These two strips overlap the opening at the forward end by about
three feet. At this end the two strips are loose and have a
toggle inserted at the end to which the ripping cord is tied.
The ripping cord is operated from the car. It is led aft from
the ripping panel to a pulley fixed centrally over the centre of
the car, from the pulley the cord passes round the side of the
envelope and through a gland immediately below the pulley.

The nose of the envelope is stiffened to prevent it blowing in.
For this purpose 24 canes are fitted in fabric pockets around the
nose and meet at a point 2 1/4 inches in front of the nose. An
aluminium conical cap is fitted over the canes and a fabric nose
cap over the whole.

Two ballonets are provided, one forward and one aft, the capacity
of each being 6,375 cubic feet. The supply of air for filling
these is taken from the propeller draught by a slanting aluminium
tube to the underside of the envelope, where it meets a
longitudinal fabric hose which connects the two ballonet air
inlets. Non-return fabric valves known as crab-pots are fitted
in this fabric hose on either side of their junction with the air
scoop. Two automatic air valves are fitted to the underside of
the envelope, one for each ballonet. The air pressure tends to
open the valve instead of keeping it shut and to counteract this
the spring of the valve is inside the envelope. The springs are
set to open at a pressure of 25 to 28 mm.

Two gas valves are also fitted, one on the top of the envelope,
the other at the bottom. The bottom gas valve spring is set to
open at 30 to 35 mm. pressure, the top valve is hand controlled