DC8 vs B707
 

Can any of the older fraternity please explain how the DC8 had pretty much the same performance as the B707 in terms of payload/range and yet did not have leading edge devices.
Many tks

I have flown them both. The DC-8 has leading edge slots to improve low speed handling.

Once the wings are clean, the devices have no effect on range, so I don't really understand what you're asking here. ??

------------------

Hello Quid,

Not having had the pleasure of flying either, I must have been under the misapprehension that the DC8 family were never fitted with leading edge devices of any kind. I of course bow to your experience and declare the question therefore irrelevant. As a matter of interest which of the two did you prefer to fly?

Cheers

flew the 8,and later the 727(both for 10yrs)the dc8 didn't sweep the wing as far back as Boeing,so it had (with the aforementioned slots-with flap extension)acceptable "slow speed"(approach)characteristics.Boeing develped the"07"originally for the USAF as a tanker(kc135)needing the higher speed wing-requirering the Led's(slats/flaps) for approach handling.Cruise of M.80+ to 135k approach.This successful concept was carried over to the "27"(providing it with some 4000 airports in the US).with the call for flaps15,one recieved 48% of wing dissasembly..Both the DC8 and the B727 were excellent aircraft.The 27 as a pilots aircraft(even on one engine)the Eight as the last economic trans ocean aircraft(the 63' burn't 11000lbs/hr for 200pax at M82)

It's been many years since the 707/720. I now fly the DC-8. It's always a challenge. I don't remember enough to pick one over the other.

My favorite - no contest. It's the 727.

------------------

According to Jane's encyclopedia of world aircraft here are the comparisons:
Boeing 707-320C
powerplant:4*JT3D-7
max speed:627 mph
service ceiling: 39,000 ft
range: 5,755 miles
MTOW: 151318 kg
wing sweepback= 35 degrees

Douglas DC-8-63
powerplant: 4*JT3D-7
max speed: 600 mph
range: 4,500 miles
MTOW: 158,757 kg

But as far as looks go, the DC8-71 wins hands down!!!

------------------
"Recovery was marginal..."

Just checked my manuals and the 8 has 30° sweep at 25% chord, so according to the janes info it is definitely less, that would seem to answer the question. Just to clarify though, pegleg, your question is not irrellevant. The slots on the 8 are only on small portions of the wing just inboard of the pylons. They are much less extensive than the LEDs on the 707. I have often asked myself the same question, now I know! Thanks guys!