The Future Airplane

General Comments

We’re looking at two possibilities for follow on versions of the basic Phoenix concept, both involving the installation of a turbine engine to create a turbo-prop.  The first involves replacing the present Continental engine in the two seat airplane with a turbine engine.  The second involves stretching Phoenix to 4 seats and installing a turbine in that airplane.

Going to a turbine has both an upside and a potential downside.  As you know, turbine engines are inherently very reliable.  They’re small and very light and their vibration characteristics are excellent.  In addition, they’re operationally simple to use.  From a market standpoint, they’re a “hot” item.  That’s the upside.  On the downside, they’re expensive (the cost of Phoenix would almost double) and they burn a lot more fuel than a recip (you’re looking at a 50% increase in fuel consumption even at the 20,000 to 25,000 foot altitudes where they run efficiently; remember the price of oil).  So, the question is, what does the market want?  We’re looking at that and, if you’ve got some ideas along those lines, we’d be happy to hear from you so please let us know what you think.

The Two Seat Airplane           

The Rolls Royce 250-B17F turbine engine would replace the Continental TSIO-360-BD engine and is an excellent candidate for Phoenix.  The engine has a very good history with respect to reliability and has been installed in a number of aircraft.  Because of its small size and light weight (205 pounds), it would be possible to install the engine at the very rear end of the fuselage eliminating the present shaft.  The 250-B17F is rated at 450 Brake Horsepower (BHP) for take-off and we don’t need that much power for two seats so the plan would be to flat rate the engine to 55% of this power or 250 BHP.  This would enable the engine to produce 250 BHP up to an altitude of 18,000 to 20,000 feet.  Cruising at 90% of this value (normal operating procedure for turbine engines) would produce 225 BHP and, at this power level, our wind tunnel data show that Phoenix would reach a cruising speed of approximately 300 miles per hour while using approximately 24 gallons of fuel per hour resulting in mileage of 12.5 miles per gallon (mpg).  Compare that to 22 mpg at 270 mph for the Continental powered airplane and you can immediately see the fuel cost trade-offs in going with the turbine engine.  Considering the other, very favorable characteristics of the turbine engine, is this a good trade-off?  We think the jury is still out but we’re looking at it and we’d very much like to hear from you on this one.

The Four/Six Seat Airplane

We believe that there’s definitely a market for the 4/6 seat version of Phoenix and we know that the 2 seat airplane would stretch to 4/6 seats without a whole lot of trouble.  In terms of the engine, installing the turbine in the 4/6 seat airplane makes, perhaps, more sense than installing it in the 2 seat airplane in that the added fuel costs are split among 4 seats rather than two (fuel costs per seat mile, to use the engineering jargon).  The engine of choice would probably be the 657 BHP Walter 601D engine and we would, again, as described above for the 2 seat airplane, flat rate the engine to, say, 350 BHP for take-off.  Cruising at 90% of this value (normal operating procedure for turbine engines) would produce 315 BHP and, at this power level, a preliminary estimate shows that the 4/6 seat airplane would reach a cruising speed well into the 300+ miles per hour range.