411A From United States of America, joined Nov 2001, 1826 posts, RR: 10 Reply 1, posted (4 years 10 months 1 week 3 days 7 hours ago) and read 1543 times:
Only the B707-320B and 707-320B (advanced cowl) models were equipped with 14 (or 17), 25, 40, 50 flap selection detents.
All of the other B707 and B720 models used 20, 30, 40, 50.
LTU932 From Germany, joined Jan 2006, 13864 posts, RR: 53 Reply 2, posted (4 years 10 months 1 week 3 days 5 hours ago) and read 1534 times:
Quoting Blackbird (Thread starter): I know the B-720 has flap settings 20/30 and 50, is the 720B the same?
I don't think there are major differences between both. If I'm not mistaken, the 720B is the very same 720 only with JT3D turbofans, and not turbojets.
Blackbird From , joined Dec 1969, posts, RR: Reply 3, posted (4 years 10 months 1 week 3 days 5 hours ago) and read 1527 times:
Were the 20/30 settings on the 720/720B of the same effectiveness as the 20/30 settings as on the 707-120/120B
To 411A:
Were the 707-320 and 707-320B (non advanced-cowl) were originally 14/25/30/40/50, with 14/25 used for takeoff, then later (advanced cowl) changed to 17/25/40/50 with only 17 used for takeoff?
411A From United States of America, joined Nov 2001, 1826 posts, RR: 10 Reply 4, posted (4 years 10 months 1 week 3 days 3 hours ago) and read 1520 times:
Ftrguy From United States of America, joined Aug 2003, 357 posts, RR: 0 Reply 6, posted (4 years 10 months 1 week 2 days 10 hours ago) and read 1469 times:
I fly a 707-320 with CFM-56 engines. We have Flap settings for 6, 14, 20, 25, 40, and 50. We never use flaps 6 because the max speed is the same as flaps 14 due to the leading edge flaps/slats. Flaps 14 is our takeoff setting and Flaps 50 is our preferred landing setting. We will use 14, 25, 40, and 50 in the landing approach, but never use 20. We only use 20 for operational maneuvers.
Starlionblue From Greenland, joined Feb 2004, 15102 posts, RR: 69 Reply 7, posted (4 years 10 months 1 week 2 days 9 hours ago) and read 1464 times:
Quoting LTU932 (Reply 2):
I don't think there are major differences between both. If I'm not mistaken, the 720B is the very same 720 only with JT3D turbofans, and not turbojets.
I don't think there are major differences between both. If I'm not mistaken, the 720B is the very same 720 only with JT3D turbofans, and not turbojets.
Correct. JT3Ds instead of JT3Cs.
And that change turned the 720, which with it's non-fan JT3Cs always seemed underepowered, into a true hot-rod of its day. I still remember several 720B takeoffs where you felt like it could easily take off on 2 engines. Same power as a 707-320B/C but about 100,000 lbs. less gross weight. 720B was always my favorite model of the 707 family.
411A From United States of America, joined Nov 2001, 1826 posts, RR: 10 Reply 9, posted (4 years 10 months 1 week 2 days 7 hours ago) and read 1451 times:
No change to flaps setting on B720 aircraft that were re-engined with turbofans.
LTU932 From Germany, joined Jan 2006, 13864 posts, RR: 53 Reply 11, posted (4 years 10 months 1 week 2 days 3 hours ago) and read 1431 times:
Quoting Viscount724 (Reply 8): And that change turned the 720, which with it's non-fan JT3Cs always seemed underepowered, into a true hot-rod of its day. I still remember several 720B takeoffs where you felt like it could easily take off on 2 engines.
Didn't the pure jet 720 also have the option of using watercooling to achieve higher takeoff thrust, like on other pure jet 707s (except those with JT4A turbojets)?
Blackbird From , joined Dec 1969, posts, RR: Reply 14, posted (4 years 10 months 6 days 13 hours ago) and read 1289 times:
Nobody has even a general rule of thumb as to how much better the B-720 and B-720B's takeoff performance (takeoff-roll) in comparison to the B-707-120 and B-707-120B?
Viscount724 From Switzerland, joined Oct 2006, 18467 posts, RR: 17 Reply 15, posted (4 years 10 months 6 days 6 hours ago) and read 1271 times:
The following Boeing info may help. Click on "Airplane Performance" section in each and scroll down several pages to the takeoff runway length charts which shows required runway length at various weights, altitudes, outside temperatures (different charts for various models and engine options...shown at the bottom of each page).
Unfortunately the 707 data doesn't include the original -120 (non-fan) model, only the -120B and later models. Data for the 720 does include both the 720 and 720B.
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