Long ago...
Yes, sometimes enroute fuel stops were made, however, the record for non-stop piston ops was a TWA 1649A-98 Constellation, ORY-SFO.
Time enroute, nonstop....23 hours 10 minutes.
Keep in mind that this aircraft type, which yours truly has flown previously, was fitted with a fuselage oil tank, from which each engine's oil tank could be replentished.
In addition, it carried 9,835 US gallons of 115/145 aviation gasoline, which was also a record for a civil piston type.
It cruised at 315 KTAS, consumed 390 USGallons of fuel/hr...and if you were lucky, did not run out of oil prior to the destination.
It had a port in the fuselage top for astro navigation, and these long range flights absolutely carried a Navigator, who was truly proficient at pressure pattern navigation...which ain't easy, at least from my perspective.
My personal record in this rather unique aeroplane, 16 hours, 42 minutes, HNL-TPE.
Cruising levels.
A heavy 1649 Constellation or DC-7C would normally not get above 14,000 feet initially, for the first two hours.
As weight decreased, the aircraft could then climb higher.
Blowers (engine superchargers) were shifted to high at 13,000 feet, and a long oceanic flight would end up at flight level 210/220 eventually.
It should be noted that with these piston engine airliners, fuel consumption did not normally decrease with altitude however, the true airspeed DID increase.
These engines were always cruised at a constant power setting, usually on the order of 45 to 50% BHP, using the lowest suitable RPM.
Engine mixtures were set to auto-lean, and BMEP power recovery was used, to enhance lean of peak operation.
Last edited by 411A; 6th Apr 2007 at 06:45.