Conversion - T2 Nelson

Rev - Nov 11, 2017

By Dr. James R. Young (EAA 55981)
Sport Aviation

Fig-1: Nelson brother's conversion uses stock 1600cc VW with reduction drive.

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Talk to any five EAA’ers who spent a week’s vacation at Oshkosh and they are bound to relate many similar experiences. The beautiful Wisconsin countryside, the reuniting of old friends, the sunrise to sunset bumper-to-bumper traffic pattern, the thousands of hours in homebuilt and restored aircraft present, and certainly the sore feet and ragged voices at the end of each day are just a few.

Other overall impressions of Oshkosh 1971 surface weeks and months after the last tent stakes are pulled at Wittman Field. One of these is the fact that construction of smaller, simpler, lowered powered homebuilts is definitely on the rise. Perhaps it is the general economic cramp that everyone is feeling that is encouraging this trend, but nevertheless it is a fact that the smaller, lower more practical and realistic project for the average family man.

Stock 1600cc

Many of the homehuilders of these smaller homebuilts are cutting costs by turning to auto engine conversions for their powerplants. The attractive savings are obvious but problems association with this practice have been many. As if in answer to this need for a more reliable auto engine conversion, a two brother team in Southern California is offering a new package solution to homebuilders. The Nelson brothers have taken a stock, unaltered 1600-cc. Volkswagen engine and added a gear reduction system of their own design to yield the pictured powerplant.

Reduction Advantages

The special gear reduction mechanism is a bolt-on item and some of its advantages are:

  1. No alterations to a standard 1600- cc. Volkswagen engine are necessary, other than ignition harness, to yield an aircraft powerplant.
  2. There are independent thrust bearings in the gear reduction unit., therefore there is no strain on the crankshaft as there normally is on auto engine conversions.
  3. The gear reduction unit is bolted onto the flywheel end of the engine, therefore the propeller turns in a conventional manner and places the bulk of the engine weight closer to the aircraft CO.
  4. A special soft coupling in the gear reduction mechanism eliminates 95 percent of any torsional vibration through all rpm range, a major problem with four cylinder auto engine conversion.

The Nelson brothers’ work has eliminated most of the problems relative to Volkswagen engine conversions, while simplifying the actual conversion procedure. Their engine has been test stand run for over 70 hours to the point of this article’s writing with no problems. This conversion delivers maximum horsepower at peak efficiency, i.e., 4000 rpm engine operation for 1600 rpm propeller cruise rate. The prototype engine will be placed in the new Glenn Beets “Special” at Flabob Airport. The “Special” is a beautiful new single place parasol homebuilt that is near completion to meet the present trent toward simpler homebuilts.

Fig-2: (Top) Glen Beets (center) with both Nelson brothers on each side of him. (Lower-Right) Glenn Beets places his hand on
the operating conversion to emphasize the lack of vibration. The engine now has well over 70 hours of trouble-free operation

The Nelson brothers plan on making three packages available to homebuilders:

  • Plans for construction of the gear reduction mechanism;
  • conversion plans and machined castings to eliminate complicated metal work, and;
  • eventually the complete engine conversion ready for installation in a homebuilt.

More specific information can be obtained by writing to The Nelson Brothers at P. 0. Box 501 in La Puente, California 91747.