Percival/Hodges Safety Cell
This article was written by Rosalind Nott and appeared in
Powerboat and Waterskiing Magazine, January 1985.
The day of the cockpit is upon us. At the time of going to press
(Dec 1) the first Percival Hodges Safety Cell had tipped the scales at only 55
pounds. Bill Brown’s UIM cockpit had advanced to the main structure being
completed with the deflectors still to
be added and estimated weight was around 20 kilos.
From here the process does not get simpler – but certainly more
interesting from a spectator’s point of view. Now it’s time for testing. This
little exercise requires money, skill and hopefully a vast amount of
co-operation from the Royal Navy. It is
proposed using the experience of MIRA, the Motor Investigation Research
Association, to strap a scientific dummy into the cockpit and drop it over
100mph into water at low altitude. Technicians will record the effects to the
body while the safety cell will hopefully remain intact.
The anthropomorphic dummy is designed for use in water. Although
the main skeleton is constructed in metal the interior foam will be replaced
making the dummy semi-buoyant and semi waterproof.
In the case of the Percival Hodges safety cell the dummy will be
held in position by means of a six-point Nilam harness, identical to that used
in Formula 1 motor racing. Apart from the cell being sufficiently strong to
withstand the tremendous impact with the water the main concern centres on the
most exposed area of the body, the neck and head. To this end six accelerators
will be fitted in the neck and chest areas of the dummy. Signals from the dummy
would be recorded via a cable to an instrumentation tape recorder carried in
the helicopter. This is where the skill of the operation lies. Dropping a
cockpit into water from a helicopter is one thing, but it is imperative that
the movement of the body be recorded on impact. The cable from the dummy into
the helicopter would be attached by a simple jack-plug system, and would be
allowed to play on for a suitable distance beyond which they would part
Should the safety cell prove successful, the need for a bulbous
flotation jacket is not necessary. To this end, Hodges has had conversations
with Bill Fauntleroy of Lifeline Jackets USA. Fauntleroy understood perfectly
the requirements for this concept and has produced a jacket to be worn during
testing. Although made of impact material, flotation has been kept to a minimum
and special attachments will include arm restraints, to ensure they stay within
the protective cell during an accident and restraints onto the helmet. These
will also assist in the restriction of head movement inside the cell, especially
with the new high-sided Hodges cowling.
As far as the helmets go, testing should prove interesting.
Everitt W Vero have donated two of the open face Grand Prix Kevlar version, one
modified to take the restraints to the lifejacket, as worn by both Roger
Jenkins and Gina Campbell. After their accidents both Jenkins and Campbell
appeared relatively unscathed.
Of equal interest will be the Revolutionary helmet designed by Bob
Nordskog, publisher of US Powerboat. Although people are under the illusion
that no helmet has ever been designed specifically for powerboat racing, let’s
put the record straight, Nordskog did
just that – and some 7 years ago to boot. The helmet is more like a Skull Cap
fitting the head of the occupant from a plaster cast of the head. Its small and
its light and Nordskog is convinced it’s the right way to go. So have many
others. This helmet will have arrived from America along with the lifejacket in
So everyone is ready for the off. Mira, Hodges and Lifeline, Nordskog
and Everitt Vero, and Brown. The powerboat racing world are just waiting for
the Royal Navy to drop the green flag and set a date for testing.
The whole programme of testing will be videod and high-speed
cameras capable of 3000 frames per second will record for posterity whether the
dummy lived or died. Whatever the outcome, even if the total experience is a
failure – no-one can say that a lot of effort, enthusiasm and world-wide
co-operation has not been extended. If the project could be measured on good
will alone – the dummy would probably stand up and walk away ******.
The following article was written by Rosalind Nott in Powerboat
and waterskiing magazine, February, 1985
Well, it finally happened. After four and a half months of
intensive research, testing and finally construction, the Percival Hodges
Safety Cells were tested.
In Arctic conditions on January 14 those who were integral parts
of the test team arrived. Personnel from MIRA, the Motor Industry Research
Association, headed by Mike Kenefeck began to dress the scientific dummy in a
dry suit. The head and chest were fitted with accelerometers to record the
movement on impact and specially coiled wire, some one hundred metres in
length, was carefully positioned onto the front of the first cell.
It had been no easy task to reach this stage. Initial flight
trials to carry the cockpit at speed as an underslung load, resulted in violent
yawing as the cell lacked any directional stability. Fitting a plywood fin to
the back of the cell afforded a keel, and stabilised flight was eventually
achieved. Chris Hodges had bought ten fins, one for each drop.
The next part of the programme was possibly the most difficult to
overcome. MIRA’s plan was to locate the recording equipment in the helicopter
and the readings would be obtained from the dummy via a multi-cord umbilical
cable. Once the cell was released from the helicopter hook, the cable would be
payed out until the cell hit the water, it would then break free from the
helicopter after a sufficient time to record the impact accelerations. That was
the idea. You can imagine the lightweight cable running out of a helicopter in
forward flight, at high speed and low altitude posed the possibility of it becoming
entangled in the tail rotor or even flick up to the main rotor.
This problem was solved by using a 20 foot remote electrically
operated hook supplied by Dollar Helicopters, whose ingenious team had
volunteered to fly for the testing. In this way, the cell could be released
from a point 20 feet below the helicopter and the recording cable would break
free from that point. It was calculated that 100 metres of cable would give
between 1 and 2 seconds of recording time before breaking the weak link at the
remote hook. Hence, the cable was coiled in a manner similar to the Coast Guard
life-line rocket and taped to the nose of the cell. After a final flight test,
witnessed by the Civil Aviation Authority
Inspector, it was all set for the morning of the 14th.
Draycote Water played host to this bizarre gathering of men and
machinery with the yacht Club offering vital hot food and liquid. The dummy,
sporting the Everoak Grand Prix Kevlar open face helmet looked remarkably
realistic sitting in the cell. At last the sound of the helicopter blades
filled the air and the Jet Ranger landed next to the entourage of motor home,
transporter and the cell.
Having discussed the most advantageous position for dropping to
gain maximum tail wind, the helicopter hovered while the MIRA team hooked on
the cell. Mira, Dollars and Chris Hodges managed to manoeuvre with complete
professionalism, as if they had done it a million times before. Few realised
that MIRA had never worked with water before, Hodges had no idea whether the
whole exercise would end in a broken cell on the first drop, and Dollars had
the difficult job of flying at the legal speed at low altitude and hoping that
all went according to plan.
The helicopter took off flying over the water with the cell, now
perfectly stable, dangling underneath. At last they came in for the first drop.
‘Down 10,’ said one controller to the helicopter, ‘down another ten,’
‘three, two, one, drop’ and the hook
unleashed the cell. The ground speed was 105mph. The noise of the cell reverberated
over the lake and the Opsrey Rescue boat rushed in. It seemed hard to believe
that there was not a mark on the actual structure externally. Hodges even managed a small grin as this
first cockpit was well below the strength of the second.
The drops continued during Monday with ground speeds reaching
115mph, and eventually damage began to show in the shoulder area. The
scientific dummy, unlike a human, is constructed of steel bars and the impact
of this hitting the side of the cockpit, led to considerable external
delamination by the third drop. The structure, however, remained intact and
still did its job of protecting the driver. On the final drop, Hodges was
intent on smashing the cell and it was dropped from a good 100 feet. The cell,
with its damage, stayed intact with the inner skin still in position. Few
doubted that the cockpit was strong enough, but what about the dummy?
It was noted that the dummy’s knees had come into considerable
contact with the dash and no doubt this would have broke his legs and further
work is needed here. Also the helmet, on contact with the rear head support,
The Tuesday dawned with even more snow, fewer people, but the
second cockpit, weighing 29kg, took its punishment. Eventually, the same damage
at the shoulder section appeared but it was interesting to note the effect a
polycarbonate full face helmet which was used.
The full report from MIRA was not ready at the time of going to
press, however, the third drop had been analysed. From the movements of the
dummy’s head it was concluded that on this drop the dummy would not have
incurred any serious injury. MIRA count concussion as serious injury. The
remainder of the results on first sight look optimistic, but by next month we
will know how many times the dummy survived.
Bill Brown’s UIM cockpit, made of aluminium honeycomb was also
dropped on the Tuesday afternoon. There had been no opportunity prior to the
full testing to examine or flight test Brown’s cell and therefore a fin was
borrowed from Chris Hodges. The flying
characteristics were not similar and therefore the drop was executed at 65mph.
Unfortunately, there was structural failure and the rear buoyancy and head rest
fell off which in turn released the safety harness at the top. The main structure
suffered a split seam and one side was bowed. There is no doubt that an
aluminium honeycomb cell constructed in the correct manner would withstand high
speed impact, however, these structures are akin to Formula 1 motor racing
chassis. To this end, powerboating must look to their expertise and
constructors have moved away from aluminium honeycomb in favour of
So to the conclusions of this exercise. I doubt that powerboat
racing in Europe has ever seen such a professionally organised operation, and
they may never see it again. The funding of the Percival Hodges safety Cell
came from British American Tobacco,
Mercury Marine, Outboard Marine Corporation, Pro-One, Champion Spark Plugs
and the Water safety Research Fund.
It was interesting to note who came along to view the testing.
John Reed, Len and Eddie Britnell, Phil Stacey (UIM observer), Jack Leek from
America, but the only driver/constructor to appear was Cees van der Velden –
and he stayed the full two days. It remains a total enigma to me that after the
traumas of last year that more drivers from other formulae did not come along.
For once, this was an exercise that anyone could attend.
Videos recorded the full events and have been shown to the UIM.
Copies will be available for interested parties along with a full explanatory
tome of how to construct and work with composites. But this is only the first
stone at the bottom of a giant pyramid. At the end of the day, however, it is
the drivers' opinion that counts above all others. Renato Molinari is not
against it and Barry Woods would like to sit in one. Velden says his team will
run them this year.
If the results from MIRA are positive, it would seem that you
would be pretty stupid not to sit in one. Obviously, the leg area needs
modifications and it was decided generally that shock absorbent material should
line the cockpit, to protect the driver from the sheer strength of the cell if
both come into contact.
Personally, I was impressed with what I saw. As a legacy to his
partner, Tom Percival, I think Chris Hodges has done a superb job.