Completing the 707s turned out being a bit easier than I anticipated. I thus took the chance to re-check the earlier drawings adding some slight corrections, so please don't refer to the ones posted previously.
Moving to the various types, I've tried to split them by series, but the -220s and -420 not having any other variant except the baseline were standalone, and I opted for getting them together.
Here follows the 707 family, I've tried to go by type, featured are the 707-120, 707-120B, 707-138, 707-138B, 707-220, 707-320, 707-320B, 707-320Badv, 707-320C, 707-420, 720 and 720B:
The 707-120 is shown in the original configuration, with shorter tailfin. Starting in 1960, all were bult and retrofitted with the taller fin and the ventral fin. If anyone wants a -120 in the interim setup between the standard and the -B, just copy-paste the tail section of the 707-220.
The 707-120B is the improved version fitting P&W JT3D turbofans instead of the JT3C turbojets. The type also recieved slightly extended horizontal stabilizers (so that the elevators no longer extended to their tip) and a wing glove inboard of the inboard engines that increased its chord and area. They fitted only two sets of turbocompressors to feed pressurized air into the cabin. The ventral fin is now half the size of the original.
The 707-138 is the shortened variant (six frames removed, three fore and three aft of the wing) for extra range, solely used by Qantas. They had one less emergency exit over the wing. Apparently none got the interim large ventral fin of the -120s as they were directly converted into 138Bs.
The 707-138B is the turbofan-powered version of the 138, both as new build and as a conversion, this as well buiilt specifically for Qantas. It has the taller tail and small ventral fin, wing glove and extended horizontal stabilizer. Noticeably, actor John Travolta owned one of those machines until a few months ago, when he announced it was donating it to the australian Museum of Flying.
The 707-220 is the hot-and-high variant of the -120, fitting the more poweful P&W JT4A turbojets. It was ordered only by Braniff and five were built, although just four were delivered as one crashed during a training flight. No more were produced as it was made obsolete by the -120B.
The 707-420 is basically a -320 (extensively described below) fitting RR conway508 turbofans in place of the JT4A. Another distinctive feature is the extra HF antenna on the right wingtip. The taller tail and big ventral fin debuted on this type and were later retrofitted to all 707s.
The 707-320 is the first true intercontinental version of the 707, powered by the same P&W JT4A turbojets of the -220s. A few were initially built with the shorter tail but were soon converted to the taller one, all other new builds were fitted with it and the ventral fin from the start. Major changes from the -120/220 models were the wings, which got a plug both inboard and outboard. The fuselage was also lenghtened and the horizontal stabilizers enlarged both in area and span (6 feet total, 3 on each side). The wing-belly fairing was modified as well on the underside, now extending slightly below the fuselage.
The 707-320B switched the JT4A turbojets with the JT3D turbofans. The wing was modified again, modifying the flap setup on the traling edge and increasing its area, furthermore, the wingtips were smoothed out, replacing the blunt ends with flared ones which reduced drag and further increased their span. The wing-belly fairings aft of the wing were modified again, making it thicker, as a consequence of the revides inboard flaps and wing profile.
The 707-320C is the convertible version of the 320B featuring a cargo door on the port side forward of the wing and a strenghtened deck. This type introduced an extra pair of exits just aft of the wings, different type of secondary intake doors for the engines and new doors for the forward landing gear. Further aerodynamic improvements like extra kruger flaps (not wisible in our drawings) allowed to delete the underside fin. Most pure-cargo -320Cs lacked the extra doors aft of the wing, and in any case had all but the forwars ones deactivated, and no windows as well. Many also had just two turbocompressors. Most airlines purchased the -320Cs for full passenger service however, just because the cargo door would increase second-hand values.
The 707-320Badvanced incorporated most of the -320C changes (except the strenghtened deck and cargo door) which allowed the deletion of the ventral fin. They could be told apart from a -320C by the lack of the extra exits.
The 720 is the short-range version of the 707-120. Initially designed under the 707-020 denomination, it was renamed 720 after a request from United Airlines, which being a DC8 customer didn't want to appear as it was buying the rival 707. Compared to a standard 707 the 720 had a five-frame fuselage shrink (four aft and one forward of the wing), smaller main landing gear wheels (40 inches instead of 46), small ventral fin and only two turbocompressors. The wings got a glove inboard of the inboard engines that increased its chord and area, just like the -120B. The 720 also had just one over-wing exit instead of two, although the second was offered as an option for airlines who want to fit high-density seat configurations. Also, most 720s lacked the iconinc HF antenna at the top of the vertical stabilizer. Not all however, planes delivered to airlines that operated them on above-water routes (like air Malta, PanAm and Aer Lingus) got the antenna as well. If anyone wants the antenna or the extra door, just copy-paste from any other 707.
The 720B is the turbofan-powered version of the 720. Other than the engine swap they got the horizontal stabilizer extensions.
