolerances on occasion introduce end play differences.
In these rare instances we provide information and co-ordinate correct fitting by fax, telephone, and our written and printed instruction. After having spoken with them on the phone we have the pleasure of meeting our customers in most cases.
People either fly or drive to consult with us in person and to visit our shop facilities. One day we had a mini fly-in, 2 Glasairs and a Long Eze! We all had lunch at Johnnie’s Family Restaurant, came back to the shop and discussed auto power flying engines.
We always have an engine on a test stand to demonstrate, currently a Mazda 13B. We also have a Mooney M20 with a Mazda engine. Our visitors take notes, photos, get questions answered, and sometimes bring their engine or we locate one with them at no charge.
It is usually during these visits that the decision to purchase Ross Aero services is made. The task of implementing an alternative engine at first may seem daunting. But when some actual conversions are studied and the many questions are answered, the job falls well within the capabilities of the competent homebuilder.
In fact, the results being turned out by our customers are uniformly and almost without exception, outstanding and well thought out professional quality installations. When someone gets stumped or needs advice or help we are always available to try to assist. In many cases it is the customer who helps us!
We find our customers have a lot of expertise in related fields, ranging from super electronics products to various engine management tasks to other currently available tricks for performance automobiles. It seems to us there is more to take from the car guys than just their engines.
Our customers make engines that run better and with greater reliability than simpler installations. By being out there in the real world doing, instead of talking about it, they are showing what is really possible.
We have the entire range from people who buy the gear box and proceed by themselves, to people who spend considerable time on their project with us in our shop (Puchaser Participation Program). For example, even though we offer engine mounts for our engines, we feel our method of making them is so superior and easy that we share this with our customers!
We recently had Jacques Genest from Montreal, Canada in our shop for one week. When he left, he had a beautiful engine mount to fit a rotary for use in a Cozy! He also took dimensions of our intake and exhaust systems and will fabricate his own. Expertise and bench time is free when buying our gear reduction unit.