The combination of the new Jacobs R-755 A2 300 HP engine and new design MT propeller are producing almost unbelievable results. Performance is expected to improve dramatically in all areas of flight. Initial data suggest a substantial improvement in climb, 5+ knot improvement and top speed and reduced takeoff distances. The test program should be completed within the next week with official performance numbers available soon there after. We hope to have the test aircraft available for demo flights at the upcoming AOPA Summit in Tampa, November 5 - 8.
Carl’s thoughts, October 20, 2009
"The initial flight of our WACO YMF with the 300 Hp. Jacobs engine was accomplished today and although no official data has yet been developed, preliminary results were very favorable. The R755A2 engine and the new MT wooden fixed pitch propeller appear to be a perfect match. The MT prop is the same diameter as the previously used Sensenich at 92 in but with 8 inches less pitch, 60 in as opposed to 68 in for the Sensenich. With the engine having a higher rated horsepower at the same RPM, I was expecting this prop to not have enough pitch to hold the engine speed below the max allowable at full throttle level flight but was quite surprised to find that this was not the case. In fact during takeoff and climb the engine speed remained below 1950 RPM with full throttle and a climb speed of 75 IAS. This is comparable to the 275 HP version but the rate of climb was greater. In level flight at full throttle the RPM stabilized at 2200 and about 127 MPH IAS. This is 5 to 7 MPH better than the Sensenich equipped 275 version. When cruising flight was established at 2000 RPM, IAS was 112 MPH, again about 7 MPH higher than my experience with the B2 equipped YMFs. This excellent performance must be a result of a very efficient propeller blade design that seemingly combines the attributes of both a climb and cruise propeller and is able to take full advantage of the additional power available. At best power, fuel consumption will be about 16 GPH but will yield about 5 MPH higher IAS. At an economy power setting of 1900 to 1950 fuel burn will be about 15 GPH and will see about the same IAS as with the B2 version. Keep in mind this is preliminary data and the weeks ahead will allow us to produce real numbers."
Highlights of the new D model include:
- More Horsepower - new Jacobs R755-A2 300 HP with a 1400 hour TBO
- JPI EDM 930-7 Engine instrumentation as standard
- New MT Taper Tip Propeller
- Hamilton-Standard 2B20 continues as option
- Deluxe leather interior standard
- Front cockpit brakes now standard
- New lightweight wheel pants and wheel pant fairings
- New circuit breaker panel location
- Redesigned instrument panel w/ engineered vibration dampeners
- Standard ultra bright LED landing and identification lights
- Simplified avionics packages
- Relocated ground start plug and redesigned electrical system saves 8 lbs
- Redesigned landing gear pistons and seals
- Numerous serviceability enhancements