Take a look at the fastest civil light aircraft in the world. It can reach a top speed of Mach 0.935 (1135km/hr) at a cruising altitude of 51,000 feet - up where the sky is purple.

http://www.cessna.com/citation/citation-x

Fly from Perth to Sydney 80 minutes faster than the fastest commercial flight. (or a bit under 3 hours depending on the Jet Stream and Air traffic delays)

http://www.aviationearth.com/wp-content/uploads/2010/09/cessna_citationx.jpg

It's a steal at about $A25 million. Dream on.

So what is the fuel burn on something like that?

This is closer to my price range, the Long ez are usually built in home garages.

This one has a V8 engine can cruise 260KPH while getting 40mpg.

www.pursuitofflight.com/longezv8.html

40miles per Imperial Gallon? or US.

The Citation X burns 336 gallons per hour at cruising altitude. That would be US gallons  (I presume) so  that's 280 imperial gallons for 1135 km (705 miles). By my calculation, that's 2.5 mpg or 30 passenger miles per gallon.  That's pretty impressive for an aeroplane that flies at transonic speed.

An interesting exercise anyway.

That would be US gal and true airspeed not indicated airspeed.

So 336 US gal per hour for cruise at altitude, it would be over 500 gph for take off and low level speeding, i dont think i have seen a turbine that does not guzzle the juice.

The US military built a Long Ez and studied it, Nasa have done the same so lots of good info on that plane.

From Burt Rutan who designed it-

Quote:

At 8000ft altitude with 1325 lbs (max weight) the cruise optimum speed is 140 knots (161 mph) and requires 47 thrust Hp (55 BHP)

He says in the video the V8 gets 6 gph at 200 mph, at 250 mph it burns 16 gph.

I will probably go a Rotax 912 which is around 90 lbs lighter than the 0-235 lycoming, also has a lower BSFC at the required power outputs.

The V8 will make the plane overweight which will increase take off and landing speeds, not to mention questionable safety by flying faster than Vne.

Jim Price set an altitude record for non turbo piston engined aircraft in his Long ez at just over 35,000 ft.

Good luck to you. Keep us informed how you go.

Yeah, I figured about double for take-off but I couldn't find any details. Citation has a reputation for good fuel efficiency, but if you're flying at Mach 0.935 even at 51,000 feet, the drag factor would be around 5 or so.

As far as large commercial passenger jets are concerned, the 747-400 achieves  90 passenger miles per US gallon.

I believe that they are building two private A-380s.

Pure luxury with all the trimmings,

No idea who is getting the other one,


OC