Flash steam tethered hydroplane engines

Jim Bamford and his engines

OTW recently had the pleasure of visiting Rob Bamford who gave us a conducted tour of his father's many boats and engines. The following pictures give a detailed look at the huge variety of engines produced and illustrate the high quality of engineering evident throughout. Thanks to Rob for his time and patience in giving us this insight into one man's passion for tethered hydroplane racing.

Jim Bamford expended a great deal of time and energy trying to build successful and competitive Flash steam hydro's powered by turbines. If the turbines failed to produce the speeds expected he would remove them and run the boats with conventional reciprocating engines. Jim would devote just as much time and thought to developing these and ultimately they were to prove faster than the turbines.

All the turbines were based on a single rotor, often with multiple steam jets. With the turbines running at 100,000+ RPM, reduction gearing was necessary to run the prop at realistic revs while the fuel and water pumps required an even slower speed to work effectively. This unit was used in the second 'Hero'

The deLaval turbine disc required each blade to be cut precisely and Jim used an ingenious piece of machine tooling to create these. The rotors needed to be perfectly balanced and the bearings friction free. This is one of many rotors that Jim produced during his experimentation.

In 1953 Jim changed tack and tried a 'Stumpf' type rotor with the blades milled directly into the edge of the disc. The rotors were far easier to make but were not as effective as the deLaval. Both types lacked efficiency as they relied on steam velocity rather than expansion.

Remains of the casing after the 'Stumpf' rotor exploded at high speed.

In between the forays with turbines Jim would try conventional reciprocating engines. These were more established and gave more reliable running. This unit is an open crank uniflow type with a piston valve inlet. Large gear is for running pumps at reduced speed.

Jim's most successful flash steam engine was this vee twin used in Beebug to take the British Record. The complex fuel, water and priming pumps required on a flash steamer can clearly be seen here.
This engine is seen on the cover of 'Experimental Flash Steam' (Benson & Rayman).

The 'venturi boiler', all that is left of 'Hero 1 or 2'. The burner is at the left with exhaust at the right.

Jim Bamford's experimental nature is also evident with the IC engines that he built and raced as a distraction from the problems encountered with the flash steamers.

15cc OHV four stroke originally powered JAB 1 and for a while, JAB 2. Engine is machined from bar stock. Camshaft, contact breaker, oil and fuel pumps are across the rear of the crankcase driven by skew gears from the crankshaft. Oil tank below the motor. Parallel valves restrict combustion chamber development.

Surely the most common of home built racing engines is the 15cc, rear rotary valve two stroke motor based on George Lines' 'Sparky II' This version, now in JAB 3, has 360 degree inlet and exhaust porting. Some idea of the unconventional hull design can be seen here.

Twins have never found particular favour in tethered boats as the power characteristics are not suited. This inline version featured porting based on a Maico moto cross motor that turned out to be too extreme for boat use. It is seen here in a later '3 point' hull in an attempt to overcome problems in getting the boat away.

Experimental 'split single'. This motor has a second cylinder, seen here to the left that forces the charge into the power cylinder rather than relying on the crankcase compression. Principle was used on racing motor-cycle engines but frictional losses probably outweigh any gains in the smaller size.

For complete Jim Bamford article click here