View Full Version : Oswald's efficiency factor for DC-10-30
17th Sep 2006, 23:31
Does anyone have any sound references for the Oswald Efficiency Factor of the DC-10-30? I've seen 'e' quoted as .83 in the past but I would like to confirm this. Setting this value correct in my flight dynamics will greatly influence the induced drag of the aircraft.
As of now I have the e set at .879, but I think that's being a bit generous. Can anyone give me some references for confirmation? Thanks!
18th Sep 2006, 00:37
I seem to recall reading on this forum that .90 is about the maximum one can expect from today's aircraft, meaning the 777. In which case, .83 seems more realistic for a DC10 than .88
Last I heard was that the "E" had been barred. Mrs "E" was not be a computer widow.
I'm intrigued, exactly what "flight dynamics" are you referring too?
18th Sep 2006, 02:26
Every operator I rode in the 80's flew the -30 at 0.82 90+% of the time - I'm sure there was plenty of reasoning in that decision, although the level of sophistication today might nudge that slightly.
18th Sep 2006, 05:07
Hawk37, I am doing flight dynamics for an FS2004 DC-10-30 and the "E" is included in that.
Barit, thanks for the information! Sounds like .83 sounds reasonable.
18th Sep 2006, 13:50
True the "E" has been anything but well but is not barred! Mrs"E" has me very much terrified about being given the elbow if I don't hang up the goggles and silk scarf.
However the DC10 does have an Oswald efficiency factor of about 0.83
Fundamentals of Flight by Richard Shevell, published in 1989 is still in print. ISBN: 0133390608
Very good on that era of jets, the DC9 and DC10 being particularly well examined, Shevell being at the forefront of Douglas design at the time.
With regard to aspect ratio efficiency there are many factors including slenderness ratio, wing sweep, airfoil section. "e" may not be a fashionable notion but there are certain models and marques flying and proposed that would deserve a factor of 0.93 if the flight dynamics were explained in the lore and lingo of earlier times.
A famous engineer once heard that the topic he was now expected to mastermind was "quite simple really". His reply? "Don't worry I'll soon complicate it!" The notion of "e" was very good in its day when tables and graphs of all sorts of parameters were used to initially guesstimate upper and lower bounds of performance. I think you'll be okay with 0.83 for the DC10 but don't try to extrapolate from Shevells work when it comes to Company "A" and Company "B" products as currently offered. Wing design has moved on heaps.