Vol. 4 May 2006
Velocity's Quarterly Newsletter

Mechanic's Corner

An Interesting Comparison

Duane Swing

I was looking at the spec sheet on the Mooney Ovation2 and thought it might be informative if we made a comparison between this airplane and our XL-5.

We all know that the Mooney is somewhat crowded in the cockpit with a 42.5” shoulder-to-shoulder width in the front and a 41” width in the back. The XL is 47.5 in front and 49” in the back. In addition, anyone who has ridden in the back seat of the Mooney will confirm that the only way to fit is to make the pilot and co-pilot pull their seats forward so that the back seat passengers have enough room for their legs. The most important part for most customers, however, is the cruise speed. Both airplanes share the same Continental IO 550 engine, as does the Columbia 350 and the SR 22 Cirrus. Fuel burn would therefore be the same so long as the pilot leaned the engine to the manufacturers recommendations in all altitudes.

Here are the results of a recent test we conducted here in Sebastian on a nice Florida day with the outside sea level temperatures in the low 80-degree range. All speeds are True with corrections for temperature and altitude. Verification was by GPS. I should point out that the Velocity; with 50 gallons of fuel and two souls on board, was approximately 300 lbs. under gross weight.

8000 foot density altitude (best cruise speed, best power)

Mooney (flight manual data) 23” manifold pressure (full throttle)

and 2500 RPM.

  • Ovation2 speed = 189 knots. (flight manual)
  • Columbia 350 speed = 190 knots (advertised)
  • Cirrus SR 22 = 180 knots (advertised)
  • Velocity XL-5 = 206 knots (full throttle and 2450 RPM) TAS

The Velocity using the same engine is 17 knots faster than the Mooney, 16 knots faster than the Columbia, and a whopping 26 knots faster than the Cirrus

Data for higher altitudes was not available for the Columbia or the Cirrus but was for the Mooney and here is the rest of the story.

At 10,000 foot density altitude, the Velocity was 22 knots faster than the Mooney. 183 knots for the Mooney and 205 knots for the Velocity.

At 14,000 density the difference was even greater. Mooney was 176 knots and the Velocity was 202 knots. 26 knots faster than the Mooney.

All this was using the newest M-T constant speed propeller. The blade design has been slightly re-designed for the higher horsepower, higher speed of the 310 horsepower XL.

We are very pleased with all of the numbers we see and for those of you who are building the XL with the Continental IO 550 engine, you will be too.

Don’t get confused with indicated airspeed and true air speed (TAS). True air speed is a computed speed based on outside air temperature and altitude. As to a comparison, this is what is used by all aircraft manufacturers and is what you will see in the pilots handbook and advertise specifications.