Having flown the 1649 Constellation for about 300 hours, it was quite a nice aeroplane.
310 KTAS cruise at an optimum altitude of FL210 (or, as it was then, 21,000 feet) consumed about 400 gals/hour fuel and 4 gal/hour of 60 weight oil.
Fully powered flight controls (hydraulic boosted) and was quieter than the DC-7. due to the engines being further out on the (brand new, for the type) long tapered wing.
A very complicated systems airplane...typical Lockheed-style.