Following
in the footsteps of Count Zeppelin and the success of his early
rigid airships, in 1908 the British Government agreed a sum
of £35,000 which "should be allocated to the Admiralty
for the building of a dirigible balloon". This order to
build the first British rigid airship was a direct attempt to
compete with the German airship programme..
Statistics:
Length
512ft
Diameter
46ft
Speed
42mph
(anticipated)
Engines
2
x 180hp
Volume
663,
518cft
Designs
were already being submitted and on 7th May, 1909 the award was
given to the Vickers company. The original contract had been for
a ship to be constructed for £35,000, however Vickers advised
that they could construct the ship for £28,000 without goldbeaters
skin gasbags and varnished skin outer cover. The Admiralty would
be required to provide contractors for this work. Vickers also
asked if they could put up a constructional shed, free of cost
to the Crown, so that they may have a ten year monopoly on airship
construction as they did with the submarine boat agreement they
had with the Crown. On May 7th the contract was awarded, but the
10 year monopoly clause was refused.
By 1910 the British Government had committed themselves to a similar
path of air-weapon development to that taken by Germany. It was
originally planned that the ship be used for scouting capabilities.
The project to build the first ship had begun, and designated
"HMA No. 1" or more commonly known as "The Mayfly".
The design team was working on something that could match the
current Zeppelins of the time. These could fly 100 miles, carry
a crew of 26, and get to 5,400 feet with an endurance of twelve
and a half hours.
The Floating
Hanger at Cavendish Dock
The
Mayfly was built along similar lines to the very early Zeppelins,
but with some major modifications which were remarkable for
the time. Her original design intention was to be an aerial
scout capable of 40 knots for 24 hours, moorable on water
with a ceiling of 1,500 feet, with wireless equipment and
comfort for a crew of 20. The design was 66 feet longer than
her current German contemporary, the LZ-6, and she had a 50%
greater volume. Not only would this have given her a correspondingly
greater lift than the LZ-6, but, because the Mayfly was constructed
with duralumin and not aluminum (which the Germans would not
use for another four years), then further weight savings were
achieved.
The
engine cars had been hand crafted out of watertight mahogany,
each carrying one marine racing engine. Each engine drove
a pair of 15 foot diameter wooden propellers, mounted on the
outside of the gondolas, rotating at half engine speed.
Plan
of the HMA No1.
Work
began in 1909 both on the ship and also on the shed, which
was originally described as a garage. The shed, designed by
Vickers, was built from the wall of Cavendish Dock out to
piles driven into the basin floor. Once this was completed
in mid-1910, the actual construction of HMA No.1 began. The
mooring was to be to a mast, which the British were the first
to use as standard equipment. The Mayfly was the first of
the rigid airships to be fitted out with the mooring equipment
in the nose of the ship. The design of the ship was quite
revolutionary in that it was more streamlined than the contemporary
Zeppelins, and even the No. 9, 23 or 23X class which were
to follow. The shape gave a 40% head resistance compared to
existing Zeppelins. A more streamlined shape was suggested
for the Mayfly, but the Admiralty rejected it and it was not
until the R80 in 1917/18 that a truly streamlined ship was
constructed.
The
main delay between design and completion of the ship was due
to the delay in completion of the shed. The shed was to be
completed in August 1909 and the ship delivered two months
later, but in June trouble occurred with driving piles in
to the floor of the dock, and caused the shed completion to
be delayed until June 1910.
Plan
of the cabin in the Keel.
In
the spring of 1910 the new crew began training and then moved
in to the shed in September of 1910. On February 13th, 1911
the Mayfly made her static trials in the shed. The motors
were run and controls operated but outdoor trials could not
be completed until the weather moderated. It was not until
March that the crew were reported ready for launching the
great experimental ship.
A
new design of floating mast was erected some 38ft high and
a "screen" was erected. The mooring was designed
to have a steady pull of some 80 tons, however the maximum
pressure the ship exerted on the mast in a wind of 80mph
was some 4 tons, and hence a large safety margin has been
calculated.
The ship emerging from the Dock to the floating mast.
Some
details of the ship have come to light following the discovery
of the "Handbook for HMA No1" which some of the
following details have been taken :-
" crew :- Two crews were
used to look after the ship whilst out, as the work was
new. They lived on board the airship and suffered no discomfort
at all although no provision had been made for cooking or
smoking on board. At night the tempreature of the living
space was a little above that of the outside air, but as
the ship proved quite free from draughs in the keel and
the cabin, it was anticipated that with suitable clothing,
no trouble would be experienced from the cold."
Training of the Airships Crew
:
Joined January 25th 1910
February - At Messrs Short Brothers works, Battersea, receiving
the following instruction in working rubber fabric:-
Making joints in sheets on the
flat
Making joints in sheets on the curve
Making fabric pipes and joins in curve.
Making model gas bags
Sticking channel fabrics to gas bags
March - Instructions in petrol engines at Barrow. Lectures
on parting, running and adjusting 15hp Wolsley motor car
engine.
April - Signals. Lectures and instruction in aeronautics
and meterology
May - Further experience in workin gas bags and outer cover
etc.
When
the first calculations on weighing the ship had been made,
it was discovered that she was too heavy, and after removal
of fixtures weighing some three tons, there was hope that
the ship would become airborne.
After
more drastic surgery on the ship, she was hauled out of her
shed on Monday 22nd May 1911, stern first, by boats attached
to her side. She was gradually swung out of Cavendish Dock
and attached to a mooring pontoon. Whilst she was at the mast,
nine officers remained on board and engine trials were conducted,
although these were cut short due to trouble with the radiators.
On Tuesday May 23rd she withstood winds of 45 mph, and during
the two nights she was out on the lake, searchlights were
played across her so that her actions could be observed. Those
who stayed aboard had quarters in the keel and telephone communication
between the cars. The ship would still not rise so it was
decided to return her to the shed. It was discovered that
whilst in her shed, she floated for some five hours with both
gondolas some 4 feet out of the water! During this time the
engineers were able to perform trimming trials
A
drawing showning the way the ship was drawn out of the shed.
During
her time in the shed a new system was devised for removing
her from the shed. A series of electric winches would be
used to ease her out, even against a beam wind. By 24th
September 1911, the decision was mate to mover her out of
her hanger for full testing. However, disaster struck in
the form of a sudden forceful beam-side gust causing the
ship to lurch, just clearing the shed but laid her on to
her beam ends. She righted and was them being pivoted so
that her nose would point back out to the dock when there
were cracking sounds amidships and she broke in two. She
started to rise in an inverted "V" formation but
t he crew in the after gondola dived overboard and the stern
flew up in to the air.
The
wreck was returned to the shed the same day. The Court decided
that there was no one to blame of this incident and it would
be reasonable to support the story that the squall was to
blame. It was of such a force that later ships would have
also been severely damaged if they had encountered it under
the same tethered circumstances.
Images of the wrecked ship
The
ship was left to rot in her shed, when many decisions and
arguments were made in the Admiralty regarding the future
of Naval Airship operations. However her brief career had
supplied an immense amount of valuable information for British
Scientists. She may not have flown but she was not a dead
loss.
From the original handbook, it was discovered that the ship
was required to undertake a series of trials which are very
interesting to see what they had planned for the ship and
rigid airships as a whole :-
THE FOLLLOWING POINTS HAVE
BEEN CONSIDERED IN THE AIRSHIP TRIALS :
Speed in air 1 engine
and 2 engines
Speed on water 1 engine and 2 engines
Turning circle advance etc
Effect of auxillary rudders and hydroplanes
Locating mine field
Locating submarines
Ascertain time and distance traversed in bringing up
from full speed ahead
Lying at bouy
Towing
Moored to ship
Moored to bouy
Anchoring
Picking up post
Determing how best to watch a por, count shipping leaving
and entering
Dines recording charts to be kept
Vision - trying range at different heights
Practice fixing positions
Run along coastlines an note conspicuous objects etc
Take photo's of anything interesting
Carry out consumption trials
Time to rise to 800 ft
At what angle of depression a gun can be fired from
an airship
What amount of recoil is permissable
The maximum stress that could be taken up by the structure.
What gun is recommened for use against hostile airships
What gun is recommented for use against hostile aeroplanes
Gun positions in airship to be selected.
Airship chances against hostile aeroplanes
What gun should be carried for projecting explosives
for blowing up caissions of docks etc.
