Valley Engineering Offers An Affordable Option For Ultralights And LSA.

By Gene Yarbrough

V-Twin industrial engines such as Briggs and Stratton, Kohler, and Honda are being eyed as a viable platform to convert into a light aircraft powerplant. The engines are mass produced in the millions per year and are extremely affordable compared to typical aircraft engines. Priced on the order of $2,000-$3,000 for a base model engine makes these units attractive to modify for aircraft use.

ANN spoke with Larry Smith of Valley Engineering and discussed the newest 50 hp offering. Valley Engineering started with a customer asking to have an industrial engine converted for an experimental airplane in 2005. This initial engine was developed, flown and displayed at Oshkosh in 2006. Smith said all of the companies advertising comes solely in the form of display at Oshkosh and by their website.

The v-twin engines begin life as a 35 hp stock Generac industrial unit. The company makes no internal modification other than removing the speed governor on the 40 hp version and runs it at 4000 rpm compared to a stock 3600 rpm. The newest 50 hp version, not available for sale just yet, features high compression flat top pistons intended for use in Generac's propane fueled engines, header type exhaust, and a custom ground camshaft. Smith indicated that the choice to use the Generac platform as opposed to others was driven by the fact that the Generac unit is a lighter weight engine for the same horsepower compared to other industrial engines on the market. Technical issues overcome by Valley engineering include vibration from the v-twin configuration. Smith said that the engine is quite a handful in the stock format. Valley Engineering has developed a custom designed propeller speed reduction unit (PSRU) to overcome the vibration and resonant frequency issues. The PSRU incorporates a slack side tensioner that allows the speed reduction belt to slip slightly as necessary to dampen any resonant frequencies and smooth out power impulses.

All Valley Engineering engines features a Weber carburetor. Smith said this carburetor was selected from many others that were tested because it can be adjusted to fit all their engines from the 40 hp v-twins all the way up to the 4 cylinder 125 hp VW derivative. Smith said the carburetor could be re-jetted for proper fuel mixture control and has an accelerator pump, a must-have for light airplanes according to Smith.

Smith stated that the company currently has some 35-40 units in field. The company offers a 3000 hr warranty on each engine. Smith said that there have been no warrantee claims to date, attributable to a quality base engine and a well designed PSRU. The engines start at $4950 for the 40 hp and $5950 for the 50 hp expected to hit the market in the next few weeks. All engines come with a 20 amp alternator and custom oil pressure and tachometer gauges.

When asked about the trend for industrial engines to go to electronic fuel injection engine management systems and what impact that would have on Valley products, Smith said the company is not interested in Electronic fuel injection or computer engine management systems due to their unreliability. Smith said Valley engineering wants to stay "old school" and added "Put your money in quality parts and very few of them".

FMI: www.culverprops.com