Steampunk AC-130!? The SAB AB-Series Heavy Bombers

in the years following the first world war air warfare theorists argued long and loud about the importance of their new field in 1921 italian general gileau dougherty published the command of the air a hugely influential work that laid out the premise of the importance that strategic bombing would have on future warfare the same year the outspoken and controversial colonel billy mitchell of the united states army air service conducted a live fire experiment to demonstrate that contemporary aircraft could indeed sink capital ships the evolution of the bomber which continued to gradually grow larger and heavier led inevitably to the heavy bombers that would see such huge usage in world war ii but though the bomber would grow at a steady pace in performance and size throughout the 1920s and 30s there were the occasional attempts to jump straight to this seemingly inevitable conclusion by building some absolute monsters and it is one of those that we are going to look at today in the mid-1920s the french aircraft company dile baccalan began developing a three-engine transport and passenger aircraft the db-70 while work was ongoing on this the french air ministry issued a specification for a new aircraft a four-engine knight heavy bomber deal et baccaland were in the process of going broke and in 1930 reformed as a new company society ariane bordeles or sab for short the new company thought that the basic layout of the db-70 would make an excellent basis for a heavy bomber and so developed the ab20 from it in terms of design the ab aircraft were really kind of out there the aircraft were of all metal construction and had a twin boom layout though it is more accurate to say that they had a twin fuselage as these were extremely large and provided a large amount of internal room but the main internal area was provided by the massively thick wing the wings from the first engine set outwards were of normal thickness and cold but between the engine and fuselage the wing was extremely thick even being fitted with windows it's almost like someone decided to add annexes to the fuselage or something this design allowed for a comparatively heavy bomb load at the time of 2 500 kilograms of bombs to just over 5 500 pounds defensive armament on the ab20 was located in three positions a dorsal position behind the enclosed cockpit one in a basket underneath the aircraft and another in the nose each of these seem to originally have been intended to fit a single luis gun though had the aircraft got into service it seems entirely likely these would have been doubled up the nose on the ab20 was rather unusual appearing to almost have been bolted on as an afterthought as well as containing the nose gunner it also had glazed panels for the bomb aimer and an odd probe structure which i'll admit i have not been able to determine exactly what it was for presumably some sort of pitot tube they're a rather hefty one if so power plant was four loran 12 fb coilee engines which produced 500 horsepower each the first flight of the ab20 took place on january 15 1932. maximum speed was about 130 miles per hour 210 kilometers per hour and practical range around 530 miles 850 kilometers unfortunately the aircraft also proved quite tricky to pilot probably unsurprising considering its layout and after conducting military trials in september 1933 it was returned to sap for modifications in the meantime they had been building a second improved aircraft that fitted some of the changes requested from the initial testing this aircraft the ab-21 had a somewhat smaller wingspan being reduced by about a foot third of a meter and being slightly lower the aircraft also had its weight reduced by 1 200 kilograms 2 645 pounds coming in with an empty weight of 8 450 kilograms versus the 9650 of the ab20 substantial saving the aircraft also had different engines for loran 12 ha patrels which though producing the same horsepower were lighter and more efficient the ab-21 also had a number of aerodynamic changes as well the aircraft was fitted with a cantilevered wing that did away with the strut supports of its predecessor it also had better streamlining fitted to the fixed undercarriage and fared cowlings over the wheels for improved aerodynamics another notable change was to the nose which now had a stepped double underhung partially glazed structure to it i mean the ab20 was hardly a looker but the 21 yikes it's all getting a bit warhammer 40 000 really first flight was in march 1933 and the improvements did make a difference to the aircraft's performance maximum speed went up to 220 kilometers per hour and the range increased to a thousand kilometers about 620 miles the aircraft ceiling was also improved but again the french authorities didn't think the aircraft was worth investing in and the ab21 was apparently scrapped after testing sab had one final attempt at selling their new aircraft though when the original ab20 was returned to them for improvements they decided to try and develop a new idea the ab-22 literally a flying cannon to this end they fitted a single 75 millimeter model 1897 cannon one of the famed swasant cans into the fuselage of the aircraft this protruded out of the side and under the wing firing through two of the wing support struts ironically this concept of a cannon firing from the side of a large aircraft is now very familiar to us in the shape of the ac-130 and in fact the model 1897 would evolve into the m4 and m5 cannons that would be used on american aircraft during world war ii but with the ab-22 these were concepts still to be attained the gun's barrel's location under the wing proved ill thought out when the french military tested the aircraft in live firing it was found that the shock after firing five rounds caused alarming damage to the aircraft's wing and this largely spot the end of the ab series and though a few more test flights were conducted in october 1935 the project was shut down the end to an intriguing and properly steampunk couple of aircraft

Channel: Ed Nash's Military Matters

Views: 60,653

Keywords: AB-20, AB-21, AB-22, AC-130, steampunk, interwar aircraft, French heavy bomber, Dyle et Bacalan, DB.70, Societe Aerienne Bordelaise, 75mm Model 1897

Id: ovRc1zkMDgo

Length: 7min 0sec (420 seconds)

Published: Fri Apr 15 2022

Reddit Comments

[u/Fuzzyphilosopher]

I find these things really fascinating. Maybe it's because I like the idea of a plane large enough to live out of. These even have a nice sun room in the wings to have a cup of coffee in when on a long flight.

[u/bleaucheaunx]

I'm always amazed that four little propellers could motivate this flying building into the air!

[u/curvaton]

This reminds me of that Kalinin K-7 photoshop