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.
PHOTO
GALLERY
The
floating hanger alongside Cavendish Dock, Barrow in Furness
HMA
1 under construction in the shed, notice the ship floating
above the water.
Plan
of the HMA No1.
Plan
of the cabin in the keel
The
ship emerging from the Dock to the floating mast.
Diagram of the mooring ropes and winches
The wrecked ship
Design
and Concept
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.
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.
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.
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.
Mooring
Out Trials
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
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
Wreckage and aftermath
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.
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.