Rocket with MT V-15-BCC/C198

Does anyone have any experience with the MT 2-blade propellers on a Harmon Rocket II?

Most interested in comparisons with the Hartzell 2-blade M2YR-1BF/F8475D-4 in the areas of speed, vibration, and weight.

I am trying to find a counterweighted prop that doesn't give up much speed versus the Hartzell 8475 or 8068 blade designs.

Thanks!

2 blade MT Rocket propeller

MT Propeller has just agreed to make a 2 blade Rocket propeller, so there is no performance data available from flight test.

Their standard 2 blade propeller will weigh about 44 pounds with the spinner installed.

Their counterweighted 2 blade propeller will weigh about 50 pounds with the spinner installed.

BTW, from fight testing I performed on Ted Rutherford's HR2, the standard 3 blade Rocket propeller was 2 knots faster than the Hartzell "D" blade and just as fast as the Hartzell "J" blade at 2600 RPM, or below.

Jim Ayers

Rocket with MT Prop

Thanks, Jim. The Hartzell props you referred to on the HR2 are 2-blade props or 3-blade props?

The scuttlebut on the web is that the 3-blade MT gives up about 10 knots at cruise versus the Hartzell 2-blade. Are you saying your testing showed otherwise?

I am trying to find a lighter prop (to move the CG back a little bit on the HR2), one that is counterweighted (to guard against oil system failure causing a run-away, and one that maintains the cruise speeds available with the Hartzell 2-blade.

Thanks

2 blade Hartzell's vs 3 blade MT

The flight test data I obtained in a HR2 was with 2 blade Hartzell's and the 3 blade MT propellers.

The HR2 had the "D" twist 2 blade Hartzell, and the owner already knew that at full throttle the aircraft slowed down by 3 mph when going from 2600 RPM to 2700 RPM.

We focused on full throttle performance at 5,000' for the Reno Air Races.

The 3 blade MT Rocket propeller (198-52 blade) was 2 mph faster, but had the same characteristics as the "D" twist 2 blade propeller.
The HR2 slowed down by 3 mph when we went from 2600 RPM to 2700 RPM.

The "J" twist 2 blade Hartzell gave the same performance as the 3 blade MT propeller.
Except, going from 2600 RPM to 2700 RPM, there was a 3 mph INCREASE in airspeed.
And going from 2700 RPM to 2800 RPM, there was another 6 mph increase in airspeed.

This was on a stock 260 hp Lyc. IO-540 engine.

From another source using a 330 hp Lyc. IO-540 engine, this Rocket pilot saw an airspeed decrease when going from 2600 RPM to 2700 RPM using a "J" twist Hartzell.

Sometimes there are no simple answers.

Jim Ayers