Building a Land-Zeppelin
Some notes on Roger Collings’ 19-litre Mercedes-Maybach
During the first years of the 1914/18 war the “Hun” zeppelins which bombed Britain were much feared. They could climb higher than our fighter aeroplanes could reach and so escape destruction. A typical German zeppelin would have six enormous Maybach motors in gondolas, driving the propellers with some 1400hp, with walkways around these meticulously made engines so that, if they failed during a raid, the crew could work on and often re-start them, after perhaps replacing a cylinder or bearing…
After the Armistice of 1918 the “zeppelin scare” was scarcely forgotten before drivers at Brooklands were running big racing cars consisting of old (therefore suitably large) chassis powered with engines designed for the German airships intended to bring London and other British cities to surrender point. The motor-racing fraternity loved it — Count Zborowski and his “Chitty-Bang-Bangs” and the like…
In the last three years there has been a revival of interest among VSCC members and others in the allure of the truly large-engined motor-car — lots of litres, torque and massive power low down the rev-scale. The Aero-Engined Car Club came into being, to recapture something of those long-ago 1920s when monster aero-engined cars took to the Weybridge cement and occasionally roamed our roads. Roger Collings is the AECC’s Chairman and he has built himself a very suitable motor-car…
His previous high-performance car had been the 1903 Mercedes 60 and to outmatch its performance, which had won for Roger so many VSCC competition trophies, an aero-engine was about the only sensible solution. It seemed logical, also, to use a Mercedes chassis to accommodate such an engine. Here good fortune smiled on the Collings’s project. Major Lionel Beaumont-Thomas, MP for King’s Norton, who lived at Great Brampton Court, Madley, a couple of miles from Roger’s house near Hereford, had owned a 1906 20/25 hp Mercedes, bought from Fryer’s of Hereford who supplied all his cars. It had originally belonged to Charles Gwyer. He used this Mercedes extensively, including taking it on the annual family holidays to Borth near Aberystwyth, towing a big trailer higher than the car. The Major lost his life during WW2, when the ship he was sailing in to Crete went down, in 1942. By this time Percy Pritchard had built a bungalow at Callow, called “Ouarrybank” as there was a small quarry in the grounds, to which the family moved, from Hereford. Mr Pritchard, now at 99 the last survivor of the Gallipoli campaign, decided to build an air-raid shelter for the cottage, using an old car chassis for the roof. He bought the aforesaid Mercedes from Mervyn Davies of Wellington, near Hereford, for around a “fiver”.
The Mercedes was driven to the site and then stripped and the chassis duly incorporated in the roof of the shelter. But Hereford suffered only a few air-raids and the shelter became a store. Later the chassis frame came into the ownership of Andrew Wilson, an enthusiast who owns a Brescia Bugatti, s/c Ulster A7, etc. From him Collings was able to take over the basis of what is now his formidable Mercedes-Maybach…
The news of the release of the Mercedes chassis, albeit devoid of gearbox, axles, etc, came to the notice of Kier Helburg, via Cecil Bendall. He tried to persuade Collings to part with it, so that the Maybach Zeppelin engine Helburg owned could be installed therein. In fact, the reverse happened. Roger bought the engine, which was in America, to put into his Mercedes chassis, LuftHansa flew it across the Atlantic and it was delivered to Cagebrook Mill in a small, modern Renault van. Being an aviation engine it was light enough to be manhandled into the home workshop.
This engine is a 1916 Maybach six-cylinder Type HSLu 150 x 180mm (19085cc) aviation motor developing just under 300bhp, at the modest crankshaft speed of 1400 rpm. It was found to be in excellent condition, beautifully mothballed, but there was much to be done before the Mercedes chassis, which Roger had obtained by bartering some seat-leather upholstery with Wilson for one of his cars, was ready for it. The first move was to ring Depanoto at Nogent-le-Rotrou, that famous purveyor of “Automobiles Anciennes, Pieces Et Accessoires”, established in 1911, about a gearbox. M Boutet said that a month before he had taken in one “half the size of his office table.” So the next day Judy and Roger Collings were off in the hack Ford Escort, to return loaded with useful parts. The gearbox came from an ancient chain-drive Delahaye car that had ended its days in the vineyards. Also bought were a Lorraine-Dietrich steering-box and a Mercedes front axle, etc. It was now mid-January 1993 and Collings set the date for the Mercedes-Maybach’s firing-up as April 25, only three months later!
First a sub-frame for the huge engine and another for the gearbox had to be fabricated, the reason for separate sub-frames being to allow for chassis flexion. Roger toiled on full-scale drawings, basing the design on “Babs’s” sub-frame. This work was carried out at Gwyn Humphrey’s works at Llanharan, not far from the old Gilbern factory where Collings spent part of his youth building the Gilbern Invader. Enormous help was given to the “land zeppelin” project by all the staff there but special mention must be made of Ken Graham, who turned the drawings into reality. As the car was intended as a trials aero-engined monster about a foot was taken out of the newly shot-blasted chassis (the engine occupies 4ft 91n of it!) and the gearbox drives forward with dual chains to a countershaft, from which 35mm side-chains take the drive to the rear drums — i e six chains in all. A Borg & Beck single-plate clutch was supplied by Luk Clutches of Hereford, and incorporated within the flywheel. It should be explained that whereas the use of most aeroplane engines in cars involves making a flywheel as a substitute for the propeller-boss, in a zeppelin the engine drove by prop-shaft to a pusher propeller outside the gondola, or in some cases to a reduction or distribution (to two props) gearbox. So Roger was spared the chore of turning down a steel billet to manufacture a flywheel as the the Maybach already had one, and the engine did not have to be turned round in the chassis. So at the front are the two Bosch ZH6 magnetos firing two horizontal sparking-plugs per cylinder. The cylinders are separate and are a fine example of the craftsmanship seen throughout this Maybach engine, being of steel billets machined to a mere 1/8in thickness. Likewise, the con-rods are a genuine work of art. The crankshaft has seven main bearings, these and the big-end journals being 66mm in diameter. The mains are pressure lubricated, at 5Ib/sq in, with centrifugal oil feed to the big-ends. The dry-sump system is fed from a 8-gallon tank on the off-side sidemember, in the style of Chitty land Chitty II. Collings uses straight 30-grade lubricant.
There are five vertical oh-valves per cylinder, two inlet valves and three exhaust, operated by exposed push-rods and rockers from two camshafts, one on each side of the base-chamber. The inlet valves are 53 mm in diameter, the exhaust valves of 41 mm. The c r is 5.94:1. The cylinders are constructed by screwing the cylinder-barrel and water-jacket into a forged steel head, and the water flows from front to rear through all six heads. The coolant is sealed by large-diameter rubber rings in normal Maybach practice; circulation is by a vertical water turbine. As on Chitty II, an extra honeycomb section was inserted into the Mercedes radiator (in spite of having a larger Maybach engine than the Benz engine in Chitty II, the former engine apparently ran cooler because Chitty I appears to have had a standard Mercedes radiator). The work on the Mercedes-Maybach was done by John Underwood. The water capacity is approx 7½ gallons. Two Maybach carburettors, sans chokes, live at each end of the long, unheated straight aluminium inlet pipe of the off-side of the engine, which had to be made up, as did adaptation of the small vintage Zenith carburettor float chambers. The original cast-iron pistons are retained but, after some oiling-up at Curborough, oil-control rings were fitted. This is a magnificent engine, every part numbered; the cost of Germany’s zeppelin flyers must have been astronomical!
Methodically, Roger made visits, by air, to the Maybach Company (still making engines for marine and railway purposes) and to the Zeppelin Museum at Friedrichshafen, where he was made very welcome and given much useful data, rare books and other Maybach literature. Back home, work proceeded. A spare petrol tank for the Mercedes 60 was installed, giving a limited 60-mile range which has to be watched between filling stations — 4 mpg of leaded 4-star! The wheels are normally shod with 5.00 x 5.50 x 21 tyres, but for trials work 6.00 x 20 Lucas covers are used on the rear wheels. To meet the firing-up dead-line Norman Lloyd, John Guppy, Mark Walker, John Griffiths and Ben Collings slaved for three days and nights without sleep. There was a display of the sulks at the party (a mag-drive key had sheared) but the team persevered and at 1:30am the next morning the Maybach woke to life and ran successfully. Just a week later it was at VSCC Curborough, but teething troubles manifested themselves in the form of a defective scavenge oil pump, (clouds of smoke), a broken gearbox keyway and a mild fire in the rear carburettor. Undaunted, Roger went to Shelsley Walsh, where he clocked 55.95sec. in spite of the 1000 lb/ft torque of the zeppelin motor causing first and second gear to shear at take-off.
This was cured by substituting EN39 for EN36 steel for the new gears and installing an epicyclic 2.7 to 1 step-up gear between clutch and gearbox. (In the 1920s this was unnecessary on the chain-drive aero-engined cars because they had such massive gears and gearbox casings, such as the 75 or 90 hp Mercedes ‘boxes-cum-final drives on the “Chittys” and the 200 hp Benz ‘boxes, one of which is used in “Babs”.) The car’s next competition outing was to the VSCC Avon sprint meeting where, in spite of some clutch slip, it did 18.33sec for the ss ½-mile. It then began to show its real capabilities in the 1993 Presteigne Trial, on road tyres. Stronger springs had cured the clutch slip.
Around this time a proper four-seater body was made at the Mill (room for more “bouncers”!) by Roger and local craftsman Mike Griffiths, using Welsh ash hewn from a tree near the Rhydspence Inn. Judy Collings did all the varnishing and the entire job was completed in four days, just before the 1994 Coleme speed-trials. The M-M was now well into its stride, winning its class with a terminal speed of 100 mph, before which it had won a Second-Class Award in the VSCC Herefordshire Trial in exceptionally muddy conditions that had dragged down the heavier cars. At Loton Park hill-climb Collings easily won his class (80.02sec). A return of the clutch slip eased things up at the VSCC Jubilee Shelsley Walsh climb (51.45sec). But at Cornbury he was fastest (57.43sec). VSCC Prescott last year involved some all-night toil after the gearbox had misbehaved (56.67sec). But, on points, Collings won the prestigious 1994 VSCC Edwardian and Metallurgique trophies.
Then came a memorable run to the Nurburgring, where German hearts were warmed by the exciting spectacle of Maybach engines in the Metallurgique and Collings’s Mercedes. The latter was now going well, winning a First-Class Award in the VSCC Welsh Trial in which it was highest up Cwmheyope. After the long journey to the Nurburgring and back, the Mercedes-Maybach was driven to Salisbury from Herfordshire to give Roger’s three-day-old grand-daughter her first taste of aero-powered motoring! In all, some 7000-8000 miles have been covered, with no problems or signs of wear. The Maybach engine runs at modest revs — it weighs only 6½ cwt, the car around 1½ tons. It can be said without fear of contradiction that the Mercedes Maybach does not impede other roadusers! Its acceleration has to be experienced to be comprehended; let the official figures confirm this — the Colerne ss ¼-mile in 18.55sec, the ss kilo in 33.44sec. To curb such performance Roger designed twin-shoe rear-wheel brakes, Ferodo-lined, eschewing a possibly damaging transmission-brake.
This year has started with a Third-Class Award in the wet Herefordshire Trial. All in all this is a fine aero-engined monster constructed in the best tradition of the Vintage Sports Car Club. I said some months ago that “its time will surely come”, and come it has…