The comparatively short ranges of early aircraft dictated operational
limits even more stringently than today. Civilian operators faced long stretches
- especially on trans-oceanic mail flights with no fuel facilities. To the military
operator, with airships and bombers outranging their fighter escorts, some way
of keeping escorting fighters with the larger craft had to be found.
Overcoming distance was a challenge which some early trailblazers met by sacrificing
passenger and payload space for fuel. This was an answer which defeated the purposes
of commercial and military flights. Early mail flying-boats could - weather permitting
- even refuel at sea from ships assigned to the task. Extra fuel tanks could be
added - the drop tanks of the WW2 fighter being a good example.
A concept pursued up until post-World War 2 was to carry escorting 'parasite'
fighters attached to airships or bombers, for release when their services were
needed. The idea was modified for long-distance mail flights. But, despite some
awkward starts, in-flight refuelling eventually provided a working solution. Today
it is familiar enough to record only some early variations on these pages.
R.33 PARASITE EXPERIMENTS - The RAF experimented
with a small number of biplane types on the R.33 airship, by way of a self-contained
SKYHOOK - An 'air carrier' concept developed
in the United States in the 1920s and '30s, and tested on the airships Akron and
Macon, using a trapeze to launch and dock biplane fighters in the early 1930s.
SHORTS S.20 and S.21 - To increase the
range of their Transatlantic mail planes, the British Air Ministry and Imperial
Airways contracted Shorts to develop this composite design in the late 1930s.
VAKHMISTROV Z-SERIES PARASITE FIGHTERS -
The Russian Vakhmistrov parasite fighter program dated from 1931, and was one
of the earliest attempts to provide parasite fighter protection for heavy bombers.
McDONNELL XF-85 GOBLIN - A first
attempt by the United States to design a parasite fighter to be carried and launched
by bombers for defence in hostile airspace.
FICON - Although the XF-85 Goblin project
was not a success, a single SAC squadron of modified B-36 bombers carrying variants
of the F-84 was briefly active.
PRE-WW2 IN-FLIGHT FUELLING - Thought had been
directed towards the problem of fuel limiting aircraft range in WW1 or before.
From the early 1920s, sound attempts were made to refuel aircraft away from airfields
and conventional supplies.
IMPROVISATIONS - Whilst the method of
inflight refuelling by lines between aircraft was being developed, one or two
other methods were tried.
LONG RANGE FLYERS - The fuel questions
which worried trailblazing aviators were also a practical concern for long-distance
mail and passenger services.
WW2 IN-FLIGHT REFUELLING - When the war turned from
defence to offence for the Allies, the problem became one of reaching a retreating
enemy from a home bomber station.