1913 Mercedes 7 litre Rennwagen Grand Prix Car
Chassis number: W11572
Registration number: LL4535
The Chassis, engine, front axle and steering box were obtained from the deceased estate of Ted Lobb, a well known Australian Mercedes collector in 2003. They were from a 1914 Mercedes 28/95 sports car. The original engine in the two GP cars was built for the "Kaiserpreis" aero race and was adapted in 1914 for the sports car by removing one magneto, substituting a water-pump and fitting a flywheel, dynamo and starter. This has made the Rennwagen much more adaptable for road and race use.
The transaxle for the chain drive was subsequently found by serendipity in New Zealand. It was manufactured by SAG (Suddeutsche Automobilfabrik GmbH of Gaggenan; a gearbox manufacturer owned by Benz. It appears to be correct for the 1913 chain-drive Rennwagen! (Source Beaulieu Library research)
The 28/95 hp model produced from 1914 onwards laid the foundation of the DMG's tradition of particularly exclusive and powerful top automobiles. Within this category it is not so much the absolute representation vehicle that it corresponds to but it is seen as another member of the series of sports vehicles - just like the supercharged models that followed him, e.g. the K, the S, SS, SSK, and SSKL as well as the 8-cylinder models 500 K and 540 K.
As the first Mercedes the 28/95 hp model was equipped with the characteristic V-shaped radiator and the outboard exhaust tubes as standard. For decades these features were characteristic of the appearance of the Mercedes and Mercedes-Benz top models.
But the technical concept, too, was remarkable. For the first time a Mercedes production car was fitted with an overhead camshaft and valves arranged in V-position. The model according to which this aggregate was constructed was the Daimler aircraft engine DF 80having finished an honourable second behind Benz in the "Kaiserpreis" competition for the best German aero-engine in 1912.
A construction feature realized for the first time were the separate cylinders spun from steel of which always two were equipped together with a cooling-water jacket welded from sheet steel. Compared with conventional cast cylinders the spun steel cylinders excelled in a lower weight at a higher load capacity.
The onwer was lucky to locate an original folding log book for a Mercedes dated 1921 (the date log books were first introduced) but stating that the Date of Original Manufacture was 1913.
The DVLA accepted that this car (in its original state) is a reconstruction of that 1913 car.
The owner rebuilt the car around the remains with the 28/95 engine and Transaxle. The car is thus road registered so it can be enjoyed on the road with a period London plate. It will be am driving it all the way to Gaillon (near Vernon in France) in September to do the hill climb and has previously been driven it to St Brieuc in Brittany and round the Targa Florio Grande circuit and much of Sicily. Masetti was well placed in the 1921 Targa Florio with an uprated 6 cylinder version of the car which by then had front-wheel brakes and no chain-drive. The onwer also had it at the 2014 Lyon Centenary of the Mercedes (1,2 &3) win and was supported by Mercedes.
The VSCC were happy to designate it a 1913 car to avoid any confusion with the 1914 4 cylinder cars.
The 1913 French GP was not a proper GP and was on the Sarthe circuit. We have pictures of Lautenschlager and Pillette who was third.
One car subsequently went to Indianapolis and there are pictures of Ralph da Palma seated in it in it. The car was withdrawn after practice because of torsional vibration of the 6 cylinder engine at the higher speeds of the Indy circuit. I think this car finished up at Packard who copied it for the Hall Scott aero-engine.
The onwer, a talented engineer has solved the vibration problem by installing one of Vibration Steve's "rattlers" in the flywheel, but it is geared such that 2000 revs is ample for a top speed and usualy the revs are kept down to 2000. The original rev limit was 1475. It is impossible to put a damper on the front of the engine because of the overhead valve drive . [These “pendulum dampers” were developed for aircraft. They store the acceleration of the crankshaft as potential kinetic energy and return it back as the crankshaft de-accelerates hence it does not remove energy nor dissipate torsional vibration as heat.]
The car is currently running on twin Solex but the owner has subsequently got the correct Pallas carburettors from the original Australian engine but has not fitted them because it is going so well!
The cone clutch has been replaced, which never seemed to take the full torque of the improved engine without slipping even after trying leather and several types of fabric lining and up-rated springs. It now has a Borg and Beck and one can use all the power from a standing start!
The car received FIA papers in 2017 and is eligible for Goodwood, in particular the Members meeting which usually has an Edwardian Pre WW1 Event.
The onwer has now driven and enjoyed the car for over 10 years but is getting old enough to pass it on to another enthusiast.
It is in “as used condition” but is still pretty smart. It runs it on 15/40 semi-synthetic oil which is similar to Castor oil which was originally used. It does not burn oil but leaks a little around the oil pump and rear main bearing (as seen on many period photos of the car)
It always starts on the button and maintains constant oil pressure when hot. It is now fitted with a full flow paper filter, suitably hidden.
The car has 895 x 135 beaded edge tyres all round (as original) but had a lot of trouble with the rear tyres blowing out under race conditions (sticky rubber and sticky tracks rather than gravel!) so the onwer has now fitted straight sided tyres on the rear which have proved safe. The fronts have never given any trouble (no FWB)
The car has a good fitting toneau cover and an all enveloping waterproof fitted car cover for storage and transport.
There is a detachable luggage rack which can carry a fair-sized cabin trunk.
All in all this represents a serious Car eligible for assorted vintage racing events inlcuding Goodwood Revival etc.
