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Post by paulopp on Jul 16, 2017 11:45:06 GMT
Hello everybody,
the only thing I miss from the DC-9 package is a cruise table. Stellan Hilmerby's fantastic SAS site offers a lot of information on the realistic handling of the SAS DC-9s (after all the HJG DC-9 panels are based on his outstanding work) and HJG offer some good handling notes but it's still guesswork what the normal cruise speeds are. Does some information on this subject exist? Or did I miss something? Thankful for any help.
Best regards,
Christian
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Post by walterleo on Jul 16, 2017 13:24:52 GMT
Hi Christian: If you google around you can find a 500 page heavy DC-9 flightmanual for free: www.google.com.mx/search?q=dc-9+flight+manual&ie=utf-8&oe=utf-8&client=firefox-b&gfe_rd=cr&ei=VWZrWd-DL4uDmAGQj5zwAgIn section 4 you find information for cruise at different altitude and wheight. As always in aviation a simple question does not guarantee a simple answer...  The manual relates to the Coolsky simulation of a DC-9 30. www.coolsky.no/aircraft/dc-9-classicBut as always in flightsimulation one can use such manuals as a guide for your own experiments. The same would hold for a real DC-9 30 flightmanual as simulated flightdynamics can differ from each other and from the real thing. I use on all my "airplanes" in my "hangar" a freeware gauge lp727.Fuelstat.gau, which calculates fuel burn, fuel remaining, time to empty tanks and range so one can check against the real bookvalues.  In this case a Tu-124 the fuelburn in kg is a bit too good compared to the real value. The gauge can display in meteric (kg,liters), in US lbs and gallons and so on. A real gem! Attachment DeletedKind regards Walter |
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Post by paulopp on Jul 16, 2017 18:40:36 GMT
Hi Walter, thanks as always for your reply. The Coolsky DC-9 is calibrated for the D-7 engines, so I don't know if the figures can be compared. Thanks for linking to the manuals, anyway. The reason why I ask is that Mr Hilmerby's site almost contains everything necessary for flying the DC-9, except that his cruise table, although referenced to as an excerpt somewhere in his manuals, is missing. I thought maybe another one here in the forum knows of it. As Mr Hilmerby used it for his MSFS DC-9 flight model, I assume some degree of accuracy. I have written an email to him and wait for response. Of course, you're right, Walter, that there will be most probably a difference between the printed figures and the reality. However, one needs a point of reference from where to start the venture. I keep your handy fuel gauge in mind, I already know it from the company DC-3 of DC-3 Airways. :-) Best regards, Christian |
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Post by aerofoto - HJG Admin on Jul 16, 2017 21:01:11 GMT
My "BASIC FLYING GUIDE" observations ("SECTION 4" of our forum based/online manual for the DC-9's) record cruise velocities of between MACH 0.76 and MACH 0.79 for each of our DC-9's. Like anything/eveything else in FS though .... these simulationms can, and will, go faster .... if one allows them to do so. Typical .... and by that I mean normal .... cruising speeds/velicities for the DC-9 should be around MACH 0.77. One doesn't really need to go faster than that (assuming one wants to try'n fly economically) .... since increasing the airspeed/velocity during cruise and over relatively short sectors (which is what the DC-9 was designed to operate) isn't going to get one anywhere faster .... so .... save the virtual fuel instead  EPR values are a entirely different matter though .... and once again these observations are included within my guides too. The engine variations composed among our DC-9 simulations are .... JT8D-1 JT8D-5 JT6D-7 JT8D-9 JT8D-15 TR8D-17 JT8D-1 and -5 represent precisely the same thrust rating .... with economy of F/F being the only real difference between both and which should be slightly in favour of the -5. All/Most D-1 engines were later replaced with, or modified to, D-5 (or later) standard. Technically speaking .... the maximum EPR values (within various temperature environments) for each of these engine types varies .... as they should .... BUT .... EPR is extremely difficult to represent accurately in FS. George managed to fudge a formulae that results in relatively authentic EPR indications (certainly within the ball park of reality) for any engine N1/N2 power settings at various altitudes and temperature environments .... but generally .... and in regard to EPR at least .... we have to accept whatever these values become/however they're presented within the se simulations due to some of the limitations of FS itself. Engine N1/N2 values for each of these DC-9 simulations (and most of our others too) are quite good .... but in regard to F/F indications .... these will always be accurate "at SL", however, we're then forced have to accept whatever these become by cruising altitude .... again due to limitations of the FS base program itself. A little bit of digressing here (above) .... in the interests of trying to provide you with a clear, full, and above all honest answer to you main query  Mark C AKL/NZ |
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