Austin Racers
The
Grasshoppers
Barry Lovelock
Why were these cars given
the nickname “Grasshopper” which has stayed with it over the years.
It is believed that Bill Sewell, Lord Austin's personal aide, was
the author of the name, inspired no doubt by the well known Austin
Seven reaction to the initial transmission of power from engine to
axle!
It
was in the Easter of 1935 that the company announced it would be
entering the MCC Lands End Trial, with a team of three “Special
Austin Sevens”. At the time they were described as Austin Seven
“Speedy” sports car with a body similar to the Singer of the day.
competing in the hands of Messrs. Orford, Milton and Richardson.
Mechanically the cars differed very little from the Speedy. They
had two-bearing pressure lubricated engines and as the competition
dept. extracted more and more power out of them they experienced a
great deal of crankshaft trouble. Eventually Laystall Engineering
made a special 1 1/2inch cranks which helped, but was not a
complete cure. The inlet manifold and carburretor was "Speedy" as
was the exhaust arrangement which ran under the chassis to the rear
of the car. The petrol tank which was immediately behind the seats
and held 6 gallons incorporating a quick action filler cap, to the
rear of this was two spare wheels. One of the main distinguishing
features was the radiator cowling which was very modern and clean
looking.
Barry Lovelock
The dash consisted of a
match pair of 5 inch diameter instruments for the speedo which
shown a max speed of 120 MPH and the tachometer that went up to
8,000 RPM. Small instruments included an ammeter, oil pressure
gauge, water temperature gauge and an ordinary time clock. Gear
changing was by means of a nice remote arrangement. Visibility was
through a fold flat rather shallow windscreen.
It
was quite normal in those days to register racing variants of
models, so the first three cars were registered AOV 343 (25.3.35),
AOX 3 and AOX 4 (4.4.35). Below is AOX 3 competing in a reliability
trial doing a stop and restart in around 1935-6. The driver is a Mr
W.J.Millton who was a Dental Surgeon in Welbeck Street in the West
End of London. It appears that he used to use Douglas motor bikes
for trials, but became a friend of Herbert Austin who persuaded him
that he should have a Grasshopper.
Soon after a further four
cars were built so as to compete in the Le Mans 24 Hour Race. The
bodywork of the Le Mans cars was very similar to the original
three, but cycle type wings were fitted front and rear. Quick
action fillers were used on the radiators. They did, however, have
the benefit of a Murray Jamieson designed aluminium cylinder head
with a long water take off running almost the full length of the
head to aid cooling and fitted with 14 mm. plugs. These cars were
all registered on 24th May, 1935, with the registration numbers BOA
57 – 58 – 59 – 60. The Le Mans competition numbers allocated to the
team were 59, 60, 61 and 62. which must have caused some confusion
because of the registration numbers. In the Race the team had mixed
fortunes, as two retired and two finished in 27th and 28th places
out of 28 finishers.
1937
Trials
On returning back to
Longbridge they were fitted out to complete in Reliability Trials ,
these events were similar to the current Production Car Trials and
many manufactures took part as a good way of publicising their
products. The cars performed well but really needed more power, so
for the 1936 Colmore Trial one of the cars was fitted with a
"Blower" and the modification proved to be a great success. All the
remaining cars were then modified using a Centric Type 125
supercharger. The blower which was driven by a V-belt from the fan
pulley, sat on the forward end of a very neat aluminium manifold
which replaced the "Speedy" manifold previously used. On the rear
of this manifold was a blow-off valve which was preset to 6
lbs./sq. in., but later increased to nine. The blown two-bearing
engine would rev at 7,000 r.p.m. although most torque was developed
low down. The cars had a top speed of around 80 m.p.h., achieving
60 in third. The SU (1 3/8ins) carburettor used in downdraught form
with the dashpot lying horizontal was mounted directly on the
blower port, it was the fitting of this SU which caused the rather
inelegant bulges that appeared on the bonnets of the Grasshoppers
when in Trials trim. Supercharging was never used when the cars
were raced.
The Company decided to
build a further four cars for the 1936 Le Mans. The four cars were
registered on 12th May 1936 as COA 118 – 119 – 120 – 121 and were
soon down at Brooklands testing. Very few alterations to the
bodywork were made as compared with the 1935 Le Mans cars, although
to save weight the doors were omitted, the 10-gallon fuel tank was
used and once again cycle type wings. The engine was now in
three-bearing form and had a crankshaft with fully circular webs.
The oil feed to the centre main bearing was via a copper pipe
delivery direct from the main oil gallery which later turned out to
be a major problem. Shell bearings were used on the big-ends and
the con-rods were fully machined all over. The cylinder block had
larger water passages around the valves and ports, the connecting
water passages between block and head were elongated slots, and the
internal sweep of the inlet ports was different from other Austin
Sevens. The block was attached to the crankcase by 10 x 3/8th
studs. The block was also "taller" than standard in order to
accommodate unusually long valves. Very powerful double valve
springs were used to partner a fairly ferocious cam profile. Tappet
blocks were short and adjustment of clearance was effected by
grinding tappet "buttons" to the correct thickness. "Speedy"
manifolds were used as the engine was run without a supercharger.
The wheel and tyre size remained at 19 inch x 3.50
Because of industrial
unrest in France in 1936 the 24-hour race was cancelled, so the
cars were mothballed to await the 1937 race. In 1937 they decided
to only enter three cars. Again little modification was carried
out, but one of the changes was going down from 19in wheels to
17in. but with larger section 4.00 tyres, which only reduced the
rolling radius slightly, so that the gearbox ratios could remain
the same but they greatly improved the road holding. Disaster
struck again as all three retired when the copper oil pipe
supplying oil to the centre main bearing
fractured.
After Le Mans the engines
were rebuilt and three cars were entered for the 12-hour sports car
race at Donnington. Reliability was restored and they finished 2nd
Dodson/Hadley with Goodacre/Buckley in 3rd and 5th place taken by
Kay Petre/Stevenson in their class. The distance covered was some
1,800 miles. Soon after with moral high one car was entered for the
Paris-Nice Rally in September, 1937, driven by Kay Petre and Mme
Itier.
If
you know the position it finished at etc, please let me
know.
We now return to the Trials
scene as after Donnington the three cars were stripped down at
Longbridge and rebuilt for use in Trials. Experience had shown that
the earlier Grass-hoppers had suffered a great deal of underneath
damage, particularly to the brake fulcrum, on account of the rocky
hills tackled on these Trials. The cars were therefore rebuilt with
straight front axles and used springs on front and rear which
conformed to the Army Scout car specification. Like the earlier
cars they were fitted with Centric 125 superchargers and although
the final result looked a bit odd, with a racy body perched high on
a WD-like chassis, they became very effective Trials
cars.
One more Grasshopper was
built but not registered in England, it came to light in
Londonderry in December 1937 with a registration number UI 3345. It
is unclear where the vehicle was built or its history prior to
registration, but was sold to a Mrs Gladys Watts by J Watson an
agent.
If
anybody out there can shed some light on this mystery,
please let me know.
It is amazing that of the
twelve Grasshopper made including the above, that seven are still
around, although not necessary in original form as shown
below.
AOV 343: - AOX 3: - BOA 59: - COA 118: - 119 - 121. UI 3345:
Barry Lovelock
75th
Anniversary of the 7 in 1997 at Gaydon
Information supplied by Barry
Lovelock
_________________
Austin Seven
Racers
Captain Arthur Waite, who had been a
successful racing driver was given the job of managing the works
racing team, and in 1925 he wanted to prove that a Austin Seven
could do 100mph. The easiest way of increasing the power of an
engine is to fit a supercharger. This was tried, and the power
output increased from the normal 25 to 43bhp. In April 1925 he
covered a flying start mile at 92.44mph. It wasn't until 1930 that
a short wheelbase car was sent over to Daytona, USA, driven by
Donald Campbell. Things did not go well as he was only able to
record 94.03mph.
The first vehicle to achieve 100mph
(750cc) was an MG driven by George Eyston in France at Motlhery; he
also broke all the records held by Austin. This was the trigger to
spur Waite to decide to build a special single seater.
You will see from the picture below that it was very streamlined.
In fact, various scale models were made and tested in Vickers Wind
Tunnel. The end result was a design that had similar appearance to
the famous Bluebird record-breaking car of the day. The driver was
seated very low down and slightly to one side, so that the drive
from the engine, which was offset the other way, could pass to the
rear axle. The engine used was basically an Ulster unit but with a
special camshaft and an Austin built Rootes type two-lobe
supercharger that produced 56bhp @
6,000rpm.
The cockpit had been customised for Davis
to drive at the 1931 Easter Brooklands meeting, but a few weeks
before the event he broke his leg, it was decided that Gunnar Poppe
would be the first driver to take it out. The car was actually
painted a vivid yellow, so the crowd nicknamed it "Flying Canary".
In fact it did not do well, only completing one lap.
Artist
Impression
Later in 1931, having carried out various
modifications, the car returned to Brooklands, and driven by Leo
Cushman, soon recorded 99.0mph. It was decided to strip the engine
down, and it was found to have a cracked valve seat. The engine was
rebuilt with a new block, and after a few laps covered the two-way
kilometre at 102.28mph and the mile at 100.67mph, which bettered
Eyston's MG records. Therefore at last the Austin was the first
750cc car to do 100mph in England. The car was later taken to
Montlhery. This time the radiator was moved forward of the engine
in a separate cowling, this was done to improve the cooling, the
driver this time was Mrs Stewart who achieved the following
records.
5 kilometre at 109.1mph, ........5 miles
at 109.6mph,
10 kilometre at 109.5mph, ......10 miles at 109.06mph
50 kilometre at 98.08,.............50 miles at
98.43mph
_________
In 1932 Stan Yeal who was testing the
works Ulster Seven at Brooklands, observed that a white Ulster
Seven was recording better times than him, so he approached the
driver to find out his secret. The driver T Murray Jamieson, was
actually testing out his own design of supercharger. which had been
built by Amherst Villiers Superchargers Ltd, who had been producing
their own supercharges since the early 1920s.
On returning to Longbridge Stan told
Captain Waite, who was in-charge of the racing department, that he
thought Jamieson would be worth employing. Negotiations between
Waite and Villiers took place and the Austin Motor Company agreed
to buy from Villiers the white Ulster complete with all spares,
special tools and drawings of the supercharger. Jamieson was then
employed as a designer at Longbridge and given the task of building
the fastest 750 cc Racer.
Murray Jamieson’s first
Austin venture early in 1935 was a super streamlined body on the
Seven with a side-valve supercharged unit of his own design
enabling the engine to produce 70 bhp. It successfully attacked the
records previously held by MG.
_________
Austin Seven OHV Twin Cam
Engine
In 1935 it was decided that to be
competitive it would be necessary to design a completely new engine
along with a new chassis/body. Murray Jamieson headed the design
team along with W V Appleby and Tom Brown, who would start on the
drawings and development of this radical 750 cc engine.
Jamieson's plan was to produce a 750cc engine that would give
120bhp at 10,000rpm. Most experts at the time said that with this
specification it would smash itself to pieces. Because of the high revs
planned, it was necessary to keep the piston speed down, so the
engine would need a a short stroke of 65.09mm. So with a large bore
of 60.32mm it was possible to have a large hemispherical combustion
chamber along with large valves. Owing to the high cylinder
pressures being produced it was decided that they would do away
with a cylinder head gasket, as this item often gave trouble. The
cylinder block was completely open with the four wet liners rising
approx 1.25 inch above the top edge of the block. Four studs placed
evenly round each bore held the cylinder head against the liners.
With a perfect metal-to-metal gas joint between the liners and
cylinder head, this unusual design actually gave no trouble.
Between the block and the head was a casting that allowed the
cooling water to pass from the block to the head, with a rubber
joint washer on each face to seal the water passages.
A centrifugal water pump gave 50 gallons/min which was driven at
half engine speed. Tests showed that the exhaust valves and ports
could be 30% less than the inlet. The camshafts cams were very wide
and were plated (fescolized) to reduce wear. The steel connecting rods had plain big
end bearings. Cast aluminium pistons were used of the slipper type.
The crankshaft was machined from a solid steel billet, counter
balanced and with a roller bearing front and rear, and a plain
bearing at the centre.
Crankshaft
A single SU carburettor
connected to a Murray Jamieson Rootes type supercharger was driven
by a rear spur gear train arranged so that the speed of the
supercharger could be varied according to the type of event
entered. The maximum speed was 1.5 times engine speed or 15,000
rpm, with a maximum boost of 22lbs/sq inch. The gear train also
drove the two overhead camshafts, with each cam running in three
bearings 2 inches wide.
Two 14 mm spark plugs per
cylinder were connected to a vertical type Scintilla magneto. The
drive to the magneto also connected with the oil pump and
tachometer. Lubrication was by means of the dry sump system, with
the triple layer sump oil being fed to the centre main bearings and
big end at high pressure, and under low pressure to camshaft and
supercharger. Oil (Castrol R) was stored in two one gallon tanks
positioned on each side of the propeller shaft, with an oil cooler
positioned behind the radiator.
As there was no flywheel, power was transmitted straight through
via a single dry plate clutch. A four speed crash gearbox was first
fitted, but later on a synchromesh version was developed, with the
gate change on the left of the driver. The gearbox was then
connected to a fully floating back axle with double reduction bevel
and spur drive. This arrangement gives a particularly low
transmission drive-line, so giving the racer a low centre of
gravity.
W V Appleby
with the Twin Cam on test
The first engine was built
but could not be completed as the supercharger had not been
delivered. It was decided to test run the engine without the
supercharger, by fitting a different inlet manifold, but on test it
only produced a disappointing 22bhp. Soon after, the supercharger
arrived, and it was a different story, in that it was now producing
90bhp at 8,000rpm. After carrying out fine tuning, along with
ongoing minor changes and trying out various compression ratios, it
was found that 6.5:1 produced the best result. At the end of the
development period the engine was now producing a steady 110bhp
with short bursts up to 116bhp at over 8,000rpm.
The engine produced 90 bhp @ 7,600 rpm on
long distance fuel, with a fuel consumption of 7.5 mpg, 116 bhp @
9,000 rpm on sprint fuel (methanol added). Fuel consumption was 3.5
mpg
The hand pump on the right was to
pressurise the fuel tank, which needed to be pumped several times
in a race, as no mechanical pump was fitted. The fuel tank behind
the driver held 25 gallons.
The chassis frame had
tubular cross members extended to carry the front shock absorbers
and rear spring brackets. The special tubular front axle is
torsionally non-rigid. The braking torque is taken by struts and
ties anchored to the stub axle and frame, and the stub axles,
although held in alignment by the axle, can adjust their relative
positions axially as required by road or braking inequalities. This
construction, unlike the orthodox Austin Seven system of springing
(a transverse front spring and quarter-elliptic rear spring) made
for good stability. It
was fitted with 12.5 dia drums at front which were heavily ridded
to aid cooling, and 10 inch drums at the rear. Tyres were Dunlop
5.25 x 16.
Wheelbase 6ft 10ins Track 3ft 11ins Length
only 10 ft 1ins
The running weight was 9cwt 84lbs.
The cars first trial run was made in
October 1935 at Donnington, which proved successful, with the
official report stating, after testing that it went like the
'proverbial scalded cat'. More testing took place, and two more
cars were then built, as they needed three cars to be ready to
compete in a full programme of events for the 1936 season.
On 18th March 1936 at the Grand Hotel, Birmingham Lord Austin
announced to the press that the new racer would develop 1 bhp for
every 2 ¼ lb weight. He said he believed in spending money to
improve the breed and sincerely hoped that the new OHC Austins
would win many races, and thereby add much to Britain’s motoring
prestige. There was a complete car on show, along with a chassis.
It went on to capture the 5 and 10 mile and 10 kilometre from the
MG at the following speeds: 119.38 – 119.39 and 119.19 mph. but
Jamieson was disappointed that it did not quite make it to 120
mph.
Various modifications were carried out mainly to increase the power
and reliability. One problem was fuel surge when taking right hand
bends, causing a lean mixture. This was remedied when the SU
representative suggested that the carburettor be fitted with two
float chambers on either side, thus even out the fuel when
cornering. This cured the problem, and in autumn 1936 all the cars
were modified.
By the end of the 1937 season modified bonnet styling enclosed the
radiator filler cap. The cars having had a successful season, the
Austin OHC 750 cc Racer was now recognised as the finest in the
world in its class. In 1938 various small modifications were
carried out, the bonnet now having louvres now put in the crown and
sides.
750 Racer transported in
this trailer.