When I did a flight from KSEA to PHNL with version 1.0, I used step climbs throughout the flight. I didn't have any info to go by, so I went by "feel" (I can't think of any other term to use). As the aircraft got lighter I was able to climb higher. I have managed to get to FL410 on one flight I did, but she was light to begin with on a very short hop.

I found some interesting this info HERE. The 367-80 Prototype (1954) had a Service Ceiling of 43,000 feet and the Advanced 707-320B had a Service Ceiling of 36,000 feet. Ishall now take it that FL360 is the Maximum Altitude.

Mark

Thanks Lou. Now I need to revise the Maximum Altitude again.

Seriously though. You input is invaluable and very much appreciated.

Mark

For those who may be perplexed and not to teach anyone to suck eggs. Chasing altitude for altitude sake in these early jets is a waste of time. The wing design and engines were quite different from today's aircraft with supercritical wings and bypass fans.

Turbine and all engines for that matter, performance is rated on temps and pressures in the standard atmosphere. That is at sea level +15 degrees and 1013.25 hpa or millibars. Temperature decreases at a standard rate of 2 degrees per thousand feet and pressure by 1 mb per 30 ft. These decreases continue until you hit the tropopause where it starts to warm again.

The performance charts are designed to tell you how much you can load at the point of departure and what you can expect as a climb rate and what should be your optimum cruising level this is for planning purposes only. If you get to cruise and find is colder then you can probably squeeze some more altitude out of the bird but the tradeoof is fuel burn or lbs/nm. On a long distance flight the expected winds become critical as does the need to carry reserves.

Therefore you need to know what the current temp is at the departute point to determine whether the upper atmosphere is going to be warmer or colder than ISA? Generally tables for turbines will have 5 degree blocks but if you have a look at the 707 in the 707 perf.zip recommended by MarkOz then you will see 10 degree blocks. Not hard if is about 10 degrees warmer then it will be like that all the way up and a rough extrapolation will do.

PS - This is why not having the OAT in the Captain Sim 727 was such a pain, never knew what the temp was except by using Shift+Z.

Guys I am not sure how the model flight characteristics are put together in FSX or flight sim models but if these factors roughly equate real aircraft then a dutch roll is possible or oscillatory instability.

In the real world the game is about minimising drag (pushing the airframe through the air dependent on wing shape and aircraft shape) and maximising thrust from the engines. The four basic components of why an aircraft fly is that lift is sufficient to equal weight and thrust will equal drag. Drag is very high at low altitudes but thrust is also very high, at high altitudes drag diminishes and thrust diminishes but is a curve and the outcome is your fly as high as you can for maximum range, in general terms for jets that is between about FL300 and FL420. This generally referred to as the 'best economy band'for a jet airplane. The basic aerodynamics of jets at high altitudes v pistons at low altitudes are simple you encounter reduced aerodynamic damping, reduced stability, restricted operating speed range and reduced manouevrability, in short the margin between a stall and flying ok is small. There is then the yaw-roll couple in aerodynamics. If you roll the aricraft will then yaw or if you yaw then the aircraft will then roll. This divergence backwards and forward of rolling and yawing is the dutch roll phenomenon or the rolling and rocking described in the intial posts. The ability of the aircraft to dampen out these deviations decreases as you get closer to the stall speeds so if your at very high altititude then such behaviour is to be expected especially from a swept wing design such as the 707.

AS for the performance stuff, simple to remember, if your at Cairns Australia and the OAT is 35C then it is ISA +20 and if your at Seattle Washington at the OAT is 5C then it is ISA -10. The charts just take the complicated math away from working out what is the best altitude I can get to to to have the fastest speed and minimum fuel burn.

Hope this helps a little.

I did a flight from KSEA (Seattle) to PHNL (Honolulu) at FL360. It was more economical than I expect. That was back in the 707 v1.0. It made me believe that the 707 could be able fly about 5500nm with a 45+ minute fuel reserve. I've been meaning to do it with v1.2 to verify this, but not got around to it yet.

Mark